Thanks for doing all the hard work and path finding on behalf of all your followers. Thanks for being willing to listen to the feedback and improving the design. Thanks for always providing lots of details which makes it easier for us to leap up onto the learning curve, without us having to start from the beginning, finding suppliers etc etc. WELL DONE. I look forward to the next episode.
Your videos are great. I just saw your move to Ohio clip from last year. I'm from NYC but studied Industrial Design in Cleveland. Ohio is a great place to live. I designed a new camera rig I'm getting a small BV20L-1 to make the first run of parts manually but plan to upgrade to CNC. That said your Tormach 15L Slant Pro demo looks like the way to go. What an amazing machine. Thanks for the support.
Nice series of videos. I like that you mention alternatives. I think "but what about ..." and shortly later you're explaining the drawbacks of the alternative.
Very cool, John! There are so many choices for bearings, rails, ball screws etc. available now, that one doesn't know which way to go to get started. Seeing the parts that you use and how they work together will be very helpful to limit the choices to a reasonable set. Thanks for the video! -mike
If you need to control the speed the air cylinders they do make flow controls that would replace the 90 deg fittings and have adjustment screws on them. You'd be able to use whatever air press. you'd need but independently control how fast they move. Probably not an issue though. We also used a lot of linear bearings and really didn't have too many problems with those getting fouled with dirt and debris-- like we did with the ball-nuts.
***** In this case (using a 5 way valve) the flow speed controllers would go on the exit ports of the valve. As a bonus, they also provide silencing. :)
Suggestion, T the hoses right at the cylinder. Fewer hoses in your drag chain (bundle) Control of the cylinders should be discrete ( on/off). If the works electrically like the it does mechanically switched, just supply 12v for the down stroke. If it needs a 12v signal for return, you could use a single post double throw relay made for arduino. On, relay provides power to on post and off the relay provides power to the other post. If it's a two wire polarity swapping valve. Ie. + 12v is up and = 12v is down, use a double post double throw and you can swap the polarity on the relay. let me know if you would like a drawing. Thanks for bringing this whole project to TY
Nice work John. Gotta watch the different types of anti-static and static dissipative bags and conductivity. Sometimes they work for you and other times they can work against you as you found out ... First thing I usually do with circuit boards is add standoffs or rubber feet so that they can sit anywhere.
Hi, the DRV8818 stepper motor drive chip has a direction and clock. The easiest way to drive the air solenoid is with a simple FET. Connect the gate to the direction pin. The G code will drive the pin high or low depending on the direction. You'll need a diode across the solenoid to stop any back EMF. Great videos as always :) john b (UK)
Laser engravers have the same on/off problem with G-Code. Some examples I've seen use the fan control M106/M107 command to switch the engraver on and off. Another advantage of this is it'll give you the 12V directly. There are scripts that convert Gcode to be compatible with this type of system, it strips out any downward motion in Z gcode and replaces with M106 and likewise with upwards motion and M107.
On the subject of anti static bags.... There are two kinds. The black, silver, or black line pattern bags are usually conductive to dissipate any static charge and to prevent a discharge to the bag damaging the contents. It's wise to check with a meter as there are fake conductive bags out there! I've seen anti static conductive foam go up in flames because someone operated a circuit board sitting on a piece. The pink bags are not conductive, they just don't generate static charges as they rub together and against other objects. They won't protect the contents against a static charge hitting the bag.
I say make it binary, GX Z0=up and GX Z1=down. Another thing that would be useful is to have 2 or 3 regulators in parallel to regulate the pressure on the pen (Z1 Z2 Z3) because you may need more pressure for stainless than aluminum also could be a way to alter the stencil contrast. BTW I would not worry about the exposed rails with this type of application. Thanks for another killer video!!
I set up my laser to run on LInuxcnc a while back, which doesn't have a Z axis, but does need to fire the laser and turn off the laser. I accomplished that simply by using the DIR signal that would have gone to a Z axis stepper, if I had one. This fires the laser on all down moves and turns it off on all up moves. I haven't looked at the tiny G boards to see if that is a possibility. But the bonus to it is you don't need to modify your standard G code at all. it works fine as is. Otherwise, you will need to manually modify your G code. Search, find replace, G01 Z-0.100 to M03 and G00 Z1.000 to M05 or whatever the equivalent applicable codes are.
I have been having a play with your design but I used a Demel for the engraver got it working by having only one air ram to pull it up and some 185gr SWC's to hold it down, use the Z axis commands to turn the the solenoid on, only has to go one way. Just add or subtract weight for different materials. Great vids, looking forward to the next episode.
You might want to treat the engraving head like a plasma head. M code to activate. Also you will probably have to have an adjustable spring tension on the engraver z axis. So the tool can float and be under some preload. All of my rotary engravers have floating cutter heads. Industry standard. If you want some pics. Let me know!
One suggestion in dealing with air cylinders, use flow control with push fitting. I've been building automated pneumatic machines for years, regulator are not good for speed control of pneumatics systems. Nice job on the build.
Can the control board do M codes? EDIT: Maybe use M8 and M9, as they should be used to turn a coolant pump on or off, which would be similar to turning a valve open or closed.
I'm seriously excited about this project! I'm trying to wrap my head around this all as I want to attempt building a 4 axis CNC mill for mild steel and aluminum and this seems like the best jumping off point for me to do that. I've got a grasp on how to stepper motors controlling the motions along the XYZ axis and rotating the X axis (a?), but I'm kind of at a loss on how to actually control the bit speed and what to use to drive it. Any tips/suggestions are much appreciated!
Grab a set of mufflers for the 5 port. I happen to have a set on my draw bar it will allow you to change the air cylinders timing with out compromising how many psi needs to be sent to it. There cheap also.
MCEngineeringInc I think that would stall the machine every time you do it. I think it would be possible to use the direction output for the Z axis, I believe it will stay high/low depending on the last move
Good stuff. Love the videos. Glad to see you're still enjoying ChiliPeppr. BTW, ChiliPeppr could give you some additional options for toggling your air cylinders. There's a macro called "Send Serial to CNC and Arduino Simultaneously" that could solve your problem. Or, you could mimic what the laser solderer widget does or even use it. You could also use the macro example "Watch gcode complete..." that turns the laser on/off.
Z axis for on off, you could put the rails under the base plate, use a couple of sleeves on the Z axis it would not be hard to add them sinces the Z wont go up and down very much so they would be fine, ask on autodesk cam forum for a tiny G pp to do what you wont
You mentioned you would like to see things get more standardized which I agree. What are things like on the metal side of the professional cnc world? On the wood side a good share of everything is propriety so if something breaks your at the mercy of the company that built it.
As to chip load falling into the presently exposed side axis tracks, why not simply mount the unit to turn around on a center of balance rotation axis so that it may be 'flipped upside down', and run 'inverted' once the workpiece is secured. The various movement systems are not dependent on using gravity
What about using a single stepper with pair of variable pressure regulators to both the intake and exhaust ports you are able to dial in the exact height of the head and amount of tension against the workpiece. 0-100% one side while the other side goes from 100-0%. Simple, but not necessarily as fast and violent. Although, Z could be set ahead of time, M0/M1 could be a simple solenoid to turn the air on and off to get the "violence of action" if so desired.
Also, I understand why you like TinyG, but I am a fan of USBCNC, the controller seems to be easier to work with but lacks the embedded stepper motor controller.
I didn't have time to read all of the comments, so if I got beat to this tip, ok. If Chili-pepper uses M codes you might be able to fire the valve with one of those. Also, some flow controls will offer you some control over the speed of your cylinders without sacrificing force.
Great! Indeed, there's something mesmerizing watching the ball screws rotate :P Oh and I second the tip to se mufflers with the pneumatic actuators. They work much smoother without that "kick".
Look on the solenoids. They often have the ports for the mufflers. Then, depending on the "grain" size of the muffler, you regulate the amount of pressure released. But this is way beyond my expertise, I just have a machine using such setup here at work.
NYC CNC You should have mufflers on both exhaust ports on that five way solenoid valve. They sort of work as flow controls, but their real purpose is to keep shop crud out of the solenoid valve. There are some precision clearances inside the solenoid valve and you'll have maintenance problems if you run an open pneumatic system.
Ok my question is. What tolerances are you using for mounting aluminum plates to your linear Bearings. Like the through holes and the counterbore tolerance say for a 5mm cap screw.
I'm going to build this, i go to a school with a workshop where i can make whatever i want and purchase materials, but the only thing i'm missing is drawings for the frame and basicly everything except the listed parts. i'm attempting to make this into an actually cnc mill, using a dremel and taking shy cuts. dremel sells 3.2mm endmills!
Why not use the Arduino to send a pwm pulse to a Mac solenoid to vary the force when you want to drive z down. I did this to make a boost controller but I am for sure it would work for this. Cool thing is you would get cheap force control.
FIRST! Now that I actually finished the video. .. great work. You did a fantastic job keeping things clean. I love the cut and dried approach you took on it. This will be a very sturdy and robust machine at this rate. I typically like the video in the beginning... Just because I know I will like it!
Hi, just an idea, you can use a stepper motor that's normaly used for the Z-axis to close a contact that will trigger the solenoid, i know it isn't super efficient but it will work. PS: love your videos, keep up the good work! :-)
Your pneumatic bang-bang control of the Z axis (up or down, but no analog in between) is similar to using G code to control a laser. The laser is a 2D (or maybe a 2.5D) machine. It doesn't have various degrees of up or down. It's driven in X and Y and the laser is turned on or off. I can't tell you exactly how that would be done with TinyG, but in LinuxCNC, that's often done by setting Z=0 for laser off and Z = -.001 (or some other value) for laser on. LinuxCNC has a hardware abstraction layer (HAL) and it's possible to set a variable that is on for non-zero values of Z. It's handy to use Z control because it allows the laser to engrave using the same sort of G code that would engrave on a CNC router. The other way to do it in HAL is to define M codes to turn on the laser (or pneumatic engaving pen solenoid), much as you'd turn on flood cooling. This project is looking good! I'm looking forward to part 3!
Lasse Langwadt Christensen I use Atom based motherboards. Example: D525DW. They have four USB ports, a parallel port, a serial port, a VGA video port, keyboard and mouse ports, Ethernet port, etc. Those are getting harder to find, but it seems that whenever one Atom based motherboard that Just Works with LinuxCNC is discontinued, there is another to take its place. Computing speed isn't all that important, but low latency (no clock cycle stealing hardware interrupts) is important for realtime control. Lately, I've been adding a $9 Chinese parallel port to the PCI slot to make a second parallel printer port for twice the digital I/O. Even if you can't get a parallel port, the MESA Electronics boards are reasonably priced and they have a lot more I/O options, built-in motion control for steppers or servos, analog I/O, etc.
Hi John! I am following your projects from Buenos Aires, Argentina. Thanks for sharing with us your knowledge and experience. I am very interested in this DIY CNC Machine, do you know when next chapter is coming? Cheers! Federico
I was soo happy when you said you are going to make this series about making DIY CNC because i recently started to think about it. Keep up good work! I love that you are mixing many different technologies like pistons, ballscrew and belt drive here, so everyone can get to know what can be achieved. What do you think about polymer linear bearings and their rigidity, accuracy etc? They are cheaper, no need to lubricate and its easier to find cheap offers for students (even for free). And what do you think about using rasbberryPi + linuxCNC later in your videos, so your machine could be independent from pc standing next to it? Its probably cheaper and more comfortable when you dont have to much computers in your house.
I have a question. I see a lot of cnc-routers on ebay/aliexpress etc. They use all linier-rods instead of linier-rails, just like your machine. I think that using rods for the X movement creates flex in the whole upper section (x & z). Are the linier-rails also better for x & z? I gues you have to mount them on to a aluminium plates to get more riged-x & y travel.
With this system, would it be possible to swap z-axis from the pneumatic to a stepper instead? I'd like to try and put a dremel onto the z-axis. Mahalo! Really enjoy your videos!
Hay John I was wondering if you were going to put limit and homing switches on you machine. I was wondering if you could touch base on , or create a separate video on setting it up , hardware , and software wise in ChiliPeppr. I bought a TinyG about a year ago and now you got me hooked on doing something with it.. I'm prepossessing an old cnc table engraver that i had got my hand on. It is a very nice machine , the working travel movement is eight inches in the x, and ten inches int the y and about a half an inch in the z. the machine had the limit switches build into the machine so all I had to do is wire it up.. On the TinyG the input pins are normally pulled high , so I though that it would have to be pulled low for the TinyG to see a state change in the switch.So in ChiliPeppr i changed all the machine settings and limit settings . but when i moved the machine and when i touched the switches the machine didn't halt at all .. Please help me if there are G codes that I need to send to the board or other setting I need to Change.
How do you think the tiny-g compares to the gecko and ardruno drives? I haven't purchased anything yet for my build, but I was set on the gecko. Now with the tiny-g and ardruno/grbl Im back to square one.
I had a Dynatorch CNC plasma machine that had an optional engraving pen mounted alongside the plasma torch height axis. Like your plan here, they just used the air cylinder that extended and retracted the engraver as the Z axis locating hardware (IE no linear rails in the Z axis). This didn't work worth a damn. The air cylinders will develop slop in basically no time at all when subjected to lateral loads. Our cylinder could not locate the engraver properly from day 1 (IE it never engraved properly before we modified it), and very quickly after that began to leak from the abuse the "stock" setup was putting on the seals. Long story short, don't ask the air cylinders to do the job of linear rails while they're also doing their own job as a force element, the result will be sub-optimal to say the least. What we ended up doing was mounting a pair of linear rails along side the air cylinders to absorb the lateral loads. We mounted the rails to the engraver base and the trolley blocks that ride on the rail to the gantry, kind of inverting the "normal" arrangement of things, but it kept the rail from hanging down in the way all the time (even when the engraver was retracted).
NYC CNC I would be happy to, if I'd have taken any while it was still here. It has since gone to the great scrap heap in the sky, via a path best discussed elsewhere. Suffice to say that is a story best left to email. My setup had the engraver inside a little box made from extrusion and a couple of cap plates which was attached to an air cylinder powered linear slide actuator. Neat thing, like an air cylinder built inside a hunk of 80/20 extrusion, but not intended to locate anything laterally. What I did was affix the trucks from the two small linear rails (forgive me, I can't remember the size, but they were small, the rails were only 3/8"-1/2" wide and maybe a foot long) to the gantry on either side of the air cylinder thing, while the rails themselves were affixed to either side of the little box via machined aluminum standoffs. It only had a stroke of about 6" or so, and the twin rails worked just fine with that amount of extension. Another thing to think about is how hard you press the engraver into the part. The Dynatorch people allowed the engraving pen to float axially so it wouldn't dig in. IMO this was a cop-out (like so much of their design work, they chose the easy path that didn't work very well) to try and mitigate the poor lateral location ability of their air slide thingie. Anyway, it's something to consider, because if you push fairl hard on aluminum you might plow a furrow 0.030" deep, whereas that same down pressure on steel might only make a mark 0.003" deep.
Since the pneumatic cylinders are an on/off rather than a drive system would it not be best to drive them with a M code rather than a Z, It seems like it would be easier to integrate into your process. your program would then look like: G0 X Y M123 (pen down) G1 X Y F M124 (pen up)
great solution. but problem is you can't use any software that give you the G code, you need to writ all program by hand it will take time if it a long program .
I design CNC machines and you have some design flaws. =oP -The air cylinders are not designed to take on radial load; also they are not very precise in their movement. Your engraving may be slopping because of the lack of rigidity in the Z axis system; and overtime they will wear out and get very sloppy. I would not use them in the way you are. You should have a small 8mm or 10mm etc linear rail in the Z axis. -I would use MIC-6 for the base and machine a locating ridge and mount the linear rails directly to the base. The angle L-brackets leave a little to be desired. However, your engraver looks really nice and can't wait to see the progress! Thanks for posting another cool video!
Love your videos! The combination of electronics and cnc is awesome! Even though I lack a lot of knowledge on the cnc stuff. Anyway keep up the good work and don't stop posting videos. / Henrik
wouldn't it be possible to mount the linear rails inverted in the same position as the angle material to the bottom of the table, then use L shaped risers to connect the y axis (I believe it is) up top. this would reduce the amount of contamination that reaches the rather technical rails that wouldn't do very well with chips from milling or even just the dust created from engraving over a period of time (probably even worse than chip's on the tiny recirculating bearing setup). also about the other diy build, wouldn't it be fairly easy to replace the small single bearing guides (and aluminum angle mounts) with the preferable two or even three bearings per side to stabilize that axis... should be easily doable considering that the x axis was far longer than necessary, or so you thought anyways before realizing that the "trucks" should have been much wider to reduce slop in the mechanism. sorry for commenting on two different projects in one comment but please let me know what to think about the ideas. thanks for your time and consideration, have a great day.
Hi John, Do you happen to know what sort of runout is typical for your setup using ER collets? I just invested in some nicer collets and am getting a lot of vibration with the clear cause being runout. The inside of the tool holder it measuring under 0.0002" TIR but when measuring from the OD of the endmills, I get from 0.001 to 0.0025" variation. There is always one flute bearing most if not all of the visible wear. I need to know if this is just something to expect or if I need to give Sowa an earful for their collets.
NYC CNC Yeah, I think that may be it. I just tried slowly tightening the nut and it just got progressively worse. That's good though, since I was expecting the collets to last even if I get a new mill. Thanks!
Isn't the speed that the cylinder moving going to cause problems with the bit? Can you ramp the speed in which it lowers the engraving bit so it doesn't chip/break the bit?
You mentioned that you have not yet figured out how you were going to control your pneumatic cylinders and engraving pen. You also mentioned using 'G' Codes. 'G' Codes are preparatory codes for axis control. You want to use 'M' Codes which are 'Miscellaneous Codes'. Your engraving pen closely approximates a spindle, so use 'M03' Spindle On (CW) to turn the engraving pen ON and 'M04' Spindle Off, to turn it off. Since you are not actually going to CUT with a spindle use the 'M08' 'Coolant ON' to bring your pneumatic cylinders DOWN and 'M09' 'Coolant OFF' to RETRACT the pneumatic cylinders.
About Y axis and magic smoke from G-shield. I think you were going too fast and there is inertia in system, by rapid stopping that inertia generates current in steppers. That current goes back to G-shield and BAMM!!! :). I think that happened would like if someone confirms this. Stepper should slow down.
Instead of using the tinyG, I use separate drivers and an Arduino UNO. They are stronger with heatsinks and if you blow one driver you don't have to replace the whole unit. Here is a link to one that I use. www.ebay.com/itm/301670136936?_trksid=p2060353.m2749.l2648&ssPageName=STRK%3AMEBIDX%3AIT
Shame about the TinyG. It's actually a hard lesson for people to learn about anti static bags. NEVER never never put electronics on them. They are designed to carry the electrons on the outside, you can however turn them inside out and get away with it if it's not an internally coated bag. Best to just put them aside! Not risking anything then :)
NYC CNC Great question! Depending on the sort of bag they generally aim to make a faraday cage. This requires the use of conductive materials, and generally the black/silver bags use a metalised shielding to do this! I'm willing to bet that the inside of the bag is not conductive, but that depends on if it's only shielded externally or internally (From my experience silver bags seem to be externally shielded). As I was saying it's just best to stay away from them unless storing/shipping an item etc. Generally it's the following (From what I understand) Pink is normal plastic chemically antistatic Black is carbon powder filled Grey is metal coated All will have pretty high resistances though, likely >2M Ohm
NYC CNC Well in my mind you're basically already running a solenoid to control all the pneumatics, but with the pneumatics you're now adding lot of unneeded complexity with air hoses, regulators, compressor, and cylinders just to move the Z between 2 positions. When really you could just hook up 2 solenoids wired in parallel and get the same result without all that. Generally speaking, More parts = more problems. But I figure you probably have a specific reason for running the pneumatic cylinders which is why I ask.
sweet videos. I'm quite excited to work on my first CNC plasma cutter/MIG welder table. do you all have an even heavier duty example build? like 4' by 5" table? what diameter lead screws would you suggest for such a monster? also, subscribed.
Hay john its me again. i was thinking about what you could do to control you pneumatic air cylinders. Depending on how fancy you are going to make this machine you could use the coolant pin on the TinyG .Then you would have to by a Separate breakout board that has a 3.3v relay on board and wire you 12V A/B ported air valve to control it. I encourage you to look into the specs of the relay that you buy because some of them may not be able to handle the current that that air valve pulls because in side of though is an electric solenoid (Coil of wire) and that pulls a plunger that lets air go bu. If you budget allows try to find one that IS 3.3V CONTACT voltage but a little heavier duty be cause in electronics , a coil of wire contains a large magnetic field and it is now know as an inductor. and instructors in electronics Resist the flow of changing current and so when you open the relay . the magnetic field has to dissipate some were and some times that can flow back into the relay and then in to your board. Or if you are having troubles finding a large enough relay you can put a diode across the solenoid wires but put the diode in backwards so when you turn on the relay it wont turn on the diode . but then when you turn off the relay the magnetic field collapse and the current flows backwards threw the diode. This Simple circuit is called a free wheeling diode and i use it in a lot of my circuits even if it my not be necessary . To turn on the coolant pin on the TinyG :(" depending on what G code command list you look at you might not find it") It is a M8 to turn on coolant pin and M9 to turn the pin off . There is a M7 command but that is a Mist coolant command and i don't think the TinyG Responses to that.(en.wikipedia.org/wiki/G-code) Hope that Helps
Why don't you set your system up as a standard 3axis system but have the Z axis stepper only rotate 45ded to depress a switch triggering your air valve. . its low tech but uses a extra stepper. its redundant but works?
lowsideswitch He already has a soleniod making M-code preferable (assuming he can implement it with this hardware, idk); plus, if he learns how to use M-code he can use it for many other things on this or future projects.
Hey just a suggestion, could you group project videos in playlists. Sometimes youtube auto-plays them in series but much of the time you have to search through the entire video catalog just to watch a project build. For example I'm currently watching these diy cnc videos and the widget list is like video 41 then 42 then jumps all the way to 69 and then the final video isn't even a widget video, it makes it very difficult to watch one project from beginning to end. Anyway just a suggestion, thanks for doing what you do.
Better to use cylinders with end damping. You can run them in high speed without annoying sound :P They are running with full speed and right before they stop they slow down-> no noise, saves product lifetime, less vibrations in the system... Principle: www.festo.com/rep/en-us_us/assets/pdf/AirCushion_WhitePaper.pdf
I am assuming that since there isn't a part 3 yet, you decided the pneumatic had to go right? Or you figured out that using a solid state relay between could work? Switched to the spring loaded ones so that spindle on=down off=up? Lead Screw for the z axis riiight? DONT LEAVE ME HANGING MAN! PS Watching your channel reminds me of when my dad would watch fishing shows. Oddly Therapeutic.
If I only use adruino code, without g-code or any other software, how can I control multiple steppers? Will this piece this of code do? digitalWrite(, HIGH); delayMicroseconds(); digitalWrite(, LOW); delayMicroseconds(); i have problem when the delay adding up.
isn't a servo motor better to use if you're already using expensive ball bearings? and the drive belt, the teeth andspindel size doesn't that impact precision so wider belt, more teeth and larger spindel equals more precision?
+Daniel Mattsson I have added Encoders to stepper motors and the cost was not really that bad. Incremental encoders are cheap now of days. Still much less expensive compared to a servo.
NYC CNC Design a floating engraver mount that allows for a "pad" that contacts the workpiece with the engraver tip sticking out (to desired engraving depth) just below the pad. Make the floating travel a half an inch or so and give it enough weight to give a good engraving. This will compensate for any Z inaccuracies with the Z axis travel and will give a consistent depth engraving anywhere on the table even if the part isn't perfectly flat.
***** I designed my power draw bar with two side-by-side SMC air cylinders. SMC warns that it's generally not advisable to do this because it's impossible to guarantee that both air cylinders will operate at the same speed, and even if the air flow is initially adjusted to balance the speed, they may become unbalanced over time as the air cylinders wear. Mechanical engineers usually look for mechanical analogies to help them understand electrical systems they can't see. I'm an electrical engineer, so I look for electrical analogies to help me understand mechanical systems. The gain of a transistor is a poorly controlled manufacturing parameter. It's a bad idea to design an amplifier with two parallel transistors because they wouldn't equally share the current load. One transistor would always be fighting the other. Similarly, the velocity of an air cylinder is a poorly controlled manufacturing parameter. In the case of my power draw bar, I justified the questionable design practice by telling myself that I'll be slowing both cylinders down so much that they won't be racing each other, I can easily monitor their operation and regularly make the adjustments to keep them operating at the same rate, and (most importantly) the stroke is so short that these fat little air cylinders will never get too far out of sync with each other as expressed in relative degrees of shaft misalignment, so the shaft seals won't be side loaded to any significant degree. The other "most important" justification is that I intentionally used a lot of compliance in the design. Both cylinders push on a flat steel plate. They aren't rigidly tied to each other mechanically in a fixed system where any difference in force is translated into transverse force on the shaft seals. I could probably disconnect one cylinder and the other short cylinder would push as hard as it could and wouldn't harm either cylinder. But it's still not a good design practice. In John's case, the cylinder travel to cylinder diameter ratio is much greater (a bad thing) but the forces are much less (a good thing). I think he'll be OK. I'd score it minus three points on the design and plus 100,000 geek bonus points for the awesome. I do think John might want to add four flow controls to balance the extend and retract speed of the individual cylinders. He's currently using air pressure to control the speed of both cylinders in parallel. Controlling flow instead of pressure is analogous to controlling the electrical current instead of the voltage. You can control the air flow indirectly by controlling the pressure, but it's not a linear relationship. I think it'd be better to directly control what matters... the air flow. Besides, flow controls are much cheaper and less bulky than regulators. :-)
John Lauer video: ruclips.net/video/T2h7hagVfnA/видео.html has him using a Z value threshold in chilipeppr to toggle a laser on and off. That might be a simple way to toggle your pneumatics.
John, I appreciate all the time and effort it takes to put together a high-quality instructional video. Thank you. Suggestion: incorporate less talk and more assembly footage. A lot of your dialogue was fluff and I was less than inspired to pursue or watch any other NYC videos. Sorry.
I think air cylinder is not a rail. I know the axial effort is not so big but air cylinder is realy not made to resist to that.Maybee if they not full extend when operating they could do.
almost exactly 5 years later im doing research to build my own mill, things are still janky and complicated. the only thing really to change is that import components are now a lot cheaper.
Thanks for doing all the hard work and path finding on behalf of all your followers. Thanks for being willing to listen to the feedback and improving the design. Thanks for always providing lots of details which makes it easier for us to leap up onto the learning curve, without us having to start from the beginning, finding suppliers etc etc. WELL DONE. I look forward to the next episode.
Your videos are great. I just saw your move to Ohio clip from last year. I'm from NYC but studied Industrial Design in Cleveland. Ohio is a great place to live. I designed a new camera rig I'm getting a small BV20L-1 to make the first run of parts manually but plan to upgrade to CNC. That said your Tormach 15L Slant Pro demo looks like the way to go. What an amazing machine. Thanks for the support.
Nice series of videos. I like that you mention alternatives. I think "but what about ..." and shortly later you're explaining the drawbacks of the alternative.
Very cool, John! There are so many choices for bearings, rails, ball screws etc. available now, that one doesn't know which way to go to get started. Seeing the parts that you use and how they work together will be very helpful to limit the choices to a reasonable set. Thanks for the video!
-mike
cnc has come along way in 4 years you are a psychic sir! Information still is in the dark ages but a bit more centralized with things like openbuilds.
If you need to control the speed the air cylinders they do make flow controls that would replace the 90 deg fittings and have adjustment screws on them. You'd be able to use whatever air press. you'd need but independently control how fast they move. Probably not an issue though.
We also used a lot of linear bearings and really didn't have too many problems with those getting fouled with dirt and debris-- like we did with the ball-nuts.
I was just trying to sound like I knew what I was talking about... ya know. lol
***** In this case (using a 5 way valve) the flow speed controllers would go on the exit ports of the valve. As a bonus, they also provide silencing. :)
Yeah, that's another way and probably a little cheaper.
Suggestion, T the hoses right at the cylinder. Fewer hoses in your drag chain (bundle) Control of the cylinders should be discrete ( on/off). If the works electrically like the it does mechanically switched, just supply 12v for the down stroke. If it needs a 12v signal for return, you could use a single post double throw relay made for arduino. On, relay provides power to on post and off the relay provides power to the other post. If it's a two wire polarity swapping valve. Ie. + 12v is up and = 12v is down, use a double post double throw and you can swap the polarity on the relay. let me know if you would like a drawing. Thanks for bringing this whole project to TY
Nice work John. Gotta watch the different types of anti-static and static dissipative bags and conductivity. Sometimes they work for you and other times they can work against you as you found out ... First thing I usually do with circuit boards is add standoffs or rubber feet so that they can sit anywhere.
Hi, the DRV8818 stepper motor drive chip has a direction and clock.
The easiest way to drive the air solenoid is with a simple FET.
Connect the gate to the direction pin.
The G code will drive the pin high or low depending on the direction.
You'll need a diode across the solenoid to stop any back EMF.
Great videos as always :)
john b (UK)
Laser engravers have the same on/off problem with G-Code. Some examples I've seen use the fan control M106/M107 command to switch the engraver on and off. Another advantage of this is it'll give you the 12V directly.
There are scripts that convert Gcode to be compatible with this type of system, it strips out any downward motion in Z gcode and replaces with M106 and likewise with upwards motion and M107.
On the subject of anti static bags....
There are two kinds.
The black, silver, or black line pattern bags are usually conductive to dissipate any static charge and to prevent a discharge to the bag damaging the contents. It's wise to check with a meter as there are fake conductive bags out there! I've seen anti static conductive foam go up in flames because someone operated a circuit board sitting on a piece.
The pink bags are not conductive, they just don't generate static charges as they rub together and against other objects. They won't protect the contents against a static charge hitting the bag.
I say make it binary, GX Z0=up and GX Z1=down. Another thing that would be useful is to have 2 or 3 regulators in parallel to regulate the pressure on the pen (Z1 Z2 Z3) because you may need more pressure for stainless than aluminum also could be a way to alter the stencil contrast. BTW I would not worry about the exposed rails with this type of application. Thanks for another killer video!!
If you would like help designing a flip flop circuit I'd be more than willing to volunteer some time.
I feel very dumb sometimes when watching this stuff but I love it nonetheless. I've been toying with the idea of building a small CNC table like this.
I set up my laser to run on LInuxcnc a while back, which doesn't have a Z axis, but does need to fire the laser and turn off the laser. I accomplished that simply by using the DIR signal that would have gone to a Z axis stepper, if I had one. This fires the laser on all down moves and turns it off on all up moves. I haven't looked at the tiny G boards to see if that is a possibility. But the bonus to it is you don't need to modify your standard G code at all. it works fine as is. Otherwise, you will need to manually modify your G code. Search, find replace, G01 Z-0.100 to M03 and G00 Z1.000 to M05 or whatever the equivalent applicable codes are.
I have been having a play with your design but I used a Demel for the engraver got it working by having only one air ram to pull it up and some 185gr SWC's to hold it down, use the Z axis commands to turn the the solenoid on, only has to go one way. Just add or subtract weight for different materials. Great vids, looking forward to the next episode.
You might want to treat the engraving head like a plasma head. M code to activate. Also you will probably have to have an adjustable spring tension on the engraver z axis. So the tool can float and be under some preload. All of my rotary engravers have floating cutter heads. Industry standard. If you want some pics. Let me know!
No problem! Will do
One suggestion in dealing with air cylinders, use flow control with push fitting. I've been building automated pneumatic machines for years, regulator are not good for speed control of pneumatics systems. Nice job on the build.
Can the control board do M codes?
EDIT: Maybe use M8 and M9, as they should be used to turn a coolant pump on or off, which would be similar to turning a valve open or closed.
nothing like plans and parts list if possible .
thank you
Richard
John you are one of my favorite channels at the moment. Very interesting stuff and packaged truly great.
Great series! Looking forward to the rest of the videos.
I'm seriously excited about this project! I'm trying to wrap my head around this all as I want to attempt building a 4 axis CNC mill for mild steel and aluminum and this seems like the best jumping off point for me to do that.
I've got a grasp on how to stepper motors controlling the motions along the XYZ axis and rotating the X axis (a?), but I'm kind of at a loss on how to actually control the bit speed and what to use to drive it.
Any tips/suggestions are much appreciated!
Grab a set of mufflers for the 5 port. I happen to have a set on my draw bar it will allow you to change the air cylinders timing with out compromising how many psi needs to be sent to it. There cheap also.
NYC CNC
yup but unlike reducing pressure you will always have full strength when using a muffler. And they make it much much quieter .
Use the coolant output to drive your cylinders
M8 down, M9 up.
MCEngineeringInc I think that would stall the machine every time you do it. I think it would be possible to use the direction output for the Z axis, I believe it will stay high/low depending on the last move
looking good. i noticed i had to restart the tiny g for some settings to take effect. it'll be nice to see what kind of problems you encounter.
Good stuff. Love the videos. Glad to see you're still enjoying ChiliPeppr. BTW, ChiliPeppr could give you some additional options for toggling your air cylinders. There's a macro called "Send Serial to CNC and Arduino Simultaneously" that could solve your problem. Or, you could mimic what the laser solderer widget does or even use it. You could also use the macro example "Watch gcode complete..." that turns the laser on/off.
Z axis for on off, you could put the rails under the base plate, use a couple of sleeves on the Z axis it would not be hard to add them sinces the Z wont go up and down very much so they would be fine, ask on autodesk cam forum for a tiny G pp to do what you wont
You mentioned you would like to see things get more standardized which I agree. What are things like on the metal side of the professional cnc world? On the wood side a good share of everything is propriety so if something breaks your at the mercy of the company that built it.
I meant machinery wise not materials. Like if you blow a motor or electrical component on like a tormach is the only replacements from tormach?
As to chip load falling into the presently exposed side axis tracks, why not simply mount the unit to turn around on a center of balance rotation axis so that it may be 'flipped upside down', and run 'inverted' once the workpiece is secured. The various movement systems are not dependent on using gravity
What about using a single stepper with pair of variable pressure regulators to both the intake and exhaust ports you are able to dial in the exact height of the head and amount of tension against the workpiece. 0-100% one side while the other side goes from 100-0%. Simple, but not necessarily as fast and violent. Although, Z could be set ahead of time, M0/M1 could be a simple solenoid to turn the air on and off to get the "violence of action" if so desired.
Also, I understand why you like TinyG, but I am a fan of USBCNC, the controller seems to be easier to work with but lacks the embedded stepper motor controller.
I didn't have time to read all of the comments, so if I got beat to this tip, ok. If Chili-pepper uses M codes you might be able to fire the valve with one of those. Also, some flow controls will offer you some control over the speed of your cylinders without sacrificing force.
Great! Indeed, there's something mesmerizing watching the ball screws rotate :P
Oh and I second the tip to se mufflers with the pneumatic actuators. They work much smoother without that "kick".
Look on the solenoids. They often have the ports for the mufflers. Then, depending on the "grain" size of the muffler, you regulate the amount of pressure released. But this is way beyond my expertise, I just have a machine using such setup here at work.
NYC CNC You should have mufflers on both exhaust ports on that five way solenoid valve. They sort of work as flow controls, but their real purpose is to keep shop crud out of the solenoid valve. There are some precision clearances inside the solenoid valve and you'll have maintenance problems if you run an open pneumatic system.
Ok my question is. What tolerances are you using for mounting aluminum plates to your linear Bearings. Like the through holes and the counterbore tolerance say for a 5mm cap screw.
I'm going to build this, i go to a school with a workshop where i can make whatever i want and purchase materials, but the only thing i'm missing is drawings for the frame and basicly everything except the listed parts. i'm attempting to make this into an actually cnc mill, using a dremel and taking shy cuts. dremel sells 3.2mm endmills!
Why not use the Arduino to send a pwm pulse to a Mac solenoid to vary the force when you want to drive z down. I did this to make a boost controller but I am for sure it would work for this. Cool thing is you would get cheap force control.
thanks for discovering an engraving pen for me. fun toy lol
FIRST!
Now that I actually finished the video. ..
great work. You did a fantastic job keeping things clean. I love the cut and dried approach you took on it. This will be a very sturdy and robust machine at this rate.
I typically like the video in the beginning... Just because I know I will like it!
yes electrostatic bags ARE conductive...that's how they work :-) ! good channel you have!
Most controls have customization G and G codes for things like air blast or what not.
Very cool, John!
you can use a relay for the pneumatic cylinder actuator
I am liking this experiment, keep it up. Thanks for sharing.
Hi, just an idea, you can use a stepper motor that's normaly used for the Z-axis to close a contact that will trigger the solenoid, i know it isn't super efficient but it will work.
PS: love your videos, keep up the good work! :-)
thanks:-),
PS, did you came up with another idea yet? i'm just curius... :-)
Your pneumatic bang-bang control of the Z axis (up or down, but no analog in between) is similar to using G code to control a laser. The laser is a 2D (or maybe a 2.5D) machine. It doesn't have various degrees of up or down. It's driven in X and Y and the laser is turned on or off. I can't tell you exactly how that would be done with TinyG, but in LinuxCNC, that's often done by setting Z=0 for laser off and Z = -.001 (or some other value) for laser on. LinuxCNC has a hardware abstraction layer (HAL) and it's possible to set a variable that is on for non-zero values of Z. It's handy to use Z control because it allows the laser to engrave using the same sort of G code that would engrave on a CNC router. The other way to do it in HAL is to define M codes to turn on the laser (or pneumatic engaving pen solenoid), much as you'd turn on flood cooling.
This project is looking good! I'm looking forward to part 3!
Linux CNC is far superior. I used it on million dollar machines and on my own home 3d printer.
Mekhanic1 The problem is finding a PC with a parallel port
Lasse Langwadt Christensen I use Atom based motherboards. Example: D525DW. They have four USB ports, a parallel port, a serial port, a VGA video port, keyboard and mouse ports, Ethernet port, etc. Those are getting harder to find, but it seems that whenever one Atom based motherboard that Just Works with LinuxCNC is discontinued, there is another to take its place. Computing speed isn't all that important, but low latency (no clock cycle stealing hardware interrupts) is important for realtime control. Lately, I've been adding a $9 Chinese parallel port to the PCI slot to make a second parallel printer port for twice the digital I/O. Even if you can't get a parallel port, the MESA Electronics boards are reasonably priced and they have a lot more I/O options, built-in motion control for steppers or servos, analog I/O, etc.
+1 MESA daughter cards are the way to go if it's in the budget.
Hi John! I am following your projects from Buenos Aires, Argentina. Thanks for sharing with us your knowledge and experience.
I am very interested in this DIY CNC Machine, do you know when next chapter is coming?
Cheers!
Federico
Awesome Project so far John... Thanks for the knew knowledge!
I was soo happy when you said you are going to make this series about making DIY CNC because i recently started to think about it. Keep up good work! I love that you are mixing many different technologies like pistons, ballscrew and belt drive here, so everyone can get to know what can be achieved.
What do you think about polymer linear bearings and their rigidity, accuracy etc? They are cheaper, no need to lubricate and its easier to find cheap offers for students (even for free).
And what do you think about using rasbberryPi + linuxCNC later in your videos, so your machine could be independent from pc standing next to it? Its probably cheaper and more comfortable when you dont have to much computers in your house.
I have a question.
I see a lot of cnc-routers on ebay/aliexpress etc. They use all linier-rods instead of linier-rails, just like your machine.
I think that using rods for the X movement creates flex in the whole upper section (x & z).
Are the linier-rails also better for x & z?
I gues you have to mount them on to a aluminium plates to get more riged-x & y travel.
You are the bomb!! Thanks for doing this and the way you handle your videos/channel. I'm sure its a ton of work but it is greatly appreciated!
With this system, would it be possible to swap z-axis from the pneumatic to a stepper instead? I'd like to try and put a dremel onto the z-axis. Mahalo! Really enjoy your videos!
Hay John
I was wondering if you were going to put limit and homing switches on you machine.
I was wondering if you could touch base on , or create a separate video on setting it up , hardware , and software wise in ChiliPeppr. I bought a TinyG about a year ago and now you got me hooked on doing something with it.. I'm prepossessing an old cnc table engraver that i had got my hand on. It is a very nice machine , the working travel movement is eight inches in the x, and ten inches int the y and about a half an inch in the z. the machine had the limit switches build into the machine so all I had to do is wire it up.. On the TinyG the input pins are normally pulled high , so I though that it would have to be pulled low for the TinyG to see a state change in the switch.So in ChiliPeppr i changed all the machine settings and limit settings . but when i moved the machine and when i touched the switches the machine didn't halt at all .. Please help me if there are G codes that I need to send to the board or other setting I need to Change.
How do you think the tiny-g compares to the gecko and ardruno drives? I haven't purchased anything yet for my build, but I was set on the gecko. Now with the tiny-g and ardruno/grbl Im back to square one.
I had a Dynatorch CNC plasma machine that had an optional engraving pen mounted alongside the plasma torch height axis.
Like your plan here, they just used the air cylinder that extended and retracted the engraver as the Z axis locating hardware (IE no linear rails in the Z axis). This didn't work worth a damn.
The air cylinders will develop slop in basically no time at all when subjected to lateral loads. Our cylinder could not locate the engraver properly from day 1 (IE it never engraved properly before we modified it), and very quickly after that began to leak from the abuse the "stock" setup was putting on the seals.
Long story short, don't ask the air cylinders to do the job of linear rails while they're also doing their own job as a force element, the result will be sub-optimal to say the least.
What we ended up doing was mounting a pair of linear rails along side the air cylinders to absorb the lateral loads. We mounted the rails to the engraver base and the trolley blocks that ride on the rail to the gantry, kind of inverting the "normal" arrangement of things, but it kept the rail from hanging down in the way all the time (even when the engraver was retracted).
NYC CNC I would be happy to, if I'd have taken any while it was still here.
It has since gone to the great scrap heap in the sky, via a path best discussed elsewhere. Suffice to say that is a story best left to email.
My setup had the engraver inside a little box made from extrusion and a couple of cap plates which was attached to an air cylinder powered linear slide actuator. Neat thing, like an air cylinder built inside a hunk of 80/20 extrusion, but not intended to locate anything laterally.
What I did was affix the trucks from the two small linear rails (forgive me, I can't remember the size, but they were small, the rails were only 3/8"-1/2" wide and maybe a foot long) to the gantry on either side of the air cylinder thing, while the rails themselves were affixed to either side of the little box via machined aluminum standoffs.
It only had a stroke of about 6" or so, and the twin rails worked just fine with that amount of extension.
Another thing to think about is how hard you press the engraver into the part. The Dynatorch people allowed the engraving pen to float axially so it wouldn't dig in. IMO this was a cop-out (like so much of their design work, they chose the easy path that didn't work very well) to try and mitigate the poor lateral location ability of their air slide thingie.
Anyway, it's something to consider, because if you push fairl hard on aluminum you might plow a furrow 0.030" deep, whereas that same down pressure on steel might only make a mark 0.003" deep.
NYC CNC Sent you an email, BTW. Might check your SPAM folders if you don't see one by this afternoon.
Since the pneumatic cylinders are an on/off rather than a drive system would it not be best to drive them with a M code rather than a Z, It seems like it would be easier to integrate into your process.
your program would then look like:
G0 X Y
M123 (pen down)
G1 X Y F
M124 (pen up)
great solution.
but problem is you can't use any software that give you the G code, you need to writ all program by hand it will take time if it a long program .
I design CNC machines and you have some design flaws. =oP
-The air cylinders are not designed to take on radial load; also they are not very precise in their movement. Your engraving may be slopping because of the lack of rigidity in the Z axis system; and overtime they will wear out and get very sloppy. I would not use them in the way you are. You should have a small 8mm or 10mm etc linear rail in the Z axis.
-I would use MIC-6 for the base and machine a locating ridge and mount the linear rails directly to the base. The angle L-brackets leave a little to be desired.
However, your engraver looks really nice and can't wait to see the progress! Thanks for posting another cool video!
Nice ! looking really solid !
Hello , good job ! when will the next episode come out? Really interesting to watch , i want to see the end product !!!
At 4:19 ... so much for balancing it :-)
Love your videos! The combination of electronics and cnc is awesome! Even though I lack a lot of knowledge on the cnc stuff. Anyway keep up the good work and don't stop posting videos.
/ Henrik
Great stuff. Was there a part 3?
NYC CNC
wouldn't it be possible to mount the linear rails inverted in the same position as the angle material to the bottom of the table, then use L shaped risers to connect the y axis (I believe it is) up top. this would reduce the amount of contamination that reaches the rather technical rails that wouldn't do very well with chips from milling or even just the dust created from engraving over a period of time (probably even worse than chip's on the tiny recirculating bearing setup).
also about the other diy build, wouldn't it be fairly easy to replace the small single bearing guides (and aluminum angle mounts) with the preferable two or even three bearings per side to stabilize that axis... should be easily doable considering that the x axis was far longer than necessary, or so you thought anyways before realizing that the "trucks" should have been much wider to reduce slop in the mechanism. sorry for commenting on two different projects in one comment but please let me know what to think about the ideas. thanks for your time and consideration, have a great day.
Hi John,
Do you happen to know what sort of runout is typical for your setup using ER collets? I just invested in some nicer collets and am getting a lot of vibration with the clear cause being runout. The inside of the tool holder it measuring under 0.0002" TIR but when measuring from the OD of the endmills, I get from 0.001 to 0.0025" variation.
There is always one flute bearing most if not all of the visible wear.
I need to know if this is just something to expect or if I need to give Sowa an earful for their collets.
NYC CNC Yeah, I think that may be it. I just tried slowly tightening the nut and it just got progressively worse.
That's good though, since I was expecting the collets to last even if I get a new mill.
Thanks!
Isn't the speed that the cylinder moving going to cause problems with the bit? Can you ramp the speed in which it lowers the engraving bit so it doesn't chip/break the bit?
I though you were going program this with g code for a plasma table, like a plate marker. That is how I program my plate marker for my plasma table
You mentioned that you have not yet figured out how you were going to control your pneumatic cylinders and engraving pen. You also mentioned using 'G' Codes. 'G' Codes are preparatory codes for axis control. You want to use 'M' Codes which are 'Miscellaneous Codes'. Your engraving pen closely approximates a spindle, so use 'M03' Spindle On (CW) to turn the engraving pen ON and 'M04' Spindle Off, to turn it off.
Since you are not actually going to CUT with a spindle use the 'M08' 'Coolant ON' to bring your pneumatic cylinders DOWN and 'M09' 'Coolant OFF' to RETRACT the pneumatic cylinders.
About Y axis and magic smoke from G-shield. I think you were going too fast and there is inertia in system, by rapid stopping that inertia generates current in steppers. That current goes back to G-shield and BAMM!!! :). I think that happened would like if someone confirms this. Stepper should slow down.
Instead of using the tinyG, I use separate drivers and an Arduino UNO. They are stronger with heatsinks and if you blow one driver you don't have to replace the whole unit. Here is a link to one that I use. www.ebay.com/itm/301670136936?_trksid=p2060353.m2749.l2648&ssPageName=STRK%3AMEBIDX%3AIT
Shame about the TinyG. It's actually a hard lesson for people to learn about anti static bags.
NEVER never never put electronics on them. They are designed to carry the electrons on the outside, you can however turn them inside out and get away with it if it's not an internally coated bag. Best to just put them aside! Not risking anything then :)
NYC CNC Great question!
Depending on the sort of bag they generally aim to make a faraday cage. This requires the use of conductive materials, and generally the black/silver bags use a metalised shielding to do this! I'm willing to bet that the inside of the bag is not conductive, but that depends on if it's only shielded externally or internally (From my experience silver bags seem to be externally shielded). As I was saying it's just best to stay away from them unless storing/shipping an item etc.
Generally it's the following (From what I understand)
Pink is normal plastic chemically antistatic
Black is carbon powder filled
Grey is metal coated
All will have pretty high resistances though, likely >2M Ohm
there should be some customizable m codes for things like the pneumatics
Was there not more videos showing the rest of this build??
I was thinking, couldn't you use the direction pin of the z axis to turn on and off the solenoid. Z- to turn it on and Z+ to turn off.
What made you decide to run pneumatic cylinders for the Z? Wouldn't solenoids be a simpler and more reliable setup?
NYC CNC Well in my mind you're basically already running a solenoid to control all the pneumatics, but with the pneumatics you're now adding lot of unneeded complexity with air hoses, regulators, compressor, and cylinders just to move the Z between 2 positions. When really you could just hook up 2 solenoids wired in parallel and get the same result without all that. Generally speaking, More parts = more problems.
But I figure you probably have a specific reason for running the pneumatic cylinders which is why I ask.
sweet videos. I'm quite excited to work on my first CNC plasma cutter/MIG welder table. do you all have an even heavier duty example build? like 4' by 5" table? what diameter lead screws would you suggest for such a monster? also, subscribed.
4 ft by 5 ft. not 5 inches. lol
Was this machine ever finished? I just found part 1.
Is the Solidworks file still available?
John have you looked at or even considered a project using maker slide? Its really affordable and most reviews are very positive.
Thats a shame, i guess thats the result of low expectations.
Good stuff as usual,Many thanks for the time you spend on sharing your knowlege
DId you tapp our the aluminum yourself?
Hay john its me again. i was thinking about what you could do to control you pneumatic air cylinders.
Depending on how fancy you are going to make this machine you could use the coolant pin on the TinyG .Then you would have to by a Separate breakout board that has a 3.3v relay on board and wire you 12V A/B ported air valve to control it. I encourage you to look into the specs of the relay that you buy because some of them may not be able to handle the current that that air valve pulls because in side of though is an electric solenoid (Coil of wire) and that pulls a plunger that lets air go bu.
If you budget allows try to find one that IS 3.3V CONTACT voltage but a little heavier duty be cause in electronics , a coil of wire contains a large magnetic field and it is now know as an inductor. and instructors in electronics Resist the flow of changing current and so when you open the relay . the magnetic field has to dissipate some were and some times that can flow back into the relay and then in to your board.
Or if you are having troubles finding a large enough relay you can put a diode across the solenoid wires but put the diode in backwards so when you turn on the relay it wont turn on the diode . but then when you turn off the relay the magnetic field collapse and the current flows backwards threw the diode. This Simple circuit is called a free wheeling diode and i use it in a lot of my circuits even if it my not be necessary .
To turn on the coolant pin on the TinyG :(" depending on what G code command list you look at you might not find it") It is a M8 to turn on coolant pin and M9 to turn the pin off . There is a M7 command but that is a Mist coolant command and i don't think the TinyG Responses to that.(en.wikipedia.org/wiki/G-code)
Hope that Helps
Have you continued this series?
Why don't you set your system up as a standard 3axis system but have the Z axis stepper only rotate 45ded to depress a switch triggering your air valve. . its low tech but uses a extra stepper. its redundant but works?
lowsideswitch 45deg. *
lowsideswitch He already has a soleniod making M-code preferable (assuming he can implement it with this hardware, idk); plus, if he learns how to use M-code he can use it for many other things on this or future projects.
Hey just a suggestion, could you group project videos in playlists. Sometimes youtube auto-plays them in series but much of the time you have to search through the entire video catalog just to watch a project build. For example I'm currently watching these diy cnc videos and the widget list is like video 41 then 42 then jumps all the way to 69 and then the final video isn't even a widget video, it makes it very difficult to watch one project from beginning to end. Anyway just a suggestion, thanks for doing what you do.
Better to use cylinders with end damping. You can run them in high speed without annoying sound :P They are running with full speed and right before they stop they slow down-> no noise, saves product lifetime, less vibrations in the system...
Principle: www.festo.com/rep/en-us_us/assets/pdf/AirCushion_WhitePaper.pdf
Great tutorial 👍 What software do you use to run your engraver and / or which would you recommend?
I am assuming that since there isn't a part 3 yet, you decided the pneumatic had to go right? Or you figured out that using a solid state relay between could work? Switched to the spring loaded ones so that spindle on=down off=up? Lead Screw for the z axis riiight? DONT LEAVE ME HANGING MAN!
PS Watching your channel reminds me of when my dad would watch fishing shows. Oddly Therapeutic.
If I only use adruino code, without g-code or any other software, how can I control multiple steppers? Will this piece this of code do?
digitalWrite(, HIGH);
delayMicroseconds();
digitalWrite(, LOW);
delayMicroseconds();
i have problem when the delay adding up.
isn't a servo motor better to use if you're already using expensive ball bearings? and the drive belt, the teeth andspindel size doesn't that impact precision so wider belt, more teeth and larger spindel equals more precision?
+NYC CNC So you cannot put encoders on stepper motors to close the loop?
+Methodwake You can, but then the steppers becomes a bit expensive and then you might be better going with servo's anyway.
+Daniel Mattsson I have added Encoders to stepper motors and the cost was not really that bad. Incremental encoders are cheap now of days. Still much less expensive compared to a servo.
You didn't mention that but no encoder to the stepper ?
So the engraving bit will slam into the part surface?
NYC CNC Design a floating engraver mount that allows for a "pad" that contacts the workpiece with the engraver tip sticking out (to desired engraving depth) just below the pad. Make the floating travel a half an inch or so and give it enough weight to give a good engraving. This will compensate for any Z inaccuracies with the Z axis travel and will give a consistent depth engraving anywhere on the table even if the part isn't perfectly flat.
hi great jjob
what is your job?
Is it just me, or does the left cylinder moves more than the right one? That could cause problems when engraving.
***** I designed my power draw bar with two side-by-side SMC air cylinders. SMC warns that it's generally not advisable to do this because it's impossible to guarantee that both air cylinders will operate at the same speed, and even if the air flow is initially adjusted to balance the speed, they may become unbalanced over time as the air cylinders wear. Mechanical engineers usually look for mechanical analogies to help them understand electrical systems they can't see. I'm an electrical engineer, so I look for electrical analogies to help me understand mechanical systems. The gain of a transistor is a poorly controlled manufacturing parameter. It's a bad idea to design an amplifier with two parallel transistors because they wouldn't equally share the current load. One transistor would always be fighting the other. Similarly, the velocity of an air cylinder is a poorly controlled manufacturing parameter.
In the case of my power draw bar, I justified the questionable design practice by telling myself that I'll be slowing both cylinders down so much that they won't be racing each other, I can easily monitor their operation and regularly make the adjustments to keep them operating at the same rate, and (most importantly) the stroke is so short that these fat little air cylinders will never get too far out of sync with each other as expressed in relative degrees of shaft misalignment, so the shaft seals won't be side loaded to any significant degree. The other "most important" justification is that I intentionally used a lot of compliance in the design. Both cylinders push on a flat steel plate. They aren't rigidly tied to each other mechanically in a fixed system where any difference in force is translated into transverse force on the shaft seals. I could probably disconnect one cylinder and the other short cylinder would push as hard as it could and wouldn't harm either cylinder. But it's still not a good design practice.
In John's case, the cylinder travel to cylinder diameter ratio is much greater (a bad thing) but the forces are much less (a good thing). I think he'll be OK. I'd score it minus three points on the design and plus 100,000 geek bonus points for the awesome.
I do think John might want to add four flow controls to balance the extend and retract speed of the individual cylinders. He's currently using air pressure to control the speed of both cylinders in parallel. Controlling flow instead of pressure is analogous to controlling the electrical current instead of the voltage. You can control the air flow indirectly by controlling the pressure, but it's not a linear relationship. I think it'd be better to directly control what matters... the air flow. Besides, flow controls are much cheaper and less bulky than regulators. :-)
Just Use M08-M09 Air On/Off for Z Down/Up
John Lauer video: ruclips.net/video/T2h7hagVfnA/видео.html has him using a Z value threshold in chilipeppr to toggle a laser on and off. That might be a simple way to toggle your pneumatics.
John, I appreciate all the time and effort it takes to put together a high-quality instructional video. Thank you. Suggestion: incorporate less talk and more assembly footage. A lot of your dialogue was fluff and I was less than inspired to pursue or watch any other NYC videos. Sorry.
I think air cylinder is not a rail.
I know the axial effort is not so big but air cylinder is realy not
made to resist to that.Maybee if they not full extend when operating they could do.
Now you talk!
Just can't wait to see that crazy machinne !! :PP
I really like yours vidéos,i start learning meeling metal from you....
Fred
Just a question: Why using so much different transmission between Y and X axis?
Do u have a video showing arduino code for limit switch and homing using strppers
henri it's grbl no code writing needed.
Nice video's, Is there a part three out ?
cool, I await the video
How can I connect a pendant to tinyg??
almost exactly 5 years later im doing research to build my own mill, things are still janky and complicated. the only thing really to change is that import components are now a lot cheaper.
If you really wanted, get a super hardened steel punch and mount it hard in the pneumatic system and engrave with a dot matrix. lol