How to find XYZ - CNCnutz Episode 157
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- Опубликовано: 7 сен 2024
- www.cncnutz.com/2017/08/how-to-find-xyz-episode-157.html
This is one of my more popular requests and I have put it off far too long. It follows on from my Start / Stop video and shows how to reset your X,Y&Z after a disaster. I hope you don't need it.
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DISCLAIMER:
CNC machines and other power tools are dangerous when used incorrectly. These videos are for entertainment purposes. I can accept no responsibility for any injuries you may incur from replication of what you see in these videos. I aim to demonstrate safe procedures but before attempting any project you should have prior machining experience or have done further research. If you are in any doubt about your safety you should look for an alternative method.
I hope you enjoy.
Great video Peter. I have Limit/Homing switching on my machine and they can be useful, but only if you take note of the Machine coordinates after you've zeroed your work coordinates. Once you've zeroed your work coordinates, just take note of the machine coordinates and you will be able to get your Work Zero back pretty easy. Never rely on the controller remembering your offsets in a power out. If you don't take note of them, you'll have to work it out manually. Limit switches are extremely accurate and repeatable.
So and an example, I have zeroed my XYZ, I take note of the Machine coordinates, ie X 321.1,Y 209.5,Z -95.1. Now if I loose power, all I need to do is Home all axises with the Home All button to reset the machine coordinates. Then in the MDI type G0 G53 X321.1 Y209.5 and press enter to get your XY, Then type G0 G53 Z-95.1 and press enter and your get your Z. Now press Zero all and done. Restart the job.
I also have a pneumatic auto tool changer on my machine and Homing switches are crucial then using it.
You sir have the most informative CNC router videos. Keep up the great work.
+GlenGH
Thanks Glen
If you have no limit switches it is a good idea to jog your machine to bottom left (5mm from extents) and scribe some marks that you can use to lign up every time you need to reference your machine. Possition your part in relation to the 0,0 point in your cam software before outputting NC. It saves a lot of messing about because all you need to do is reference your machine and your good to go again. Similar to what askjerry says below.
So I am thinking that folks who make these videos probably go thru the doubting stage. You know, will this video ever really help anyone? Let me solve that , I listened to the end and even though I did not have the foresight to make a reference hole, I was able to back into my design and reestablish zero. Thus my $50 piece of Walnut was saved from power outage hell! Great video, many Thanks!
Great vid. I have similar machine. I use hard stops. Reset absolute/machine position every time i start the cnc. Make setup, set part coordination .After setup i write down the absolute position. If power goes down (move machine to hard stops) i use absolute pos to find part coordination. I only have to find z (lead screw).
Excellent video, Peter! It really helps a lot!
I use a Triple Edge Finder (TEF,) and they are fantastic, however there are applications where they won't help you find X and Y zero. For instance, if you're using a piece of scrap material that has no straight edges to register the TEF from to begin with, and you used the center of the material for your X and Y zero point. On material with at least one right angle on the outside edges, though, they really work a treat. It's helped the consistency and repeatability of my work more than I can quantify.
+Mark Lindsay CNC
Thanks Mark and good point about using center.
Cheers
Peter
Nice tip..thx Peter :)...This has happened to me as well a couple of times even the controller failing. What I do 99.9% of the time on any big/long cutting job or a job with small tolerances I ALWAYS work from a know offset or machine offset after I homed the machine after startup...or even just write down the machine coordinates for the X and Y 0. After power outage I just re-home the machine and set it to the chosen offsets or G offsets and start to cut exactly where I left off.
That is one option I did not cover as I only remembered it after I had finished the video. The biggest issue i have with the method is it requires people to write the offset down and human beings are terrible at that sort of thing until it is too late. Just look at how many people keep regular backups. As you say it is the sort of thing you do on a big job which makes sense.
I may yet do a seperate video on this method as it is good if you remember to do it.
Cheers
Peter
I agree... I normally just use my phone and take a snapshot of the screen with machine coordinates at display...but usually I just work off known offsets... No matter how you do it as long as you can get back to where you were cutting :) Cheerts
Excellent tip! Adding the hole from now on!
+Wildman Tech
Let's hope you never have to use it.
Cheers
Peter
Great video and thanks, as I get quite a few of these outages and I have a relatively small CNC setup I run through a large UPS which 1- prevents the spikes where it goes off and on quickly and 2- gives my enough time to close and save safely, but thanks for the vids keep them coming :-), Malc
+Bernie NUFC
Thanks Bernie
I've done this. The only difference is that I turn off the motors and put the endmill into the hole by moving the gantry and the router with my hand and letting gravity pull it into the hole. I then turn on the motors and set the X,Y coordinates. Very quick with no fuss. This might be easier with a belt drive like mine, since the z axis drops like a rock when power is cut.
I almost always do this but in a different way.
I set zeros the normal way then use mdi to go to some point then jog down some.
Then write down the X and Y numbers right beside the hole.
If recovery is needed I just kill the stepper power supply and use the handwheels I put on the rear stepper spindle. When I have the bit right. I just put the values in the DRo's, flip on the stepper power, rezero Z and im off and running.
Wether I need to run from start or from some other point depends...
My home brew is all lead screw and I put that switch on the stepper power supply and often I use it with NO power on other than the router as a manual vertical mill. :) Not as accurate when using it the "right" way but plenty good enough for cutting slots of some oddball width and faster than the hassle using a table saw.. Often these slots dont have open ends so you couldnt do them on a table saw anyway.
+John Ware
Great way of doing it John.
I too am guilty of drilling holes and scribbling the coordinates next to it on occasions.
I like the way you can use it as a manual mill and being able to manually move the cutter to the reference hole is probably easier than having to step it like mine.
Sounds like a nice setup.
Cheers
Peter
Excellent video, Peter! It really helps a lot!
+MegaTopdogs
Let's hope you never need to use it.
Cheers
Peter
great video as usual, the hole tip will save my bacon sometime in the future. ..
I am wondering if you were to draw a circle the size of your cutter and cut on the outside of the line could you use that to re centre any cutter without having to change cutters to drill the hole. for example a 12.7mm cutter would leave 12.7 mm little dowel sticking up that you could align to. you could even use a ball nose if you plunged on the centre of the circle first so that you could get the sides of the cutter closer to the dowel
+MelbourneAlan
I drilled a hole with my cutter so it doesn't matter what size I drew. At the end of the day if you can align the cutter with any reference mark the you can recover your position. However you chose to do it is fine so long as it works. I sometimes just manually drill a hole and write the location on the stock. I don't know if your idea would work but if it does it is a good a method as any.
Cheers
Peter
thanks peter. I was thinking this so you wouldn't need to change cutters at all
Before cutting and having home switches I am using a simple script:
1) clamp the material
2) select approx. origin on material
3) with tape measure approx. distances from home to origin (dx1, dy1)
4) homing
5) put down dx1, dy1
6) run script that allows to enter dx1, dy1 and moves to that position
For milling PCBs I found "Peter's aux hole method" too unaccurate.
Thanks
Great video Peter... very helpful although we don't have power outages in Canada LOL!
Thanks Lyle.
si queres saber lo que son cortes de energia date una vuelta por argentina somos campeones en cortes jajaja
Yup, this method, or one very similar, has saved my ass quite a number of times over the years :) .
Mine too, but the less I have to use it the happier I am.
Cheers
Peter
Hi Peter,
Nice video. While I was watching, I was wondering if you were planning on loosening the stock when you got your hole drill bit closer and then actually slide the stock under the bit (you can raise the stock into the bit by hand then slowly lower the bit to pin it). Then all you would have to do is make it parallel again while it is pinned again by the bit.
Makes sense? I thought it would have been faster and possibly slightly more accurate than jogging it in place? But it depends on the accuracy of making the stock parallel.
Even as I was setting the cutter back into the hole I was thinking about the Paralllel rule.
Unfortunately it could only be used if the stock was originally placed on the table using the rule.
This stretches credibility as no one is likely to take all of these precautions on the off chance that they loose position.
Even the simple drill a hole suggestion will go unheaded in reality.
I only use the hole mehod on large or valuable works but for other projects there is a good chance that the piece will have a hole or similar reference built into it. Lets face it. How many people actually have an up to date backup of thier computer? That is how many people believe the next cut they will do will fail and therefore will take full precautions to ensure recovery and make it easy as possible.
A good thought Steven but unfortunately people are people and it won't happen to me today.
Cheers
Peter
Another idea is to add a small laser that projects a cross. When zeroing mark the point of the cross and use it for reference.
In your machine you have two hard stops, X and Y. If you were to use those points as your G53 reference point (Machine home) and then use your G54 for everything else... your reset procedure would have been as follows.
1) Pull the machine full limit forward.
2) Pull the machine full limit left.
3) Apply power and press HOME ALL.
4) Tell the machine to go to the last 0,0 of the G54... and restart the code.
On my machine, I have the limit/home switch... but on yours, the mechanical stops are a perfect reference. Well... +/- 1/10mm or so... close enough for woodworking. And as you said... the Z-axis isn't difficult... use your touch probe or manually lower to the surface.
I have to agree with Jerry 100% on this one. Since you have rack and pinion instead of lead screws, it would be easy. Jerry did some very good videos explaining G53 / G54, and it has made life much easier for me.
I use LinuxCNC, but I know Mach 3 has the same features. Once you set your G53 home locations, you set up your machine parameters in Mach 3, and then your machine will stop automatically before it hits any hard stops past your machine parameters.
Thanks Jerry,
I have used the method you outline to manually set my machine coordinates and then manually noted the offset to the working coordinates. I will investigate further these offsets as I don't use them normally but my understanding is that Mach3 and UCCNC do not remember the offset unless you shut them down gracefully which a power outage does not do.
I agree that if you know the offset from a home location then reseting is a snap. I have to rewatch your video about G53 /G54 and as you demonstrated the machine could find the G54 home point after the machine was turned off because it was powered down correctly and could save the offset. The real question is could it find G54 if you had just set G54 and the PC stopped because of a power outage. The consensus so far is no but you are using Linux CNC so it may be different. I will need to do more testing and might have to have a chat with you sometime. I like your Frankenlab series.
Cheers
Peter
CNCnutz (Peter Passuello) I get back home Saturday... so I'll plan to do a test to verify what would happen in a failure.
+askjerry
Thanks Jerry. I look forward to the results.
Cheers
Peter
Yeah, good one.
Good tip, Peter. Thanks!
Thanks Paul
Some good tips there but limit switches can be setup for about $10 and is one of the easiest and most effective things to do and one click and it's back to xyz in seconds. I ran my machine for 6 years without them and now can't imagine life with out them. But seriously a $10 add on so why wouldn't you especially since you've probably spent at least $4000 building it. Anyway that's my 2cents
Hi Chris
If limit switches can indeed reset a lost X Y Z working coordinate position after a power outage then I would be very interested indeed. I would really like to see this in action but as yet no one has been able to point me to a video or document showing how it can be done.
I see you have a few videos on your channel. Would you be interested in showing the process or point me to an existing video that someone has made?
After repowering your machine and homing it how do you get back your working coordinates back? I know they are saved if you close down the PC in the normal way but it doesn't seem to be the case if you switch the power off. The working coordinates are lost when i try it.
I can very easily and accurately recover position using a manual method where i note down the working coordinate offset from a home position such as my hard limit location. I should have demonstrated this as well but didn't. I am hoping for a limit switch based solution such as the 1 click fix you mention. I just need to understand how to do it and would really appreciate your help if you are able.
Cheers
Peter
Ps Nice looking machine you have there.
CNCnutz (Peter Passuello) thanks for the reply Peter. I am in the process of rebuilding a Bridgeport style mill. I run my machine off a laptop so in the event of a power out I have battery back up to save and close down. Others have mentioned saving in work offsets which you can then pull up and home your machine and get back to xyz. I'll do a video soon showing how it works in the next few weeks. Subscribe and check it out soon.
+Cut and Carve
Thanks Chris.
I have someone doing some testing this weekend for me and it will be interesting to see the results. Will subscribe and thanks.
Cheers
Peter
Peter.. can you do a video on, "run from here". It seems that every time I try this, I end up dragging my cutter across my work and either ruining my work or breaking my cutter. I think I have everything set, with my Z height set up high and the cutter moved out the way and believed I was ready for the move but realize I screwed up once again. A good review of this procedure would be so helpful. Thanks for all the good videos.
+Ted Gauthier
I already did and the link for it pops up during the video and at the end of the video. The link for it is also included in the webpage article I wrote for this video. The link for it is directly below in the description box.
Cheers
Peter
CNCnutz (Peter Passuello) Thanks Peter.. don't know how I missed it. Another brain fart.
Peter Outstanding video thanks.
+Lou Flores
Thanks Lou
really helpful one Peter
Thanks Tom
I love my limit switches. :D
Can you tell me if they retain offset from home in a power outage as demonstrated to make resetting easy?
I'm sure it will if you save position when closing your controll software but a sudden loss of power might be a different kettle of fish. I really curious to know as it would be an excellent and easy option for those with homing capability.
Cheers
Peter
Yeah, Mach3 forgets the offset when not shut down properly. That's why I have a white board next to my machine, where I write down the XYZ of the job offset before starting the program. So recovery after a power loss comes down to moving the machine into the home position and typing in three numbers.
Alternatively, you can save the offset in Mach3 before starting the program and load it if needed. That might be easier than writing it down, but I forget to do it :D
Thanks, I had a sneaking suspicion that was the case.
I like the whiteboard idea but I am lazier than you and use my phone to photograph the screen to capture offsets.
I forgot to mention this method when i made it but I reason if people can't drill a hole they probably can't remember to note offsets either. I think I will do a quick video to cover this method in the near future.
Cheers
Peter
um... The easiest method by far is to get into the habit of using G28 before ever starting your cuts.
1) Set up the work piece
2) Turn on the machine and home it.
3) Jog to your work origin.
4) Send G28.1 to the machine.
5) Begin processing your gcode..
If power goes out, or for any reason you need to find your origin again, simply home the machine, and send the command G28
You machine should now automatically position to the X, Y, and Z axis it was located at when you sent the G28.1 command.
From here, you can restart your cutting job,.
OR...
Depending on your software, and comfort with your skill at using it, you can skip ahead through the GCode until you get close to the point you left off, and resume cutting.
There's really NO excuse for not having limit switches.. They are cheap, easy to install, and very simple to use.
Hi ArcAiN6
G28 is not a Gcode command I am familiar with.
I have had a read and it was not sinking in so I had a play with it on my machine and see how it behaves and watched some videos.
What i found is G28 simple sends the axis to machine coordinates X0Y0Z0.
G28.1 changes the machine X0Y0Z0 coordinates to the location you have the axis sitting when the command is issued so G28 takes you to your works origin point which is what you want.
So after a power outage if you home your machine and reset your machine coordinates then giving a G28 will surely take the machine to the normal machine X0Y0Z0 and not the stock origin point because the machine coordinates have changed.
Now I still don't have switches installed so maybe this is screwing me up with my testing but after watching a few videos on the G28 command no one seems to be using it the way you are suggesting.
It sounds a great way of setting an auto recovery since G28.1 can easily be automatically added to the Gcode with a simple change to the post processor for those who wanted it.
I see you have some videos up on your channel. Would you be interested in showing the process before and after a power outage?
I'm sure there would be plenty of interest and i for one would like to see it in action. It sounds such a simple thing to do.
Cheers
Peter
That only works if your limit switches are extremely precise and are repeatable all the time. I found that is not always the case. I think that the solution Peter offers is one of common sense and should be done at all times to make sure that you will find back the exact positions of X and Y, even if you have "accurate" limit switches.
+Paul van Driel
Thanks Paul
I tried it... the G28 command works great... unless you loose power... it saves that position on program EXIT. (At least in LinuxCNC) which means it's lost when you power on again. If the shutdown was normal... then yeah... you still have the offset.
@Askjerry
If you are having issues with limit switches, more than likely the issue isn't with the switch, but rather your settings.. you should always have debounce time setting, and an exact pull off..
You will also want to use sheilded wires for your limit switches to help reduce noise..
set the debounce to 2000 and then drop it down a bit at a time until you start seeing false
triggering, then bump up slightly.
i.e. when your switch triggers initially, there can be noise from the contact in the switch "bouncing".. This can cause issues in lower end CNC controllers that do not electronic noise filtering.. A setting of 10ns - 50ns in most cases should work.. I myself use 31ns on my limit switches after recording them with an oscilloscope and doing the math..
I would also suggest a 6mm / ¼ in back off setting.. meaning after homing, the machine pulls off of the switch contact by that amount, ensuring no accidental, or partial triggering of the switches..
Homing speed is also important.. You don't want to fly towards your limit switches at full speed, as you'll simply crash into them.. A slower speed will reduce this, and ensure proper, and repeatable triggering, without excessive wear, or damage to the switches, and will also mean the mechanical components stop reliably, and at repeatable intervals. Full speed means more inertia.
Hey Peter. Why did you zero the part outline bit off of the table when you zeroed the other bit off of the surface of the work piece?
+Ryan Ballard
I like my table top too much to cut it up unnecessary when cutting through the stock so I use the table top as my reference. For the other cut I needed my cut to be accurate to the top of the stock. I cover these in 2 videos "Don't spoil your spoilboard" episode 51 and also "CNC magic" episode 125
Cheers
Peter
Sir cnc machine 4040 chaina made, it's have leadshine servo motor and drive and mach3 controller RJ45 connecector have in controller, my Gantry fixed but table moving, so how to start resume Engraving , if power cut off and Engraving half designing complete, so please. Guide me how to start resume Engraving on if power cut, my job work only iron carving, so please guide me. 🙏
Please see episodes 119, 157 & 158.
Together they should help you understand how to restart a program if it is stopped.
Cheers Peter
great great fantastic
Thanks Masoud
Sir how to resume cutting in mach3 after power cut failure.please help me
This video shows everything I know.
Cheers Peter
Great videos and thanks for doing this. I am new to CNC and have been using mine to cut foam and love your videos thank you for these. I want to know if you can help with a few questions.
1. Where did you get your pendant and will it work with Mach3? If so send me the information please.
2. I ran into something the other day and I have a feeling it has to do with my offsets. My z offset is +2.39, however I used the auto z touch plate and the machine said +1.5. But when starting it went into my part and drug across the part in that z position tearing it up and then moved to the start point and then went down more through the part. Ouch. How do I prevent that? Does it have anything to do with how long my cutter which is about 4 inches long?
3. What chuck/collet do you use to go from 6.35mm to 6mm shank. I would love to know what your using because I tried a new 6 mm cutter inside my 1/4 inch collet and when I was done it just stuck there and was very hard to remove and when I did it ruined the collet and can no longer be used as a1/4 inch collet.
1. The pendant I bought is available from here ebay.to/2HXaaMl
This is the newer version with an extra set of keys for the A Axis. I also have a video on how to configure it in Mach3.
2. Check what you have for your Safe Z setting in Mach3. Note that the Safe Z uses machine coordinates not working coordinates. This may be the cause of the problem.
3. My old router had a1/4" collet and will not hold a 6mm bit.
I turned some custom collets on my lathe to hold 6mm, 3mm and 1/8" cutters.
I now have a spindle with and an ER20 collet set so have the full range of sizes from 0.5mm to 13mm
Hi Peter, thank you so much for the quick response. However I have 2 follow up questions.
1. The pendant link provided was a a wired device and I am looking for a good recommendation for a wireless pendant that will work with Mach3 and how to set it up. If you can send links that would be great.
2. The Safe Z seems to work, however in the middle of the screen it shows in the status bar on the front page that Safe Z is not enabled. Here is my setup. I have a homemade vacuum table on a 4x4 machine and I don't want to run my bit into that table ever again (ok, I have done this 2 times now, yuck) and I sometimes need to cut very close to the bottom of the part or even through it. So I would like very much to not ever have my bit run into the top of the vacuum table. Do you have a video explaining this whole procedure and setting the Z axis (PS. I use limit switches for x,y but not z)? By the way your videos are very well done. I am really impressed on how fast you put these up. If you need screenshots, I can provide.
With regards the pendant I only have a wired one so cannot recommend a wireless on to you.
You will need to ask around.
I went and checked my Safe Z setup and should have said that default is machine coordinated and I have mine set to working coordinated. This means it will raise the specified amount above the Z0 you set ion your working coordinates. I don't think the Safe Z height is the culprit here.
Rereading your original post it sounds like your touchplate didn't work properly or isn't setup properly. The length of your cutter is not an issue. It should probe down and then the custter should rise to a preset height and the DRO will update to reflect the height. If the height is not what you expect then I would measure and not proceed until you figured out what was going on. You mention you did the touchoff and the DRO should have read +2.39 but it only read +1.50.
This would indicate and issue with the probing routine at a guess but trying to diagnose the problem is impossible without a lot more information. If you take a quick video explaining the problem and showing the issue I might be able to figure something out.
With regard setting the Z the only videos I have is setting Z0 using a modified autozero,
It may help avoid cutting your vacuum table. The first video is backgroud and explains the concept while the 2nd video shows a better method.
Hope it helps
Cheers
Peter
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ruclips.net/video/F1fpdYbBFfI/видео.html
Hi Peter, can u make a video how to use 2 steppemotors on one axis, how do i wire it up? i know in Mach3 i have to set one moter as slave, but how is the wirring, how did u do it?
Wire it up the same as the one you are slaving it with and reverse its direction in Mach3 motor settings if you need to.
Send me an email and I will see if I can help.
Cheers
Peter
I use stronger words than that :-) great video as usual.......
I have my moments when the camera is off as well.
If I didn't know you live in NZ I would swear we have the same power company.
Maybe we do.
I'm with the Dodgy Spark Electric Company.
I think they're international ;-)
It got so bad I bought battery back up for the Laser and my computers
Homing switches....if you go with the induction type you'll be "dead nut on".
Awhile back you did a video on various keyboards to use with the CNC. Cannot find it. Can you help?
I think this is the one you are looking for.
Cheers
Peter
ruclips.net/video/Mnum5PgvHWw/видео.html
I would love to have the file of the calendar if its possible so I could make one.
Follow the links under the calendar video for the files.
Cheers
Peter
Do you just put known coordinates in mach3 like that?
Just type them in but if you are in reset you. Will find it won't change but returns to the previous value. If you are out of reset then just type it in and it will change.
Cheers
Peter
thanks, I'll try that....
You don't use a fixture offset (G54, G55 etc)?
+Keith Green
No I don't use them.
It will make your life MUCH easier once you start. Just use the hard position as machine home (G53) then when you set 0,0 for your cut... it will be the G54. You can always go back to that exact point. When I make a jig... it mounts in reference to the lower-left corner. I zero it out... then write the offset on the jig. I can pull a jig I built last year, put it on the machine and type in G10L20 X_ Y_ (x an y are the offset values) and the machine is set. Done.
why not use an edge finder?
I have to admit I didn't think of that and of course I don't have one. That said now that I have a touch off plate I could also use it if I align it with the edge of a cut. A touch probe would work well for this. You have have given me something to think about or at least a reason to make a touch probe in the future.
Cheers
Peter