RDWorks Learning Lab 223 Air Assist Why, How and When
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- Опубликовано: 9 дек 2021
- There are many myths and misunderstandings associated with air assist. .Does more air pressure mean a deeper, faster or cleaner cut? Efficient cutting requires a "sharp" laser beam intensity profile. A "blunt" beam will still cut but much slower and with more collateral damage such as scorched top corners and dark/burnt edges. I cannot test for those conditions because I have sharp beams on my machines. Because of my advantage, it is possible that I will not see the gains that others claim from more powerful compressors.
This was supposed to be more of a demonstration session to share my experience but as I was demonstrating I saw new possibilities for improving the engraving air assist.. Oh dear, I feel another design project awaits. 
Наука
I've been watching your videos for the entire 5 years that I've had my laser but I feel like I'm only just recently getting smart enough (or understanding the laser well enough) to get full benefit from your expertise. It's never just down to one thing with laser cutting. It's the perfect point where all of the variables are just right... Thank you for all you do.
Hi Marti
If you have understood much of what I have discovered by experimentation and research so far, then you are a pretty clued up laser user by now. Although I realize that I have still quite a lot to learn (thus I am still a student), I thought I had a pretty good grasp of most of the variables that this technology throws at you. I was wrong. There is one big surprise that I discovered while investigating the way that lenses and laser beams interact. Optical companies make perfect lenses and lasert tube companies strive to make the perfect M2=1 output beam ( a spec for our glass tubes is M2=1.1). Sadly, it appears that two perfect parts ofour machine do not produce the perfecr result you would imagine. Perhaps you would like to watch these two recent videos to see what I mean.
ruclips.net/video/7N8Th1-IF4s/видео.html
ruclips.net/video/v7-VArJbJTs/видео.html
Best wishes for your journey to perfection. Russ
Brilliant Russ. Extremely well explained and a lesson to us all. Thank you.
Thank you very much for this most excellent explanation. Bought a silly Chinese pump and will stick with it! Anyone using a laser with air assist should watch this!
What can I say? Your enthusiasm and ability to share this knowledge with us is impressive. Thank you very much.
An external air mod is something I have been contemplating for a few months and your test has now kicked me in to doing it. I still use the original Chinese pump for cutting but have my machine set up with very small and cheap fish tank pump teed in to the air line which runs when the main pump is off. I use this to keep smoke off the lens when engraving and it seems to work well. I have only just changed from the supplied 2 inch lens after nearly 5 years. Ruida's air control triggers one of the relays I fitted when I rewired the machine and when normally closed this relay runs the small pump then when triggered by the program calling for air it switches to the larger pump. I like the idea of a permanent flow meter and will be fitting a spare one I have this afternoon. Great video once again Rus, you have answered a load more questions I had buzzing around.
You are a genius. I wish you would have been my high school math teacher.
Thank you for this really interesting and entertaining video! Nice to see this glow in your eyes when it comes to technical processes ;)
Thank you for taking the time to explain this , very helpful
Now that was a great lesson again. So nice how you explain things. It’s easy to follow and sometimes i can give the answer before you did. Just because it’s so clear where you’re going to (Ok,I’m very interested physics too). I sometimes laugh out loud at what you say, that makes it fun to watch. Thx 👍🏻
Hi Russ, I still use the small compressor with the solenoid to provide very low flow for engraving and high flow for cutting. I have also mounted the compressor and extractor in sound proof boxes now life is good :-). Thanks for a very comprehensive video. Again
Nice work! One solution for the humid filled air coming from the big compressor woul be to install one of those air regolators and water separators. They are inexpensive and common where air is used for some delicate works including air painting guns etc.
Hi
That is a good suggestion for those that relly want to fit a big compressor ( I already have such equipment) but the point of this videeo is to show that it is unecessary to use high flows and high pressure. I have done a furhter video on this subject that may interest you see ruclips.net/video/QwOkOLBp1pE/видео.html
@@SarbarMultimedia I will watch it for sure. Your tests confirmed my suspiction that air flow is important throughout all processes: cutting and engraving. The general theory wants air assint not necessary while engraving, even counterproductive. Your test with the lateral air blow shows exaclty the opposite. How about using both for engraving? a tiny blow from the nozzle and from the side to blow debris away?
Well done. Thanks for all that info which I hope I can put to good use. Cheers.
Very well explained as always! I suggest you link this video to some of your first ones because when you initially used the stronger pump I was thinking of upgrading because of the video. Now this great explanation shows that the little Chinese pump does the job very well.
amazing demonstration Russ
awesome information as usual,,, it's funny how sometimes slower is faster. going to take some time for this concept to penetrate my reality and to own it.
(and your lense problem, reminded me of running a plasma cutter on shop air without a dryer. burned up a handful of consumables before figuring that out.)
Your videos are incredibly helpful Russ. Hopefully one day you'll do some experiments with the diode lasers as opposed to CO2 lasers, as sure it would be an interesting journey for us all.
Hi
Thanks for the kind words. For 6 years I have been self educating myself on the minutia of laser technology.The CO2 10,640 nm wavelength allows me to really examine the characteristics of the laser beam. The way that it uniquely evaporates acrylic and leaves "footprints in the sand" provides an invaluable research tool. The fibre laser (1064nm) and diode laser ( about 450nm) have no such association with any material and thus are difficult wavelengths to explore. A laser beam is a laser beam and will ideally have a Gaussian intensity distribution within the beam regardless of its wavelength, thus my acquired knowledge with the CO2 laser is applicable to all other laser types. However, understanding laser technology is only half the problem. The other half is all about how materials react to different light wavelengths. I have explored the world of CO2 RF lasers and there is no "magic" there despite what the big companies would have you believe. I have explored the world of fiber lasers and that is an interesting but limited technology aimed at marking materials. Again there is lots of hype about fast marking speeds and yes, under certain limited circumstances and with specific materials, that claim is true...... but over a very limited area. The main feature of low power fibre lasers is their ability to micro machine material surfaces. The marking colour or colours achieved with Q switch or MOPA lasers is different to the chemical changes effected by CO2 or diode lasers that is really damage materials. The fibre laser manipules the surface texture to create light absorption (black) or various light reflections and wave interference patterns to create false colours as you see on a butterfly wing. Google it and you will see a full explanation. Given enough time it is possible to cut a limited range of materials with a low power fibre but unless you work with kilowatts this is not a cutting technology. As the wavelength of light shortens, the type of damage and range of materials that can be damaged decreases rapidly. My interest is understanding the science (it keeps my remaining 2 grey cells exercised) of laser technology and materials. Sadly I cannot see myself entering into the world of diode lasers. Yes it is a cheap hobbyists entry into laser technology and CNC control , and there are now some very interesting and novel machines appearing (Laserpecker 2) but it's ability to extend my education is very limited.
Best wishes
Russ
Russ I appreciate your enthusiasm and research. You are a natural teacher/instructor. I learn with each video.
Thank you very much.
Wow..... why do I feel like a fool Russ?? LOL!!! Brilliant video once again.
Great work.!!!. Impressed.. :o)
So glad I anticipated some of this and added a pump to the purchase of my first laser which is currently with the courier! I'll have a look at the nozzle when it arrives to see what forethought has been put into the Ortur Laser Master 3. If there is a big orifice then I'll 3D print a filler with smaller sub-nozzles to point the air directly over the cut or maybe redirect it like in your sideways pointing flow. I'm laughing here at 51 minutes, thinking about the expected condensate in your nozzle from the high pressure to low pressure exit. Don't take it badly, you're doing amazing research and making it public, a laser company should have already snapped you up except that you are giving your research on here for free. I was initially thinking ahead that maybe the higher pressure was cooling the workpiece and reducing temperature but then I thought about pressure reduction and heat wave lensing effects which led me straight to thinking of condensate from your high pressure hose. Raising pressure slightly by restricting nozzle flow is another way to defeat condensate inside the nozzle.
Hi Graham
The diode laser you are expecting is a laser operating at a completely different wavelength to the CO2 laser that I concentrate on in this series. 10,640nm light is much longer wavelength than the 450nm you are going to play with and the shorter wavelength affects less materials, some more efficiently and other less so than CO2. However, the great advantage you will have is mechanical simplicity. The laser is a compact single unit that requires no light path guidance around the machine. Sadly, there are many disadvantages. You have very limited lens options (on some units, none) and the so-called air assist is really a down flow cooing air for the diode unit. This in itself can be bad news as it will blow your tar laden fumes down onto the worksurface. Because of the low power and the fairly poor quality laser beam (typically M2=1.5) it is not well suited to cutting but is ideal for the "soft" power application required for engraving. You cannot regulate the power of a diode laser, it's always 100%. Pseudo power control is achieved by controlling the exposure time via a PWM duty cycle principle. The "soft" intensity distribution, low power and PWM control system allow you to do delicate engraving tasks that are impossible with a CO2 laser.
Many of the science principles I speak of are transferrable to diode lasers but the lens technology that we spoke of recently may not apply because at such low wavelengths, normal glass lenses can be used and I have no idea what multiple lens systems are used internally to change the square light output from the chip to a usable round focused beam. I have seen many focused diode beams that are elliptical i. e. the X and Y kerfs are different. I'm sure with your curiosity, it wont be long before you invalidate the warranty and dig inside the unit!!!
Best wishes
Russ
Ps watched the Ted video and yes, I summarized it in just a few words We are not amazed at how our eye works so its not a massive leap to extend the same basic principles to smell. It was several years ago that I first came across this idea in a TV documentary. Here is just a snippet
www.google.com/search?q=jim+alcalili+quantum+smell&rlz=1C1CHBF_en-GBGB911GB911&oq=jim+alcalili+quantum+smell&aqs=chrome..69i57.16947j0j7&sourceid=chrome&ie=UTF-8#fpstate=ive&vld=cid:445db102,vid:3P7B_LkSlKQ
Your already seeing the newer explanation of scent explains your rather quick response earlier! Agree, diode vs CO2 laser. I am very much at the start of my laser journey. I'm old enough to feel some awe still at how far our technology has come during my life time. I'm really curious with my coming 60 watt JPT MOPA laser to see how much focus wanders on a flat plane for a beam that has different radius the further it moves from vertically under the lens. I got lenses for areas of 50, 150 and 300mm, hoping to get some optimisations to maximise it's damage to metal with the 60 watts being there to reduce frustration at ablating times hopefully. It's not a thunder laser but I'm looking at this as more or a design prototyping tool than a business at the moment.
@@fluiditynz
Hi Graham.
Many years ago I questioned my science teacher after a lecture about smell, when at that time the lock an key priciple was the accepted explanation. I asked why it wasn't vibration based like sight and sound. I was just a silly notion at the time but it was not until I saw the full documentry on quantun smelljust a few years ago that it all came back to me. However, it still seemed far fetched. It was not until I started to understand how light interacted with molecules to damage them with a laser beam that I began to understand how our eyes worked by detecting light waves at unimaginable frequencies. The idea that smell was akin to this sense that our body already posessed, suddenly became really understandable.
When you get your MOPA laser they may not send a user manual. Here is where you can download it.
mail.google.com/mail/u/0/?tab=rm&ogbl#search/JPT+/FMfcgzGmtFBWGfrsCTzfQLpBWnNDGJvX?projector=1&messagePartId=0.1
@@SarbarMultimedia Thanks. Luca says he wasn't the first to have the idea about vibration but I give him credit for putting the pieces together. I don't see much of him on line but every time I do he continues to surprise me. I saw a thing on mitochondria communicating with each other late 2021 and put it together with my skepticism on genes passing instincts between generations and my not feeling an intuitive fit for long term delayed memory retrievals being in the brain alone and here was suddenly a marvelous missing link in my understanding, our mitochonrial symbiont that has co-evolved with us through the millenia, it seemed to me to be occams razor like, that their communications would intertwine with our own and be the solution to my questions. Fast forward and Luca Turin and a team have been given scope from their sponsor to investigate human consciousness and half way through the video, Luca starts talking about mitochondria. I think this is not far away from becoming accepted science but it also has implications for AI consciousness, Luca has the insight to believe something is missing from our current accepted science but it is that current accepted science that has been driving neural network development. I'm not sure why I haven't been able to find others speculating on my theory of Mitochondrial intellectual symbiosis but I think the internet and current science is at a level where there's no going back on this theory and it will be researched and soon.
I bought a relatively low flow Hailea 9820 pump - just like the low PSI cheap chinese ones, but without the pulsing. It's quiet and provides a nice steady air flow. I would recommend looking into it.
Hi
That pump delivers a max pressure of about 2psi when the flow is almost zeo and close to 60 l/min free flow with almost zero pressure resistance. I have not been able to track down any performance graphs but my guess is that at the flow I estimater is needed for reasonable cutting, (about 8/min) the pressure will be about 1psi.. All 3 of my machines are Hailea pumps. They specialize in soleniod driven diaphragm pumps and are a Chinese company. The aco 9820 is still a pulsing output but at its very low pressure capability the pulsing will not be dramatic. In general terms, quiet means low power and at 35 watts is pretty low. Thanks for the recommendation
Best wishes
Russ
This immense, really. I was on my way to buying a 140 l/min pump, but I will stick to my 50 l/min pump. With this video, I now owe you one hundred pints of beer, if my calculations are not wrong :P
I am running all the improvements as you are also doing (cutting nozzle, full flow rate, 1 HP extraction turbine, nozzle 3,5 mm away from cutting surface) but I am still getting browning over the top of my work, also from one side of the kerf. The only difference I find is the jet of air coming from the aperture at the machine door enters at the top level of the work instead of the bottom level of the work. Do you think this might be the cause of the issue?
And just before answering that, add another beer to my bill. Cheers!
Thank you Russ!
I found another thing that worked well for me/us by accident.
Our big laser has 2 heads, and 2 fishtank pumps and so 2 air supplies to the heads via 6mm OD tube.
Even if I use only 1 laser, I always have both air pumps running so that smoke and crud can't drift into the nozzle & onto the lens of the head that's not being used.
However, I had a bunch of things (BMP pictures) to engrave in bamboo, and the air supply to the 'off' head had come loose, and had aimed itself at the other head, so while the 100w head was lasering, and the little (approx 3psi?) air pump was chuffing through the air nozzle, the OTHER hose at the same time was actually fanning the smoke right away, by flukey virtue of where it had unsprung itself to.
The result was a bunch of very clean engravings.
After I discovered that, I plugged it back where it was supposed to be and did 2 more objects- and they were yuk! Dirty, with tarry stain blown ontop the image - hence the usual statement about turning the air off when engraving. But that can also create problems with gunk lodging under the air nozzle and falling into the job on big runs.
At any rate it was well worth my using the 2nd air hose to run blowing down outside the air nozzle, as an extractor of a sort, or a deflector, which left me with a finished job and NO debris to clean off - 1 air hose ending inside the nozzle, and 1 outside at about a 60 degree angle down.
(end of story)
On one of our other lasers, I had set it up originally, piped back to the 40psi air compressor, but found it a pain - often enough the air blew the substrate away- moving it and ruining a job. After I turned it down enough, I decided I may as well just use the old fish pump, so I did - but I kept the air compressor connection, and added 6 ft of air hose and a dust gun, and used it manually to blow out flames that tended to come up at times under 20mm acrylic, when you can't always see it happening.
Hi Ian
I only demonstrate basic principles and how to achieve them simply. In addition I am alwsys thjinking about more efficient ways to achieve tjhe same crud -free outcome. In general you should never jhave crud buildup on the nozzle IF you are set up correctly for engraving with a BIG gap between nozzle and work (12 mm at least) . However, there ar times when cutting and engraving with the same nozzle that compromises have to be made and yes, I have encountered the debris drop off (especially with photo engraving acrylic). I usually stop the program after engraving and before I enable the cut layer I swap lensesandn nozzles to do the cut layer.. Its easier for normal engraving becuase I usually drop the work 6 to 8mm out of focus for the engraving and then raise the work with my programmable Z axis to do the cutting withnthe small air gap. As you saw in this video I have also experimented with a "fantail" air assist. Your twin head is a rather special arrangement that very few possess so the fact that you have been able to find a neat solution with the extra air assist is a great win for you. Accident or not, acute obsevation and realizing what you are seeing is key to progress. Congratulations.
Best wishes
Russ
@@SarbarMultimedia Thanks, and yes. I'm thinking for a single head, a tee piece in the air delivery line near the head and the ability to point it where wanted, might be a big improvement- with an adjustable air valve ...
@@ianstewart-koster9982Hi Ian
Thinking about it after I wrote.. Your machine bed will be quite big and I suspect you will either have bars or a fixed honeycomb bed Neither are suitable for my "managed airffcvlow" system so your accidental flushing system is clearing the local fumes away by an air curtain effect of expanding air from that downward facing opern air pipe.that is moving rapiodly across your engraved surface. It's an interesting discovery that I must experiment with.
Best wishes
Russ
@@SarbarMultimedia Correct, Russ, re the bed: it's vertical blades. Thanks for the replies. I was just amazed by how clean the jobs were with this 'double blowing' happening, one out the nozzle and one sideways from it.
🤔 you still have your conical nozzle and it's attached airflow pipe attached while you pass air across its face with your new setup. Will the Venturi effect of the cross flow air, draw air in through the, presumably, open original pipe, and clear the air under the lens? Or, to put it another way, would the efficiency of the process be reduced by blocking the original pipe end, thus reducing the movement of air under the shrouded lens?
If the original pipe is actually enhancing the clearing property, is it therefore possible to loose that benefit if the pipe is placed in such a way that it would actually draw in smoke from the surrounding cabinet?
Excellent video, thank you.
Hi Russ, normally "professional" engravers (business-wise) who do a lot of cutting work use compressors that can deliver around 200 Liters/min at 8 bars or greater. And they use water separators so you don't get the effect you talked about which destroyed your lenses. And if you could repeat your test with around 4-6 bar (50 to 90 psi) I would like to see the difference. That is the information I got from those professionals. And I must say with my normal cutting I use 4-6 bars and get way better results than with the little membrane pump and on top, my silent compressor is much more silent than that Chinese membrane pump. Maybe you could try to get another compressor? Thank you for your enthusiasm and great work :-)
Hi Sebastian
The numbers you cite will be for a hydrovane compressor that can deliver 230 l/mi at 10 bar but requires 2.2kW to run it. At about £2000 for the compressor plus almost another £1000 for a dryer to handle that capacity, that's a step too far for my simple shed science. However, I note that you are already using a high pressure and high flow system that is giving excellent results. Perhaps you could post a video of your setup with high and low flow rate test examples so that we can assess if the difference in speed, cut depth or finish is worth the investment for hobby use. What is your nozzle orifice diameter and how far away from the work surface is it? What compressor/dryer system do you use?
My new cheap Chinese diaphragm compressor was not bought for this air assist application, that was just a coincidence. My 30 year old piston compressor is now shaking itself to pieces and it's replacement does not have to last another 30 years!!!!
Best wishes
Russ
@@russsadler3471 Hi again Russ, unfortunately I only have a simple water separator, but the compressor is a STAHLWERK ST 510 Pro this can deliver a continuous output of approx. 200 liters at 8 bar pressure, the price of 500 € (~ £ 425) is also moderate for this performance. I have different nozzles and lenses currently I have the set of American Photonics 25mm diameter lens tubes with ZnSe. The focal lengths are 1.5 ", 2.5" and 4 ". The nozzle outlet is very small with this set (but has to be re-measured). Second, I use a Cloudray E series head with a 2.5" lens, also ZnSe here I say the difference in beam quality to American Photonics lenses is extreme. That means the lines of the Cloudray lens are clearly "worse" as far as I can tell, despite the correct focus. I usually do not cut very thick material because 90% of the time I only make decorations for the children and women when I have the time. However, the difference in the cut quality at 2.5 "distance with the E-series head is very large from the membran pump to the compressor at 6 bar. The American photonic heads have significantly less distance to the substrate, similar to your attempt at the nozzle outlet far on the workpiece, in contrast to the E-Series head. Unfortunately I don't have much time at the moment, but I promise I'll do a few tests with my machine, maybe I'll come between the holidays. I still have your email address would then provide you with the results.
@@Sebastian-kc7id
Hi Sebastian
My genuine thanks for sharing this information and there is no immediate rush to create a video but it would be good to see some of your results in the new year
Have a safe and very happy Christmas
Best wishes
Russ
Thanks for the info. A lot of people are suggesting the pumps that put out about 1100 GPH... I think that's way more than what is needed for a small, blue diode laser. I find that I'm getting more air out of the inlet filter from too much back pressure than I get out of the nozzle. It's like building a 600hp car engine then putting a 1" diameter exhaust: you lose power and it becomes less efficient because of the restriction. I just don't think 1100GPH is necessary (that equates to about 69LPM if my math is correct). Thoughts?
Hello! I’ve bought the universal lens tube holder, the cutting nozzle and made myself a 3,5mm spacer so I can be closer to the cutting area. I have the same chinese air pump as you do, however I can’t seem to get clean edges when I cut. I’ve tried all sorts of speeds on the 2,5 and 4 inch lenses.
To get even cuts on 10-12mm plywood, I typically need to go down to 5-7mm/s.
I bought a big air compressor just to test and blew lots of air through the nozzle, but still burnt edges. (Wiping with tissue)
I probably have a B grade 80W laser tube, and I know the laser beam is a bit high on the third mirror.
I have been able to cut square through 20mm solid oak with this though.
Any help would be higly appreciated.
Hi
I think you have probably already answered your question if you really do have a B grade tube. B grade tubes are rejected at the manufacturer's plant because they fail to make peak power specification. This is usually because the internal mirrors are not PERFECTLY aligned to each other. Only a slight imperfection causes loss of INTENSITY at the core of the beam. It is this high core intensith that provides efficienetclean cutting. A "blunt" beam will engrave just fine and will still cut to a certain extent but the lack of central core intensity will cause low intensty charring of cut edges as instead of the cleam edges left when material is effeviently vapourized.. This simple mode burn test will tell you if your tube is a butter knife or a Samurai sword.
see ruclips.net/video/R6Wqn5-HMzM/видео.html
Air asist aids cutting but I am afraid it cannot cure fundamental issues. The manufacturere of the tube cannot fix this issue once the tube is manufactured so it gets sold at scrap value for "repurposing" by the less trustworthy section of the Laser market.
Best wishes
Russ
Very good explanation of color white is all colors black his absence of color
I was wondering if 'vacuum assist' could be implemented at the nozzle (in addition to normal extraction). I guess to make it practical you would need a fairly large vacuum nozzle which would be too bulky for the moving head.
But if the ultimate aim is to remove any particles that are forming between the lens and the cutting surface that could absorb and lessen the lasers impact on the materia,l it could be an interesting experiment.
Lots of wonderful information in your video, I'm pleased I set aside the time to watch it all, and that you took the time to make it.
J
Hi James
As this vodeo shows for engraving you will get material spewing upwards with a volume and speed related to the depth of cut (power applied). The problem is you must have a small positive pressure in your nozzle to exclude the fumes but NOT have a JET of air from the nozzle that will blow the fumes back onto the work....turning it breown as the fumes recondense. Long ago, before I studied what was happening to the fumes, I had the same idea as yourself and rigged up a small shroud around the nozzle and used a piece of 25mm flexi conduit tube to try and pull the fumes away with a small vacuum cleaner.. Result was noisy and unsuccsessful and as you imagined , rather cumbersome.. Vacuum is not the way to go.. It is far more important to understand the simple principles of air flow management through your machine because the Chinese machine designers have totally ignores it.
Watch this video from 43 minutes onwards to see a demonstartion of what I mean. ruclips.net/video/AHnJ2WxNo5Q/видео.html
Best wishes
Russ
@@SarbarMultimedia Many thanks for the reply.
Yes, there certainly seems to be a real science to getting minimal air-assist which is just enough to keep the beam path and lens clear from particles, coupled with enough extraction, across the surface of the work piece, to prevent the particles falling back down and adhering to the surface.
I engrave a good quantity of wooden wine box lids for a Wine Merchant in the UK often with small bespoke elements which makes laser engraving the most practical option over screen printing etc...
For these I tend to use a sacrificial layer of transfer paper (which is effectively masking tape but it only has a very weak adhesive on the back) it works flawlessly but does slow the work flow. I am now experimenting with blocking/forcing the extraction to draw from above the work piece and lowering air assist pressure to see if I can get a repeatable result with no masking required.
Your series of videos have been very valuable, so I am most grateful for the time you have put into producing them.
I rather strayed into owning a laser cutter to held a client as part of a larger project (3D printing is my main hobby/business) and had to learn on the fly so your videos are a superb resource.
I am just starting to experiment with the laser marking of metals following your other video.
James
Nice video Russ, so saw you moving the nozzle end up and down, i have a china blue and cant move that part. Can you get tube extensions for these machines so your lens is still at the focal distance but the nozzle tube can be closer to the cutting surface? I can only move my bed and substrate up to the nozzle which will then put my put of optimum focal distance
Hi
You have an 18mm diameter lens fittred in your nozzle and retained by a screwed bush
If you want to lower your nozzle but not changerthe focal distance, then that's the same as raising the lens. Just make an 18mm outside and 14mm inside diameter washer 3mm thick and drop that into your nozzle first, That will give the effect you are after.
Best wishes
Russ
Hey Russ, Fantastic video sir!! Can I ask what pump are you using and where did you get the attachment to regulate the air pressure?
Hi Alan
It took a while to find a proper ball valve that allowed me to really control the flow of air but this is it
www.ebay.co.uk/itm/175129091789?hash=item28c681decd:g:eq0AAOSwL29h8QCE
the pump is the 70l/min Hailea ACO 328. Rememeber to suspend it on a wire or string from the handle otherwise it will be quite noisy
Best wishes
Russ
@@SarbarMultimediathank you so much, you are a legend
Principal Engineer here with four decades of experience. Sorry for the argument from authority, but otherwise I'd fall into a bucket of non-technical people just saying things. :-) I do like your advice about moving the nozzle closer to the work (if the setup allows for this). I regret I'm not a fan of the rest. I don't mean to come off as debating or negative. I'm just trying to offer objective facts and guidance. I've run similar experiments including one using the same piece of ply and cutting three test boards (the one with circles in a 5x5 matrix) and the enhanced cutting performance was both significant and undeniable. I had already upgraded the OEM air assist to one putting out 4x the flow, as I was skeptical of the compressor claims myself. Yet the difference in cutting performance between that upgraded air-assist and using a compressor at 30psi was greater than 50% (calculated to be 63%, but that was performing the experiment just once, so...) The ONLY variable was air pressure in that experiment. And, yes, I saw differences in cutting performance up until around 30psi. As for moisture, a simple water/air separator (inexpensive from Amazon) is all that's needed on a compressor. Arguments have been made a drier is needed as well, but I don't believe that. Since the lens is not 100% transparent to the laser, the laser heats up the lens enough so that moisture will have a difficult time condensing on it. Without a water/air separator the danger is the temperature of the lens might still be under the dew point. With a separator, this is highly unlikely to occur, but to be clear - this is speculation on my part as I have run no experiments to prove it out. Just experience with many hours of laser/compressor time and no ill effects. What you need to do is run an experiment with a control and vary only the pressure. Pick a nozzle distance and keep it across all tests. The results, favoring the compressor, will be quite clear. Again, I doubted it, but needed to see for myself, in the face of all the compressor hype. The hype turned out to be true.
Hi
I have done a lot more testing off camera but I am always open to advice and the wisdom of other's experience.. I would be interested in a few more details about the actual cutting tests as I would like to emulate them as far as possible for others to see. If I have not given the subject a fair assessment, I have no problem expanding what I found with others experience which I will gladly credit jf you are happy to share.. The sort of details I would be interested in are, the type of machine you are using, (RF or glass tube), the power you use for the test. The type and thickness of plywood, the cutting speed range before and after raising pressure, The diameter of your nozzle orifice and the distance away from the work. Finally what type of lens and focal distance are you using.
ps I accidently touched the reply button before saying thanks for the comment. I am always grateful to people such as yourself sharing their experience. I do not regard it as criticism, it is another learning opportunity for me.
Best wishes
Russ
Do you think it’s more helpful to point At the cut or to point it sideways to simply blow the smoke away?
When you first start a cut there is no path out of the BOTTOM of the cut so the fumes have to escape upwards. You will always see a brown surface mark at the point because the fumes are blown DOWN onto the work. Once a through cut has been established you must blow the fumes out of the bottom for efficient cutting. Smoke within the cut absorbs some of the laser energy and reignites the fumes. This will cause charred cuts. You can cut with almost no air assist and with a large ( say 12mm plus) gap between nozzle and work. It will be slower and you may ignite any up-welling fumes with the incoming laser beam. With a big gap and a good cross flow of air across your work is exactly what you need for engraving where all the fumes have to escape upwards.
Best wishes
Russ
Where could I find the ball valve you’re using for your air assist? I’d like to keep my stock air assist but be able to reduce the flow out of my nozzle for leather engraving.
Hi Josh
Try this description on Ebay. BCU 6mm pipe
www.ebay.co.uk/itm/155402093584?_trkparms=amclksrc%3DITM%26aid%3D777008%26algo%3DPERSONAL.TOPIC%26ao%3D1%26asc%3D20221115143056%26meid%3D162d9298a0254d52b60c47f5ce063078%26pid%3D101612%26rk%3D1%26rkt%3D1%26itm%3D155402093584%26pmt%3D1%26noa%3D1%26pg%3D4375194%26algv%3DRecentlyViewedItemsV2%26brand%3DUnbranded&_trksid=p4375194.c101612.m4236&_trkparms=parentrq%3Ade79fa781890a8cd8943d226fffee5a2%7Cpageci%3A905abbe2-3754-11ee-8374-266f7fd681da%7Ciid%3A1%7Cvlpname%3Avlp_homepage
When I'm in focus my tip of my nozzle is 20mm away from the material, is there a different nozzle I can get that will get close to the material?
Hi Robert
The answer may be no but it depends on the head and lens tube arrangement you have. I think it best if you send me your email so yo can let me have some pictures of your machine.
RUclips will not transmit even lightly disguised email addresses but there are ways to fool their basic algorithms. Embed it in a sentence like cryptic crossword clue. Example. Selvey is preceded with a dot and robert. I use the g/m/a/i/l service.
We can decode this easily but computers?
The alternative for a more secure communication is to fill in the contact form on laseruser.com website
Best wishes
Russ
Where can we buy a flow valve as you used in your video "Air Assist", Thanks
I presume that you are speaking of the flow meter for measuring air flow.
if so see
www.amazon.co.uk/dp/B08G4K73C5/ref=sspa_dk_detail_5?psc=1&pd_rd_i=B08G4K73C5&pd_rd_w=gQMV3&content-id=amzn1.sym.84ea1bf1-65a8-4363-b8f5-f0df58cbb686&pf_rd_p=84ea1bf1-65a8-4363-b8f5-f0df58cbb686&pf_rd_r=TXYKNWR16AS3SRN9ZCTG&pd_rd_wg=B1Qod&pd_rd_r=10304024-3642-493c-b7c0-cbee25dc1387&s=diy&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWw
If you mean the ball valve that controls the flow then see BUC 6
www.ebay.co.uk/itm/295896867443?hash=item44e4d3e273:g:4AMAAOSw8s1k5WKy&amdata=enc%3AAQAIAAAA0G4S5PKeXlfgLtI%2B1CzSH4K27%2FRQIuyh8S%2FL39UYN5PY%2F93PFM4s5aAPpXBMIziVPGdH%2FCi6K9CbHSap81%2BBnmY66kUCG006XTCFazMqJ0AZ4%2BsLe8D%2BPJzxW2u1zFLac0pUTLNPF3Lr%2Fh9W2NN4vr%2FDS%2Ba3hxxIY%2BUDHNF2jlErx7YM%2FFsUCR9jgXIsoCMKcpK%2FoXI8CCqWNns%2BnLmmW3%2Fb%2FEuyByFFVrILuUxPeu%2BK%2BxwGY2Pjy8nOVTYA3Gxog%2BI7uKGHB5Bh82H9pOs93sQ%3D%7Ctkp%3ABk9SR7Klq_rGYg
Your excellent explanation has lead me to a bit of thunk. Could you design a dual nozzle system for the air assist? One nozzle blowing across the orifice for scanning and one through it for cutting. They could be switched using air assist on/off function via a dual outlet solenoid air valve. No signal to solenoid valve defaults to across orifice (Scan mode) Air assist signal changes output to through orifice. (Cut mode). Keeping the solenoid valve near the pump(s) and installing 2 pipes would save wear & tear on the stepper motors. A light weight 3D printed across air nozzle would do the same. You can have the patent in exchange for a free sample. :p
Hi Derek
When did you last check with the patent office? Remember this was quick instant thought and test to see if it worked after I had watched the way that smoke was still blowing down even with a light whisper of air assist. My thoughts at the time were planning for the possibility of swapping the tubes on my air assist valve and bringing two pipes to the head . However, in reality I don't believe I need two pipes because the existing arrangement will suffice. Cutting and engraving are usually done with two different nozzles. Thus if I do a better engineering job of integrating the fishtail air blast onto the engraving nozzle, when I use an engraving nozzle I will use the YES blowing function. When I swap to the longer CUTTING nozzle I will use YES for cutting layers and NO for engraving layers as I often do at present with low quantity mixed jobs. There are many times when I have nameplates, key fobs or coaster to engrave where the shape remains constant but the engraving is different. I always break these jobs up and cut all the blanks first and then make a jig for engraving.
Thanks for the nudge .......I must cancel that patent application and save myself at least £20,000
I genuinely appreciate your thunk. I enjoy it when thoughts coincide but equally I am not that proud about using someone else's good idea. I will never steal an idea , I always credit the innovator and honestly admit that i am jealous of not thinking of it first.
Best wishes
Russ
How about the Ultimate Air Assist, and how it relates to what you have learnt lately?
Just starting to watch, Russ, but as an engineer I like making predictions just to see if I got the right intention. So: Current understanding is that you blow away the gas phase in a manner that it can not condense on your piece to have a clean result. Especially with wood the condensed gas phase looks ugly and makes the surface sticky. Optimum for me would be a pre-heated high velocity airstream that slows down the condensing and blows it away, off the area of the piece you are creating. Now let see what happens...
Ok, Russ, georgeous pictures. Epered a pretty neat gas explosion with PMMA cutting it. The vortices are amazing. To the topics. Okay, the humidity thing is something you only think at when you do lots of pneumatic maybe. Interresting. With anything else I think I am not too far away from. Best solution for me momentary for engraving is SUCKING away the gas phase and keep a good room temperature. The material you go to engrave is also better in result, when the piece is also RT what was sometimes not the case when tooking it out of the outside shelf... my experineces.
Conclusion: the mission is to prevent gas phase to condense on your piece. That means to me not blowing it downward, not working with cold materials and shift condensing to an area outside the piece. So maybe blow in pre-heated air passing the whole piece and not thru the nozzle assisted with a good sucking fan on the back of the machine.
Have you ever experimented with an air assist nozzle that produces laminar air flow? I imagine It would improve the cuts in the same way that a water jet cutter is able to cut using laminar flow
Hi
The physics of flow dynamics in liquids is TOTALLY different to that of gasses. Those amazing illuminated dancing fountains in LasVegas all work because of laminar flow in a liquid. To achieve this flow is no simple matter . Take a look at this DIY version to get an idea of what's involved. ruclips.net/video/o5L6W0YoAd4/видео.html
Liquid is incompressable and is the reason this works. Without getting deep into science, it is possible to have gas laminar flow INSIDE a tube. However, flow implies pressure difference to drive the flow and thus as soon as the gas exits the tube the gas will expand and the flow will become turbulent. Large volumes and low flow are the key ingredients for laminar flow in air (Google laminar flow work cabinetes). Any air coming from a nozzle implies a jet flow although for real jet flow you require supersonic velocities. Take a look at the images on page 7 of this pdf to see what happens when expanding gas exits a nozzle arxiv.org/ftp/arxiv/papers/2202/2202.04122.pdf. If the pressure is low the expansion takes place much closer to the nozzle.
I have seen the so-called laminar flow air assist nozzles that are based on the liquid laminar flow principles. Hmmmm....I hope the explanation above shows how improbable such a claim is.
The most efficient way to get air into the kerf is low pressure , a small orifice and keeping that air flow orifice as close to the work as possible. Its still less than 10% efficient because the kerf is only 0.2mm wide (at most) and the nozzle orifice will be 2 to 2.5mm typically. If the orifice was smaller the efficiency will increase but the tolerance for beam setting becomes impossibly demanding.
Best wishes
Russ
What about making a laminar air flow nozzle?
Hi Robert
I assume you are referring to a 3D printed "laminar flow" nozzle.. The principle was based on the design of the sort of laminar flow generators used in the dancing fountains at Caesars Palace in Las Vegas. That design is specifically for incompressible fluid. Sadly air is compressible and the principles are unusable.. I'm not going to explain the physics of gas laminar flow I will leave you to Google that and then decide if you could design the nozzle you imagine. If you watched the whole video then you will have seen my demonstration of viewing the nozzle airflow. into a puddle of water. I showed what "nearly" laminar flow looked like and then how ineffective it was for cutting.
I genuinely appreciate your comment/question because you are the not first to ask about a laminar flow nozzle. So many thanks
Best wishes
Russ
Dear Sir. I'm Tuan_ from Vietnam. Thanks for your videos. Thank you so much!!! In Vietnam have many many people need your help to operate their laser machines. But they don't know English. So can I translate your videos to Vietnamese and edit them ? Of course I will paste the video links in the edit videos. If you agree my idea I will try ... Thank you so much ❤️. Sorry about my English.
Mr. Tuan.
Dear Mr Tuan
Please remeberthat my video series is a diary of me learning about the non-metal cutting technology. In my early videos I was searching to find answers but 7 years ago there was little help on the internet so I had to take baby steps and make discoveries for myself and often made mistakes. I eventually corrected them as I learnt more but I have left all my videos live because it is a path for others to follow ......but not the quickest and most efficient path.
I always promised to condense all my knowledge and experience into series of videos that were not exploratory but explanatory.. I am currently working my way logically through that series and I have granted sole publishing rights to a good friend of mine. I mention this because he has put together a very good website that auto translates my speech into one of 19 languages. I know that Vietnamese is not there at present but if you visit his website it is much better organized and because the videos are more concise (about 30 minutes each) it may save you a lot of work. Here is the contact page if you wish to contact him to see if Vietnamese is one of the language options he can offer. I am sure he will welcome a discussion with you.
laseruser.com/contact/?doing_wp_cron=1639180910.3443839550018310546875
Back to your original proposal. If you find that laseruser.com is not what you want then I have no problem with you carrying out the immense task of translating and editing y videos. I just want to share my knowledge because there is so much misinformation and bad advice available for this technology. I only try to work with logic and facts and try to demonstrate in detail how I arrive at conclusions.
Best wishes
Russ
On RUclips you can activate the subtitles and translate them in any language.
@@russsadler3471 Hi Mr Tuan
I have just checked Gonzalo's suggestion and YES, youtube has now added an auto translate to ANY language including Vietnamese.
See ruclips.net/video/LZz03myFuWA/видео.html
Best wishes
Russ
Maravillosa introducción a la teoría del color y como lo percibimos Ya leí en su día a GOETHE precursor de esta teoría, investigación que hizo sobre la naturaleza de las sombras del color, Goethe explica que los colores son parte de nuestra visión y por lo tanto
una percepción sensorial.
Lógicamente fabulosa masterclass y documentación gráfica acerca del caudal alto y bajo del aire y como repercute en grabado y corte....... Me encanta como funciona la bomba china...seguiré utilizándola. Gracias por ser tan intenso.
Wonderful introduction to the theory of color and how we perceive it I already read GOETHE, the forerunner of this theory, research he did on the nature of color shadows, Goethe explains that colors are part of our vision and therefore
a sensory perception.
Logically fabulous masterclass and graphic documentation about the high and low flow of the air and how it affects engraving and cutting ....... I love how the Chinese pump works ... I will continue using it. Thanks for being so intense. Felices fiestas
by all means a great video and great information however if i can comment on anything I must say I feel like the information may have been just as effective from a less than 15 minute video. otherwise good job