LaserUser.com Forum (formerly RDWorksLab)

Gene Uselman wrote: Wed Aug 14, 2019 What Russ added was to shut his air pump off when it was 'deadheaded' as he was concerned about it running with no air flow. I use a sho air compressor with a tank so have never worried about it. My daughter's laser has been going for 2-3 years without that mod with no problems. Russ sometimes over thinks things I believe. That schematic looks like the one with Cloudray's UAA kit that was set up with Russ' help I think.

I would like to use my garage air compressor as well, but I haven't succumbed to running a line either through the attic or running through my house to get to my office. A portable tank could also work but not as convenient.

Based on his results, it seems like the reduced flow really helps keep the smoke off the work when engraving. This mod lets you use the RDWorks software to control the air assist intensity by using the on/off function in the settings. How have you handled the smoke or residue that forms on the surface during engraving? Tape, water & scrub, etc?

I agree, mods aren't necessary to make this a running machine. I've been very successful with it already just by leveling the bed and making a pin table. I'm just looking for ways to increase productivity/repeatability/reliability of the machine as I try to grow my (small) business.

Have I convinced you yet?... Me neither. I really just like to take things apart and feed my inner curiosity, I guess. I think Russ has a simple goal of trying to understand CO2 lasers, how they work, what makes them work better/worse and I find him pretty entertaining. I can see how some people think he tinkers too much but it has really helped me understand what's under the hood of my blue & white.

Bryan Boyd wrote: Wed Aug 14, 2019
Once you're convinced the laser is square, use the laser itself to cut the zero corner. Mount the material to the bed and fasten it down. Then have the laser cut off the excess. This results in a corner that is exactly aligned to the laser.

I did the "machine square" corner on my cnc router where it was easy to cut the material away and into the wasteboard. For the laser.. do you just lase down to the aluminum/steel bed? I guess it shouldn't matter if it's just a small amount of material so maybe I'm over thinking it.

[/quote]

Short answer - Yes.
Many people cut stuff w/ their lasers without the benefit of a pin bed or honeycomb table.

The air assist is most useful for cutting [blowing the burnt or evaporated material thru the material], for engraving that material has to come out the top so you normally want only a very small amount of air flow to keep the debris away from the lens. What you really want is good airflow over the top of whatever you are engraving to move it away, also engraving from the bottom to top helps to clear the debris. I always mask my material.

Jeffrey Aley wrote: Wed Aug 14, 2019 Short answer - Yes.
Many people cut stuff w/ their lasers without the benefit of a pin bed or honeycomb table.

I guess the only lasers I have seen have either a honeycomb, knife table, or pin bed so I never thought anybody cut directly on their metal bed. Seems like there is a big risk of getting power reflected back into the lens or the backside of your material charring more. Again, maybe I'm over thinking it.

Gene Uselman wrote: Wed Aug 14, 2019 The air assist is most useful for cutting [blowing the burnt or evaporated material thru the material], for engraving that material has to come out the top so you normally want only a very small amount of air flow to keep the debris away from the lens. What you really want is good airflow over the top of whatever you are engraving to move it away, also engraving from the bottom to top helps to clear the debris. I always mask my material.

Thanks for explaining! I guess masking can be part of the process. I have only been annoyed when I'm cutting really fine details and have a lot of small pieces of tape. I might try a wet dish towel soon and give it a good rubbing.

I have been leaving a 1/2" gap under the lid while cutting. I also have a 4" booster fan that I had laying around hooked up in line with my exhaust out the window. I 3d printed a 6" to 4" adapter to link the 6" blue hose to the fan. I just recently reinstalled the factory fan to increase the air flow and we will see how that works out. I also ordered a 3 pin DIN connector to hopefully wire my CW3000 into the water protection circuit. I hope I always do my mental checks before hitting Start but I don't trust myself that much.

Bryan Boyd wrote: Wed Aug 14, 2019

Jeffrey Aley wrote: Wed Aug 14, 2019 Short answer - Yes.
Many people cut stuff w/ their lasers without the benefit of a pin bed or honeycomb table.

I guess the only lasers I have seen have either a honeycomb, knife table, or pin bed so I never thought anybody cut directly on their metal bed. Seems like there is a big risk of getting power reflected back into the lens or the backside of your material charring more. Again, maybe I'm over thinking it.



Thanks for explaining! I guess masking can be part of the process. I have only been annoyed when I'm cutting really fine details and have a lot of small pieces of tape. I might try a wet dish towel soon and give it a good rubbing.

Re: Reflections from the bed - it depends on what the bed is made from. A copper bed would be a Bad Thing because copper does a good job of reflecting IR radiation. Steel absorbs it, and so does stainless steel.

Re: Masking - I forget what you're cutting, but if it's compatible, you might try using liquid dish soap for masking. Search the forum for details. The advantage is that you just rinse it off after you're done engraving.

Jeffrey Aley wrote: Thu Aug 15, 2019
Re: Reflections from the bed - it depends on what the bed is made from. A copper bed would be a Bad Thing because copper does a good job of reflecting IR radiation. Steel absorbs it, and so does stainless steel.

Re: Masking - I forget what you're cutting, but if it's compatible, you might try using liquid dish soap for masking. Search the forum for details. The advantage is that you just rinse it off after you're done engraving.

I have put a steel plate down on mine after seeing Russ explain the same things. I guess even something as simple as lifting the material with magnets or another type of shim on a steel plate would be alright.

I'm mainly engraving logos & small designs on hardwoods to be inlaid with resin, but also planning to make some jewelry and other wood items. The liquid dish soap is interesting and may be worth a try. The only concern would be if it somehow repels the oil finish at the end. Maybe a heavily diluted solution would help. Thanks for the idea.

The dish soap method is for use on no porous/absorbent materials where there is no chance of the soapy liquid getting absorbed. For example, you would not use it on raw wood.

Doug Fisher wrote: Thu Aug 15, 2019 The dish soap method is for use on no porous/absorbent materials where there is no chance of the soapy liquid getting absorbed. For example, you would not use it on raw wood.

I've been testing using sanding sealer, wood wax, then masking tape for laser & resin protection and it has worked pretty well. I still want to turn down my air assist when doing engraving so I ordered a manual valve to at least I can manually control the flow for now.

I also wired in my CW-3000 with the water protection by using a relay & DIN connector so it prevents any forgetful late nights or if the radiator shuts off. It was pretty easy to check the voltages and map out the circuit once I got in there. I didn't realize 24V would be coming from the laser and the CW-3000 but it made sense after a couple hours of scratching my head and reading online.

This week I'll probably try to install the ammeter. I bought some 18 gauge wire with thick insulation to splice into the laser path. My girlfriend and I have really been enjoying the machine so far. She's made quite a few earring designs already and likes running the laser. It's so much more convenient and easy to run vs the router but each have their place.

I installed the ammeter last night in the front of the machine and it turned out great! I ended up just undoing the zip tie downs that held down the negative laser wire and it easily stretched to the front without having to splice in extra wire. I'm getting pretty comfortable working on the machine now and its becoming clear how it's wired up. Seems like 70% gets me to 20A with the stock 40W tube so ill probably use 65% when cutting.
I also added a manual valve to the air assist line and I've noticed a big difference when engraving by turning down the air flow. There is very little smoke staining.
I really wish my machine had a powered Z table so I feel like I will have to either make my own or look for existing products (LightObject). For now, I'm designing and 3d printing a new knob to replace this slippery, barely knurled black cylinder.