Laser Cutter And FRC
 

I recently got a membership to TechShop in the Bay Area, a hackerspace that has a fairly extensive shop. One of the many machines they offer for members to use is the Epilog Laser Engraver. I was wondering what experiences people have had with this machine in specific, and with laser engravers in general for FRC use. Were there any cool or innovative uses you found for this tool? What kind of parts did you use it to make, and how did they perform?

The first specific use that came to my mind was using this machine to make plastic gearbox plates, out of either polycarb or ABS. Has anyone tried this? What kind of tolerances can this type of machine hold? Is this a good/bad idea?

If I do end up trying to make plates like this, I'll be sure to share the results with the community.

Re: Laser Cutter And FRC
 

I've used their laser cutters for a few things, I wouldn't suggest using them for transmission plates. I haven't tried any decent tolerance parts on it, but from visual inspection of other 1/4" things I've done, taper is gonna be a issue. Also the kerf does not always appear to be constant, as at the speeds slow enough to cut 1/4" delrin, heat will build up in non consistent ways. Overall I think your going to have pretty big issues cutting transmission plates with reasonable tolerances. I'd suggest just using their router instead, as that should give you no issues holding tolerances. Good Luck

EDIT: Also you can't cut polycarbonate on those laser cutters, as they do not have adequate filtration to handle the toxic gases they create.

Re: Laser Cutter And FRC
 

Pretty sure they won't let you cut polycarb due to fumes.

Re: Laser Cutter And FRC
 

Generally the laser cutters can be pretty accurate (about .005, depending on machine/settings) but that's only the center point on the laser. Other issues mentioned above will prevent any highly delicate work to be done.

My general decision on laser cutting VS Milling/watterjet:
Does it need to be done fast?
Is Acrylic/Delrin/Wood okay?
Are the tolerances okay?

Typically, a gearbox plate has a no in all three of those questions!

That being said, I'm uploading pictures now of entire robots I've made on a laser cutter for WPILib as well as classes.

Re: Laser Cutter And FRC
 

We used the TechShop lasers to make timing belt pulleys for our drivetrain this year. We use 9mm GT2 and our pulleys are made out of layers of 1/8" acrylic that are then attached to each other with acrylic cement. These pulleys are very cheap and they allow us to avoid having to wait for timing belt pulleys. One of the biggest benefits to making our pulleys this way is that we can use the laser to cut the hex which we have no other way of doing. The pulleys have not had any issues throughout the entire season. Its is also really easy to bring spares in case something happens as they are both cheap and light. We also used the laser to make the timing belt pulleys for our pick up. This was interesting because one of the pulleys was mounted on a piece of abs tube. The pulleys we cut for that were very flimsy as the bore size was not that much smaller than the outer diameter. After attaching them to the abs with the same acrylic cement, we have not had any issues with them breaking. We have access to a router at the school, but things that require a hex or other special patterns, we use the laser as long as the part will not be taking too much load.

-Mihir Iyer

Re: Laser Cutter And FRC
 

We have a Versalaser that is handy for all sorts of things. It sees very little use for the FRC robot itself, but we use it for small mini-sumo robots for class projects and for engraving giveaways. We have done 1/4" ABS on it but it did not turn out great. Right now I have a problem where the laser is weak and struggling to cut 1/8" acrylic. Need to check it out and get it fixed.

Re: Laser Cutter And FRC
 

I have seen a lot of teams using them for hex spacers and such. This year we used the engraver to cut wheel treads because it was much easier than doing them by hand or on the band-saw. Also when you buy the big rolls and need to make the notched shape for the new performance wheels it makes it much easier and cheaper.

Re: Laser Cutter And FRC
 

We've used a laser cutter from my college for many things over the past few years.

• Delrin Spacers
• Belt sprocket flanges
• Wood and acrylic prototypes
• Frisbee shooter skid plates
• Sensor mounts
• Other sheet delrin and ABS parts

Don't expect to use it for major structural components, or to do the kind of work a sheet metal shop would, but it's great for a lot of little things. Good tool to have in your back pocket.

They make cool small robots as well.

Re: Laser Cutter And FRC
 

Hex patterns can easily be milled/routered. You just need to open up the corners.

Re: Laser Cutter And FRC
 

Laser? Talk to FRC 1899 Saints Robotics. They know laser.

Jason

Re: Laser Cutter And FRC
 

Lens might be dirty. At least with the epilog, the lens needs to be cleaned every so often.

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We love our laser cutter. We use it for tons of stuff, mainly with ABS. Our team considered ABS gearbox plates, although we did not actually do it because we were using supershifters for the first time and did not want to take the risk. We still believe that it would work out, though.

We did use ABS for other things on our robot this year. All of our sprockets were made using it, and worked really well. Plus they were lightweight.

We had linear actuators consisting of a double pulley moving up and down aluminum c-channel. The entire pulley module was made out of ABS, and although we had problems with them, the problems did not stem from our choice to use ABS.

We then created an ABS template which we used to lay it on top of all the layers of our wood and polycarb arm and drilled in all of the holes. Without the template, it would have been nearly impossible to manually sketch out the dimensions of each and every hole.

Our frisbees traveled down a curved path on our arm. We used stacks of .25in ABS as rails to guide the frisbees. There is absolutely no other way in our capabilities that we could have machined such a thing.

Our wrist was 75% ABS. Besides increased machining capabilities, this also allowed us to have a lightweight wrist.

Finally, we lasercut our "daisy" floor pickups using rubber. What the rubber basically did was whack the frisbee into the arm.

In sum, we basically used the laser cutter and ABS for 2 main reasons: to give our low resource team machining capabilities comparable to high resource teams and to create lightweight components. Next year, we have even bigger plans for this amazing machine.

Re: Laser Cutter And FRC
 

Cutting polycarb on a laser is messy (toxic fumes) and with many thicknesses doesn't always leave a clean cut. It can be... melty. I wouldn't really consider it.

I would not make any competition robotics parts out of acrylic, which is the material most plastic laser cutters are used to cut. There is nothing good that can come out of acrylic on an FRC robot.

I don't know a lot about ABS / delrin laser cutting, but it's much more doable than polycarbonate.

I don't think lasering a gearbox plate on this machine is going to be the best idea. If you're at a good hackerspace, they have higher precision equipment (e.g. a decent router / mill) for this purpose.

Re: Laser Cutter And FRC
 

Besides making things for your robots there is a lot you can do for spirit and for sponsors. Our team personally does not have a laser but some of our friend teams do. This year they made us key chains with our name and number as well as little name tags for all our kids. They also made us plaques to give out to our sponsors. Each plaque was engraved with the sponsor, their level (depending on how much they donated), a little sentence about thank you and our logo. The sponsors loved them! They really like having something that they can hang up in their office and show off to everyone that comes in.

Re: Laser Cutter And FRC
 

Damp,

If you wanted to make a nice compact 3 CIM ABS/Delrin gearbox housing with a PTO port. Think about repackaging the VexPro Ball shifter design.

I would be willing to lend you a hand and get you some Engineering and CNC machining time. I wanted to make a video for our team to show how a Solidworks design is imported to Gibbs Cam and how the geometry is used to create the tool paths and G code and how the part would be made on the CNC mill.

Re: Laser Cutter And FRC
 

We've cut our electronics board with the exact same machine as you now have access to (epilog laser engraver) for two years now. We used 1/4" ABS both times, and learned some lessons between the two. The first year (last year), we had lots of issues with fire/smoke and the lens of the laser. Burnt ABS has just a lovely smell! The lens would get clouded, we'd have to replace it, etc. I was in the shop til Midnight and my mentor was there longer finishing it (I got called out by my parents).

The key with 1/4" ABS is to make multiple passes (like 4, maybe 5 just to be safe) at a lower power to minimize the burning and the lens issues. I could get the exact settings we used for you if you ever want to use this thickness of ABS. The electrical team is in love with the stuff, because modification is easy, and laser cutting it makes assembly really smooth and we can just plan and execute the whole thing from CAD. I now have a(n unhealthy) love of lasers. Hopefully I can save you some trouble if you're ever using this material.

I know my team's cut 1/4" acrylic on one of these (or similar), but that was before my time.