Small Laser or Plasma Recommendations, Please!

We recently got a non-trivial grant for upgrading our manufacturing capabilities–for some years now we’ve made our robots with the VexPro Versachassis/Versahub product line and gussets galore, and because CnC companies locally are basically nonexistent, we are looking to be able to do something more with sheet metal and aluminum in-house.

We have a small Tormach CnC mill (16"x8"x8" travel distances nominal) for aluminum and a 4’x8’ ShopBot router which is great for plywood or polycarbonate, but the ShopBot is in the wood shop and so cannot be outfitted with plasma or a laser for safety reasons [even if we come up with a plan to make it safe, I’ve already been assured that the Fire Marshall’s answer is “no”, so this point is a non-starter.]

We do not have the space for another 4’x8’ machine, but can accommodate maybe a 4’x2’ (and definitely a 2’x2’), so we’re looking for a laser or plasma machine in that size range. Ideally, we’d be looking for a laser or plasma that can handle up to 1/4" aluminum, but I know that’s a big ask for a small machine – 1/8th would still be amazing compared to the nothing we currently have.

I figured that CD has a gazillion years of collective experience with such beasts and would be full of excellent advice on the matter. So here I am.

Thanks!

If your goal is more throughput of aluminum parts, would you consider 2 Omio CNC routers? In an ideal world you’d get 1 laser for fast wooden prototypes, and the router for aluminum. Iirc @AllenGregoryIV had some laser recommendations for various budgets, though I can’t think of any that could handle aluminum.

I’m surprised though, can the shopbot not handle aluminum? I thought they were decent for that application.

177 and my former team 11 both use CNC plasma cutters, however this does need post operations for hole patterns and bearing bores. In my opinion it isn’t the ideal solution but we definitely make it work. @Peter_Matteson can chime in on that. However it isn’t my recommendation to get a plasma cutter in your situation.

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Our school lab has a small laser that is great for MDF. It is great for iterating prototypes. MDF is a lot cheaper that Al or Poly. We are still incorporating out Omio into our work flow, but I like it. regular 3D printers are great for brackets/spacers. My Boomer mind is still blown when I say we could use a small spacer or bracket and a short time later, a printed one appears. Having a printer that can print high end materials would be nice. The ongoing material cost are high though. Personally I would go with an router over a plasma cutter. The router has a higher precision.

Since you cut wood wire a laser, it would make sense you can make it safe for an otherwise safe wood shop environment. If you are not managing your dust/cuttings well your wood shop is not safe. :slight_smile: But you are wise to avoid conflict with your Fire Marshal. Even when you are right he is the Fire Marshal.

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What is a “non-trivial” grant? $10k? $100k? If $10k, plasma or router is probably where you are at. If $100k, you absolutely should consider a laser. If somewhere in between is where you are, maybe a router with a nice spindle and maybe tool changing.

You are going to be north of $70k for a metal cutting laser that can do $1/8 aluminum. But, if you do have that kind of budget, let’s talk. I have suggestions.

If a plasma is more aligned with your budget, there’s several choices and you’ll get similar results out of most of them. For the money and for something small-ish, it’s really tough to beat the Langmuir Crossfire Pro.

On 696 we had a 4x4 PlasmaCAM. It worked fine, and was super fast, but the software is kind of weird, the lack of a water table is a bigger deal than I realized when we bought it (the smoke you get without one is horrendous), and the pricetag was a bit over $15k all fully loaded. I think they do make a small one though.

On a plasma, we often had trouble with 6061-T6 warping on us due to the heat. We had much better results with 5052-H32 alloy.

Keep in mind, you will need a compressor that can keep up with it. This would typically be like 3.7 HP (minimum) or 5 HP and 60 gallon tank. Such a compressor gets pretty loud if it’s inside. A screw compressor like the little Eastwood one would probably still keep up ok, and would be much quieter. A compressor will add $500-$3000 to the cost depending on what you get. Ideally, you want an air dryer too. That will add another $800-$1200ish.

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We have access to a CNC plasma cutter, multiple routers, and a smaller laser.

I’ll only discuss the CNC plasma cutter because I think a vast majority of teams do not have one. They have their place, and can be incredibly productive if used properly. If your construction style is a lot of lightened 1/4in material they will be wonderful, you can blast out the rough-cut on a plasma cutter and then hand-ream or do final cutting on a CNC router or mill. We used to do this frequently, and even a 45A plasma torch can slice 1/4in aluminum absurdly fast. It took just minutes to make these lightened 1/4in plate arms.

Here we used it to blank out 3/8in aluminum parts that were later milled to final shape.

The Northern Plasma table we used to have in the shop was not great. Poor customer support and it broke often. The current JD^2 table is mechanically better, but the software is so different/clunky that I can’t keep up with using it. Our workflow has moved on to rely more heavily on our sheet-metal sponsor.

My shop’s router is made by Torchmate, who also makes some nice-looking plasma tables tailored for educational use. I like the controls and programming for my Torchmate stuff, so I would recommend looking at them: Torchmate CNC Educational Packages - Built For Teachers and Schools | Torchmate

You will NEED exceptionally good ventilation and smoke management systems to safely implement a plasma table. Not a deal breaker, just be aware. A nice side-benefit is that the plasma table can be a great place to spray-paint parts when the smoke extraction is turned on.

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We were discussing upgrading our CNC capabilities. I am not much help to you on plasma models but I was curious where your grant came from?

Private individual thinks we’re the bomb-diggity.

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Call it $40K

What laser are you using for MDF?

Epilog Zing. I believe. It is well under your budget. I have not used it myself, but the students do lightly supervised

We have a Thunder Laser Nova 51 with 130W laser. Love it! We mostly use it to cut acrylic prototypes. The large bed is super nice. Of course it won’t cut aluminum.

I am drooling over a FabLight FL4500. They are supposed to be able to cut up to 3/16" aluminum. I like the size of the machine. They are about $100k-$125k depending on the options. Its on my wish list if we ever got that level of magical grant funding and I could find a suitable location to set it up.

I have found that 2’x4’ material stock works well for us whether it is acrylic, polycarb, or aluminum. 2’x4’ seems to be the sweet spot on between bulk material cost vs. shipping costs for us. I can, of course, buy more sq. inches cheaper by buying larger sheets but the shipping gets expensive and I still have to cut it down to fit in the machines we have. So 2’x4’ seems to get us the most sq. inches delivered for the least cost and easiest to store and handle. We also have a Velox VR-5050 which is fantastic. We cut polycarb and aluminum on it. We also bought a OMIO just before the pandemic hit and we simply haven’t had the time to get it fully up and running so no parts were cut in it this year. It’s on the off season to do list. A CNC plasma cutter would be nice but we simply have no good safe place for it or any welding “hot work”.

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We have a welding station in the technology classroom, and the tech teacher’s enthusiasm for adding a plasma cutter to that room might sway us in one direction rather than another, but we’re still in the investigation stage.

I assume you can’t cut polycarb with the laser, right? (I’ve heard that’s a big no-no, but this isn’t an area where I have anything even remotely approaching expertise.)

Biggest thing I’ll say here, is if you do cut polycarb on a laser, make sure it’s extremely well ventilated. Don’t want to be breathing any of that stuff in. I’ve also heard the gases let off can deteriorate your machine faster, tho I have no experience with that myself.

I’m sure many others will be on here shortly to jump on warning you about the hazards of laser cutting polycarb.

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Chuck,
thanks for your input. We are looking for a laser in the price range you mentioned, looking to order later this year.

-Glenn

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We do not/have not cut polycarb on our Nova51. I have heard all sorts of reasons why not to for cut quality to toxic off gasses to damaging the machine components. I’m sure some people do it just fine. We just aren’t one one of them. If we cut polycarb we use the Velox (and hopefully the OMIO soon). I know Spectrum has a Thunder Laser as well. IIRC it’s also a 130W Nova51. @AllenGregoryIV might could comment further on their experiences with cutting polycarb on theirs if they have.

Our “work flow” is typically CAD something flat and cut it on the Nova51 out of mostly 1/8" acrylic but sometimes 1/4". Check for fit and functionality. Iterate. Once we are happy with it the cut final parts out of polycarb or aluminum on the Velox. The only thing we typically change is the diameter of bearing holes. The laser tends to slightly oversize bearing holes due to the diameter of the laser so we CAD those a few thousands under what we cut on the CNC due to the slight differences between laser diameter vs. CNC spindle runout. No big deal to change a few bearing hole diameters depending on what machine is running the part. There is probably a better way to deal with this minor issue but it works for us.

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With a Thunder Laser, I’m guessing you guys use Lightburn to program your parts/laser. There is a function in Lightburn called “Kerf offset”. It should allow you to compensate for the width (or “kerf”) of the laser beam.

While I definitely wouldn’t bother messing with your workflow in the middle of the season, it could be something to play around with in the offseason.

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Thanks! Yes, we use LightBurn. I’ll look for that setting. I’ve never even thought about looking for a setting in LightBurn.

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As a follow up to this thread about cutting “impact modified acrylic”, it cuts fine but man does it stink! Even with good fume extraction. It left the edges a little sticky but that sort of rubbed off easily enough. We tested a few parts and while the “impact modified acrylic” was far more impact resistant than regular acrylic it wasn’t up to polycarb for sure so we just stuck to polycarb off the Velox for competition bot parts.

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@waialua359 @ChuckDickerson The FabLight FL4500 is definitely a nice machine, and I would recommend it. If I were to start an FRC team from the ground up and I could buy only one machine, this would be it. 696 has one. We were the first high school in the country with one. We gave it quite a workout in 2020, and I understand they’re still using it quite a bit. Once you work with a fiber laser, you’ll never want to plasma or router aluminum again. The great thing is, maintenance is really minimal, and there’s no consumables really. And, it’s fast and easy to use. There’s not a whole lot to mess up or go wrong on it. You can go from CAD model to a simple bracket in your hands in less than 5 minutes. Cut speed is slower than a plasma (FabLight does about 30IPM in 1/8 aluminum) but the accuracy and quality is way better.

The tube capability on the FabLight is not perfect, but I have used it extensively. It does work for the most part, but you should expect your tolerances to be +/- .005 not +/-.001 like you’d get on sheet. I would definitely recommend the 4500 machine, but if you were on a budget, you might consider going without the tube capability, or possibly putting that money into a press brake instead.

I never got around to trying 3/16 material on the FL4500. Realistically, you should consider 1/8 to be the practical maximum on that machine. But, that’s plenty for most FRC applications. You might just have to change up your design style a bit, and chances are your robot will be lighter for it.

The air for a fiber laser is kind of critical. You need lots of it, and it needs to be very dry and very clean. You need to get kind of particular with the compressor. You want one that is 5HP or more and goes up to 175psi or more. There aren’t many choices with that pressure in that size range. Most cap out at 165psi. The issue is most of them have a 40psi differential on their pressure switch so they don’t kick on until they get down to 135psi, which is pretty marginal for the FL4500 on thicker materials, especially stainless. I can give you the particular model number of compressor if you need one. And then we ran dedicated lines, filters, and dryer. I can also give you these part numbers if needed. Instead of air, you can run it on an N2 bottle which works very well, but it will eat a whole bottle in about 20 minutes of run time. Anyway, let me know if I can answer any more questions on the FabLight. It is a great machine that’s kind of in a class of its own.

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Thank you so much! We are building a new building at work and one of the items on my wish list is a FabLight FL4500. So maybe in the next year or so I will be in the market. I would love any additional recommendations you have on the air setup and part numbers.

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