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CNC / Laser Newb assistance needed

#1
Hi Everyone,

I've been out of the hobby for 10+ years and got back in this last February. I found the FliteTest site and have been very pleased with what you can do with DTFB. I've built several FT kits as well as a couple of scratch builds from plans.

Over the last month or so I've been reading on CNC and laser cutting machines to see if that's something that I could get into. I don't enjoy the current method of printing plans, transferring them to poster board, and cutting parts. I'd much rather have it done by a machine.

I'm struggling with going down the CNC or laser cutting route. I'm a little concerned with using a laser because of the possible safety issues including the beam as well as fumes generated. I do understand that these can be mitigated with a good pair of goggles, an enclosure / ventilation system.

So if I were to build a CNC, is it possible to cut foam with a precision router bit? Or do you need to use a needle type design (I've seen this posted in an post on this forum). Would the same CNC be useful for cutting balsa / hardwood also? Or would it be better to just go with a laser and just address the safety issues appropriately?

Thank you!
 
#2
Hellcat, welcome back to the hobby..just got here a few months ago myself.

I can’t answer your question on cnc... on laser i can add a wee bit.. (owning two) first which ever way you go..you MUST deal with the safety issues.. (for example...this example has nothing to do with foam board... but with lasers, typically a c02 laser...introducing a substance with chlorine in it is very bad...think ww1 chlorine gas).. so you will need adequate venting with a fan...& preferably a filter system. With lasers a lot of folks go cheap to fit there budget...but in may cases it doesn't work or you will be fiddling for some time.. I am not adverse to folks tinkering but have seen far too many who go cheap & can’t modify what they need. If you can’t afford to go that route consider doing your own file & taking it to someone to laser for you.

Another consideration is with this trade war heating up..many laser parts & pieces come out of china...and the cost may have just gone up...don’t know what is on the lists but worth considering. Hope that helps somewhat.
 

Fidget

Active member
#3
@hellcat287, I haven't built one yet, but the Rascal CNC is designed to cut foam board and some wood with a small router bit as you describe. I have about half the parts and plan to finish it this year. The guys that are organizing it slowed down when it came to making the build videos and making the wood parts available, but 3/4 or more of the work is there. My understanding is that it is designed to be large enough to cut a whole sheet of foam board but still be inexpensive, with the tradeoffs being that it's DIY and not rigid enough to cut carbon fiber or thicker wood. Someone on either this forum or Facebook was going to mount a laser to it, but it's not specifically designed for that.

If you wanted to buy one, you could presumably use a small bit like they do and get going faster.

When I've looked at laser cutters, I've had the same concerns you do. Imagining drilling a hole in the side of my garage for fume extraction has steered me away from that.
 

TEAJR66

Flite is good
Mentor
#4
You could use the rascal or the mpcnc for all your cutting needs. Needle cutter, spindle and bit, laser, or even a plasma cutter (saw a YouTube video of an MPCNC using a plasma cutter). The precision comes from how finely you build and tune the machine.
 
#5
Hellcat,
I am cutting foam board with a diode laser cutter. see my post here: Laser Cutting
"IF" you can afford it, get a Co2 laser cutter. That is what Flitetest uses and it will cut foam board and wood all day long. But a Co2 laser that can handle a full sheet of foam board can be very expensive.
A diode laser will NOT 100% cut white core foam board. Best I can do is about 1.5mm deep. good enough to mark the foam board and finish cut it with a knife. Black core I can cut 100% or any depth needed, but the paper they use on it is crap.
I can 100% cut my own motor mounts and control horns. ( takes about 6 passes I do not have air assist or a moveable Z axis yet)
Best thing I like about it, once I have the plans converted, I can laser out a sheet in about 10 minutes. Mess up a part, just grab a piece of scrap and remake that one part.
I no longer have to print the plans, glue/tape the plans in place, cut up the plans in the process of cutting out the foamboard.

Goodluck with your venture
Bob
 

Kananga

Active member
#6
Do a search, there's a lot of threads already on cutting parts out.
Laser cutting will give you problems on white foam.

Do a search for cutting with a needle, there's a lot of work going in on those threads and may be a better place to start.

Personally I've just cut out the parts for a mini arrow, it took around 2 minutes to print and tape the pages together and around 15 minutes to cut the foam parts out. For me it's simply not worth the bother doing it any other way.
On bigger models it will take longer.

I've a little tip/cheat for drawing plans on foam board that im going to make a thread about over the next day or so ;)