# Would others be interested in a CNC machine for $2k-$4k? laser/plasma cutter options

Discussion in 'Hangar Flying' started by CobraCar11, Mar 2, 2016.

1. Mar 2, 2016

### CobraCar11

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I am designing and building a CNC unit that can process 4'x8' sheets of plywood and other materials. The height (z axis) limit would be 2' to 4' max (still deciding). It would be able to use plasma cutter, laser options as well if someone wants to add it on.

I am doing this because there is some stuff that I want to design, build, and test, and also build my own airplane. Sending out ideas for prototypes is looking expensive, and I can modify and create things in real time.

Some of my friends are seeing the price I am getting this down to , and are getting pretty excited. They want one too. I have benefited from so much help and support here, I thought I would give back.

I am not trying to make a company our full time job with this. I was thinking that if so many other people could use something like this for their projects and ideas, maybe it could help other people as well.

Would other people be interested in owning one? It was suggested to me that this could make building an aircraft more affordable to others.

It would be a kit - one would have to assemble it. Software would be open source. I think I am going to make it that you need to connect a home computer to it to run it.

Let me know if others are interested. I am not going to make this something that is an industrial giant that can CNC tons of metal every day for years. It will be able to cut a project for the user.

Let me know.

Safe Flying

2. Mar 2, 2016

### Victor Bravo

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Re: Would others be interested in a CNC machine for $2k-$4k? laser/plasma cutter opti

If the accuracy and rigidity are precise enough for real airplane parts to be made within a reasonable CNC tolerance... and not flexing or bowing... then yes people will want one. Make sure you design it so it can use a router, laser, plasma, etc. to be useful on wood, aluminum, steel.

3. Mar 2, 2016

### Midniteoyl

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Re: Would others be interested in a CNC machine for $2k-$4k? laser/plasma cutter opti

What would the minimums be for the computer to run it? I have several old P4 based computers and laptops that are doing nothing at the moment and this seems a better use than another linux server or HTPC.

4. Mar 2, 2016

### Aviator168

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Re: Would others be interested in a CNC machine for $2k-$4k? laser/plasma cutter opti

Precision depends on the stepper motors used. A P4 is more than enough. All it does is to send commands to the stepper controllers.

This is actually is the challenge for home built CNCs.

OP, What is machine made of?

5. Mar 2, 2016

### CobraCar11

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Re: Would others be interested in a CNC machine for $2k-$4k? laser/plasma cutter opti

Aviator 168 - You said "What is machine made of?". Are you referring to the motors? I am looking at NEMA motors for the minimum, but I am considering servo motors for their position reference. NEMA's can be great for their steps, but there is no feedback. Servos are great, but there is so much out there for NEMA's, more support groups and forums, and more hardware/software for them because they are used in other things like 3D printers.

It would use open source software, and talking to others, commercial software can work too. Most of them. Depends on the requirements of the suite. I will probably use Raspberry Pi, Arduino, etc. type units as well to keep the cost down for people. It also will allow people to upgrade, or add additional features, like sensors, to theirs.

I am learning as I go, and by no means an expert.

This isn't me "selling" anything.... yet..... I don't know that I will sell this. Some have suggested I do a kickstarter campaign and let a bunch of people get them also. If I do that, I may ad a percentage markup for all the work coordinating. If I don't, and I just order some extra parts for a few people on Home Built Airplanes, than I don't know that I will do a markup.

I don't want to do this as a business, so this might be a one time deal.

Victor Bravo
- I will definitely make this as tight a tolerance as possible. I have worked on this more than a year, and it's not a toy to me, so I want it to be useful. Also, if I add a laser to this, there is no sense making a great laser cutter, but not have tolerances that would benefit a laser. Might as well use a Dremel then, right? ha ha.

I am brand new to aviation, and so many of you guys have been so great to help me out already. I will probably get to know others and PM them bugging them for advice someday. I would be doing this extra work to help others here get to build they plane they want. I can't afford a plane, but I could maybe afford a plane if I built it with some of the techniques i have learned. ( Yes, I understand that many planes you can buy cheaper than you can build. ) It feels like a thing of honor and accomplishment to say that I built something that I can fly.

Anyway, forgive my lack of "SELLING" this to everybody. I'm not trying to run a business. I figure if it helps me, it could help other people. This won't happen next week, but in the next few months (hopefully). Contact me if you are interested. I may not add all the laser, plasma, waterjet, etc. to mine, but if you want it, I can order it for you even if I don't get one for myself. Hopefully this makes aviation a little more affordable for someone someday.

One of the reasons I want to build it is I mentioned it last school year when I volunteered at my kids' school. Now, other school kids remember and ask, "SO, DID YOU BUILD IT YET????" ha ha.

Let me know of any people that are interested. It's not a commitment or anything, I just want to know a ballpark number of how many would like one.

Safe Flying!

6. Mar 2, 2016

### CobraCar11

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Re: Would others be interested in a CNC machine for $2k-$4k? laser/plasma cutter opti

Aviator 168 - Just thought about your question some more, and it occurs to me that you may be referring to more than just the motors.

It will be solid TITANIUM!

Just kidding!.... I was thinking of wood, to keep the cost down - heavy frame, less vibration, etc. Then I started thinking of expansion, moisture change, temp change, all those things that could change the dimensions just enough to wreck your project! No thanks.

I don't want to do belts. It will be screw-driven. Not the threaded rod at Home Depot. It will be precision ball-screw stuff from industrial sources.

The body will be extruded aluminum and braces.

Does that help?

Safe Flying!

7. Mar 2, 2016

### Hot Wings

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Re: Would others be interested in a CNC machine for $2k-$4k? laser/plasma cutter opti

Kind of like designing an airplane - speed and rigidity tend to drive the design in two different directions. Make it stiff and the moving bits get heavy and then the inertia demands more power to keep the speed up. Try to do it with less power and you probably have to sacrifice either speed or accuracy.

For cutting aircraft plywood and/or plasma, both of which are essentially 2D, resolution really isn't a problem and the forces needed tend to be small so accuracy also tends to be reasonable. Moving up to 1/4" aluminum, or full 3D cutting, starts to get exponentially more expensive to get the same cutting rates and accuracy.

What would the minimums be for the computer to run it?

Mach3's default setting is only 9600 baud for the serial port so even an antique 286 would probably be fast enough :gig: You do need a serial port with something like Mach3 or add on software to generate a steady clock pulse. USB ports can't do that.

8. Mar 3, 2016

### Hot Wings

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Re: Would others be interested in a CNC machine for $2k-$4k? laser/plasma cutter opti

Ball screws are nice, but 2500mm ones run over $300 each for C7 grade (more than good enough IMHO for this type of project) so the ball screws alone are going to be near the$1k for just the X and Y axis. Dual belts, or chains, for the X axis would probably keep the cost down and can provide the kind of accuracy we need for most home built aircraft wood parts. HBA member FritzW seems to be able to built nice parts with his table, and I believe it's belt driven.

Disclaimer: I have no real world experience with either a belt or chain driven CNC. All of the ones I've used are either ball screw or rack and pinion.

9. Mar 3, 2016

### TahoeTim

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Re: Would others be interested in a CNC machine for $2k-$4k? laser/plasma cutter opti

Go to open builds website. This has been done using very nice extruded rails. I built an oversized Ox 2' x 4' in the x and y but I only have about 6 inches in the z. 2 to 4 feet in z seems way thicker than necessary. I am using a smoothie board controller. My head will take a router and a future laser. I made the mounts on my 3d printer.

I 3d printed some parts for my kitfox. The neatest part is a standoff that allows me to ziptie wires and fuel lines to the round frame of the kitfox. They stand off the wires away from the frame.

Midniteoyl likes this.
10. Mar 3, 2016

### Midniteoyl

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Re: Would others be interested in a CNC machine for $2k-$4k? laser/plasma cutter opti

I'm sure it is .. Was actually meaning the architecture being used (requirements of the software)..Which was answered.

11. Mar 3, 2016

### Midniteoyl

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Re: Would others be interested in a CNC machine for $2k-$4k? laser/plasma cutter opti

Bah, serial..

12. Mar 3, 2016

### Aviator168

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Re: Would others be interested in a CNC machine for $2k-$4k? laser/plasma cutter opti

Good that you mentioned. With that thickness in the z, there might be problems with the cutting tools. Also, why does it have to be 8' long? Molds can be cut in separate pieces. As a matter of fact, that's exactly what I will be using for.

13. Mar 3, 2016

### Hot Wings

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Re: Would others be interested in a CNC machine for $2k-$4k? laser/plasma cutter opti

Been cleaning a rental and their plug in air fresheners must have been effecting the brain cells. Hate those things!

Should have typed printer/parallel port, not serial

Last edited: Mar 3, 2016
14. Mar 3, 2016

### Midniteoyl

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Re: Would others be interested in a CNC machine for $2k-$4k? laser/plasma cutter opti

I dunno.. nothing like slapping down an 4'x8' plywood and having it cut all your pieces at once

15. Mar 3, 2016

### Aviator168

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Re: Would others be interested in a CNC machine for $2k-$4k? laser/plasma cutter opti

Or just buy carbon-laminated 0.5' thick foam and cut all the ribs.

16. Mar 3, 2016

### CobraCar11

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Re: Would others be interested in a CNC machine for $2k-$4k? laser/plasma cutter opti

I guess if ball screws are the deal breaker in price, someone could just use belt drives, then stack all the ribs together and use a router bit to true them all up to the same shape.....

The reason for the 2' or 4' was a sloooooooooooowwww z axis cut for oversize projects. 95% of the work will be nearly 2D cutting of plywood, foam, etc.

Is anyone here familiar with the "stitch and glue" method for building boats? I wonder if anyone has ever cnc'd a few sheets of ply, and "stitch and glued" the pieces into an aircraft! :gig:

Safe Flying!

17. Mar 3, 2016

### Aviator168

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Re: Would others be interested in a CNC machine for $2k-$4k? laser/plasma cutter opti

A few is OK. Too many is not good. The machine should have 3D cutting capability. Even 6 inches (travel) on the z is good enough.

18. Mar 3, 2016

### ScaleBirdsScott

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Re: Would others be interested in a CNC machine for $2k-$4k? laser/plasma cutter opti

There are plenty of good resources out there, but the confusion abounds as a result of the low signal to noise. It took a few months with a starter kit to go by, but I got a machine out of it and learned a lot.

Build it, don't overthink it at first on terms of getting beast motors or ultra precision: for less than $3000 there are a ton of compromises to make, but the result should still be something quite capable. I had a lot of ideas of a versatile machine at first, some of that is built in but yet to be implemented, things like a swappable Z arm to enable longer travels with a removable table section to allow for deep z carving in foam when needed but without extra burden during normal machine time. Things like that might be ways of circumventing the norm. I find that a spindle strapped to the end is going to do 90% of the work on my unit, with a drag knife and maybe a laser someday as some options when it comes time to make stencils for paint jobs and cut decals, fabric, etc. Those are among the things an airplane maker's cnc table should be able to do. I like metal frames but I think wood is probably a good way to go for low cost rigidity in your case. 19. Mar 3, 2016 ### Aviator168 ### Aviator168 #### Well-Known Member Joined: Sep 21, 2012 Messages: 2,205 Likes Received: 246 Location: Brookville, NY. USA Re: Would others be interested in a CNC machine for$2k-$4k? laser/plasma cutter opti To make a wood frame rigid, it would be very heavy. I am thinking carbon reinforced wood. Especially the OP is think a 4' by 8' platform. 20. Mar 3, 2016 ### ScaleBirdsScott ### ScaleBirdsScott #### Well-Known Member Joined: Feb 10, 2015 Messages: 929 Likes Received: 597 Location: Uncasville, CT Re: Would others be interested in a CNC machine for$2k-\$4k? laser/plasma cutter opti

A few notes on drive:

Rack and Pinion is great and fairly cheap and fairly expandable and there are few downsides. Only major issue that it isn't the cheapest or easiest of all options.

An option that I have considered is using a toothed belt, but instead of making a long, stretched donut loop, have it so that the belts are pressed into eachother, except where the gantry is rolling over the belt, having idlers pick the top belt up and loop it around a drive wheel before inter-meshing it back down onto itself. The bottom belt can be then glued/taped to the frame to reduce flex even more. There's been some success with this method and I recall a commercial outfit even sells some advanced versions of that setup: The benefits are the belt has much, much less flex and stretch issues and can be fairly robust and accurate in this way by having the belts inter-meshed like that. Also, it keeps dust/debris out of the belt more easily as the teeth are never exposed except inside the drive area which can be enclosed.

Before I went with a rail kit that included pinions pre-installed, I was going to go that way. When I upgrade my machine to steel rails, I'm probably going to experiment with this type of belt drive; that or a full-steel rack drive setup like the CNCRP system.

If you want to go with a lightweight gantry I suggest making sure that the Z-axis can't torque very much while drilling. The main issue with my experience on the ligh machine is that drilling sheet anything over .025 will cause the head to torqe out of perpendicularity with the table as it drills. In sheet I can't find problems with the resultant holes for any practical purpose here but in .125 thick alum I've had to do peck drilling in very small passes to avoid holes that start to get out of whack.

Running steppers, I can't think of any times when in normal operation I've lost steps. I've crashed things and lost zero that way but, no helping that with servos.