# New CNC machine for plastics & wood



## pet3r (Oct 11, 2013)

I'm inquiring for a friend of mine that wants to CNC cut 1/32" acrylic or plexiglass sheets. Pretty simple material I think, but all of my expertise is in the woodworking. I've been doing fine woodworking for well over a decade now, but never any CNC stuff. 

My friend is willing to finance a CNC machine in exchange for cutting all of his plastics he needs. I'm already equipped with table saws and dust management.

Since this will be stored at my shop, and realistically for my own use, I'd like to find a CNC machine that is strong, reliable, and fairly straight forward in setup and operation. I'm pretty savvy with computers.

His needs are minimal: 1/32" acrylic sheets cut into small business card sizes, at around 20,000 pieces per "order". So something that is fast and automated would be nice. A 24x48" would be preferable...48x48" might be too big for my shop. Anything smaller than 24x36" is too small for his sheet size.

For me, the ability to do other woodworking would be really a bonus for me. Cabinets, custom designs, etc. Again, this is more a hobby for me, so nothing mass production.

I'd love any recommendations as the more I read about it, the more I'm realizing there are TONS of options out there in all price ranges.

I've found the Zenbot, but it seems to be the bargain unit. I think it would work pretty well for the plastic cutting, but it doesn't scream "quality" to me.
ZenbotCNC (dot) com

Another one I found is the Fireball. It has the size capacity, looks quite a bit sturdier, and looks like it'll last a heck of a lot longer. 
Probotix (dot) com

His budget is flexible, but something under $6k is probably good.

Any help or guidance in the right direction would be appreciated! Key needs include:
-24x48" potential
-fairly simple to use and setup
-reliable (a commercial product is probably a better option than a DIY kit, something that has support behind it)
-fairly quick and long-term accuracy


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## SteveMI (May 29, 2011)

*Smaller CNC*

Shopbot has a desk top model, but only cuts 24" x 18", so if you could cut the 36" in half it would work. I use their Buddy and Alpha machines, they are sturdy and accurate. List price is 5K and you might be able to negotiate.

Steve.


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## pet3r (Oct 11, 2013)

Thank you Steve, I've heard great things about the Shopbot, I just think for the size I need, it's a tad overkill in the quality for what I want to accomplish. 

The more I read about the Probotix Fireball, the more it seems like the better fit for me.


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## tom klass (Jul 23, 2013)

I have a camaster stinger1 24 x 36 solid as a rock I would highly recommend it. I researched different cnc's for over a year before I went with mine and I'm glad I went with what I did.


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## rwbaker (Feb 25, 2010)

*Cnc*

I hope you are successful in your venture, but there are a few considerations you may wish to think about.

You mentioned that you would have up to 20,000 pieces a order, at 1 minute per item that is almost 14 days straight. True industrial grade CNC equipment does not run for 14 days straight without issues. Who pays to fix the machine 4 times a month? Who provides storage and shipping of the finished items. I am assuming that you are using a CNC because you wish to engrave these blanks; If they are all the same it would be faster to order from a plastic production house (injection or press mold) and this is the kind of order the Chinese love. If these are just blanks of different sizes then a Water-Jet should be reviewed. If they are all unique then who is going to program 20k items? I'm not trying to bust any bubbles but I've lived in industry my entire life and seen people go bankrupt from friendly deals such as this. If you go forward, make sure you put everything in writing.

Good Luck - Baker


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## fixtureman (Jul 5, 2012)

I think a Laser cutter would be better than a router it would give a better finish on the edges. Also a table saw would be faster


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## dick in ia (Jul 23, 2007)

For the thickness that you are working with, I would check with the plastic supply Co. and ask for their recommendation. You might want to consider paper cutting equipment. For just cutting, that might work quite will??


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## Carlswoodturning (Mar 6, 2013)

I'm not an expert on how to cut the plastics, but have a few comments about the CNC idea. A normal CNC is usually best at custom work in small quantities, the versitality comes at the cost of production speed.

I have built 2 machines, just to get familiar with the mechanics. One of the great complications, (and expenses) is the software needed to design, convert to a movement of the tool to keep it within working limits, (path, speed, order of cut) and finally convert it to "G Code" the language of the computer controls. 

The good news is that to cut thousands of the same piece, you don't need the versatility. To make 2D squares takes simple commands. To carve a model of your sports car, make a 3D sign, then a prototype part for an airplane, requires complex G Code.

I have used my 2'x4' CNC router to cut 2d shapes much more complex than what you need to do, with simple G Code commands which I wrote, and I'm not a programmer. No need for CAD software etc.

Bottom line is, with the right cutting tool, (laser, Water jet, etc) and the right enclosure for safety, it could be mounted on a very high precision frame, high quality bearings for precision movement, stepper motors, and a $100 software program to run the G Code. 

As was mentioned, your project is very high production, down times for service and repair could be costly, but with a simple custom design, almost all spare parts could be on hand, and changed out quickly. The cost could be a fraction of a typical low production machine. The whole operation can run on an old garage sale computer, with 2 more on standby if it crashes, or you could spend the same money on dinner out.

Although I have some experience, most of what I say is theoretical. I am planning to make a several different dedicated machines each designed for a specific job, and have just enough experience (and expert friends for advise) to know I can do it.

I would love to see if I can help you with this, not for financial profit, but for experience, and future opportunities. Depending on your time frame and location, ( I'm in USA) maybe I can help. 

Carl


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## pet3r (Oct 11, 2013)

Thank you everyone for the replies, I really appreciate the advice.

I would love to have a plastics manufacturer actually make these to size, but the problem is these plastics need to be "tinted" with custom, critical colors and optical quality. So far in the research, you have to purchase several tons of each color for anyone to be interested in making custom colors for you. Since I need 14 colors total, well, then it gets a bit more difficult.

As for the 1 minute per piece, I think thats a bit of a stretch. Because they are all identical, based on my calculations of where the bit will travel, and cut, it can cut two edges at once if each identical piece is positioned and programmed properly. 1/32" polycarbonate isn't a terrible thick material, so speed should still be decent. We calculated around 15 seconds per piece, since once you have completely cut out your first piece, 1 side on 2 other pieces has also already been cut.

Size is roughly 4x3" with round corners, and sheet yield is around 104 per 24x48" sheet. We are planning on layout out the cut to actually cut the "excess", and then we are left with the rectangular pieces as the leftover material.

Granted we've never done this before, but this is our thinking. Is it flawed?

I appreciate everyone's comments!


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## pet3r (Oct 11, 2013)

Also, the 20,000 per order would be maybe 3-4 orders per year. So setting aside 2-3 days with some part time automation wouldn't be a big deal...I think 

I've also planned on modifying the Probotix Meteor to have a vacuum table which will give us tighter tolerances between pieces, giving us greater yield per sheet.

My friend had originally been quoted by a few local suppliers to die cut his sheets, and ended up around $.25-.49 per piece. So at 20,000 units, he can afford to purchase a decent CNC and save some money over time. CNC edge will be nicer too, as the die cut pressure will somewhat pinch one side of the plastics a bit.


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