Friday, October 14, 2016

DIY CNC 3040 Router, Free Blueprints

Here is my DIY Plywood frame 3040 (300x400mm work area) CNC Router.

CAD files here

http://www.thingiverse.com/thing:1826302

I am on my third build of this machine.

This is the first successful running CNC Router I made.  the one that started me on building CNC routers.

Basically a few years ago, I had ordered some 3D printer parts from a machine shop, and he did not deliver in time.  I was running very low on money, so I put together my last $300, found a set of blueprints online and built this:


It looked like crap and was always breaking down.  Mostly because I failed to use lock nuts for critical parts and the vibration caused the nuts to loosen constantly.  It was a good learning lesson, as I basically did everything wrong and had to learn how to do it right.

Version 3 has come about because I have a order for some CNC routered items and it requires a small cheap router to do it.

I started out with a set of files from Thingiverse, but have modded it and re-drawn it so much to basically turn it into a whole new machine.

Latest version is cut on the 40 watt co2 laser from 1/4 inch plywood. and 3 identical pieces are laminated together to make a 3/4 inch wood part.

For this project I am not shooting for perfection, rather just repeatability and reliability.  It will be used to make small wooden boxes to hold wedding rings which then someone else will engrave and customize.

Lessons learned from version one and two:

1 Use ball screws, but if ball screws are not available, use large thread rod.  The original used 8mm thread rod which whipped causing the machine to lose steps and jam.  At present I am out of stock of 600mm ball screws, I only have stock of 500mm ball screws.  I can make them work, but I figure I will simplify things and just use 12mm thread rod instead.

2 Use Mach3 controller if possible.  At the moment I am one stepper driver short for a Mach3 machine, so initially I will run a Arduino on the machine until the next batch of controllers arrive.

3 Use a real spindle motor not a trim router or dremel.  The noise is horrendous and the wood resonates the sound.  It also burns up the bits with the trim router running too fast.  I got a 500 watt model on its way via DHL for $126 which is cheaper than the bosch colt routers and it comes with mounts, and extra collets to handle different size bits.

4 larger guide rod.  First machine used 5/8 inch pipe.  I went up to one inch pipe now.

5 lots of lock nuts and thread lock.

6 The first machines were laminated plywood also, but this time I am doing a big difference in the adhesives.  I used marine epoxy before.  The marine epoxy is not as hard or as strong as the gorilla glue I am using now.  It also takes 24 hours to cure vs the couple hour cure time of the 2 part stuff and is much simpler to apply.

7 If you have the chance to make this from Acrylic, or metal, do that.  V4 of this machine, will most likely be steel.  Basically the same files, with some mods for CNC bending and bolt together construction.

8 Screws AND glue construction.  I got a big bag of drywall screws to hold it together while the gorilla glue cures.  Glue provides the majority of strength.  I also use screws in the lamination process now.  Basically apply glue according to instructions, then screw it together.  Since it is 3 pieces of 1/4 inch plywood I am using 3/4 inch screws.  After curing they can be removed or left in.

9 Paint.  Humidity here is a bitch.  Sealing with spray laquer clear and then a quick shot of color should seal it in.  With acrylic I should not need paint.

Since time is of the essence for this current job and there is not a lot in the budget this month, I chose the plywood construction as I can make that here without sending the steel out or using $150 in 12mm acrylic.

I will be re-using a lot of the hardware from v2 for v3.  The ball screws unfortunately can not be used as my helper broke it while disassembling v2 about 6 months ago.

If this goes as planned, I will have a row of these machines running in the shop cranking out various parts for a cleint.   The prices offered are enough to hire another full time worker to run maybe 3-4 routers running at the same time.

Update 2

Photo of the gantry.

Found a problem with one of the files.  The hole for the guide rod on the base was not enlarged to 1 inch and a couple parts on the z axis are not symmetrical.  

Will re-draw and re-release tomorrow.


UPDATE October 19, 2016

New files on Thingiverse.

Update November.

Router project temporarily on hold. Other projects that actually make money have come in.

Some future mods to this project, will be substitute the roller bearings and hardware ($50 cost) to machined HDPE bushings made in house.  

The router jobs could not wait on this project, so that is why I got a big 2x2 Torchmate router in the shop now.

Also I think the plywood I used was not good enough for this project.  It is marine grade, but Filipino marine grade and it appears to be too soft.  

I think that I should be using hardwood phenolic plywood instead, of the type used in concrete forms and scaffolding. 

I will revisit this when I got time, or feel free to mod the files in thingiverse.

1 comment:

SiGraybeard said...

Thanks for that, sir! Nice of you to improve the design and list your lessons learned.