IND-E, A newbie MDF build

[GregRF]

Welcome to the IND-E thread. After reading up on many builds and borrowing lots of tricks from this site over the past year, its finally my chance to contribut in this post-build log.

I am a Mechanical Engineer and have played around with electronics so I thought I could take on this project pretty well. I also only have a limited number of tools (though this expanded throughout this build ) so I wanted to build this cnc router to be able to play and prototype cheaply at home. But this also limited my capacity on my first build. So with my limited tools and limited knowledge I started my design with inspiration from buildyourcnc.com.

When I started a year ago, I figured I could crank it out in a couple of months. And here a year later I'm the proud owner of IND-E.

Check out the initial design.

[GregRF]

Evolving from the buildyourcnc design based on tips from this forum I decided to try and build a torsion box for the bed. It is not quite as complicated as a Joe's build, but provides a relatively flat surface and good strength. It is built from 3/4" MDF, with the bottom skin made of 1/4" plywood.

Another worry I had at the beginning based on other's tips was warpage of the MDF, so I tried to prime and paint along the way and even primed the inside of the torsion box. (My house can suffer some high humidity especially through the winter in the redwoods of California).

Note: These pics were taken on 7/01/2009

[GregRF]

Once the torsion box was built, it sat ... and sat ... and sat. Travel for work, a new roomate, installing windows, blah blah blah. Basically life got in the way. So the box sat from late July til early December.

But once the build resumed in December it was full speed ahead. Here the base is finished and some aluminum angles for tracks are attached.

On the bottom you can see that the torsion box does not extend all the way to the legs, this was intended to give a small area for a yet to be designed workpiece clamping scheme.

[GregRF]

And then there was a gantry.

I guess this is a good time to explain some of the construction. All of the construction was done with bolts and cross dowels. All the hardware and aluminum angles were sourced from McMaster Carr.

For lining up all the drilling for the cross dowels and bolts I made a jig out of a 3/4" of plastic with a drill bushing hammered in. With this I could clamp it to the edge or top of the boards and make a relatively straight hole. (only after buying the parts did I learn that there is a jig out there for this exact purpose that you can get cheap at harbor freight).

For the holes to insert the cross dowels I marked a drill bit with some white out so that I could drill the correct depth and not through the board (well most of the time anyway ).

[GregRF]

And the gantry can slide!

[GregRF]

Time to give IND-E some flavor. I went for an industrial look.

[GregRF]

And now for a Y axis car.

As you can see this car was successful on the second try. I guess this is what happens when you don't plan out where are the bolts are going to go. This first one had a bit of interference.

The Z axis is starting to come together on the right of the picture.

[GregRF]

And the Z axis is attached.

The roller track design of buildyourcnc.com works pretty well. I do have a bit of a problem with the tracks as I built them though. All of the MDF boards with the angles attached were made on my table saw. The edges were cut with some 45 degree angles to give a good seat to the angle. Somehow with this on my table I ended up with a slightly thicker section in the middle then at the ends. So the roller tracks are super tight in the middle of the X and Y axis, and a bit loose towards the edges.

[RomanLini]

Nice clean machine design!

Re "being thicker in the middle" it might be that it was a bit tight and the ends have compressed a little?

[CarveOne]

That can happen if the MDF has a slight bow or cup in it. It's hard to slide it while keeping the MDF perfectly flat on the table saw.

CarveOne

[GregRF]

I think the thicker in the middle part has to do with my table saw. There is an insert next to the blade that is slightly lower than the table. This doesn't hurt accuracy when making straight cuts, but when cutting at 45 degrees the ends can drop when near the blade and this causes a bit extra wood being cut on the bevel.

At some point I'll just need to get out the calipers and a sanding block to try and fix a bit of this.

[GregRF]

The build so far was done mostly over the christmas/new years break. Next was time to drive this thing. The next couple months were split between building the electronics and the drive train.

On the electronics side I decided to go with the hobbycnc pro 3 axis board and built the power supply from recommendations on the hobbycnc yahoo group. Most of the electronics were sourced from mpja, digikey and a great electronic store I just found in town called Santa Cruz Electronics. It was fun to finally warm up the old soldering iron, but I'm not sure how happy the wife was that the project took over the dining room table for a couple weeks .

The drive train I kept up with the low cost options and went with half inch acme rod one start all around. The rod and some acme nuts were bought from enco. Some of the bearings came from vbx, and most other parts came from McMaster or local hardware stores.

The stepper motors were sourced from Keling (KL23H276-30-8A).