Eggbot hack

I was preparing today for an upcoming Eggbot demonstration, when I noticed a lot of play in the pen arm.

This wooden piece had a lot of play because it had
loosened from the bushing it was glued to.

CNC controller case.

Though I don't think I'll have Apple banging down my door to design their next iHip^TM device, I'm slightly proud of the fact that I turned this:

Into this:

Milling Hotend Nozzle Mount

How's *that* for a racy post title!

My Zen CNC is fairly usable now, so I've turn my attention to getting the 3D printer functionality. One glaring task is how to mount the nozzle to the extruder. You know what they say, the 7th time's a charm:

I'm not 100% sure that the most recent one will work, either. But I did actually have a lot of fun designing and figuring out how to design and mill parts. The parts above are ordered chronologically from left to right. #5 and #6 were milled using a cheapo 1/8" "Roto-zip" bit, since I was worried about the wear and tear on my one and only carbide end mill. I also experimented with various feed rates. #5 was milled at 1000mm / minute horizontal feed rate, with the cheap bit. I could actually see the bit flex as it moved.

The result was not pretty, you can see how bad it looks. I also think the bit was probaly not the appropriate shape for the job, cheapness aside.

I'm pretty pleased with the final one:

Ugg, what's up with the shadow? Would it kill me to take a decent picture?

The "burrs" on the edges are non-structural, and rub off with your fingernail, I believe its just an artifact of MDF.

--P

CNC update

I hit a milestone with my CNC project tonight, I made my first cut!

Here's the current state of it configured for milling:

I'm using the Zen Toolworks 12x12 , F8 edition. The F8 edition has an extended Z-axis travel on the gantry, which is needed to be able to use the device for 3D printing. One thing I didn't realize initially were that: 1) configured as a milling machine, the spindle will not reach down to the bed, and 2) the extra Z axis travel does not benefit milling as much, because the gantry clearance is one of the limiting factors. The two possible approaches to address the first issues are to either re-work(ie invent your own) the spindle mount to lower it close to the bed, or to build an elevated platform as your new work area. I decided to do that because it reportedly reduces error due to frame torsional forces. I could always build a new mount and remove the table. The Zen is pretty flexible in that way, a good deal of the design can be up to you.

CNC progress pic.

Just a quick shot of my cnc build in progress, I'll post more about it later. I had a slow start waiting for all the parts, I think I'll avoid ordering big stuff around Christmas next year.
Tonight I'm working on end stops and the y-axis of thr Zen Toolworks chassis.

New Project - CNC/3D printing

While physical computing has captured my fancy the past few years, one thing that seems to have frustrated me is the physical construction for my projects. I have a degree in Mechanical Engineering, though I went into Software Engineering professionally, so that struck me as odd. I think I've grown accustomed, spoiled even, on the fantastic availability of free and low cost tools available in the software world. I'm used to having as powerful tools to develop software as a hobby as the professionals use. Not so with hardware. Things are getting better though.

I've decided to take it to the next level, and I'm investing in a small CNC that will also be capable of 3D printing. I'll document my progress on ByteCruft. (My robot project is not stalled, but I'm putting the CNC project first, since there's a long lead time with getting up to speed.) I currently know very little about milling beyond what I remember from school almost 20 years ago. I expect my progress to go faster than my typical  'epic' level project, since I'm focusing less on trying to do lot of design myself. I'm mostly cherry picking various kits and packages and making them work together.