Mechanical Parts Completed

WOW! That's about all I can say now. I threw together the Zstage and it looks great. It even holds up better than I expected. I was originally planning on putting two supports on the ends of the X rails to keep this from falling over but it doesn't look necessary now. As it is now this thing will have a range of 20" in the X direction, 16" in the Y direction and maybe 6" in the Z. The treaded rods are hanging down now, I need to translate those up to the top so I can access them with the motor. Also I've got some more room on the Z carriage if I go back to the laser.

In other news I got my motor controller working but only slightly, using the motors I "harvested" from a printer the controller only works with a supply from 6 to 8V. The power supply should be giving this 12V. I am going to try the controller tomorrow with some more "standard" motors. The motherboard is nearing completion.
http://www.cnczone.com has a lot of good information.

well documented boards

Soldered up all of stepper motor controller. Used toaster oven reflow for the controller IC, not necessary spacing on pads very comfortable. Have not tested yet. Will test after oatmeal.
The motherboard I was getting ready to solder and The Dangler stepped in and asked me if he could do it. He wanted to show off for the lady in the room. (He stated that out loud.) The pictures shown here are his workshop and the finished product of the ICs on the motherboard. Very, very, very good work. THe final product of his soldering is pictured here also.

These boards are super well documented. I would like to make that clear. The circuit is easy to understand, and easy to assemble. I never looked at the documentation to solder up the stepper controller. I think that is a testament to the great documentation done by the RepRap team.

Z stage completed

Well almost, I need to attach the motor yet. I have not addressed where I'm going to attach the motor and what I will use for gears to spin the threaded rod. Perhaps acrylic?

Reaping the rewards of painful learning

"An expert is a person who has made all the mistakes that can be made in a very narrow field." -Niels Bohr
I made a lot of mistakes on the laser, and now I've got a pretty good handle on it. Yesterday I made a lot of progress on the laser and my acrylic Z axis, where do I begin?
Well first I quit my job on Friday, so I've had a lot of time to work on this project. It's still feel a strange feeling to not be busy doing something I don't like. I like this personal fabricator.
My parts from Makerbot came yesterday also after 4 weeks. I asked one of the founders to throw in two boards to make up for the mistake by throwing in two bare PCBs for the stepper motor controllers. They threw in two free PCBs, but they threw in the wrong PCBs!
Back to my Acrylic, I made this "capture nut" and press fit assembly to attach vertical and horizontal pieces. I made the gap to attach these 2mm larger than the material thickness; that was loose as a goose. I later made the gap the same dimensions as the material thickness and that works beautifully. It is a very tight fit, I had to do a little filing but once the pieces went in they were not going anywhere. I had a fear of the capture nut weakening the material, but 1/4" acrylic is very strong.

The picture here is the Z base with two press-fit supports attached using no capture nut, there is a nut in one piece but no bolt.

Heavy Nut

Part of the new Z stage I designed was the capture nut. This method of attaching two 2D pieces to make a 3D assembly relies on a nut being captured and not turning. This is accomplished by keeping the slot cut out for the nut too small. When my parts came out of the laser the slot was larger than expected. I found a solution to this by going to the hardware store (OSH in NorCal) and buying a new nut. The new nut needed the same threads 5/16" but a larger outer diameter. They carry this at the hardware store and it's called "Heavy Nut".

My new novel Z axis is not done yet, and will need another set of captured nut assemblies. I will reduce the tolerances so a standard nut will work.

Results from the Friday's Laser Session

Pictured here are the results from my laser session on Friday night. I did not get all the parts I designed printed out. I learned a few things.
1. Saving a pdf from Solidworks directly is 1/10 of the actual size when I import the pdf to Adobe Illustrator.
2. Pdf's imported using this method get printed 3 times. DXF files get printed 21 times.

The 3x lasering made some dimensions on my parts larger than expected.

New Z stage, from the ground up

I spent some time redesigning the Z stage. To the right is a screenshot from SolidWorks of the components I have used. I used a technique new to me, called capture nut. I will add more details on how this works later, I will bring it to the laser tonight. The small square is a 1" by 1", this is used for calibration as the dimensions get altered when I import this into Adobe Illustrator before printing.