Thursday, February 24, 2011

A2ZCNC Leadscrews Upgrade - Fabricating the Z-Axis Stepper Motor Mount - Part 2

After being certified to be competent to continue to work for my organization, I hitch a ride back from my colleague back home.  I was almost tearing up my day job working gear when I got home and headed straight for the shop.

The first thing to do is to face off the motor mount that the tool dug into, spinning the column out of alignment.  About 0.5mm was removed from the surface to rid it of the ugly tear marks.  This leave me about 11.5mm in thickness.  Next, I spent quite some time figuring how I should hold the workpiece with what's available on hand to profile the semi-circle to clear the leadscrew.  The running of the code took a while to complete as I was going at 0.25mm per pass with an 8mm endmill to avoid the same problem encountered in the previous session.  Feeds was also much slower.  Guess the last incident really freak me out.

Ok, some pics posted below to keep up with tradition:

Flycut away those ugly marks.

Pretty much cleaned up. This also show good effort in tramming the mill from left to right.  Front to back is off by 0.01mm.  No big deal.

The workpiece was mounted on the 1-2-3 blocks (actually 25-50-75).  The 8mm endmill was also zero'd to the bottom right corner.  I'm now ready to run the gcode.

About 1/2 way through.  Total of 40 over passes.
Finally through!!!
Ok, I believe this is a simple job for most.  The difficulty I encountered was work holding.  I thought of using the 2 clearance holes further away from the area I'm milling to fasten the work to a piece of wood or scrape piece of aluminium.  But I do not have long enough metric screws to go through them and I do not have tap for those that are long enough.

I'll be leaving the nut mount rectangular.  Once the precision leadscrew is up, I'll be working on a better piece.  Likely to go with Tang Kee's design, which is a modified version of Graham's.  Tang Kee's design seems more suitable for mills with the 8 directions column as it allow the spindle to go lower.

Time to sleep.  It will be 2am in 4 mins time...

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