Sunday, December 18, 2005


Central core of vertical axis ready

I've assembled the central core of the vertical axis. The 4mm bracing was needed, and stabilises the design beautifully:

All we need now are the electronics to drive the stepper motor (currently on a breadboard) and the carriage FDM component. Then the vertical axis can join the linear axis.

For those pondering how it works, the four inner rods are just bracing. The three outer rods are connected to the large gear wheels like this:

When the motor goes round, a pinion gear on it drives the big gear wheels. These rotate the 3 larger threaded rods. The whole assembly is suspended from the three nuts on those rods. The nuts are held still, and the whole mechanism moves up or down depending on which way the 3 rods are rotated.

A turntable or stage will be attached to the top of this assembly.

Vik :v)

Um... I thought I understood what you were up to, Vik. Looking at the assembled mechanism now, though, I'm pretty sure I don't.
Thanks for the additional description Vic. I think I understand how the gears work and all. What I don't understand is how a stage is going to get raised and lowered. However, it looks like your three inner threaded rods, which I take to be locked in place and there to make the assembly more or less rigid, preclude the geared threaded rods from raising or lowering anything. Where am I going wrong here?
Vik - My son showed me how it works. LOL! No more descriptions needed. Thanks. :-)
Nice flurry of activity lately.

Great shots, Vic. And btw, I'm trying to recall the material being used for the FDM parts. Could you confirm that these parts are ABS (typical Stratasys)? I think I recall that entry, but can't find it atm.

Also, do you have any sense for how the FDM material you're using might compare to the material one might use in the device itself (or point me to the post/wiki entry - apologies if it's there and I'm not finding it). And by extension, any early thoughts on how material differences might affect device geometry?

Many thanks.
The Stratasys uses ABS - the same stuff as most monitor and keyboard cases.

The Polymorph we're using is more flexible, but harder wearing. I'm designing all the bits "chunky" so they'll work with Polymorph. If things go soft and soggy, we just reinforce with bolts :)

The PLA we're looking at for longer term use is more rigid.

But establishing the principle of operation is the important thing. We need to get a machine out there for people like you to experiment with.
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