Re: [CAD_CAM_EDM_DRO] 3D Printer

>Seeing them run at the shows, I often wondered if I could stick a hot
>Glue gun on my Zaxis. One would have to find a "glue" that would not be
>stringy or like you indicate, find a wax in the shape of glue sticks.
>Wax Temp could be controlled easy enough. But I think we would need to
>locate a self closing dispenser tip. Even the software for toolpath
>creation might not be all that hard. Just need it to move to a known
>spot, pause, Spit "x" amount of glue or wax, move to the next spot, spit
>some more.

This is a fascinating subject - especially as I'm just playing around with
the Gingery design for an injection moulding machine which is, itself,
basically a big glue gun for plastic! The biggest problem would seem to be
the regulation of droplet size but perhaps you could use a kind of cylinder
and plunger but with some form of solenoid to tap the top of the plunger and
make it squirt a 'standard sized' drop of wax out of the nozzle. It may also
need some kind of hot scraper bar to pass over the work as each layer is
built up so as to level it off to a known level.

I was playing around with a couple of these rapid prototyping machines a
couple of months ago but never thought to really look closely at the way the
wax machine worked - I was far more interested in the one that made an epoxy
model at the time! Unfortunately, I gave up on the idea of making such a
machine when I found out the cost of raw material - over 10,000UKP for
enough of the special epoxy resin to fill the bath of the machine which was
just over a foot cube!!! The principle of the machine was simple enough -
the model is built as layers and the top of the model is kept just a
hairsbreadth below the top of the liquid as a laser beam traces out the
design and hardens the epoxy it passes over. As each layer is complete, the
model lowers a fraction more to make a new wet layer (this is scraped over
by a bar before the laser is used so as to regulate the layer thickness)

As a matter of interest, when I was there, the wax machine was making
prototype cylinder heads for a high performance car engine. These were in
2-cylinder units and had so many convoluted water ports that it would be
impossible to cast or machine them by any other means. The waxes were
costing around 1000UKP each to make and, as I followed the process along to
see one cast by a small company at the other side of town, the caster
dropped one and ruined it - I'm glad I wasn't close enough to get the
blame!!!

Best wishes,
Ian
--

Ian W. Wright
Sheffield, UK


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