Tuesday, January 02, 2007
Scrape and Fill
The general idea is to use a semi-solid material as a combination support / mold. Something about the consisency of modeling clay might do. The process would go somthing like this:
1. Lay down a thin layer of material (trowel, squeegee, something)
2. Scrape away the areas where the part will be
3. Fill the empty space with plastic
What got me thinking along these lines was the extrusion speed. It seems like scraping away a negative image might be faster than drawing a positive image. This would be especially true if you could use multiple tools to scrape the area. Wide ones for larger areas, for example.
I really need to get off my butt and put together a test rig to try out a few things.
Taking lessons from my current project, I got a design in the works similar to it, made from almost exclusively 1x4 lumber and drawer slides. Should be quite simple, compared to the alignment horrors that have been had using only rod sliders.
Mind, Adriaan's creation of the Universal PCB for the mainstream RepRap is going to take a LOT of the pain out of getting the electronics right.
Cat has been running into the teething problems with getting the Java control programme working that I rather suspected was going to be the case. That will sort out in the fullness of time, though.
The really finicky bit, imo, is the Mk II. That thing, groundbreaking as it is, needs another design iteration or two with the notion of making it easy to fabricate kept in mind. Right now, getting the threaded polymer pump working right and the extruder head fabricated are far too intimidating for newcomers.
Here's the problem. Molten plastic doesn't pour like molten wax. It is extremely stiff in the molten state and will take a LONG time settling into a mold in an oven.
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