Ah who am I kidding. We don't really have a good excuse for not posting an update. Sorry.
as for stuff done, sadly there's been a little bit of progress, but not much. We've got part of the CAD model for the done, and more research on the extruder. David will talk about the extruder research in the next post.
As always, finding cheap local suppliers that have what you're looking for isn't very easy. Thanks both to Tina and Devon for the supplier suggestions. Both look like good choices (I've ordered a teflon sheet from fastenal, and I'll be checking ultimachine to see if anything they have can work).
The CAD model pictures:
overall shot of the whats been modeled so far (as you can see, not too much). The aluminum angle frame (which has already been constructed) is the box frame structure to which everything bolts to. Following both bothacker and makerbot layouts, the bottom empty space is reserved for all the microcontrollers, relay boards, power supply, etc. The second level (the grey slab 1/3 up the image) is a 1/2" sheet of lexan plastic, and its where the motors and idler pulleys for the z axis will be located. You can see the x stage motor at the top right of the image.
here's a closeup of the upper part of the frame, with the x stage rods and z axis bearing supports visible in the image. Originally I was thinking of using a simple groove in the lexan bearing holder (that thick grey block in the image beside the rods) as a guide for a teflon slider, but i discarded that idea for fear of any binding issues, especailly with the timing belt positoned on one side of the stage and not in the middle. Maybe future versions that use more precise machining would be able to incorporate such a simpler design in the future.
closeup of the z axis rod build platform connection. You can see that the nut isn't bonded or bolted directly to the build platform (which is made from aluminum and will hopefully be heated). This will hopefully take care of any wobbles in the z stage axis and the minimal expanding of the build plate during heating while maintaining the same z position. Thanks to our machinist friend Kal Sobel for the idea.
That's it so far in terms of the cartesian stage of the build. Hopefully next time it'll be a more complete CAD model and we can show you what it looks like all built up and shiny.
Till next time,
Eric
