Sebastian, good catch. I always hate to find out that I was not the first to think of an idea , but it is all-to-often true ! I agree that making the plaster, sand, ceramic molds on the reprap and then doing the melt and pour externally will be the limit for quite some time. But I like to get people thinking about and suggesting improvements for more distant additions so that they will beby rocket_scientist - Kartik M. Gada Humanitarian Innovation Prize
The stepper motors and easy drivers boards arrived today. The steppers are 200 steps per revolution, and the easy drivers default to 8 micro steps per step, so that is 1600 microsteps per revolution. to Keep 1/1000 of an inch control, that means the drive pulley needs needs to be 1600/1000 inches in circumference, or 1.6 inches, or 0.56 inches in diameter. For 0.025 mm precision, it means 1.27 cmby rocket_scientist - General
One option for building more reprap structural parts, and even strong fastners, is to print a mold directly and pour liquid metal into it to cast the parts. Aluminum melts at a low enough point that something similar to the extruder head could heat up rod or wire and pour the liquid into the mold. This technique is already being done by Zcorp. It would be very useful to work on a formula similarby rocket_scientist - Kartik M. Gada Humanitarian Innovation Prize
Thanks Krafter, murd. When the rest of the parts arrive, if I have trouble I will ask. I guessed on the acrylic and ordered 3/8" polycarbonate on ebay. It was about the same price as acrylic! I will look into belt or wire cable based movement, as I have more than the standard tools in my garage, though not a metal smith by a long shot. Mikeby rocket_scientist - General
Among the many ideas I have already thrown out, and that other people have posted, I still think that the best second non-conductive material to extrude is fiberglass. ABS plastic is very good, but not as dimensionally stable as metal, and has a much higher coefficient of thermal expansion. It also is prone to creep from stress over a long period. But adding fiberglass to the material as it is deby rocket_scientist - Wire and Thread Embedded Extrusion
I share all your concerns. Right this minute, the laser printer route is much easier and faster. I use this kit to make them better with the transfer paper and laminator, but I have also made boards using my iron and ironing board. My goal here is to start discussions that will lead to better future models. I am trying for the Gada prize, and my plan is for a 4 head machine, and the conductive maby rocket_scientist - Kartik M. Gada Humanitarian Innovation Prize
There is a kit that helps the laser print/copier approach work even better. They sell a transfer paper with a water soluble surface, so that 100% of the toner ends up on the copper. They also point out that the toner is not completely water proof, some acid gets through and starts to edge the traces. They sell something they call a foil, which only adheres to the toner that makes a water proof coby rocket_scientist - General
I am just starting to build a McWire to repstrap a Mendel. The assembly instructions and pictures are helpful, (although no mention is made of how thick the stage plastic sheets need to be if laser cut pieces are not currently available from RRRR), but there seems to be almost nothing about the electronics, software, and extruder. What do you use if the current supply of Mendel boards is out of sby rocket_scientist - General
Beagle Fury, if you overlap the lose ends on one side, then there would never be a point where the stage would go so far that the cable pulls up short. I also tend to think of bolts with a whole or slot drilled in the end and a pair of nuts to set the tension and lock it in place. ________# /#_________ (0 0) \ / \ / \ / \ / \/ /\by rocket_scientist - General
One of the possible ways to manufacture a PCB board using a reprap is to press heated copper wire onto a thermoplastic substrate. It turns out that this has been done before, and there is a US Patent for this technique, which has no expired. But it means that we can build on this technique if it turns out to be a good way to build the boards needed. The patent refers to insulated wires goingby rocket_scientist - Kartik M. Gada Humanitarian Innovation Prize
To build a truss or panel bigger than the working surface, it is necessary to add new material onto already made pieces that have been moved to extend of the edge of the bed (secured by movable arms/clamps and positioned with registration pins). This means that the extruder has to build right up to the side of something taller than the current piece under construction. Normally, the extruder headby rocket_scientist - Kartik M. Gada Humanitarian Innovation Prize
I doubt that I will ever come close to being the prize winner, but I would like to declare a team and base design. I don't have a blog yet, (or even a working RP!), so I will add that later. The basis of my design is a cubical structure, with a fixed bed and 3 axis gantry for the extruders. The fixed bed will allow the largest possible piece to be only the width of the extruder and gantry mounby rocket_scientist - Kartik M. Gada Humanitarian Innovation Prize
What about using a meat grinder? Something that worked in progressive stages, so that large objects to be recycled and something like a tree shredder cuts them down to smallish chunks. Then a coarse grinder to get them to the chip stage. A meat grinder to make a coarse powder, and maybe a wheat grinder like pair of counter rotating disks to grind that to a fine powder. Mikeby rocket_scientist - Kartik M. Gada Humanitarian Innovation Prize
I was thinking that a ceramic extruder would be useful for making molds for casting aluminum, tin, pewter etc. With advances in technology, this could be raised to the level of casting copper and/or steel. I remember seeing a 3D prototyper somewhere that cast plaster, cement, or some other ceramic like material, but I can not remember more clearly right now. A quick Google search has shown that tby rocket_scientist - Kartik M. Gada Humanitarian Innovation Prize
Good points. Sorry Larry for using the term 'braided'. I had a brain freeze and could not remember wire rope, or if I did, I thought it wasn't specific enough. For our work, uncoated is essential. As I remember, many drafting tables, back in the day when drafting was done by hand, used the same figure eight tight cable and pulley system to keep the horizontal drafting bar perfectly parallel throuby rocket_scientist - General
I would like to point out that there are more choices than just lead screw versus belt drive. Some have mentioned rack and pinion as being faster, but moving the motor onto the stage. Another approach is to replace the belts with aircraft cable (braided wire cable, not sure what it is called in Europe). This has the advantage that it can bend in several directions, allowing the wire to wrap (posby rocket_scientist - General
I am at the other end of the country. I am in Phoenix, AZ. I am starting a McWire to bootstrap to a Mendel. I am hoping to someday bring some support back to the McWire project so that others can start making parts a lower initial expense. Although, I am beginning to wonder if the stepper motors and electronics and extrudder are most of the non-RP parts, and there might not be much difference inby rocket_scientist - Pennsylvania RepRap User Group
A second benefit of adding sides, top, and bottom, even of acrylic, is that it would help maintain an even temperature of the piece being built if a hot plate is used under the part. And for future enhancement, if metal extrusion becomes possible, it might work better in a low-oxygen environment. This will be much easier to achieve with a fully enclosed reprap machine. To make the machine morby rocket_scientist - General New Machines Topics