On Sun, Jun 12, 2011 at 4:29 PM, Colin K <cwk....@gmail.com> wrote: > On Sun, Jun 12, 2011 at 5:46 PM, Mike Payson <m...@dawgdayz.com> wrote: > > > On Sun, Jun 12, 2011 at 1:31 PM, Colin K <cwk....@gmail.com> wrote: > > > > > > For a long time I was very skeptical of the whole "machine that makes > its > > > own parts" aspect as I thought, "why bother, aluminum extrusion is > > cheap?" > > > > > > > I am actually working on a design that uses the printed parts, but > replaces > > the threaded rods with aluminum extrusions. It should be considerably > more > > rigid and allow faster print times without as much of a degradation in > > print > > quality. The only downside is cost... instead of $15 in threaded rod, it > > will require about $45 in al extrusions. I know that raises the price to > > high for many, but sometimes you cannot avoid it </sarcasm mode off>. > > > > Not sure where the joke begins or ends there :) But seriously, is rigidity > in the frame lacking? Because I was thinking that I could replace the 5/16" > threaded rod with something like 3/8" or 1/2" drill rod and just turn an > inch or so of 5/16" thread on the ends to attach to the brackets. But not > sure what the limiting factors are... I was figuring I'd start stock (or > very close to it) and re-engineer parts as experience dictated. Though > making aluminum motor mounts was pretty high too... >
The problem with the rigidity is not due to the threaded rod, but how it is all put together. It is quite rigid in the Y axis (parallel to the triangles), but is pretty flexible in the X axis. You certainly could make the current designs more rigid, but not without making them more complex at the same time. The design I am working on is generally simpler than the current designs, but it is also more rigid. That said, if you want to build one, I _strongly_ recommend you start with a standard Prusa Mendel (http://reprap.org/wiki/Prusa) and only start experimenting after you have got that up and running. The current design has it's limitations, but they are relatively minor and the current design is used by so many people in the community that it is easy to get support for it. FWIW, there are parts that are problematic, but I would say that the motor mounts are not among them. > Will they ever print their own stepper motors? Probably not in > > > the next 10 years, but I would not be shocked if in that time we were > > > printing PCBs and using the RR as a pick-and-place machine. Even that > may > > > be enough to significantly alter some of the dynamics of the > > macro-economy. > > > > You cannot print PCBs yet, but you can use the RepRap to apply resist for > > home etching boards. Personally, I don't see the point when you can buy > 10 > > PCBs from China for $13 delivered, but others like it. It is a nice > option > > to have at least. > > > Yes. But the problem with China is that the minimum spend is $130, while > batch services add weeks to the build cycle. No, you can get 10 2x2" PCBs for $13 US delivered. Not $13 each, $13 total. That is with slow shipping (typically 2-3 weeks in transit), but you can get them sent via DHL for about $30 more which only takes a day or two. Larger boards are cheap as well, for example 10 4x4" boards are $29 delivered. I have used both these suppliers and they both do good work at that price: http://iteadstudio.com/store/index.php?main_page=index&cPath=19_20 http://www.seeedstudio.com/depot/fusion-pcb-service-p-835.html?cPath=185&zenid=1b82e8551d60a29f6b0874a1d89574df That said, drilling holes by > hand is a huge PITA and I love soldermask on my boards. So I'm wondering > whether the typical RepRap bot could handle, say, a Dremel running PCB > drills. And whether you could make a soldermask "stencil" by extruding > plastic over the pads to cover them, then spray soldermask, let dry, then > knock the plastic bits off to expose the bare pads. If all that works, then > keeping an etch tank around doesn't feel like too big a burden. All this has been talked about in the community. Some people have mounted dremel's to their bots, it certainly is possible. Personally I prefer "real" boards, and have no aversion to designing small boards (I like the challenge) so I tend to just attempt to keep my designs under 2x2 and get them from China. ------------------------------------------------------------------------------ EditLive Enterprise is the world's most technically advanced content authoring tool. Experience the power of Track Changes, Inline Image Editing and ensure content is compliant with Accessibility Checking. http://p.sf.net/sfu/ephox-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
