Friday, February 17, 2012


I've been trying to learn OpenSCAD recently to work on (Open) OM90, and I am banging my head against the wall. I want to do something like this:

//assume pi and the math functions are already defined
void polygon(int r, int N, int theta, int x_off, int y_off)
int x[N];
int y[N];

for(int i = 0; i < N; i++)
x[i] = r*cos((2pi*(i/N))+theta)+x_off; //calculates the X coordinate
y[i] = r*sin((2pi*(i/N))+theta)+y_off; //calculates the Y coordinate

But I don't think that's possible in OpenSCAD. Can someone help me? (also, does anyone know how to do real code posting in blogger?)

Wednesday, February 15, 2012

Design Changes and The Future

       OM90 is rapidly progressing. All MDF is cut and all of the dimensions are correct. Portions of my design are now 0.75" MDF and some are 0.5" MDF. I cut 28 aluminum angle brackets to bolt the frame together, these need to be drilled still. I printed out the X-End-Idler today, which was about 40% successful - the print detached from the bed, ruining itself and nearly munching my thermistor in the process. I was able to check several dimensional things with my design - namely the 8mm rod channel, since the lower one was about 80% done when the print failed, enough to check, and I was able to check the size of my M8 nut traps for the Z lead screw. Both are OK! I also achieved the best surface finish to date with the MakerGear Prusa at school. Printing these parts is helping me to solve all of the teething problems associated with building and using any FFM 3D printer. The MG kit is a beautifully put together machine, and I have had ZERO problems with it that were the printer's fault. It's a great kit to start with, since everything is included. One order, one box. It also comes with clear instructions - on where to find clear instructions.
       In other news, OM90 is going to progress to a "version 2" of sorts soon. One of the big things I've been seeing as I work on my build is that there is a good deal of interest in the community, and people ask often for various features, and make suggestions, which I love. In light of that, to make it easier for the community at large to play with my design, I'm going to begin migrating OM90 from a SolidWorks designed machine to OpenSCAD, which will be quite the transition, as it's my first real play with OpenSCAD. I'm hoping that having a real design target will guide my learning curve. I am NOT going to just give up on SolidWorks OM90 - I'm going to print all of those parts as-is, for the most part, and I'm going to provide pinaise, a friend from #reprap on, with a set of STL files for LM10uu bearings based on SW-OM90. Then, I'm going to take the lessons learned from those parts, and use the hopefully functional SW-OM90 to make the new upgrade parts for "O-OM90" (OpenSCAD-OM90). That's it for now. If you want to see some pictures of the failed X-End-Idler in progress, or of the OM90 designs and work to date, check here.      

Monday, February 13, 2012



Intro to the OpenMendel90

I've started this blog in order to catalog my progress in building my OpenMendel90 design, found here, and debugging all of the problems that no doubt exist, or will soon. I will also simultaneously be building a Prusa Iteration 2, and blogging occasionally about solving issues on the MakerGear Prusa that I built at school. I must clarify: the design ethos of OpenMendel90 WAS NOT MY IDEA. All I did was implement someone else's design with more common parts (Prusa rod lengths, 8mm rod, LM8UU) and publish files. I'm not even sure my design works. Wherever possible, please, please, defer to Nophead's judgement. His work can be found here

As of right now, the OM90 (OpenMendel90) design is just barely in progress. All that exists right now are the MDF parts, some in 0.75" MDF and 0.5" MDF. Also - unfortunately for most of the world - most of the units on this blog will be imperial, as I'm from the States, and it's what I know best. Sorry. I'm going to start dogging the frame together with aluminum angle clamps in a few minutes. I'll post pictures as it moves further along.