Mendel Prusa – time to make it happen.
Using the Marlin firmware.
Measured the X and Y transport at 100mm and it looks reasonably close. Using 80 steps per unit on the x and y axis by using Prusa’s RepRap Calculator
I try to run some filament through, but it just doesn’t go. After pulling apart the extruder and cleaning the hobbed bolt a number of times, I decide to go further and pulled apart the Arcol v3 hot end. It took quite some time, but I found that there was some filament clogged in the bottom. I didn’t have something small enough to poke through the .5 mm hole, so I grabbed the other Arcol that I had put together for Bottie Bot, but never installed. I had put off preparing the connector, so I had to fire up the soldering iron.
After some looking on google, I see that the Arcol hot end uses a much higher temperature. On Bottie Bot (Makerbot MK6) I use 212 for ABS, and it works fine. On this machine, I need to go to 250 (!) to make it extrude well. I think it is because the hot portion is so small that the temperature must be hotter to melt the filament enough.
I find that my extruder steps are way off. So I used the method described here for slic3r to try to figure it out. I measured 100mm of filament, told Pronterface to run 80mm through, and it ran 96mm. I had it set to (760 * 1.1), so 836 steps per mm. 836 * 80mm is 66880. Divide that by the actual number length (66880 / 96) gives the better value to use: 696.67. Plug that value into the Configuration.h file, rebuild and install the firmware, and try it again to get closer. Ran 80, got 74. so 696.67 * 80 is 55733.6. Divide by 74 gives a better value – 753.16. Let’s try that. Got 78. Do it again. Now we’re at 81. One more time…
I had to disconnect Pronterface from the USB port, go to the Arduino tool, make the change to Configuration.h, set the USB port on Arduino, compile and upload the software, set the USB port to something else to free it up, go back to Pronterface and reconnect. Rinse and repeat.
Okay, now that plastic is squeezing out pretty well, gotta figure out how to get it to print something real. It’s nearly 4am. More later…