Prusa Mendel Documentation

This is the page on how to use the newly built Prusa Mendel (iteration 2)

Current Machine Status

Operational

Workflow

CAD/Thingiverse -> Netfabb -> STL -> Slic3r -> Pronterface -> PRINT!

CAD

Any modelling software that can output the file format STL.

Some programs of interest might be the following: Google Sketchup, OpenSCAD, TinkerCAD, Solid Works, AutoCAD, Rhino.

And in case you don't want to model anything and simply want to print stuff, go to Thingiverse.

Netfabb

software for checking the "3D printability" of the model you created. Go to Netfabb and download the Studio Basic option. You can also simply use their cloud offering and have a repaired model emailed back to you.

if your model has issues, run the repair function with default settings and see if that remedies the issues. The repair function can be used by clicking the "first aid" symbol found at the far right on the tool bar.

STL

current format for 3D printing (AMF is coming around the corner).

at this point, your file should be patched up and ready to print.

Slic3r

software for creating 3d printing toolpaths

precompiled binaries can be had from Slic3r.org or be built built from github.

use the profiles already generated for best results.

Pronterface

GUI for controlling the Prusa.

where you will connect to the printer, home, warm up and send print jobs from.

can be built from github or download precompiled binaries for Windows/Mac here.

preview G-Code generated by Slic3r.

Print

File is good to go, toolpaths are generated, time to let the robot do what it does best, PRINT!

Materials

• PLA
• ABS

PLA

Polylactic Acid

made from corn starch, smells like waffles/syrup while printing

less prone to warping

more brittle compared to ABS

needs a fan, it remains much more molten after being extruded

lower operating temperatures (160C-200C)

Preferred plastic of choice

ABS

same plastic in which LEGOs are made of

flexible

higher operating temps (220C-240C)

smells like death, can release carcinogens at higher temps

requires a heated bed (110C) or warping occurs

requires kapton/PET tape on heated print surface for best adhesion. Possibly a light sanding of the surface and slurry of dissolved ABS in acetone for further warp prevention.

John

• 1x RAMPS 1.2
• 5x steppers
• 1x wade's extruder (assembled and working)
• 1x 36mm brass barrel
• 1x 0.5mm mbi nozzle
• 1x 0.5mm makergear bighead nozzle
• Insulator materials (have to make and document on lathe)
• nuts/bolts/washers - I have tons
• plywood/mdf for build platform

Heated Build Platform

1x Prusa PCB HBP Mk1

Offers

• Alden has a Tiny G board... this is attractive
• Andy has fresh smooth and threaded rods to swap for all the rusted rods

How to flash firmware

• download Arduino23 from arduino.ccunzip the arduino package
• get the latest Sprinter fw from https://github.com/kliment/Sprinter or Marlin fw from https://github.com/ErikZalm/Marlin
• open up Arduino and open the fw of choice (select either Sprinter.pde or Marlin.pde)
• edit the configuration.h file to list a motherboard type of 21 (make sure right thermistor settings are chosen as well)
• plug in RAMPS 1.2
• set the board to Arduino Mega 2560 under "Tools"
• set Serial Port to appropriate port
• save/compile/upload the sketch

How to connect and control the printer

Download latest PrintRun from http://koti.kapsi.fi/~kliment/printrun/ for Win/Mac (precompiled), https://github.com/kliment/Printrun: Linux

• If running Linux version, checkout the Readme for dependencies
• If you dled for Win/Mac from link above, all dependencies are built in (INCLUDING Slic3r!)
• fire up pronterface.py
• set the serial port to one which RAMPS is connected
• make sure baudrate is set to appropriate setting (set in FW)
• click connect to printer button
• you should see confirmation of printer connection in the monitor box on the right
• load stl and slice it with slic3r in the gui, or load up a gcode file you're already processed with other slicer

To do

PSU: Done The electronics need an ATX supply (200W minimum probably, 350-700W+ would be needed if we run a heated bed) to power the mobo, and we'll need to hack out a 12V and a 5V line to connect up to the larger perfboard electronics that run the extruder/heatbed (these should be on a 12v2 rail on newer psu). I've got some connectors to do this the next time I'm in the space, or we can just cut the connectors off of the atx wires. Steppers: The P4AC 4 axis board will need to be pulled from the cupcake, and the XYZ connected to the mobo. (we'll need another 10pin idc cable. the current rainbow cable on the gen3plus setup is the X stepper cable from the cupcake stepper controller and will have to go back once we swap out the p4ac to the mendel. I have some 10pin idc cables at home I will bring in to replace the one in the gen3plus) I have the 4th pololu in the larger perfboard, but I can easily drop in a 10pin idc header so that we can have all the pololus on the one board, which I'll do the next time I'm in the space. Mosfets: tip120 replacements are attached to the board in case the current ones die or if someone has time to do the replacement. The Nchannel Power Mosfets on the larger perfboard were ones I got from radioshack, so I'm not sure if they'll be able to run the heated bed, but they should be fine for the extruder. I have proper 50V 10A mosfets I can swap in place the next time I'm in the space or if the ones in there right now fail. Motor Connections: The motor wires need to be connected to the pololus. Any 4 conductor cable should work fine. I have solid core 4 conductor wire I used on my bot at home, but the single conductor is a bit fragile and I'd recommend a nice stranded set instead. I have matching molex connectors and crimps so the connection to the p4ac board is via a plugged connector instead of soldered in or done with some other hacked connector. Endstops: The ends stops need to be hooked up. The p4ac board has breakouts for the endstops, so just need to wire up microswitches on to that board. only need two wires to each switch, signal to the COMmon contact and GND to the NO (normally open) contact, the firmware uses internal pullups for the endstop pins.