MOST RepRap Build

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Sunhusky.png By Michigan Tech's Open Sustainability Technology Lab.

Wanted: Students to make a distributed future with solar-powered open-source RepRap 3-D printing and recyclebot recycling.
Contact Dr. Joshua Pearce or Apply here

MOST on RepRap: Projects and Publications], Methods, Lit. reviews
Twitter updates @ProfPearce


This page is part of an international project hosted by MOST to use RepRap 3-D printing to make OSAT for sustainable development. Learn more.

Research: Open source 3-D printing of OSAT RecycleBot LCA of home recyclingGreen Distributed Recycling Ethical Filament LCA of distributed manufacturingRepRap LCA Energy and CO2 Solar-powered RepRapssolar powered recyclebot Feasibility hub Mechanical testing Lessons learnedMOST RepRap Build

Make me: Want to build a MOST RepRap? - Start here! • Delta Build Overview:MOSTAthena Build OverviewMOST metal 3-D printer Humanitarian Crisis Response 3-D Printer


This page documents the RepRap build for the Michigan Tech Open Sustainability Technology Research Group.


-March 2012 - Printing with a purchased J Head hot end. Calibrating and making test prints for mechanical testing.

-12/9/2011 - First extruder hot end failure. Going to change from nichrome heater to embedded resistor.

-12/2/2011 - Fixed problem of having the printer move slowly despite the high feed rate set in Skeinforge. I had "Cool" activated which sets a minimum layer time, and since I was printing a small part, it forced it to take a minute per layer no matter what the feed rate is. Deactivating "Cool" solved the problem, although a shorter Minimum Layer Time should work also.

-11/30/2011 - Fixed some problems of having inconsistent extrusion by tightening the pinch-wheel bolt on which the gear was slipping. Still had problems with too much filament being extruder causing build up. In Skeinforge under Fill I changed the Infill Width over Thickness ratio from 1.5 to 2.5. This has fixed the problem enough for me to complete my first print. It is poor quality, but is a starting point for making adjustments. I think changes need to be made to the Feed Rate/Flow Rate and Layer Height.

-11/9/2011 - Mounted and testing heated print bed. Using glass as the print surface on top of the PCB with the thermistor taped to the top of the glass. Still trying to figure out problems with the G-code from Skeinforge.

-11/4/2011 - First printing test. Had problems with the extruder speeds in the G-code as well as problems with the extruder not putting out filament when it should. Couldn't complete an entire print due to the filament not sticking well to the bed and aforementioned extruder problems. Currently I am using Skeinforge to generate G-code and then I am running it in RepSnapper.

-11/2/2011 - First extrusion test, successful with nozzle temperature around 230C for ABS.

Two printer Reprap species are in place: Mendel and Prusa. In order to minimize spares inventory and ease machine maintenance, where possible, common parts/software will be employed:

Common Components (mostly)

  • RAMPS 1.4 electronics
  • Marlin firmware (only stable versions will be loaded on production machines) [[1]]
  • Mechanical end stops
  • NEMA 17 motors
  • T5 belts
  • AlephObjects 12 tooth x/y drive sprockets [[2]]
  • Standard Wade's extruder [[3]]
  • 11/39 involute spur gears for extruder [[4]]
  • Printable LM8UU bearings [[5]]
  • Parametric z-axis coupling [[6]]
  • Wire holder/standoffs [[7]]


  • Model: Mendel
  • Printed Components: Commercial RP parts from Queen's University
  • Control Software: RepSnapper - Tim Schmidt Version (as of 10/31/2011) [8]
  • G-Code/Slicer: Skeinforge
  • Print Bed Heater: Josef Průša PCB Heatbed MK1 [9]
  • Print Surface: Glass covered with Kapton tape

The Build

To build the RepRap Mendel, follow the instructions on the RepRap wiki.

-Build Manual
-Mechanical Construction

Deviations and problems not found in the above documentation are described below for each sub-system.


Instructions - X-Axis Build


Instructions - Z-Axis Build


Instructions - Y-Axis Build


Instructions - Frame Build


Extruder Troubleshooting

Bolt - cut grooves with Dremel instead of hobbing

Print Bed

Heated bed mounting instructions - June 14, 2011 Post

To get the PCB to mount at the correct height on the wood bed, the bolts mounting the wood bed to the Y-chassis need to be countersunk.

Installing Software

Arduino - Download, Instructions for Ubuntu with screenshots

RepSnapper - Tim Schmidt Version

-Use instructions for Ubuntu 10.10 if you have Ubuntu 10.04 or you won't get all the dependencies
-When connecting to printer, make sure you set the correct baud rate or you can't talk to the controller. Default baud rate in Sprinter is 115200.

Sprinter Firmware- Sprinter Instructions and Download, RepRap Sprinter Guide

-The instructions are for using it with Sanguino, but you can still use it for RAMPS.
-Works with Arduino 0022 also.
-Modifications to the configuration.h file need to be made as explained on the RepRap page
-Configuring Sprinter Video

Cura -

Skeinforge - Download, Documentation

Description of G-Codes
Reprap Wiki: G-Codes
Forum: Skeinforge Settings
Forum: "Nozzle Drag" - Discussion of getting correct fill parameters
Mendel-Parts Forum: "Skeinforge 40 setup notes" - General overview of initial Skeinforge settings
Gary Hodgson - Skeinforge E steps issues and settings
Set non-printing axis speed in Carve->Maximum Initial Feed Rate

Useful Links

Configuring Sprinter - [10]


Calibrating X,Y, and Z Axes -[11]

General Calibration Equation: <math> {Desired\ Distance \over Actual\ Distance} Steps\ in\ Firmware = New\ Steps </math>

Setting Z-Axis Height - Forum: "How to set the Z axis home?"

Extruder Volumetric Calibration:

Josef Prusa E steps calibration
Wiki Volumetric Dimension Settings
Forum: Discussion on E steps and Filament Density Packing Ratio


-May have to clean the nozzle to remove built up, burnt plastic

See Also