Template:RepRapPro printing next steps

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Revision as of 11:49, 8 March 2013 by SallyRepRap (talk | contribs) (Tuning your printer)
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Tuning your printer

The skeinforge print profiles are tuned based on an assumption as to how much plastic is fed into the extruder for a given number of steps of the extruder drive motor. A critical parameter affecting the quality of the prints is how accurately skeinforge knows the volume of plastic it is feeding into the extruder. In practice, this will vary slightly between machines. This is due primarily to the actual filament diameter, and to variations in the effective diameter of the hobbed stud.

The filament diameter should be measured and the value entered in skeinforge's Dimension plugin.

The E steps/mm setting can be adjusted without uploading new firmware, using M92 Ee, where e is the new E steps/mm value. By default the firmware has this set to 980. When this value is tuned, the top surface fill will have virtually no gaps between lines of filament, and no extra plastic at the ends of the lines. To check and adjust it do the following:

  1. With the machine off remove the tongue from the extruder drive;
  2. Wind filament through by turning the gear by hand; the end of the PTFE tube will come out of the drive;
  3. Wind through about 50mm of filament and cut it with sharp sidecutters about 5mm downstream of the drive;
  4. Carefully mark where the stub of filament is flush with the drive exit with a fine felt-tipped pen;
  5. Turn on the machine, send it an M302 command (allows for cold extrusion), and extrude 100mm of filament;
  6. Mark again with the felt-tipped pen;
  7. Extrude another 10mm and cut off your measured sample;
  8. If the sample is L mm long and your current steps/mm is e, then change e to be e*100/L; (using M92 Ee, where e is the new E steps/mm value)
  9. Run the test again to check you now get 100mm;
  10. To make the change permanent send an M500 command to store the values in EEPROM
  11. Heat the hot end up to temperature;
  12. Push a little filament through by hand from the 50mm you left sticking out, then pull the filament out to leave the path free;
  13. Reload the machine in the usual way.


If the E steps/mm is set too low, a gap will separate the fill lines


A good test piece for this exercise is a 3mm high 30x30mm square.

Once you are happy with your E steps/mm value, you can edit your firmware as per these instructions. Please update your firmware even if you don't need to change this setting; new versions come out regularly for fixing bugs (like the bug where an unplugged/failed thermistor means the heater goes to full power)!

Print another RepRap

So can I print more RepRaps in my RepRap?


Your RepRapPro printer has been designed to replicate - that's what the Rep stands for. Indeed, RepRaps are humanity's first self-replicating manufacturing machines.

Replicating the plastic parts for another RepRapPro is easy. You can then use them to make a new RepRap (maybe with your own experimental design changes). Or you could make the RepRap plastic parts for a friend. Or you could sell sets of RepRap plastic parts to other reprappers on eMakerShop or eBay.

RepRap's free GPL Licence means that you are completely at liberty to do all of these things.

Go to this wiki page to find out how to print a complete set of RepRapPro Huxley plastic parts.

Go to this wiki page to find out how to print a complete set of RepRapPro Mendel plastic parts.


Printing with different plastic may require modified print profiles. Have a look at this page for details, and if your plastic isn't listed, please add to the table once you have worked out the best settings.

Changing Filament

  1. Heat nozzle to operating temperature.
  2. Reverse filament until it comes out of the extruder drive (about 380mm). You can do this at 600mm/min.
  3. Command M84 to turn the motors off. Feed the new filament in by hand.
  4. Drive/feed the filament to just before the hot end.
  5. Command the filament at 200mm/min until it squirts out of the nozzle. You may need to hold the bowden tube straight for the filament to go down into the hot end easily.