FAQ on RepRap Prusa i3 3D Printer

Published on in Series RepRap Prusai3 Build Manual


Heat bed not reaching target temperature

This can be due to

  • Due to not enough power, Heat bed requires at least 12V, 500W power supply. Try upgrading it
  • Surrounding environment is too cool, You need to build a heat chamber to keep the printer warm
  • Fan blowing on your heat bed, try lowering the fan speed

Hotend not reaching the target temperature

  • Surrounding environment is too cool, You need to build a heat chamber to keep the printer warm
  • Fan blowing on your heat bed, try lowering the fan speed
  • Not enough power, try upgrading your SMPS unit
  • Check the thermistor and heating cartridge

What is the extrusion temperature for PLA/ABS?

  • The range for PLA: 170 - 200 degree C (default 190C)
  • The range for ABS: 190 - 230 degree C (default 200C)

First set the temperature to default and check if extrusion works properly, Then gradually increase/decrease the temperature and find the best temperature for your filament

How steppers work and how to adjust their drivers

Stepper Motor not turning or Vibrating

This can be due to 2 reasons, Improper wiring or Insufficient current [or] Incorrect stepping mode

1. Improper wiring

signal mapping and wiring diagram are below

  • Red: 2B
  • Blue: 2A
  • Green: 1A
  • Black: 1B
2. Insufficient current
  • This is mainly due to insufficient current, in case of RAMPS board turn the POT on Step Stick till it starts rotating.  Also make sure you power supply is at least above 10A.

How To Assemble JHead Hotend for RepRap Prusai3

3. Incorrect stepping mode
  • RAMPS for marlin should set to 116 stepping mode. The stepping mode is selected based on the jumper setting under every step stick. for 116 mode all 3 jumper should be shorted using jumper cap.

Printed parts come out mirrored

It can be fixed by changing Marlin firmware configuration, edit Configuration.h file

#define INVERT_X_DIR true
#define INVERT_Y_DIR true

You need to invert the above define macros, depending on axis.

  • Printed object is horizontally flipped, you need to change INVERT_X_DIR
  • Printed object is vertically flipped, you need to change INVERT_Y_DIR

If the above macro is set to true, then set it to false or vise versa depending on the axis

How to clean extruder nozzle?

Everything you’re using to 3D print with should be perfectly clean.

Cleaning ABS: Just wipe everything down with acetone after every print you do.

Cleaning PLA: it’s a little harder, but a good solvent to use is a propanol/hydroxide mixture. [or] If that doesn’t work, try heating the syringe carefully with a torch, having removed it from the rest of the machine

How to clean Heatbed?

Cleaning Print bed: Make sure you wipe any dust and residue off of your build table before each print and if you’re using blue tape over a build surface, remove it after each print.

How to solve Nozzle Clogging issue?

Every time a large, high-quality print is run, clogged nozzles will always be a problem. The problem arises generally because of a build up of filament inside the injection syringe. When the filament gets too hot, it fully liquefies and the pressurised plastic shoots out of the nozzle. Another cause is burnt filament, which solidifies inside the syringe and won’t budge for anything. There’s a few steps an operator can take to avoid this problem.

Can I switching between filament?

Using PLA, then ABS, then PLA, then ABS, will likely to cause problems eventually, Don’t forgot to turn the printing temperature down and the nozzle burnt or some other issue.

What is the temperature for extruder ?

Make sure you’re working at optimum temperature. The ABS and PLA optimum temperatures vary by a few degrees depending on what type and colour of ABS and PLA you’re using.

  • PLA: 170 to 200 C
  • ABS: 190 to 230 C

Some known printing issues and reasons

Bed levelling

Levelling Print bed is to be done to get perfect prints

Help us improving this documentation, leave your comments, suggestion and correction in the comments section.


This article is part of RepRap Prusai3 Build Manual series.

  1. Bill of Materials for PrusaI3 3D Printer
  2. How To Assemble RepRap Prusai3 Frame
  3. Wiring RAMPS Electronics for RepRap Prusa i3 3D Printer
  4. How To Configure and Compile Marlin Firmware
  5. How To Configure Slic3r for RepRap Prusai3
  6. FAQ on RepRap Prusa i3 3D Printer [This Article]
  7. How To Calibrate 3D Printer for Better Prints
  8. 3D Printer Troubleshooting Guide

TAGS: prusai3 faq

Share on: Email Facebook Twitter


View/Write Comments