Tweaking Manual

Troubleshooting

XY speed too fast, extruder too slow, or layer gap too big

As you can see there are gaps in the infill where it has failed to be laid down properly. This can be caused by:

1. The XY carriage moving too fast,
2. The extruder extruding too slowly,
3. The gap between one layer and the next being too big, or
4. The polymer filament jamming in the extruder.

In the first three cases the solution is obvious. The XY speed is set by the following parameters:

1. Extruder0_XYSpeed(0..255) The bigger this number, the faster the maximum possible XY speed. There's a detailed explanation here.
2. Extruder0_OutlineSpeed(0..1) This is a direct fraction of the fastest possible XY speed above.
3. Extruder0_InfillSpeed(0..1) This is a direct fraction of the fastest possible XY speed above.

The extruder speed is set by

1. Extruder0_ExtrusionSpeed(0..255) The bigger this number, the faster the extruder extrudes. It controls the PWM signal going to the motor. 255 give continuous 12v; 0 powers the motor off. The effective voltage sent to the motor varies linearly between these extremes. Note that a linear change in voltage does not necessarily imply a linear change in speed.

And the gap between one layer and the next is set by

1. Extruder0_ExtrusionHeight(mm) This is the number of mm the Z stage moves down between layers.

In the fourth case, we have found that some polymer filaments are not quite within RepRap filament tolerance specification (which is 3mm +0mm, -0.3mm). In particular occasionally you get a few hundred mm length that can be 3.2 or 3.3 mm in diameter. Such sections jam in the 3mm hole down the PTFE rod that links the extruder to its heated nozzle. There is a simple solution to this problem which sounds drastic, but actually is benign. It is to drill the PTFE out to 3.5 mm (1/8" might just do it, if you have access to Imperial drills, though that's only 3.175mm). The extruder works fine at this diameter. There is no need to do anything with the heated barrel - the polymer is melted all the way down that.

XY speed too slow, extruder too fast, or layer gap too small

This is the exact opposite of all the cases immediately above, except that extruder jamming is obviously irrelevant here.

Got it!

And this porridge was just right...