M302 not working. Any ideas? Printing with PCL at 130 °C and PVA as support

[Tsn 0]

I am trying to print a model with PCL (Polycaprolactone) from extruder 1 (which has a very low melting temperature and needs the extruder to be 130 °C) and PVA as a support material from extruder 2 on the Ultimaker 3.

To enable cold extrusion I changed the Gcode and inserted the M302 command at the start of the Gcode and uploaded the file to a USB drive to print via USB.

The first layer is printed perfectly, but at the second layer no extrusion of PCL occurs. The PVA extrusion is working at every layer.

As a test i inserted the M302 command at every new layer in the Gcode (after each line ";LAYER: ...") But this did yielded the same result. Extruder 1 with PCL only extrudes ate the first layer.

Is there a way to lower the minimum extrusion temperature of extruder 1 so that extrusion at 130°C is  possible?

Edited March 1, 2017 by Guest

[Daid 306]

After a T0 or T1 you need to use M302 again, as the hotend lifting code is disabling and enabling the minimal extrusion temperature.

[Tsn 0]

Thank you Daid!

When printing a model with a single material yesterday one M302 command at the start of the Gcode did the job, so I got the feeling that it had something to do with the hotend change.

I started a small print of 15 layers in which i added M302 after each T0 and now I have extrusion on every layer with both extruders. So it works!

I just started a larger print of 378 layers, so we will see how it turns out.

Thanks again for the quick answer!