G-code custom formula in the CURA start code

[OUPS65 3]

He,

I print with 0.2 and 0.15 nozzles with CURA 4.0.0. The few cool filament remaining in the nozzle at start tends to generate on  the next print an under-extrusion or worse a clogging. I eliminate this problem  by extruding -before each new print- 5cms at the first layer temperature + 15 °c.

In the same spirit, I fully retract the filament at the end of each print : G1 E-160 F600 … again with an extrudeur T° set at first layer temperature +15°.

It works perfectly and I have no more worries.

I set both higher T° manually in my start/end g_codes but have to update them  at each first layer T° change (filament change).

In the start/end g_code, the formula  M104 S {material_print_temperature_layer_0}  to obtain a T ° equal to the first layer T° defined in CURA 4.0.0 profile works fine.

But how to increase it by + 15 ° ?

I tried unsuccessfully various formulas: M104 S{material_print_temperature_layer_0 + 15} or M104 S {material_print_temperature_layer_0    +15}, or M104 S{(material_print_temperature_layer_0) +15} or M104 S {material_print_temperature_layer_0 * 1.1}

None works.

Any suggestion ?

Many tks

Philippe

[ahoeben 1,968]

You can not do arithmetic in Gcode snippets in Cura, sorry.

[OUPS65 3]

Tks for your answer.

kind regards