Injection moulding material guide
Every setting that lives on a Injection moulding material, and where each number comes from - usually a supplier's data sheet or an invoice.
A material is something you buy, so most of these numbers are on an invoice or a data sheet rather than in your head. Price and density are the two that matter most; get those right and everything else is a refinement.
Materials live in the Library too, so a price change is one edit even if five configurations use it.
Every setting on this page
These are in the same order as the editor, with the same help text. Each one has an anchor, and the ? beside a field in your console links straight to it - so if you are reading this because you clicked one, the setting you were looking at is highlighted.
Thermoplastic: moulding
Melt temperaturemelt_temp_c
Temperature of the melt entering the mould.
Price: Hotter melt takes longer to cool; also checked against the press's barrel.
Typical: PP 230 · ABS 240 · PC 300 °C.
Mould temperaturemould_temp_c
Temperature of the mould surface.
Price: A hot mould cools the part more slowly.
Typical: PP 40 · ABS 60 · PC 90 °C.
Ejection temperatureeject_temp_c
Temperature the part may leave the mould at without distorting.
Price: The closer it is to the mould temperature, the longer the cooling.
Typical: PP 90 · ABS 95 · PC 130 °C.
Thermal diffusivitythermal_diffusivity_mm2_s
How fast heat moves through the melt.
Price: Cooling time is wall² over diffusivity: the main term of the piece price.
Typical: 0.07-0.15 mm²/s.
Cavity pressurecavity_pressure_bar
Pressure in the cavity the clamp has to hold shut.
Price: Projected area times this is the clamp force, which decides the press.
Typical: PP 350 · ABS 450 · PC 650 bar.
Hold timehold_s
Packing time after the cavity is full.
Price: Added to every shot.
Typical: 2-6 s.
Cold runner sharerunner_pct
Mass of sprue and runner per shot as a share of the parts' mass.
Price: Material paid for and scrapped or reground on every shot; zero on hot-runner tools.
Typical: 10-30 %.
Thinnest wallmin_wall_mm
Thinnest wall the melt fills reliably in this material.
Price: No direct price effect: the threshold of the thin-wall warning.
Typical: PP 0.6 · ABS 0.8 · PC 1.0 mm.
Thickest wallmax_wall_mm
Thickest wall before sink marks and very long cooling.
Price: No direct price effect beyond the cooling time: the threshold of the thick-wall warning.
Typical: 3-4 mm.