Ordliste
Die wear — definition
Gradual degradation of the steel tool from thermal shock and erosion, which over time shifts the dimensions of the part.
On every shot the die surface is heated and cooled again. Over time that produces a fine network of micro-cracks, known as heat checking, which prints onto the part. At the same time the steel erodes where the metal flows fastest, typically at the gate.
The practical consequences are three: flash increases in the parting line, dimensions drift slowly, and the surface becomes gradually rougher.
This is why tool maintenance is a continuous delivery rather than a one-off job. A part inside tolerance at shot 1,000 has to still be inside it at shot 200,000.