The finish of an injection moulded part is not decided after moulding. It is cut into the steel of the mould, before the first part. Changing a texture on an existing mould is expensive, sometimes as much as re-machining the cavity.
The main finish families
Texture (grain) is produced by chemical etching or EDM of the cavity, with the VDI 3400 scale as the reference. A grain hides visual defects, weld lines and small scratches. Polish is the opposite: SPI classes from A1 (diamond mirror polish) down to D3. Mirror polish makes sense for transparent parts and premium surfaces, and it scratches in use.
Post-moulding finishes (painting, pad printing, laser marking, metallisation) each add an operation, so a cost per part. The right question: does function or branding require it, or is a well-chosen grain enough?
⚠️ Texture and draft angle are linked
A textured part grips the cavity at ejection. The deeper the grain, the more draft angle you need: roughly 1 extra degree per 0.02 mm of texture depth. A deep grain on a part designed with 1 degree of draft means scuffed or stuck parts. A feasibility analysis catches this before the mould is machined.
Soft-touch overmoulding
For a rubbery grip, the robust option is overmoulding a TPE onto a rigid body. It is a real injection operation, not a coating: it does not peel or turn sticky the way soft-touch paint does.
Send us your 3D file: our partner LGR analyses feasibility free of charge, draft angles and finish choice included.