When a customer sends over a part drawing, the first decision on our floor is never which machine is free — it's which process the part actually belongs to. Injection molding covers the widest range: wall sections from roughly 0.5 mm up, tight tolerances, and complex cores and sliders in hardened P20 or H13 tooling. Blow molding suits hollow bodies where parison control matters more than cavity steel; extrusion handles continuous profiles where the die, not the mold base, does the shaping. Thermoforming, rotomolding, and compression molding each have their own boundary conditions. Picking the wrong process means fighting the tooling for the entire program, so we map part geometry, annual volume, and material first, then commit to a mold concept.
Setup is where good intentions go sideways. On injection jobs, we log melt temperature, injection speed, and holding pressure per shot and watch cavity pressure balance across the tool — a starved end-of-fill cavity usually points to a gate or venting issue, not a machine setting. For blow molding, parison drop timing and mold closing speed decide wall thickness distribution; chasing it with air pressure alone just moves the defect. Extrusion die tuning is iterative by nature — adjust the lip, pull a sample, measure, repeat — and we keep a die log for every profile so the next run starts close to the last good setting. The common thread: fix the tool and the process window before touching the control panel.
None of this works without disciplined documentation. We photograph gate locations, record cooling line layouts, and note ejector positions on every tool so that when a mold moves to a second machine, setup doesn't restart from zero. That habit — treating the mold drawing and the process sheet as one document — has saved more debugging hours than any single machine upgrade. For teams sourcing molds or comparing process options across suppliers, visiting MoldSo (www.moldso.com) is a practical next step for mold sourcing information.