Every injection molding job starts with the mold, not the machine. Before touching a parameter screen, confirm the structure fits the part: two-plate vs. three-plate for gating and runner balance, slider and lifter layout for undercuts, ejector type and placement for release, and cooling circuit design for cycle time. A hot runner system suits large-volume, thin-wall parts where runner waste hurts, but adds thermal control complexity; a cold runner keeps tooling cost down for short runs. Gate location drives weld line position, packing efficiency, and warpage — get it wrong and no amount of tuning saves you. Steel selection and draft angle (typically 1–3° on walls) belong in this same conversation, because ejection marks and sticking parts usually trace back to tooling decisions, not machine settings.
Parameter setup is a sequence, not a guess. A workable ten-step order runs: barrel temperature and soak time, shot size, injection speed profile, switchover point (position or pressure), packing pressure and time, hold-on, cooling time, mold temperature, screw back pressure and decompression, then clamp force. Set melt temperature per the resin datasheet first — a 30–40°C window is common for commodity grades — and let it stabilize before judging anything else. Profile the injection speed so the melt front stays uniform; fast fill at the gate, slower through thin sections. Set switchover by position for repeatability, then tune packing to part weight: weigh parts at increasing pack pressure until weight plateaus, then back off slightly to avoid flash and built-in stress. Cooling typically consumes 50–70% of cycle time, so mold temperature control is a cycle-time lever, not an afterthought.
Document every change. A setup sheet with actual values, not nominal ones, is what lets the next shift reproduce a good run — and what tells you whether a defect is a tooling problem or a process drift. Keep first-article samples and short-shot studies on file; they settle arguments fast. If you are sourcing molds or comparing tooling quotes, visit MoldSo at www.moldso.com for mold sourcing information and supplier references.