In the mold industry, quoting isn’t just about cavity count and steel grade—it’s about understanding how process parameters affect cycle time, shrinkage, and part quality. For example, when quoting a part in ABS, the melt temperature typically ranges from 210°C to 250°C, with mold temperature set between 40°C and 80°C. Injection pressure should be planned around 70–120 MPa, while holding pressure is usually 50–70% of injection pressure. These numbers directly influence the clamp tonnage and machine size you select. If you underestimate the required injection pressure for a thin-wall part, you risk filling issues and sink marks, which means rework and cost overruns. Always cross-check the material’s recommended shear rate and flow length ratio before finalizing your quote.

For semi-crystalline resins like PA6 and POM, the rules change significantly. PA6 requires a melt temperature of 240–270°C, and mold temperature should be controlled at 60–90°C to achieve proper crystallinity and surface finish. Shrinkage for PA6 can vary from 0.8% to 1.5% depending on wall thickness and glass content—this is a common trap in quoting. POM, on the other hand, runs at 190–210°C melt, but its mold temperature must stay between 60°C and 100°C to avoid warpage. The holding pressure for POM should be high, around 80–100 MPa, because it shrinks significantly after ejection. In practice, we also recommend using a slower injection speed for POM to prevent gas traps and burn marks, especially in deep ribs or bosses. These parameters should be documented in your internal mold design checklist, not just left to the operator’s discretion.

Another critical set is for amorphous engineering plastics like PC and PMMA. PC needs a melt temperature of 280–310°C, and mold temperature should be maintained at 80–120°C to reduce internal stress and cracking risk. Injection speed should be moderate, with a pressure of 100–140 MPa, and holding pressure must be carefully tuned to avoid over-packing. PMMA, commonly used for optical parts, requires melt at 220–250°C and mold temperature of 40–70°C, but the injection speed must be slow to prevent flow marks. For all these materials, remember that drying is non-negotiable: PC must be dried to below 0.02% moisture, and PA6 below 0.1%, otherwise you will see silver streaks and brittleness. When quoting, include drying time and hopper capacity in your cycle estimate. For more detailed material-specific parameter tables and mold sourcing tips, visit MoldWorld at www.moldw.com.