Material decisions shape cost, appearance and durability. This hub collects our practical guides on molding resins, mold steels and surface finishes – written by the engineers who use them daily.
Molding Resins
From commodity PP to high-temperature PEEK: properties, typical uses and selection advice. Injection molding materials guide →
Mold Steels
P20, 718H, H13, S136 and NAK80 compared by hardness, polishability and tool life – with our honest recommendations by project type. Mold steel selection guide →
Aluminum Tooling
When aluminum molds beat steel – cost, lead time and tool life compared honestly. Aluminum molds guide →
Design Rules That Depend on Material
Draft angles, wall thickness and gate strategies all change with the resin. Mold design guide → and mold flow analysis → show how we de-risk the combination before tooling.
How to choose a molding material
Material choice drives part cost twice over: once in resin price per kilogram, and again in mold design, because shrinkage, glass content and abrasiveness change steel grade and cooling layout. ABS remains the default for housings because it molds easily and paints well. PC earns its higher price where impact strength or clarity is needed. PA66-GF30 replaces metal in brackets, but its 0.3-0.5 percent shrinkage range demands careful flow simulation before the steel is cut.
Start from these guides
- Injection molding materials guide – properties and typical uses of 20+ resins
- Mold steel selection – matching P20, H13 or S136 to resin and volume
- Aluminum molds – when a 7075 tool beats steel on cost
- Clear injection molding – PC, PMMA and PETG without streaks
If you send only the application – outdoor, food contact, 85 C continuous heat, UL94 V-0 – our engineers propose two or three candidates with a cost comparison in the quote.
Two practical notes from the molding floor. First, resin certificates matter: we mold from sealed, lot-traced material with certificates of analysis, and food-contact or medical grades carry their own compliance documents – mixing lots is how appearance drift starts. Second, regrind policy is worth deciding before production: virgin-only for cosmetic and regulated parts, controlled regrind percentages (typically up to 15-25 percent) for internal industrial parts where cost matters more. Both options are priced transparently in the quote – see the materials guide for property details and the cost guide for how resin choice moves piece price.
Last, a note on material substitution: when resin prices spike, the cheapest switch is rarely the nearest equivalent. Moving from PC to PC-ABS changes shrinkage and requires a drying change; moving from PA66-GF30 to PPA-GF30 changes processing temperature entirely. We model substitutions in simulation before recommending them, and re-quote the piece price honestly rather than assuming the old cycle time holds.