Views: 0 Author: Site Editor Publish Time: 2026-11-10 Origin: Site
Many buyers ask whether they should choose an aluminum mold or steel mold for their new injection molded parts. These two tooling options are not simply “cheap vs expensive”. They have different material properties, service life and quality performance, and fit completely different project scenarios.
Aluminum molds are widely used as rapid prototype tools. The common grades are 6061 and 7075. Advantages
Lower upfront mold cost
Fast machining and shorter sample lead time
Excellent thermal conductivity, faster cooling and shorter molding cycle
Soft material, easy and low-cost to modify when the product design changes
Disadvantages
Low hardness and poor wear resistance. 6061 lasts roughly 3,000–8,000 shots; 7075, the best aluminum grade for tooling, only reaches 8,000–20,000 shots with non-filled plastic.
Not compatible with glass-filled, mineral-filled or corrosive flame-retardant materials. Fillings will scratch the cavity and gate quickly.
Dimensions and surface quality gradually drift after continuous production; parting lines turn fuzzy easily.
Cannot achieve high mirror polish.
Best for these cases
New product prototype, DFM check and assembly testing
One-time small trial order with no confirmed repeat demand
Frequent design revisions
Material is unfilled plastic such as pure PP, ABS or PE
Short-run production only, no long-term mass production plan
Not recommended when You have stable annual repeat orders, use abrasive or corrosive resin, require high cosmetic standards, or your total required volume exceeds 20,000 shots.
Steel molds are the standard choice for mass production. We select different steel grades based on your material and quality requirements. Advantages
Outstanding wear resistance and long service life: P20 supports 100,000–500,000 shots; hardened steel can reach over 1,000,000 shots.
Stable dimension and consistent appearance through repeated production runs.
Wide selection of steel grades for different needs: P20 for general parts, 718H for cosmetic parts, H13 for glass-filled material, S136 for transparent and corrosive resin.
Supports fine texture, etching and mirror polish.
Works with most engineering plastics, including filled and flame-retardant compounds.
Disadvantages
Higher initial tooling investment
Longer machining lead time compared with aluminum
Higher cost for mold changes
Best for these cases
Stable annual repeat orders and regular replenishment
Strict tolerance and consistent appearance requirements
Glass-filled, mineral-filled or flame-retardant materials
High-gloss finish or detailed texture
Long-term production, to avoid extra cost of re-making molds
Not recommended when You only need a small quantity of samples, have no future production plan, and expect frequent major design changes with a tight budget.
Item | Aluminum Mold (6061 / 7075) | Steel Mold (P20 / 718H / H13 / S136) |
|---|---|---|
Upfront mold cost | Lower | Higher |
Shot life | 3,000–20,000 shots | 100,000–1,000,000+ shots |
Cooling performance | Excellent, fast cycle | Moderate, longer cycle |
Wear resistance | Poor, not for filled resin | Good, grade selection for abrasives |
Dimensional stability | Drifts after continuous runs | Stable for long-term production |
Mold modification | Fast and low cost | More expensive |
Surface finish limit | Simple texture only, no mirror | Mirror polish, all textures available |
Ideal use | Prototyping, one-time trial order | Annual repeat orders, stable mass production |
Aluminum mold is economical for sampling and short trial runs. Steel mold is the reliable, cost-effective solution for long-term repeat orders. Even for pure PP or ABS, aluminum mold will hit its shot limit quickly if you have yearly demand.
