Plastic Injection Molding Services

Granules of plastic resin are fed into a heated barrel and melted. The molten plastic is then injected into a precisely machined mold cavity under controlled pressure. Once cooled and solidified, the mold opens and ejects the part. The cycle repeats with tight consistency across high-volume runs.

Injection molding delivers low per-unit cost, excellent dimensional accuracy, and repeatable quality at high volume, but carries significant upfront tooling cost. 3D printing suits lower-volume runs and frequent design changes with minimal setup cost. For sustained production of a finalized part, injection molding is the more cost-effective path.

We mold commodity resins including ABS, HDPE, LDPE, PE, and PP, as well as engineering and high-performance resins including PEEK, POM, Nylon, PC, and TPU. Our engineering team confirms the best resin for your part requirements at the feasibility review.

Standard options include SPI polished grades, textured and matte surfaces, painted coatings, pad printing, screen printing, hot stamping, and laser engraving. Secondary operations such as insert placement and ultrasonic welding are also available.

Standard production lead time is 4 to 8 weeks, with tooling and first-article timing confirmed at the quote stage. Rush programs can be reviewed case by case.

Injection molding carries high tooling cost, so it is built for recurring production rather than one-off parts. We will tell you at the quote stage whether your volume is a fit and recommend the most cost-effective process.

Cost splits into two parts: upfront tooling and per-unit price. The injection molding machine and mold are the major investment, quoted transparently before you commit. Once the tool is proven, per-part cost drops sharply across high-volume runs. We quote on landed cost, so tooling, freight, and duties are in the number before you see it, with no instant-quote guesswork.

We mold commodity and engineering thermoplastics including ABS, HDPE, LDPE, PE, PP, PC, Nylon, POM, and high-performance PEEK, plus TPU and other elastomers for flexible parts. Glass-filled and fiber-reinforced grades are available where added stiffness is needed. Our engineering team confirms the right resin for your part geometry and service temperature at the feasibility review.

Plastic injection molding delivers repeatable parts at low per-unit cost, tight tolerances, and consistent surface finish across long runs. Multi-cavity and family molds raise output per cycle, and the process supports complex part geometry, undercuts, and overmolding that would be slow to machine. For sustained production of a finalized plastic part, it is the most cost-effective path.

Beyond standard injection molding, we offer overmolding and two-shot molding, insert molding for threaded or metal inserts, and multi-cavity and family tooling. Aluminum rapid-tooling molds suit lower-volume or prototype injection molding, while hardened steel production molds carry the highest-volume programs. CNC machining and other secondary operations finish the molded parts.

Inconsistent wall thickness causes more production problems than any other design issue. Non-uniform walls produce sink marks, warpage, and internal stress in the finished part. Redstone reviews wall thickness at the DFM stage and runs mold-flow analysis to flag problem areas before tooling is cut. Tolerances tighter than the process can reliably hold are also a frequent cost driver.

Redstone embeds its own quality staff inside each facility to manage inspection daily rather than relying on occasional audits. Every part starts with a critical-to-quality (CTQ) plan that identifies the dimensions driving assembly fit and function. Once process capability is established through validation runs, interval-based checks replace 100% inspection, monitoring the process rather than every individual part.

Working through Redstone adds a layer of confidentiality. The facility sees only that Redstone is producing the parts and does not know the end customer or application. For sensitive products, Redstone can split a project across multiple facilities so no single one receives the full drawing set.

The initial tooling investment is amortized across production volume, driving per-unit costs down at scale. Runs above 500 units typically reach a strong cost-per-part position. We will tell you at the quote stage whether your volume is a fit and recommend the most cost-effective process for your part.