Plastic Injection Molding Services

Plastic injection molding costs depend on three primary factors: tooling, material, and production volume. Tooling is typically the largest upfront investment, with injection molds ranging from a few thousand dollars for simple single-cavity tools to $50,000 or more for complex, multi-cavity production molds.

Once tooling is in place, per-part costs drop significantly at higher volumes, making injection molding one of the most cost-effective manufacturing methods for mid-to-large production runs.

Material selection, part complexity, wall thickness, and secondary operations like insert molding or overmolding also affect overall cost. Working with an experienced contract manufacturer that offers Design for Manufacturability (DFM) analysis can identify design changes that reduce tooling complexity and lower your total cost per part before production begins.

Injection stretch blow molding (ISBM) is a plastic manufacturing process used to produce hollow, thin-walled containers with high clarity and tight dimensional tolerances — most commonly bottles and similar packaging. The process involves injecting plastic into a preform mold, then stretching and blowing the preform into its final shape using pressurized air inside a second mold. The result is a lightweight, strong, flash-free container with excellent surface quality.

Injection molding is compatible with a wide range of thermoplastics, each offering different performance characteristics. Common materials include Polypropylene (PP), Polyethylene (PE), ABS (Acrylonitrile Butadiene Styrene), Nylon (Polyamide), Polycarbonate (PC), Acetal (POM), and Polystyrene (PS).

Specialty engineering resins such as PEEK, PEI (Ultem), and glass-filled variants are also injection moldable for high-performance applications. Material selection should account for the intended use environment, required tolerances, chemical resistance needs, and whether the part will be overmolded or combined with metal inserts. Our engineering team helps customers select the optimal material for their application during the DFM process, balancing performance requirements with cost.

Wall thickness in plastic injection molding can range from approximately 0.5 mm (0.020 inches) for thin-wall molding to 4 mm or more for structural parts, depending on the material and part geometry. Most standard injection molded parts target wall thicknesses between 1.5 mm and 3 mm (0.060″ to 0.120″) for a balance of structural integrity, cycle time, and material cost.

Thin-wall molding, generally defined as walls below 1 mm, is achievable but requires specialized tooling, high injection pressures, and tight process control. Uneven wall thicknesses are one of the most common design issues that lead to sinks, warpage, and dimensional problems. Our team can help you evaluate wall thickness early to ensure your part design can be molded consistently and cost-effectively at full production volumes.

Designing an injection mold begins with a thorough review of the part design using Design for Manufacturability (DFM) principles. Key design decisions include determining the parting line (where the mold separates), gate placement (where molten plastic enters the cavity), draft angles (typically 1 to 3 degrees to allow clean part ejection), wall thickness uniformity, and placement of ribs, bosses, and undercuts.

The mold must also incorporate a cooling system to manage cycle time and dimensional consistency, and an ejection system to remove finished parts without damage. Injection simulations are run before the mold is machined to identify potential issues like weld lines, air traps, or uneven fill. As a full-service contract manufacturer, we design and fabricate tooling in our 14,000 sq. ft. in-house tool room, giving us direct control over mold quality from prototype to full production.

Choosing the right plastic for your injection molded part starts with clearly defining the part’s function and use environment. Key selection criteria include mechanical requirements (strength, stiffness, impact resistance), thermal performance, chemical or moisture exposure, surface finish needs, regulatory compliance (especially for medical or food-contact parts), and whether the part will be overmolded or bonded to metal inserts.

Cost and processability also matter. Some materials have narrow processing windows or require specialty tooling. Common starting points include ABS for rigid consumer parts, Polypropylene for chemical-resistant or flexible components, Nylon for wear-resistant mechanical parts, and Polycarbonate for transparent or high-impact applications. Our engineers work with you during the DFM phase to evaluate material options, model shrink rates, and ensure the chosen resin meets both the performance spec and the manufacturability requirements of the part.