Injection Molding Tools – Cost Considerations
Xcentric was founded by expert tool makers who created an expert system to simplify and automate many aspects of injection mold tool design and manufacture. The result is an extremely efficient process resulting in delivery of injection molded components in less than fifteen (15) business days on average at a very competitive price. Factors affecting the cost of an injection mold are discussed in this section.
Cost of an Injection Mold:
Custom injection molds can be very expensive to manufacture. One of the key factors that drives the cost is the tool material selection. Typically, injection molds constructed out of tool steel cost more than double than that of aluminum. This is due to the much slower machining process required for steel, and the slower manual benching process to complete the molds prior to molding. High volume projects (millions of components) normally require tool steel due to its wear resistance.
Given the advancements made in aluminum alloys, higher grade aluminum such as QC-7, QC-10 or aircraft grade aluminum close the gap between the durability of steel and aluminum while retaining the cost and machinability advantages of aluminum. Today, aluminum molds can produce hundreds of thousands of parts and maintain accuracy and surface finish. In addition, when molded parts require highly abrasive materials, aluminum tools can be coated or engineered with steel inserts for high wear areas of the tool.
When it comes to the molding process itself, aluminum tools can offer faster molding cycles due to better heat dissipation for cooling, reducing the longest portion of the molding cycle. Shorter cycle times equate to lower piece part prices.
Other Factors Driving Cost:
The cost of plastic injection molds depends on a wide range of factors such as: the number of cavities, size and complexity of the parts, number of parts to be molded, surface finishes, and textures.
Consider the following when designing your part for injection molding as these will have an impact on pricing:
- Delivery Time – Xcentric has built its reputation around delivering injection molded parts in low to medium volumes extremely quickly compared to traditional mold makers. Starting from a standard delivery time of fifteen (15) business days to first molded samples, two faster levels of expedited production are available. Expediting fees are substantial however, so it is important to properly assess the value of requesting this level of service.
- Annual Volume – Volumes over 100,000 annually typically require multi-cavity tooling. This will increase the tooling price significantly but will reduce the piece price by as much as 60% per additional cavity. For this reason it is important for our clients to specify annual production volume accurately at the project inception to maximize production rate and minimize piece part pricing.
- Undercuts– Although we can handle unlimited undercuts in the part geometry, these add cost and complexity to the tools. Xcentric’s sales engineering team will assist in evaluating a part for moldability and can suggest ways to minimize undercuts and other mold features that add cost.
- Inserts and Overmolds – Molded components requiring metal inserts or overmolded features using a second material on a molded substrate are daily business for Xcentric. These features require additional work and process care to assure a high quality outcome, which naturally increase pricing. It is important to discuss the project objectives with our sales engineers to assure we consider the needs of the final application, whether prototype or production, when producing parts with these features to minimize cost implications, particularly if larger volumes will be required.
- Surface Finish – Xcentric offers surfaces finishes from “as machined” to nearly optically smooth. Generally speaking the finer the finish the more expensive due to the additional labor and time involved to achieve best possible finishes. Tip: If the molded part is to be hidden in an assembly, money can be saved by choosing a 320-sand paper finish.
- Part Complexity – Part complexity can drastically increase the cost of a tool. The more faces or surfaces in the CAD model has, the higher the cost. Consider this when adding blends or unneeded features.
- Mold Construction Materials – We will assist you in determining the best materials to build your plastic injection mold. This is why we offer a lifetime mold warranty because we stand behind our work and engineering.