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How Design and Material Choices Impact Injection Molding Costs

Stratasys Direct
Stratasys Direct May 01, 2024
May 01, 2024
A machined injection mold | Stratasys Direct

Navigating the world of injection molding production presents a myriad of challenges that can dictate the efficiency, cost, and quality of a project. Particularly for manufacturing engineers, understanding the nuances of design choices, material selection, and post-molding operations is essential. Seemingly minor decisions made in the design phase can have significant repercussions on the budget and lead times while maintaining the desired level of quality.

Avoiding Die-Locked Designs

Die-lock is an industry phrase to describe when parts can't be easily ejected due to features with undercuts and inadequate draft on walls in the line of injection ejection. Components that become trapped by their design require complex mold mechanisms, like slides, which also escalates costs. By conducting a thorough draft analysis and orienting features on a single plane, engineers can streamline the ejection process and negate the need for these costly mechanisms. Stratasys Direct offers free Design optimization support, partnering with customers early in the design stage to optimize manufacturability and minimize unnecessary expenses.

The Importance of Coring and Wall Thickness

Coring refers to the removal of material from thicker sections of a part to maintain uniform thickness. Disparities in wall thickness can result in problematic cooling rates and undesirable visual defects, like sink marks. Ensuring homogeneity in wall thickness prevents pieces from falling out of tolerance due to uneven shrinkage, a discrepancy that could lead to scrapped parts and costly tool adjustments.  Stratasys Direct offers custom workflows and tolerance checks to ensure that these potential issues are addressed before they manifest in the final product.

Draft Application

Drafts, or angled wall sections, are a critical part of the design for manufacturability (DFM). Proper incorporation of draft angles facilitates the mold ejection process, safeguarding against part damage and reducing the likelihood of a part being rejected or scrapped. Neglecting sufficient draft angles can lead to distortion, scuffed surfaces, and the need for tool reconfiguration, as well as the creation of new parts.

Parting Line Precision

The parting line, or the boundary where the mold halves separate, is a critical aspect of the design process. Its proper placement can prevent ejection obstructions and streamline the separation of the mold halves, thereby averting the need for intricate and expensive tooling adjustments.

Advanced Tooling Strategies for Efficiency

Our tooling strategy is tailored to meet the specific needs of our customers. Single-cavity molds are ideal for low to mid-volume production. For higher quantities, we can create multi-cavity molds to increase production output. Additionally, we offer family molds, which combine multiple parts of similar size, volume, and material within a single mold.  With runner shut-offs included in all family molds, we have the flexibility to produce one geometry if necessary, offering an economical solution to support low quantities of multiple geometries.

Material Selection

The choice of resin has a significant impact not just on the quality of the final product, but on the project costs. Resins with specific additives or features—and those that aren't readily available—often come with a steeper price tag.  In addition, materials with longer cooling periods can inadvertently inflate cycle times. Stratasys Direct works with customers to advise them on the optimal materials to balance functionality, aesthetic appeal, and cost-effectiveness, drawing upon a vast repository of expertise within the field of injection molding.

Maximizing Post-Molding Efficiencies

Textures and finishes can be cosmetic and functional. Specifying intricate texturing or detailing can lead to additional manual labor requirements, subsequently inflating overall production costs. To mitigate these excessive expenses, integrating features such as textures and lettering early in the design phase can significantly reduce the need for post-molding labor.  Our full suite of services includes audits and advice on these design complexities, ensuring that customers receive the most economical and efficient path to mass production. As a final step, Stratasys Direct also confirms critical dimensions are measured to make certain parts meet tolerances specified by the customer.

The inclusion of post-operational machining or additional surface finishing can also add to both cost and lead times. Designing with these end goals in mind—integrating as much detail into the original mold as feasible—can greatly reduce dependency on post-molding operations.

 

Start to Finish Injection Molding Parts | Stratasys Direct

From Start to Finish, Stratasys Direct Can Help

The most streamlined path to a cost-effective and successful injection molding project is to partner with your manufacturer early, and throughout the entire manufacturing process. By engaging with us at the inception of a design, clients can take advantage of the design for manufacturability services, thereby preventing costly complications arising from design oversight. Stratasys Direct uses steel tooling to extend the life of a mold, which enables us to meet tight tolerances, and allows the mold to maintain consistent temperatures during processing. With a combination of onshore and offshore capabilities, we are adept at balancing costs without compromising on quality or lead times. Stratasys Direct also does not impose setup fees, lowering the entry barrier for projects of any scale.

Your Trusted Partner

In summary, a well-executed injection molding project requires meticulous attention to detail from design to post-mold operations. Stratasys Direct offers an inclusive partnership, enhancing projects with free Design for Injection Molding optimization recommendations to ensure cost-efficiency and superior quality.  Our expertise, zero setup fees, and advanced workflows make us a critical ally in your project's success. Our commitment to informed design, strategic material choice, and minimization of post-production steps helps our customers avoid unforeseen costs and maintain project timelines and budgets.

For further design insights and to maximize your project's potential, download our Injection Molding Design Guide and talk to one of our manufacturing experts. We’re here to help.

 

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