TIPS WITH TONY: Rapid Injection Molding vs. Conventional Molding

How do you know if you should use low-volume injection molding or traditional methods? What benefit does soft aluminum tooling provide? These are just a few questions we hear regularly, so we wanted to shed some light on these important molding considerations.

Prototyping
Before Proto Labs began in 1999, prototyping with injection molding was costly and took months to receive the very first sample parts. We took a low-volume approach to injection molding where it was possible to get a handful of parts in a few days rather than the large-scale approach that nearly all other manufacturers used that involved part minimum in the tens of thousands and full-scale production in the millions of parts.

Proto Labs specializes in aluminum molds that use high-speed CNC machines to create a standard single cavity mold in as fast as one business day with the ability to produce up to 10,000 parts or more. Complex parts are also possible by using pin-actuated slides as well as hand-loaded mold inserts. We try to take the difficulty out of injection molding design by simplifying it.

Conventional molding uses a much more complex molds that take weeks to design, where Proto Labs is highly automated. Complex multi-plate mold designs using lifters, collapsible cores and multi-cavities are able to produce much more complex parts at high volumes, and typically, mold creation for these molds take anywhere from four to 12 weeks.

Bridge Tooling
We discovered that there was a much greater need for low-volume manufacturing. Customers were placing additional orders for a few thousand parts that were being used to set-up production lines and even limited short-run production while the conventional tooling was being built.

Conventional tooling is your production mold. It’s difficult to have a bridge tool produced without having your production molder hold off on manufacturing while they create a bridge tool. Using both methods allows you to have two manufacturers producing molds side-by-side to ultimately have parts produced faster.

Multi-Cavity Molds
Don’t worry about being limited to one cavity. We can produce multi-cavity molds ranging from two to eight cavities depending on part size, geometry, complexity and gating. Side-actions may limit design complexity and space to one or two cavities as direct gates are not allowed. We recommend discussing the possibility of multi-cavity tooling early in the design process to ensure the best possible mold design is used.

Conventional production molds provide a much higher cavity count and lower part price with even more complex part geometries, but with this comes a much higher mold cost. At minimum, look at the overall project to decide what makes sense, what projected life expectancy you need from your tooling.

Click life cycle infographic to enlarge:

Supply Chain Emergencies
What happens when your large-scale supplier has capacity issues? If you started with an aluminum mold from Proto Labs for initial low-volume production, it’s waiting for you (in our massive mold storage facility) for just these types of situations. It’s like a built-in insurance policy that you can call on when you need on-demand parts.

End-of-Life Planning
We know we’re not the right fit for every situation, but we also know where we fit into the product life cycle — prototyping, bridge tooling and supply chain emergencies, for sure, but rapid injection molding is also used during end-of-life planning. As market demand decreases for a product and production dramatically slows, you can reduce financial risk by eliminating warehousing costs and excessive inventories by once again leveraging low-volume molding. Want to produce 5,000 parts at time instead of minimum orders of 50,000 or 100,000? Try Proto Labs.

If you have questions about how rapid injection molding and conventional tooling compare — and most often — complement each other, contact one of our experts at customerservice@protolabs.com or 877.479.3680. We have knowledgeable onsite sales and engineering support staff that can help.

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About Tony Holtz

Tony is a technical specialist at Proto Labs with more than 10 years of experience ranging from CNC mill operator to mold designer to customer service engineer. While his formal education is in industrial machinery operations, he has extensive knowledge and experience in both traditional and advanced manufacturing processes and materials. Throughout his tenure at Proto Labs, Tony has worked with countless designers, engineers and product developers to improve the manufacturability of their parts.

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