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.

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.

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EYE ON INNOVATION: Apollo Mission Pics Show NASA’s Pioneering Spirit

Our quest for innovation this week is a special shout out to those space exploring innovators at NASA.

Last month, more than 40 years after NASA’s historic Apollo missions orbited and landed on the moon, Kipp Teague, an archivist, released thousands of images from those missions on Flickr. Some photos have been previously published, but most have never been seen before.

As the New York Times reported, the archive comes unedited with limited information about the specifics behind each photo. Despite the lack of details, the images — and there are a stunning variety — are a treat to view.

Here are a few from Teague’s giant collection.

Eye on Innovation is a weekly look at cool technology, products and scientific advancements that we’ve mined from crowdsourcing sites and other corners of the Internet.

TIPS WITH TONY: Watch Out for Warp, Sink and Voids!

In my years of working closely with product designers, I’ve seen some really great designs, but on occasion, I’ve encountered part designs by both novice and experienced designers and engineers that have needed some work to improve moldability and reduce cosmetic defects. Let’s look at some common design mistakes that could result in parts with sink, warp and voids.

Wall Thickness
Why is uniform wall thickness important? Thermoplastics simply don’t like transitioning from thin to thick sections due to the ununiformed cooling. All thermoplastics shrink as they cool but when thin areas cool before thick areas, stress is created. The results may vary depending on material selection and part design, but if you’re not following the proper material guidelines for wall thickness and mold design, you may end up with unsightly voids, sink and possibly even warp within your parts.

How can you reduce the risk of these molding concerns? Provide proper wall thickness through appropriate coring, rib and boss design, which in turn, helps you avoid excessive thick or thin wall sections.

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EYE ON INNOVATION: New Fridge Keeps Cool Without Electricity

A new powerless refrigerator uses evaporation to keep food cool and prevent items from spoiling.

Students from the University of Calgary put a new spin on refrigeration.

Great news for your next camping trip, yes, but even greater news for those parts of the world that are deprived of reliable electricity sources. As reported by, for those who live in these regions, refrigeration isn’t just a way to preserve favorite foods, “it is a matter of survival itself…”

The idea for the electricity-free fridge recently captured first place in the Biomimicry Global Design Competition, sponsored by Montana-based Biomimicry Institute, which challenged students and researchers worldwide to develop nature-inspired products that address critical sustainability issues. Continue reading

Finding the Right Surface Finish

Molded parts are everywhere — from highly cosmetic housings hiding in plain sight to internal components where a fine polish is unnecessary. Most people pay no attention to the surface finish on those parts, but for product designers and engineers, it’s an important design consideration.

Identifying the right surface finish is dependent on a few important elements, namely the development or production stage that your parts are in, the materials they’re being manufactured in and their end-use applications.

On custom finishes, use color coding to provide a clearly marked image of your CAD model with its required finishes.

This month’s tip discusses:

  • available surface finishes for injection molded parts at Proto Labs
  • how to create a custom surface finish involving two or more finishes
  • navigating finishes within ProtoQuote
  • why gating and ejection play a limited role in liquid silicone rubber parts
  • secondary options applied to magnesium components

Read the full design tip here.