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.

MD&M Show in Minneapolis

Minnesota’s Lt. Governor, Tina Smith, and Proto Labs CEO, Vicki Holt, talk shop.

Proto Labs is at MD&M Minneapolis this week (Wednesday and Thursday, Nov. 4-5) in conjunction with Minnesota Medtech Week. Stop by booth #327 to talk with manufacturing experts, learn about newly launched capabilities and, of course, see prototypes and parts in all shapes and sizes made by our 3D printing, CNC machining and injection molding services.

We kicked today off with a visit by Lt. Governor of Minnesota, Tina Smith, who met with Proto Labs CEO Vicki Holt to discussed the state of Manufacturing and Proto Labs’ efforts.

At this week’s show, we’re all about speed-to-market and reducing development time, so Proto Labs will be participating in the following two conference sessions:

Tony Holtz.

  • Our technical specialist, Tony Holtz, will be at the Tech Theater stage on Nov. 4 at 2:30 p.m. talking about prototyping and low-volume production for medical applications. He’ll go in-depth on how to accelerate the development of medical devices and quickly launch products to market.
  • Eric Utley (our expert on everything 3D printing) will also be participating on a panel discussion titled “Going Beyond Prototyping: Accelerating Regulatory Approval and Speed-to-Market” on Nov. 5 from 1 to 1:40 p.m. The group will evaluate common pre-development design failures, how to differentiate prototypes from final products, and tactics to better analyze the composition of prototypes versus final products.

Haven’t registered for the show yet? Enjoy a FREE Exhibit Hall Pass from Proto Labs. Register online and enter promo code: MYPASS

See you there!

TIPS WITH TONY: Using Additive Fillers to Improve Durability

There are hundreds of thermoplastic materials available for injection molding, and various grades provide strength, durability, impact resistance and many other beneficial attributes. By adding compounded fillers to the equation, you can further increase the durability of your parts.

A component molded with glass-filled nylon to improve durability.

Glass-Fiber Filler
Glass is the most commonly used additive in plastics. Glass-filled materials provide a higher level of strength and rigidity to a part versus an unfilled base material. You can adjust the level of glass in a material depending on your needs, but be cautious as glass can affect how a part turns out dimensionally and cosmetically. We typically see 13 percent and 33 percent glass-filled materials, but occasionally it pushes upwards to 45 percent.

Other Additives and Fillers
There more additives than just glass fiber, and many of these are easily compounded by material manufacturers for your specific needs (or they may already have a pre-compounded material that meets your needs). Glass bead, mineral, metal, carbon, glass mica, talk and Teflon are just a few that Proto Labs has worked with in the past. These fillers can improve:

Strength Conductivity
Chemical resistance Impact resistance
Hardness Flame retardancy
UV stability Heat resistance
Stiffness Lubricity

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