‭Design Essentials for Injection Molding

A good rule of thumb is to apply 1 degree of draft per 1 inch of cavity depth.

‭There are multiple paths to injection molding. Some parts are first prototyped through 3D
‭printing where moldability considerations are of limited concern. Others take a more
‭traditional machining route that allows for iterative testing in engineering-grade materials
‭similar to that of molding. And many simply jump right to injection molding.

‭Before production begins, there are important design considerations that will improve the
‭moldability of the parts, and ultimately, reduce the chance of production hiccups,
‭cosmetic defects and other issues.

In this month’s design tip, we walk through these key design elements:

  • ‭Draft and radii
  • ‭Wall thickness
  • ‭Coring out and ribbing
  • Ramps and gussets
  • ‭Undercuts
  • Gating and ejection

Read the full design tip here.

Autodesk University Includes Launch of $100-million Investment Fund

If you didn’t attend Autodesk University this week in Las Vegas, here is one big item you missed. Autodesk announced the launch of Forge, a $100-million investment fund to support the creation of a cloud-based platform that will connect design and manufacturing ecosystems in an effort to help developers bring new ideas to market faster and more often. We at Proto Labs are excited to be one of Forge’s inaugural partners in this effort.

As a result, Autodesk Fusion 360 users now have seamless access to our design for manufacturing analysis and web-based, interactive quoting right from Fusion 360 CAD program. “We are excited to bring this seamless quoting and ordering process to the Fusion 360 users and look forward to continued collaboration with Autodesk on the Forge platform,” said Rob Bodor, Proto Labs’ Vice President and General Manager, Americas.

Meanwhile, in the exhibitors’ area at Autodesk’s annual event, Proto Labs representatives talked with a variety of attendees, including electrical, civil and mechanical engineers and various educators (below).

Read more about the Forge initiative here.

TIPS WITH TONY: Can 3D-Printed Parts Take the Heat?

Here’s a question that’s often asked: How do materials used in 3D printing compare to injection-molded thermoplastics when the temperature rises? To answer that, I’ll briefly dissect the materials used in stereolithography (SL) and selective laser sintering (SLS) processes as these are commonly compared to injection molding.

Stereolithography
SL involves a thermoset resin that is solidified by an ultraviolet laser, followed by a UV post-curing process to completely solidify the resin. As far as material properties, the big takeaway is that SL parts are built from thermoplastic-like resins, so they do break down over time in direct UV light.

SL uses materials that mimic ABS, polypropylene and glass-filled polycarbonate, and they offer an array of material properties still exist. But today we’re concerned with the thermal properties of the materials that are best suited to handle the heat — 3D Systems Acura 5530 and DSM Somos NanoTool. Both are offered in post-cured states and there’s an additional process for thermal post-curing that increases the operating temperatures.

The chart shows optimal heat deflections for SL materials. The other materials offered in SL have a much lower heat deflection ranging from 120˚F to 177˚F.

Material

UV Post-Cure

UV Post-Cure +
Thermal Post-Cure

3D Systems
Accura 5530

85˚C (185˚F)

250˚C (482˚F)

DSM Somos NanoTool

225˚C (437˚F)

263˚C (506˚F)

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EYE ON INNOVATION [Black Friday Edition]: Nifty Gifts for Techies

The season for gift giving has arrived, kicked off today by the frenzied shopping event Black Friday. With the holiday season in mind, consider these items for that techie on your list.

Makr Shakr. This robotic bar can make any cocktail you want and a whole lot more — shake up a martini, mix a mojito, thin-slice a lemon garnish, etc. It was a huge hit at the recent Milan Design Week, where furniture usually takes center stage. Makr Shakr is a collaboration between MIT Senseable City Lab and Carlo Ratti, an Italian architecture firm.

Ninja Coffee Bar. Fully programmable, this coffee maker can do it all: automatically brews java by various amounts, strengths, personal tastes; creates cappuccinos, lattes; includes a milk frother; and even features an iced-coffee function.

 

Small Drones. Drones are popular gifts this year. The BLADE Nano QX RTF Quadcopter is rated by Tomsguide.com as Best Drone for the Money — it sells for about $80. As Tom’s Guide muses, the drone won’t break the bank “if you happen to misjudge the top of a tree and get it stuck out of reach.” Speaking of drones, a recent Proto Labs Cool Idea! Award winner is the developer of another drone, the ultra-portable Sprite.

WooBots. These wooden transformers make “old-school toys look cool again,” says Popular Mechanics. The WooBots include an 18-wheeler cab named “Truck,” and a transforming Beetle, bus, jet fighter and warship.

 

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

TIPS WITH TONY: The Right Way to Text

In this week’s tip, we look at best practices for designing text on parts, and answer questions like raised or recessed, which fonts to use and alternative options.

Raised or Recessed?
Features can either be raised up or recessed in to part surfaces, but which way is best? Because molds are machined, we prefer to mill the actual text or logo instead of milling around those features. This allows for faster machining, easier polishing and eliminates very small mold features that may break off.

Please extrude the text/logo features by a minimum of 0.010 in. and a maximum of 0.020 in. This allows your text to be legible and not stick in the features while molding — any deeper and you risk having the text peel off and remain in the mold. So, design raised features on your CAD model to improve moldability during manufacturing and legibility on final parts.

Raised text on part is recommended.

If you must have recessed features on your part, many of the same guidelines still exist, but there is one additional concern that you will need to address in regards to the spacing between characters. Having text recessed on your part now means that the features in the mold are raised and we need to machine between each character. Features with less than 0.125 in. of clearance require spacing between each character at a minimum of 0.020 in. to properly remove all material to ensure the legibility of text.

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