Published 6/4/2019

3D Printing Prototypes: Iterate and Validate

3D printing is a common tool in product development, but for this fan manufacturer, it occupies two distinct steps in the process.

Additive Manufacturing

Stephanie Hendrixson

Executive Editor, Additive Manufacturing

At Big Ass Fans, 3D printing has two different roles for prototyping. It can be used to iterate designs in the development stage, or to validate them when it is time to move to manufacturing. The yellow motor cover shown here is an example of the former; it was 3D printed in four pieces with “jigsaw” joints held together with adhesive. Sanding, painting and decals completed this look-and-feel prototype.

R&D Manager Jay Fizer stands beneath a fan in one of the testing rooms at the Big Ass Fans’ research and development facility in Kentucky. This room has an adjustable ceiling to imitate different room sizes and is equipped with an anemometer to measure the speed of the air moved by the fan. Equipment like this enables the company to measure how small features like winglets affect the performance of their products.

This 3D printed winglet is an example of a prototype fan part made by the R&D lab with its Raise3D printers for design iteration. The size and shape of the winglet affects the amount of air that will be directed downward when the fan spins.

Michael Smith, prototype designer, stands next to one of the company’s two workhorse Raise3D printers. Selected for their generous print bed (measuring 12 by 12 by 24 inches) and material versatility, each of these printers puts in about 2,000 hours per year creating prototypes, molds and tooling. Their primary use is for design iteration of fan components.

The Big Ass Fans headquarters is equipped with two Stratasys 3D printers (this Objet 30 Prime and a Fortus 370) for a purpose that differs from the R&D facility. Rather than rapid iteration of in-process designs, these more precise printers are used for final design validation before a product goes into production.

A selection of other parts made by the Raise3D printers, including prototypes, urethane molds, a motor insulator, and the motor cover shown on the first slide. While the Raise3D printers offer an ample build volume, sometimes it makes more sense to print things in pieces, Mr. Smith says.

First, Iterate

The R&D facility houses Big Ass Fans’ design iteration capacity: two Raise3D Pro2 Plus 3D printers. These filament-based systems are used for their spacious build volume (measuring 12 by 12 by 24 inches), speed, and compatibility with a range of materials, says Michael Smith, prototype design engineer. Open parameters and support for temperatures ranging to 300°C make it possible to print with a range of filaments from Raise3D and other providers, with the ability to adjust traction, speeds and extruder temperature for best results. Mr. Smith also finds this model reliable and trustworthy, even when running unattended (though he’s also installed Nest cameras for remote monitoring, just in case something should go wrong). Each printer puts in about 2,000 hours of work per year — equivalent to the hours worked by a full-time human employee.

These printers make fixtures, assembly aids, master molds for urethane casting, and occasionally end-use parts, but their primary use is to manufacture functional prototypes for product development, such as the winglets mentioned above. Whereas in the past the R&D shop would have needed to machine the parts from Delrin or outsource to another supplier, it can now quickly produce its own prototypes for testing. “When I need to iterate, I print,” Mr. Smith says.

For a new product, design engineers in the headquarters building first create and simulate a design using Ansys modeling software. That part file is then kicked over to the R&D facility for prototyping, iteration and testing. It’s at this point that Mr. Smith leverages his Raise3D printers to manufacture the prototypes, often creating several different variations within a few days. For a small part like a winglet, Mr. Smith might print as many as five design iterations (each one a set of six or eight winglets) in a single build. Then, the designs are rigorously tested so that the team can gather empirical data on their performance.

Testing facilities in the R&D lab range from a large room measuring 100 by 100 by 55 feet for testing a fan’s thrust without recirculating air, to smaller chambers (including some with adjustable ceiling height) that are more representative of a fan’s final installation environment.

As test configurations move through the facility, the R&D team is gathering information about the output of each one—the thrust of the fan, speed of the breeze produced, what temperature human occupants would feel, electrical emissions and more. Often the data gathered during this testing is used to inform further design iterations that can then be printed and tested. “There’s a lot of back and forth before we get to hard-tooling anything,” says Jay Fizer, R&D manager.

Then, Validate

The data captured during R&D testing is fed back into Ansys so that engineers can tweak the design before the final prototype is 3D printed on one of the tinker room printers. The tinker room houses a Fortus 370 and Objet 30 Prime 3D printer, both from Stratasys, for this purpose. These higher-end printers are more expensive to own and operate than those in the R&D lab, but they offer the precision and aesthetics desired for the final design validation.

Where R&D is concerned with printing successive iterations, engineering’s goal is to print designs already believed to be valid, Mr. Fizer says. And because of the earlier print and iterate cycle, they often are. The company has found that testing early with 3D printed prototypes has improved designs and helps expedite time to market for new products.