Obsolete parts can create a major snag in the maintenance and repair of plant machinery. The accessibility of 3D printing has changed that, but certain types of equipment components are better-suited than others for reverse engineering and manufacturing.

“The best components for reverse-engineering are obviously those that you don’t have drawings or CAD models for,” says Lonnie Love, manufacturing systems research group leader at Oak Ridge National Laboratory (ORNL). “One example is legacy parts for older equipment. The military has a lot of aging equipment that is still operational and requires replacement parts, but there are no longer tooling or drawings. The same thing goes for automotive, appliances, machine tools — reverse-engineering and 3D printing enables us to keep equipment running for far longer than originally planned.”

The frustration of searching for parts that are no longer available is perfect for 3D printing, explains Mark Norfolk, PE, president at Fabrisonic. “Fabrisonic can reverse-engineer a part from drawings or even old parts,” he says. “Whether parts are metal or plastic, today’s equipment operators now have choices when OEM parts cannot be obtained. The reproduction is fast and often a very cost-effective option. Often customers ask us to build an exact duplicate part. However, all 3D printing systems have the ability to improve upon the original design. Sound engineering judgment must be used to make sure that changes do not affect operations. Another advantage of 3D printing is that oftentimes parts can be made lighter and less expensive through effective CAD engineering.”

Plants should beware of a few potential missed steps when reverse-engineering a component and having it 3D-printed. “Surface finish is one fundamental problem, and, if replacing cast parts, internal features that are not easily accessed by scanners,” says Love.

But how is a plant able to 3D-print an obsolete part that’s been reverse-engineered without running the risk of patent infringement or warranty violation on equipment? “The best option is to first make sure the part is obsolete,” says Love. “If the company no longer is in business or manufactures replacement parts, patent infringements or warranty violations should not be a problem. It’s best to err on the side of checking first.”

Mike Bacidore is chief editor of Plant Services and has been an integral part of the Putman Media editorial team since 2007, when he was managing editor of Control Design magazine. Previously, he was editorial director at Hughes Communications and a portfolio manager of the human resources and labor law areas at Wolters Kluwer. Bacidore holds a BA from the University of Illinois and an MBA from Lake Forest Graduate School of Management. He is an award-winning columnist, earning a Gold Regional Award and a Silver National Award from the American Society of Business Publication Editors. He may be reached at 630-467-1300 ext. 444 or mbacidore@putman.net or check out his Google+ profile.

There are many 3D scanning/software packages available, advises Mike Littrell, president at Cideas. “Some scanners are better-suited for large organic shapes like sculptures and fenders, while others are specifically designed for capturing small complex components,” he explains. “For 3D printing, there are roughly four major industrial, non-consumer, processes that are either thermoplastic or photocurable-resin-based — SLS, SLA, FDM and polyjet. It is important to have an understanding of your needs, such as intended part size, resolution, end use, and desired functionality. Specific to use on an assembly line or for end-use parts in a plant, I recommend thermoplastic-based processes — SLS by 3D Systems and EOS or FDM by Stratasys.”

Without CT scanning or destructive 3D scanning, it can be very difficult to capture internal data on a complex part,” says Littrell. “Strength of the printed part will typically be less than an injection-molded or CNC-machined part, so care must be made in build orientation and process selection,” he says. “Patent infringement on objects that are 3D printed is becoming a very hot topic and will vary from component to component.”

Voxeljet’s main application is investment and sand casting, explains Stefanie Riker, marketing manager at Voxeljet. “Who can create the ready-to-print CAD file?” she asks. “What kind of scanning equipment is needed, depending on internal structures and their accessibility? In general, you need a 3D scanner from a manufacturer such as Faro or GOM, and a 3D printer, depending on the required material set, application, and its requirements.”

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