Calming the Additive Manufacturing Cacophony

There has been increasing buzz in the past few years about the possibilities of using additive manufacturing (AM) side by side in subtractive manufacturing shops. Some of the questions for traditional metalcutting shops include whether there is an economic place in the business for this relatively new process.

In 2012, Production Machining’s sister publication, Modern Machine Shop, launched a supplement devoted to coverage of the emerging interest in AM. Reader response has been good in large part because the dearth of technical and application information targeted at our readers of metalworking trade magazines.

Starting with its October issue, Additive Manufacturing launches as a full-size publication. It is edited by MMS’ Pete Zelinski, already well respected for his work in the AM community. Pete’s 18 years with MMS brings his metalworking manufacturing experience to help present balanced judgement to the presentation of when to consider additive versus subtractive in practical applications.    

In conversations I’ve had with PM readers, there is serious interest in the potential of AM, yet much of the published material deals more with consumer uses as opposed to more functional applications. The new publication will address use of AM for making tooling, molds and functioning prototypes as well as cover technological advancements leading to an ultimate goal for manufacturers—end-use production parts.

I visited a shop in the aerospace industry many years ago that was making APU (auxiliary power units) for aircraft. As the name implies, these units provide lights, run the environmental systems and other systems needs beyond the main jet engines.

The main body of the APU the shop created was a complex aluminum casting that required significant machining on the company’s horizontal machining center. The casting was a new design, so the shop was starting from scratch to create a parts process.

Back then, AM material selections were much more limited than they are today. Plastic or paper were about the only choices, and quantities were limited to prototypes. Today, with various powdered metal machines available, the sky is the limit, and I think this is one reason metalworking has turned to AM.

To expedite the lead time for making its APU, the maker did something using AM, which I thought was interesting and efficient. As a former foundry man, I understand the process of making castings, especially in quantities. The lost foam process is relatively fast, but not for quantities. That leaves making a pattern.

In our foundry, the pattern makers were among the highest paid workers because the skills needed (such as working with shrink rules) are very high. These were complex castings and therefore complex patterns with many cores.

The lead time to get the castings was bid at 6 weeks for delivery. Typically, the machining process preparation would start when the castings were delivered.

AM changed that. The shop I visited used AM to create a prototype of the casting for use while the patterns and castings were being manufactured.

The prototype was made of the plastic material available then, but was good enough to be an accurate representation of the part. They built fixtures to mount the prototype on the HMC and began tooling up the machine to cut the incoming casting.

They programmed the tool path with an offset so they could dry cycle the program without damaging the prototype. The offset would reset when the castings were delivered.

AM allowed this shop to save more than 6 weeks by letting them be ready to go when the castings were delivered. That application has stuck in my mind for years because it seemed so practical and was made possible by AM.

I think readers of AM magazine will find many application ideas that can help integrate AM into their production. The technology is moving forward at a rapid pace, and AM magazine, along with its website, additivemanufacturing.media, is a repository of relevant content. 

Interest in additive is spreading for metalworking shops. Now there is a place to keep up with its growth and a place to find ways it can help your business. After all, that’s always been the mission of manufacturing trade press.