To prototype a design, or even to handle short-run production, you would probably need:

–one or more subtractive machines (such as a mill, lathe, drill press, stamping press, etc.)

–at least one or more injection molding machines

–at least one or more additive manufacturing machines (such as stereolithography, extrusion, multi-jetting, various material laser sintering systems, and so on)

–materials for all the equipment you have

That’s a lot of investment to handle one-offs, or short runs. But you would need all of this capability and flexibility because you don’t design just one type of part.

It would be nice if additive-manufacturing vendors, for example, could invent one additive system that handles three or four of the seven plus additive technologies. Machining centers offer such capability, for example. But such a scenario is probably not going to happen with additive in the near future.

So, for the engineer who needs a prototype or short-run production using multiple additive, and even subtractive, technologies, the best recourse is the service provider.

Service providers come in all sizes and capabilities. Some focus just on additive technologies. Some offer the three major legs of manufacturing—machining, injection molding, and additive. In addition, many additive manufacturing vendors are offering prototyping and short-run production services with theirs or others additive technologies—touting an additive agnostic approach.

One service provider is Proto Labs. In the Minneapolis facility, it offers machining and injection molding. In North Carolina, it offers additive manufacturing. I recently had a chance to tour the North Carolina plant.

At this plant, Proto Labs offers five additive technologies: stereolithography from 3D Systems, laser sintering from 3D Systems, direct metal laser sintering from Concept Laser, Polyjet from Stratasys, and HP’s multijet system.

Notes Eric Utley, applications engineer, “at Proto Labs, we offer a one-stop shop approach with access to the major manufacturing technologies.”

One of the benefits of going with a service provider is that you have a better chance of working in the material your design needs. Even though many additive vendors encourage the use of materials specific to their systems, service providers often offer alternatives. At Proto Labs, for example, the engineering team has the expertise to mix and match materials among the systems. The view is it’s important to have the mechanical properties you want or need rather than limiting your material choice. The engineering team works with laser sintered thermoplastic polyurethane and polyurethane blends, flexible materials, and materials from Prodways among others.

An interesting development the Proto Labs team is seeing is more requests for elastomeric materials. Noted Utley, material flexibility is a big trend, especially in the medical and consumer products product. The Polyjet machines fit this trend well.

One thing Utley noted was the part quantity capabilities of the HP 3D printer. The increased speed and lower price of the HP printing system increases the envelope of viable jobs, meaning whereas current 3D printing may only be economically viable up to ~500 copies of a theoretical part, HP printing could potentially push that number higher to 1000 or 1500.

A perennial trend is fast delivery of your order. Each service provider manages order production differently, and it’s a good idea to ask. Some use custom order entry systems to speed the process. Some use a batching process to produce orders quickly.

Even with all the benefits of additive manufacturing, drawbacks remain.

Even though the body of knowledge on additive processes and materials is growing, the validation of these still inhibits wider adoption of this technology.

Another issue is that additive manufacturing has a perception issue—the perception is that it should be easy to do. The reality is that additive is not as easy as portrayed.

And, the cost per part for additive is still not competitive with the cost per part for subtractive and injection molding—at least not competitive enough for additive to be used for anything more than high value, low-volume, custom, geometrically complex, one-off parts. The labor cost per part is part of this issue as well. Progress is being made here, however, with some of the recent additive system introductions.

Leslie Langnau
llangnau@wtwhmedia.com