This technical information has been contributed by
Proto Labs, Inc.

Cool Ideas for Quick Turn Parts

Quick Turn Parts

Options range from highly functional FDM parts to complex cast, injection molded, and CNC machined parts

Proto Labs, a Maple Plain, Minnesota-based manufacturer of quick-turn CNC machined and injection molded parts, launched a Cool Idea! Award earlier this year to give product designers--who may otherwise lack the resources to get their ideas to market--the support they need to bring innovative products to life. The program provides award recipients with $100,000 worth of prototyping and short-run production services to help them take their product idea or part from a 3D CAD model to its first-run production stage.

In discussing the Cool Idea! Program, Proto Labs CEO Brad Cleveland drew a connection between it and what he said was the foundation of Proto Labs' own success. The success of Proto Labs, he said, is due to "a cool idea that made quick turn injection molded prototypes a reality." When the company's founder, Larry Lukis, was with LaserMaster, a large scale printer company that he co-founded, he was troubled that it would take 6 to 8 weeks and cost $20,000-$30,000 to have some relatively simple plastic parts molded.

"He just didn't think it had to be that expensive or take that long," said Cleveland. "So when he left LaserMaster, he set out to find out why it took so long and why it was so expensive. It turns out that a lot of the time and money goes into the non-recurring engineering side of it--the actual design and manufacture of the tooling. And a lot of that has to do with the manual process of doing the geometry analysis and the tool path generation for machining the mold components.

"Larry thought it should be possible to write software to automate much or all of that process, and he set out to do that," Cleveland continued. "He was successful at it, and the original business concept for Protomold was 'Simple Parts, Fast.' So, if you had a simple geometry, and you could express it in a 3D CAD file, you could work with Protomold--in those days--to get parts turned around in five days, as long as it was a fairly simple, small part. So Larry's cool idea was automating the non-recurring engineering out of injection mold manufacturing, using software."

Proto Labs' proprietary software runs on multiple compute clusters totaling over 2 trillion floating point operations per second, according to Cleveland, who adds that the geometry analysis required to prepare quotations, generate mold designs, and create tool paths is "very intense."

"To support the requirement for a scalable environment capable of doing hundreds of quotes a day and designing dozens of molds a day in each location, we created geometry analysis algorithms that are parallelized and spread across a network of processors, hundreds of applications at a time," he explained. "This gives us the bandwidth to support the quoting, mold design, and toolpath generation scalability that's required in our fast-growing business."

Proto Labs was "about a million dollar a year company of about 12 people in 2001," when Cleveland joined the company. "We've continued to invest in the software ever since," he said.

Proto Labs ( offers two parts-making services: Firstcut and Protomold. Firstcut, a quick-turn CNC machining job shop, supports part sizes of up to 10 inches by 7 inches by 3.75 inches. The company uses 3-axis machining from up to six sides on a part. "We don't currently offer 4- or 5-axis machining, although we plan to do so at some point," says Cleveland. "But you can make some very complex geometries with just 3-axis machining from six sides, and we support more than 30 stocked resins and several metals."

Customers upload their 3D CAD model at the Firstcut or Proto Labs website. As part of the process of preparing a quotation for the customer, the company automatically analyzes the geometry and generates all toolpaths required to machine the part. The quotation is then sent to the customer in the form of a web page; it's called a FirstQuote®, as in "Firstcut Quotation."

"It's really cool; you get an illustration of the part with color-coded areas where it may differ from the original design due to limitations of the machining process," says Cleveland. "You can rotate it around on your screen, and zoom in on it, and so on. This allows the customer to determine whether or not the differences are significant enough to care about.

"For example, with a CNC machining process, it's difficult to do an inside sharp corner, although this is typically not an important issue for the designer," he continues. "But on the other hand, with the limitations of our particular process, we may not be able to reach certain areas (for example, 45 degree angle holes), so those will be highlighted, and those may not be acceptable unless the customer can post-machine those features themselves."

The FirstQuote also provides drop-down menus that allow the customer to select the material that they require and the number of parts needed, for example, while the resulting price is updated interactively. Then the customer can enter the order online.

"So it's a CNC machining job shop, but it's extremely fast with no non-recurring engineering charges," Cleveland says. "We are very comfortable taking single part orders because there isn't any sort of set up or fixturing or programming charge associated with single parts. That's the really unique thing about Firstcut: we're just as happy taking orders for one part as we are for 10.

"It's the fastest growing part of our business and serves many different markets. Typical applications are one or two prototype parts, up to dozens of low volume production parts in either plastic or metal."

Protomold, the original business of the company, works much the same way: Engineers upload their 3D CAD model, and Protomold's software generates a ProtoQuote® for them based on an analysis of the geometry of their part. "In this case, we actually give moldability guidance," Cleveland says. "We look for things like sufficient draft on the part, so that the part can be effectively removed from the mold, or whether or not they may have thick or thin wall issues. On a molded part, the more consistent the wall thickness is, the more likely you'll have a high-quality molded part. All of this is done through the use of color-coded indications on the 3D model that they can examine on their computer monitor.

"We also use 3-axis machining in the Protomold business, which means there are certain types of inside undercuts we can't handle, so we'll highlight those for them," he continues. "We can handle many types of external undercuts through the use of side actions on a mold. But internal threads, for example, we can't handle, so we'll point that out to the customer in the same sort of way. And then if they're OK with the feedback and there are no required changes, they can place their order online and we can ship their parts as fast as the next business day."

Customers Seeing 'Design for Function' Advantages of FDM

Broadening its powerbase in rapid prototyping and direct digital manufacturing, Stratasys Direct Manufacturing recently expanded its Fused Deposition Modeling (FDM) capacity with the acquisition of one Fortus 900 and six Fortus 400 machines. The purchases signal a solid investment in FDM technology and will enable faster turnaround for short-run functional models as well as long-run, end-use production parts.

"We're expanding rapidly in FDM. It's a technology that rounds out our offerings," said Stratasys Direct Manufacturing Director of Marketing Scott McGowan, adding that the company doesn't like to "force fit" an application to one or two technologies and enjoys the breadth of additive manufacturing technology on the market.

The company is invested heavily in selective laser sintering (SLS) technology and has about 20 such machines. However, the technology has its limitations due to warpage from high heat, McGowan said, and that's where FDM fills the gap. The Fortus 900 offers the largest FDM build envelope available at 36 x 36 x 24 inches, which makes it well suited for large parts, and can complete up to a 3-ft x 2-ft x 3-ft part with a seamless build.

"With FDM, it uses production plastics, so it's produced in ABS. Our customers and the market in general like to see even their prototypes come out in the material that they intended it to be," McGowan said. "With FDM, there's a wider availability of products for our customers; there's more choices. Like the fact that you can get into additive layer manufacturing with production materials other than nylons, which is what SLS offers."

Stratasys Direct Manufacturing ( offers a number of thermoplastic FDM materials, including ABS in both natural and black; medical-grade PC-ISO polycarbonate; and SABIC Ultem-9085 for high-temperature, fire-retardant applications. The company provides rapid prototyping, direct digital manufacturing, tooling, and production molding services. Capabilities include PolyJetTM, stereolithography (SLA), laser sintering (SLS), Fused Deposition Modeling (FDM), QuantumCast cast urethanes, CNC, and composite prototypes and short-run production parts. The ISO 9001, AS9100 certified company is based in Valencia, Calif., with five U.S. manufacturing facilities in California, Arizona, Texas, and Michigan., a subsidiary of Stratasys Direct Manufacturing, is a self-service website providing same-day shipment of prototype parts with the slogan, "The Fastest Prototypes on the Planet." As long as the customer has the 3D CAD data, ZoomRP can build everything from figurines to patterns for prosthetic ears. The service is said to be ideally suited for smaller parts that don't require special processing and can be delivered at an "unheard of" speed. Customers can upload an STL file, and choose a "ship today" or "ship tomorrow" option. ZoomRP utilizes PolyJet, SLA, FDM, and SLS technologies to create physical parts and prototypes directly from 3D CAD data. ZoomRP can offer such quick turnaround because it is supported by the "huge capacity" of Stratasys Direct Manufacturing, McGowan said.

"With our additive manufacturing machines, we have over fifty platforms between PolyJet, stereolithography, selective laser sintering, and now FDM. So we've got a machine opening up every hour or half hour to put a job on," he said.

Say, for example, a ZoomRP customer wanted to order a part made of white PolyJet prototype plastic. If they upload a geometry by 5 p.m., the part would be built and shipped via Fedex priority by 10:30 a.m., McGowan said.

Recently, an air duct part with three air vents was made using one of the Fortus 400 FDM machines for an aerospace customer. Using the traditional method, the part would have been a five-piece assembly requiring manual work to be glued and clamped together. But with the additive manufacturing process on the Fortus, the CAD data was sliced into layers, with one layer printed at a time, so that the part was manufactured as one solid unit.

"That represents being able to design for function, not design for a manufacturing process," McGowan said, summarizing the fundamental difference in approach that additive manufacturing brings to the table. As for the future of additive manufacturing, McGowan said it has grown from being seen as a prototyping technology and is now moving more towards manufacturing of parts with geometries that are much more difficult to produce using other methods.

"The thing that surprises me about additive layer manufacturing is that there are still a lot of people out there who aren't aware of what it is or that it's available. We still surprise engineers regularly who just aren't aware that these processes are available."

Company Produces Complex Castings, Machined Parts Rapidly

Clinkenbeard ( helps companies speed their products to market by providing very early design hardware--machined metal castings and parts from solid stock material--within short lead times. According to Ron (Reg) Gustafson Jr., the company's project manager, the process typically starts with engineering mock-ups to prove the design concept form, fit, and function. "We make these mock-ups very quickly from customer-supplied 3D data," says Gustafson.

The next step in the process is rapid engineering hardware for testing. "Many times, we are making machined parts / machined metal castings from 3D data, prior to the creation of 2D drawings," says Gustafson. "This allows companies to start testing much earlier than alternative or production process deliveries can offer.

Based in Rockford, Illinois, Clinkenbeard employs a patented process by which it makes metal castings "tooling-less," allowing the production of multiple design iterations in parallel. Gustafson points out that some engine component designs, which are designed in parallel with an engine, require engine test data to match the component to the engine. "Until the engine can be tested, the component geometry can only be estimated," he notes. "Making multiple design iterations allows immediate testing / matching as soon as the new engine design is up and running."

The Clinkenbeard® Toolingless Process is known for machining sand cores and molds without the expense of tooling. Gustafson says that Clinkenbeard makes blocks of sand in its shop, then machines the cope and drag part cavities into the blocks using CNC milling centers. The company also machines sand cores from these blocks of sand. "Metal is poured into the assembled molds to make metal castings extremely quickly and accurately," says Gustafson.

In addition to allowing the design to be tested prior to--or in parallel with--investing in foundry pattern tooling, Gustafson says that the Toolingless Process permits changes to be made quickly and inexpensively, and allows multiple design iterations in parallel. The result is significant time and cost savings and no tooling to store.

"In some cases, we can modify sand cores and molds made using production foundry tooling--to implement critical program-saving changes in the 11th hour," says Gustafson. "In this case, the parts are still made from qualified production tooling."

Gustafson adds that the Clinkenbeard Toolingless process is best suited to small-quantity, complex parts with multiple cores. "The more complex, the greater the benefit, typically," he says. Conversely, the process isn't as well suited for very simple parts that can easily be made using conventional pattern fabrication or machining from solid stock, or in large quantities.

Clinkenbeard began in 1966 as a pattern shop that serviced the aerospace industry. Since then, the company has evolved from making foundry patterns for highly-cored aerospace castings to providing one-stop machined castings from a customer-supplied 3D model. According to Gustafson, having intimate knowledge of foundry and metal castings allows the company to design tooling in a way that makes downstream processes--like machining--easier, faster, and of the best quality. Over the years, he says, the company has migrated from conventional patternmaking techniques to modeling all foundry patterns in SolidWorks and then using CNC milling centers to cut them.

The company has established a niche in supplying small-lot production runs, which provides the advantages of speed and the ability to bridge the gap to production in the event that the production supplier isn't able to ramp to production on time. "The parts we make are, in most cases, production quality and provide the customer a dual source in the case that the production supplier is not able to make good parts in time for initial production builds," says Gustafson.

Clinkenbeard makes machined engineering prototypes using 5-axis CNC machining, a process that comes in handy for complex geometries that are easily modeled in 3D CAD systems but are difficult to machine using conventional methods. Traditionally, a fixture would be required for each set-up, or set of features that are not on the same plane. But by requiring only one setup, as opposed to many, simultaneous 5-axis machining reduces the need for multiple fixtures (and the costs) and provides superior accuracy.

Another fast service available from Clinkenbeard is the company's ability to provide show quality mock-ups, which are typically machined from plastic and metal using CNC milling centers. Most of the company's mock-ups must be durable to withstand the rigors of handling, shipping overseas, and mounting mating componentry. "This is one reason we machine them from durable materials, such as urethane," Gustafson says. "Some fragile and unmachinable geometries are grown on rapid prototyping machines." Additional finishing is required to give the show quality mock-ups an automotive quality-plus finish. Depending on the size and complexity of the mock-up, lead times range from a few days for simple parts, to a few months for complex mock-ups.

PolyJet is a trademark of Objet Geometries, Ltd.

Ultem 9085 is a trademark of SABIC Innovative Plastics IP BV.

This technical information has been contributed by
Proto Labs, Inc.

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