Prototyping for Profit
It’s Not Only Product Designs That Must Prove Feasible in Early Stages—Manufacturability Must as Well
When we think of a prototype, we tend to imagine a device in action, proving itself by doing what it was designed to do—the artificial knee bending and flexing, the heart stent allowing blood to flow, the hypodermic needle piercing flesh. It is easy to forget that there is another goal in the prototyping process, one just as vital as trials under real-world conditions. That is, in creating a prototype, engineers and tool designers get the first inkling of whether the product or component can be mass produced in a way that maintains the integrity of the design while, at the same time, keeping unit costs low enough to turn a profit for the OEM. Absent such a manufacturing process, no product, no matter how ingeniously designed, can make it to the marketplace.
Various components manufactured at Lyons, which specializes in in the kind of small, intricate components that are a challenge to mass produce. Processes include wire EDM, forming, machining, grinding and electropolishing. Photo courtesy of Lyons Tool and Die Company.
It’s not an easy task. Following is a look at some job shops that specialize in walking the thin tightrope between function and cost, between the theoretical and the practical, and how they maintain this delicate balance.
Rapid Prototyping Gains Ground
Prototypes have been around since there were products to test, but the term “rapid prototyping” is relatively new. It usually means a host of related technologies that create objects by adding and bonding materials layer by layer. Other names for it include additive fabrication, 3-D printing, solid free form fabrication or layered manufacturing. The basic idea is to form an object without building a mold, creating an elaborate machine setup or engaging in final assembly. The prototype is formed from the inside out, one layer at a time. A great deal of technological advancement has occurred in this field over the last 15 or 20 years (see “Prototype Metals Without Machining or Casting” on page 58), and existing rapid prototyping methods continue to decline in price and become more accessible.
However, “rapid prototyping” also can refer to speedily produced prototypes created by conventional methods, such as milling, wire EDM or stamping dies. Such methods sometimes are called subtractive fabrication because the raw material is cut down into the required shape. These processes may occur in an ad hoc kind of fashion, with unconventional subassemblies or the hand crafting of parts occurring in ways that would never happen in normal production, perhaps also without the tight tolerances and strict documentation that are standard in creating medical parts or components.
Regardless of how the prototype is fashioned or whether it is called “rapid,” speed of delivery remains very much a priority among OEMs, which continue to view being first to market with a new product as the most effective way to capture market share. A well-run prototyping phase can shave four to 24 months off the product development cycle, according to industry experts, and OEMs want every day of that savings if they can get it.
“What we typically see is when customers want prototypes they don’t want to wait; they want it as soon as possible, which could be a week, two weeks or three weeks. People don’t like to wait three weeks for something; they would prefer it sooner,” noted Bob Lamson, director of northeast sales for MicroGroup, Inc., headquartered in Medway, MA.
Another continuing trend is customers asking for smaller and smaller parts. This plays to MicroGroup’s strength because the company specializes in developing tubular devices, which increasingly are necessary in laparoscopic, arthroscopic and other minimally invasive surgical techniques. Right now, slender, tubular endoscopes are all the rage among product designers.
“Tubing is all over the place,” said Matt Fratantonio, engineering manager at MicroGroup. “It’s used in everything from hypodermic needles to getting activity at the end of a device. A lot of times a tube within a tube is how the device creates motion inside the body, and then there may even be a wire inside the second tube. Tubing is a natural fit for medical devices these days just due to the nature and the mechanics of what they [designers] are trying to get done.”
Shown above is a 10-cavity RTV mold for molding flow cell housings. Photo courtesy of Mack Prototype.
All contract manufacturers agree: the first step in taking on a prototyping job is to make sure you have an open and clear line of communication with the customer. You cannot meet the customer’s expectations if you don’t know what those expectations are. But this can be difficult because, sometimes, in the early stages of product development, the customers themselves are not sure what they want.
“One of the challenges is when an engineer calls who has two weeks or less to get prototypes in his hand for a presentation. The last thing he wants to hear is a bunch of questions,” said Les Duman, sales manager at Pleasanton, CA-based Peridot Corporation, which specializes in small precision parts and assemblies—often, electronics used in handheld medical devices. “But, sometimes, these important questions can be handled with one phone call. For example, among the first things we want to know is, in the company’s wildest dreams, how many of these items might they sell per year? Some products maybe they expect to sell 10 or 20 units a year—some, maybe a few hundred a year. If the product is disposable, it could get into the hundreds of thousands. But in knowing that up front, we can better assess what prototyping processes will be best to use. Then, whatever we do use, we want to make sure that it can be translated and evolved into an effective production process. If all you are doing is pressing for quickness, you can wind up designing yourself into a corner when it comes to production.”
Duman said the next step is to assess how attached the company is to its initial design, how open to suggestions. Usually customers are willing to entertain new ideas if improving manufacturability is the goal, he noted.
Next it is key to determine the purpose of the prototype, knowledge that can reveal shortcuts. “I may find out on a battery contact prototype, the engineer only wants to see how strong the spring action is going to be. Well, in that case, there is no need to construct an elaborate battery contact. We can make a simple spring finger rather than a complete part, and that will be enough to test the spring force.”
Also, creating several iterations at once can save money and time. In the aforementioned example, if the engineer was unsure of the spring strength needed, Peridot could fashion one in the strength specified by the design, another 20% stronger and a third 20% weaker. Thus, the customer could experiment with a range of options within the same time and approximate cost frames.
Before the prototyping process begins, there is an opportunity to make suggestions aimed at improving manufacturability. An example cited by Duman is a hand piece for a disposable surgical device that his company prototyped. At the business end of the device, the design called for a hollow, narrowing metal tube with two strips of holes and slots cut in it, situated 120 degrees from each other. The initial assumption was the holes and slots would be drilled by Peridot Corporation’s rotary cutting laser. But on further consideration, Peridot employees suggested that the design be altered to orient the slots and holes 180 degrees from each other, on opposite sides of the tube. By making this change, the company could manufacture the slots and holes using a combination of EDM drilling and wire EDM cutting.
“Number one, this allowed us to cut two orifices at once because we are going through two walls of the tube and, more importantly, the EDM leaves a virtually burr-free edge [unlike the laser]. So post-cut finishing was extremely minimal,” said Duman. “Therefore, at the project’s end, we produced a lower-cost product of better quality and better consistency.”
Meriden, CT-based Lyons Tool and Die Co., which specializes in producing small, complex metal components (the type often necessary for laparoscopic and endoscopic devices), prides itself on being able to handle difficult prototyping programs.
“Our specialty is developing new products where others may not choose to accept the challenge,” said President Will Lyons. “Our engineering group is fluent in the prototyping process, and there is a strong emphasis placed on communicating with our customers. Our engineers review the models or drawings provided and then make recommendations or express concerns related to the manufacturability of the component in the initial stages of the process. Communication is critical at this time, and Lyons is committed to keeping our customers informed.”
When the job is particularly challenging, this communication can take the form of discussions relating to manufacturing issues and their potential solutions.
“If we are not sure a component can be manufactured as provided by the customer, we inform the customer up front and look to provide an alternate configuration,” Lyons said.
Because it often is difficult to estimate the cost of the co-development of a complex process, Lyons may suggest billing on a time and material basis, setting milestones at which the prototype’s progress can be assessed. This format often provides the most expeditious development process. It may be considered worth the risk for an OEM or sub-tier manufacturer to structure a partnership in such a way, Lyons said, because the payback realized from a successful product launch that precedes a competitor’s launch can be substantial.
Staying at the vanguard of device manufacturing technology requires continual capital investment, Lyons added. “Lyons has strategically invested in new equipment and has developed customized tooling and processes to better serve our demanding customer base,” he said. Recent prototyping equipment acquisitions include the company’s third new Fanuc Wire EDM, two new Mazak four-axis high-speed machining centers, software upgrades and training in SolidWorks and MasterCam. Also, the company has purchased its second Baltec Precision Work Station for forming metal-stamped components, “as well as other various support equipment,” according to Lyons.
Manufacturability Still Key
No matter how carefully engineers, designers and tool makers examine the plans and models, check each others’ mathematical calculations and suggest design changes, nothing can match the utility of creating a prototype from scratch in a factory setting. It is the only proven way to assess if the design can work in the real world. This stage is becoming more critical as OEMs push the engineering envelope in the name of competition.
“A lot of decisions made by engineers and tool makers are based on mathematical calculations, which predict how the metal will react,” explained Zev Asch, vice president of marketing and sales at Popper and Sons, Inc., a company in New Hyde Park, NY that provides a wide range of reusable and specialty hypodermic products to the medical, laboratory and industrial markets. “As parts get smaller and smaller, and tolerances get tighter and tighter, the metal is being forced to do things it likes to do when it is much bigger.”
Ideas that work on paper do not always work once the prototype process is up and running, he said. “You get the order and you develop the tool and start running it, and you find out that maybe the tool works for X number of parts and, after that, it begins to wear off quicker than normal because of the tight tolerances and small size. Now you have parts that are not compliant. This happens to us every once in a while,” he noted.
Others in the industry agree: there is no substitute for a trial production run. “Parts are so small and intricate that even with years of experience, like a lot of my people have, predicting outcomes is not always a slam dunk—especially with tubing, when you can cut a slot in the tube and the residual stress causes it to want to spring open,” said Fratantonio of MicroGroup. “How much is it going to spring open? That is very hard to predict. With these odd geometries and cutouts, you have no clue.” A prototype will help the engineer figure out what type of material movement is going to occur, what level of tolerances can be achieved, what can compensated for and what cannot, according to Fratantonio.
Building production tooling that will manufacture parts or components represents a huge upfront investment for an OEM. So there is great incentive to ensure the production tooling setup will accomplish what is it is designed to do. Mack Prototype, based in Gardner, MA, can create prototype tooling prototype, often in one week or less, according to President Ric Perry.
“We can produce RTV [room temperature vulcanizing] molds…from these molds we are able to produce plastic parts, polyurethane plastic parts that are very similar to what the production resins will produce.” On other occasions, the company may be called on to produce an aluminum prototype tool to test the viability of an injection molding process and resins. The latter type of job might require three or four weeks lead time, Perry said.
Often, the company will work on prototyping a part/tool and the production tool at the same time. This kind of parallel design project offers huge savings to an OEM in terms of getting end-use products to market, explained Fran Preseault, program manager for Mack Molding Co., located in Arlington, VT (both companies are wholly owned subsidiaries of the Mack Group Corporation).
On jobs in which prototypes and production tooling are produced by separate entities, there may be a great deal of engineering “clean up” that occurs when part and tooling come together under one roof. “I’ve been involved in projects where a customer has had to make 25% to 50% of the initial production tooling costs in engineering changes on those production tools after we got the first samples from the production tools and the customers did their initial fit ups,” Preseault said.
In contrast, on a recent program in which the tooling and product was prototyped prior to production tooling release by Mack, less than 3% of the tooling costs were needed for engineering adjustments, he said. Given the huge expense of designing tooling—in this case, an outlay of $2 million by the OEM—this represented a significant cost savings.
Preseault and his team, who are responsible for the production tooling and manufacturing of the product, often visit Mack’s prototype facility to determine the exact size of parts, the number of inserts for secondary operations and other assembly requirements.” Our manufacturing engineer has been able to see the different assembly steps and put together his work instructions ahead of time, before the production tools even come on line,” Preseault explained.
Much of Mack’s work involves cutting-edge uses of plastics (the company was recently named Plastics News’ “Processor of the Year” and has a patent pending for its own custom made plastic resin). Because today’s plastics can be autoclaved and sterilized, they can be used in low-volume production parts, which opens the field for additional prototyping options, according to Perry.
In terms of the future, those in the prototyping business expect current trends to continue, at least in the short term. New technologies probably will gain wider acceptance, with 3-D additive fabrications perhaps allowing for more subassemblies during the prototype phase. And smaller parts remain a trend—always smaller parts, experts said. At a recent trade show, Fratantonio of MicroGroup was astonished by a new micromachining center that creates parts so small, they only can be seen in full detail under a scanning electron microscope. “I looked at that and I was amazed,” he said. “But then I thought, in five years, I’ll probably need one.”