This technical information has been contributed by
Profile Plastics

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Thermoforming Giant Opens up on Work for Medical, other Industries

Thermoforming

Mark Shortt
Editorial Director
Design-2-Part Magazine

Strong engineering adds value to projects for medical and other close-tolerance applications

Listen to Steve Murrill give an overview of Profile Plastics, the company that he serves as president, and you're sure to get much more. Murrill, a degreed chemical engineer with an MBA in finance, has been actively involved in working to advance not just his company, but the entire thermoforming industry since he bought Profile Plastics in 1986. In a December phone interview, Murrill traced his company's progress from the mid-'80s against a backdrop of technical milestones and trends—the evolution of pressure forming and 5-axis CNC machining, for example, and the greater use of molded-in features—all the while explaining what they've meant to the success of thermoformers everywhere.

Profile Plastics (www.thermoform.com), a custom thermoforming company in Lake Bluff, Illinois, specializes in producing highly engineered plastic parts to close tolerances and high cosmetic requirements. The company has reportedly won top honors at 19 of the annual SPE Thermoforming Parts Competitions, sponsored by the Thermoforming Division of the Society of Plastics Engineers, since SPE began sponsoring them in the 1980s. Murrill himself was honored as Thermoformer of the Year by the Division in 2011 after winning a Lifetime Achievement Award in 2001.
 
We asked Murrill if he had enough room at his facility to hold all those awards. He wasn't biting.

"We don't rest on our laurels," he replied, adding that although many of the winners were state of the art at the time that they were awarded, time marches on and new challenges continue to emerge with each passing year. "It's fun to look back at the old ones, and we have some, believe it or not, that are actually still in production. The very first one, in fact, is still in production."

Murrill was referring to an air conditioner plenum for a mainframe computer room, which requires very precise temperature control. "The part we make has nothing to do with the air conditioning system, but they needed a 2-foot by 4-foot, complete air distribution and air intake plenum to put as the room interface between the air conditioning unit and the ceiling and the room," he explained. "So this unit is 2 feet by 4 feet, and it has the air filters for the return air and the air distribution network, if you will, to distribute the conditioned air very efficiently. We developed it in 1986 and it's still being sold today."

Profile's 100,000-square-foot facility includes more than a dozen dedicated thermoforming cells and a similar number of 5- and 6-axis CNC trimming cells, providing the capacity and flexibility to meet a variety of fast-changing production and product design requirements. The company offers custom vacuum forming, pressure forming, and twin sheet forming, and can manufacture parts up to 8 feet by 12 feet from thermoplastic sheet up to 0.5-inch thick.

The ISO 9001:2008 certified company also takes pride in its success in expanding the viability of thermoforming, largely through use of what it calls value added engineering. A good example, Murrill said, is the increased use of molded-in features. "By being able to mold more features in, that often times cuts costs," he said. "Because one option is to not have many features molded in, and either machine them in or bond them on separately afterwards. That raises the cost and increases the opportunity for rejects.

"A significant push is towards a lot of tooling creativity to mold in features," Murrill added. "The other part is in this attention to detail on the backside, developing the 5-axis CNC machining strategies to capture a part repeatedly in a nest or a fixture, and programming the 5-axis machine to trim it consistently, and then have ways to QC and monitor the process of the parts to be sure that the consistency is maintained."

Murrill also said that the breakthrough of 5-axis CNC machining helped thermoformers compete with injection molders by enabling them to produce parts with the consistent fit and function required of precision injection molded parts. "To go after that market, the part had to have a consistent trim and a consistent fit. And in the early days, it was all being hand trimmed, which was not only very labor intensive; it was very imprecise," he said. "So the 5-axis CNC machining, which came largely from the woodworking industry in the late 80s, was really kind of the breakthrough to solidifying the quality of the fit."

Thermoformed parts produced by Profile Plastics are used in a range of application areas requiring large, highly cosmetic parts that are manufactured to tight tolerances and in relatively low volumes.  One of the company's core markets is medical equipment, including covers and enclosures for imaging machines and carts. But the company also does work for OEMs in the industrial, transportation, food and beverage, and recreation sectors.

One project for a medical OEM challenged Profile Plastics to provide multiple parts for what was intended to be an aesthetically appealing dental imaging unit without any hint of trimmed edges in its final assembly. Profile's engineers designed the tooling for nine of the component parts, most of them using articulated undercuts to ensure that trimmed edges weren't visible in the finished product. Pressure forming was used to ensure that final parts showed consistency in color, texture, and gloss throughout the entire product. And with a view to final assembly, engineers optimized the points of attachment to ensure that it could be assembled easily.

When all was said and done, Profile completed the complex project on time and on budget, enabling its customer to meet its production and marketing goals. But although it neatly represents Profile's ability to meet the stringent requirements of medical equipment OEMs, its relevance extends beyond that. Over the years, customers have come to recognize that Profile Plastics, sharpened by its experiences in the medical arena, brings to each project the same manufacturing know-how, the same commitment to engineering excellence, and the same thirst for creative problem solving that it turns loose when working for medical equipment OEMs.

"There's not too big of a difference in terms of the way we deal with the customers," says Murrill.

Following is an edited transcript of our conversation with Steve Murrill.

D2P: As a provider of heavy-gauge thermoforming, Profile Plastics offers vacuum forming, pressure forming, and twin sheet forming. Could you talk a little bit about the factors you consider when using each process?

SM: Definitely. Vacuum forming, generally, is for non-cosmetic parts or very low volume parts where the least costly tooling is advantageous. Pressure forming has higher cosmetics, which means more expensive tooling. You can get higher cosmetics having the sheet molded against the tool—the cosmetic side against the tool. So it's generally a tooling issue that separates the two.

Twin sheet is an innovation that allows two-sided forming that you can't get in pressure forming versus injection molding, which is two sided by definition. The folks in the automotive industry started calling it (twin sheet) sheet blow molding, and that's a pretty good definition of it because it really now can do products that blow molding would do. But blow molding has two significant advantages: At very high volume, it's low cost, and if polyethylene will work for an application, they (blow molders) will be very cost effective. But if it's not polyethylene, and the volume's not that large, the blow molders aren't really set up to handle those situations.

Twin sheet forming can operate underneath that gap or void in the market with lower run, shorter run requirements. Any resin we can find in sheet form, we can twin sheet. We can have the advantages of two different types of materials, two different thicknesses of materials, two different colors. It also creates a hollow space between two parts, which is useful many times for insulation—either sound insulation or temperature insulation. By creating that space, you also create places you can run wires; you can use the part to be an air duct.

There are some headliners that have twin sheet ducting systems in them that are very sophisticated. It's like an airplane—how you have the air drop over every passenger's seat. Well, you can do the same kind of thing in automotive or truck, having a web, if you will, or a network of one big twin sheet part that will duct the heat or cool to specific areas in the vehicle. That's generally not a cosmetic application. You just want to get wires or air—hot or cold—from one part of the product to another part of the product.

D2P: Medical is one of your core markets. Do you see any major trends in the medical industry that are impacting the types of products being developed, or the way they're being manufactured?

SM: I see two. One is the one we all know of, but it can't be overlooked. We tell the story that we made the covers for GE Medical's first ultrasound machine, and it was approximately 5 feet tall, 3 feet wide, and 3 feet deep. It was huge! And a couple of years ago, in GE's corporate annual report, they had a picture of their ultrasound unit, and it was a notebook. It had the same sensors, the patient contact sensors for the key readings, but it was all about a computer and now is the size of a notebook. So that miniaturization of computers has had a huge, huge impact on the medical industry because things have gotten smaller, and as they get smaller, injection molding is more cost effective.

On the other side, the patient contact is still the same. People are still the same height, weight, and have the same needs for testing. For an X-ray, you've got to have a table for them to lie down on, and with an MRI, the machine has to be as big as a person. So even though the computer is smaller, the patient interfaces are similar. So that has helped our industry because we're more cost effective versus, say, injection molding, the physically larger the parts are.

D2P: If a design engineer for a medical device manufacturer were to ask you what some of the latest capabilities in plastic thermoforming are that could help them bring their product to market, what would you tell them?

SM: The very first question is 'What would you like it to do, and what can it do now?' There are some resin breakthroughs in terms of high temperature or high performance, or high chemical resistance. The evolution of plastics, polymers, is continuing, and now you can get more and more technology in the sheet than you could, perhaps, 10 years ago, or, certainly, 20 years ago.

You can get more in the sheet. We'll take the aircraft industry, which is not medical, but the aircraft industry now has what is politely called, 'No nothing' sheet—no smoke, no toxic emissions. It's suitable for putting it in an airplane where people used to die from asphyxiation due to the outgassing of the interior components. So that technology is huge, and there are bound to be areas in medical equipment, in particular, where that's used.

Many of the medical applications [for thermoforming] are carts, which deliver technology to the patient's bedside. In that sense, it's operator conveniences that have been invented—you know, creative ways to design things. It's in the design, put it that way, and not so much that the process brings that. The designer brings that and the process is able to complement it.

D2P: Your website (www.thermoform.com) shows an example that Profile worked on for the medical industry. It was pressure formed dental imaging equipment that was converted from the initial design to be compatible with thermoforming. What processes was that product originally designed for?

SM: In the early days, it was largely metal and metal castings. Let me back up slightly and say the precursor was the film X-ray machines that we all know from sitting in the dentist's chair for 20 years. It wasn't a conversion from a digital old technology to new digital; it was really from X-ray technology to digital. And in so doing, the patient interface, the way the machine wants to have the patient oriented, was different enough that they chose to redesign the way that it interacts with the patient. That required about 15 different parts, and it was highly cosmetic because it's in a dentist's office or a hospital.

So the cosmetic needs were high, there are multiple pieces, and there's some chemical resistance. This type of thing—that the product had to withstand chemicals—is normal to the medical environment. And that package really just meant that the alternative to the designers was injection molding, and pressure forming just presented a much, much lower-cost alternative tool-wise, and given that the volumes were relatively low to injection molding volumes, it, overall, gave them a cost effective solution.

D2P: Is it possible to say what types of parts were made for that product? Were they covers?

SM: They're all the covers, yes. One thing: Generally, thermoforming is not structural; it's generally cosmetic. One of the innovations, as an aside to your innovations question, is trying to find thermoplastic composites that are structural. That's under development and that will be coming. There's a lot of it now, but there'll be more and more coming and there will be more that will be practically priced.

Twin sheet is a structural product because of the hollow beam strengths that you get out of twin sheet parts. So there are some structural advantages compared to, as we say, a plain old die forming, or pressure forming, which is a single-sided part.

D2P: This product had nine mating and matching parts that were developed concurrently, and you were able to optimize the points of attachment to be "assembly friendly. "What went into that process of optimizing the points of attachment so that it could be assembled more easily?

SM: In general, there were no exposed fasteners. So in the sequence of assembly, a part would have a hidden tab, and that tab would be hidden by the next piece, incorporating that into the design. Also, machining—by being able to machine the receiving insert, let's say, and bonding it on the back of the part, it can be adjusted for changes in the machine, difficulties in assembly. It can be more iterative because with an injection molded part, you have to decide where you want the points of attachments, and they're machined into the tool, and it's difficult to change those things. Here, you can change the blocks, alter the blocks, for better fit and/or for some unforeseen change that they had to make along the way. It's not like a particular clever thing that no one's ever thought of; it's more of design flexibility.

D2P: With regard to Profile's work on this project, what were you most proud of in terms of what you were able to achieve for your customer?

SM: Well, for most of these projects, particularly multi-part projects, the customers always come to the covers at the end, largely because they don't know what they're putting covers on until they finish the machine. So by definition, it's at the end, but they're always up against a trade show, up against a formal introduction that's—from a corporate standpoint—carved in stone. And so [we're proud of] being able to develop these simultaneously, get them all to fit together, and get them to the customer on time.

One advantage of pressure forming is that you can make the parts and paint the first ones to get them to the trade show. Once we texture the tools, they save a lot of money by having molded-in color and molded-in texture. But we can get them to market faster with these multiple pieces. That was the significant contribution to their project.

D2P: You mentioned earlier that the patient interfacing equipment needs to be on the larger side, which is an advantage for your processes. Can you talk about any other advantages that your thermoforming capabilities have for medical applications?

SM: I think that, typically, medical equipment has long lives, and industrial equipment, certainly. As sort of blanket statement, thermoforming does not do well in consumer products. We do great in kids' swimming pools, and sleds, and saucers, and things like that, but in a durable good cover for consumers, the consumer market changes too rapidly to make pressure forming and thermoforming cost effective.

In the medical world, there tend to be 5- , 10- , and, believe it or not, which is just amazing to me, there are some 20-year-old medical devices that are still as robust as they were five or ten years ago in terms of their sales volume, their applications. The long tail on the products, I think, is what makes it very cost effective.

D2P: What are some other examples of applications that you've done for the medical industry?

SM: "Carts" doesn't sound technical enough, but there are quite a bit of carts that have the computer and the smarts of the piece of equipment, but that need to be taken to the bedside of the patient. Everyone wants their cart to look a little different, and they have consumables and different supplies that need to be brought along with the cart, so you have to have different ways of packaging them or putting them on board that cart. X-ray tables, the diagnostics imaging technologies, the CT Scans, the MRIs, those physically large pieces of equipment lend themselves well to our process.

D2P: Besides aesthetics, what are some of the top concerns of design engineers in making these products? Are there any others that typically come up?

SM: Typically, there's the aesthetic part of it on the computer side, let's say. But on the assumption that it may be a blood analyzer, for example, there are a lot of moving parts and lots of interaction between the machine operators and the machine, so they need access points, they need clear windows to view operations. Those are generally some of the concerns. The trick is in how can you get as few parts as possible and still cover all the critical areas of the machine.

It's really sort of a triage of 'This is what this machine has to do.' The machine designers haven't finished their work; they just know these tasks have to be incorporated, so it tends to be an iterative process of 'We could do it this way,' and they say, 'Well, yeah, we could turn it this way and then that would allow this idea to be incorporated into the design.'

So it's a heavily interactive process. We don't get many blueprints in—they're not blueprints anymore—many CAD files in anymore that say, 'This is it; just quote it and tell us the price." No, it's 'Here, literally, is our napkin sketch. We see two pieces; we see it doing this. Can you come in and work with us on it?'

D2P: That seems to be one of the company's strong suits—the design and engineering capabilities that you have to help customers with.

SM: Yes. I think, relative to most companies in the industry, we have a strong engineering department, which is good in product design, and our sales people are sales engineers. So we have good upfront experience. And I think we're just as good when comes down to actually doing the production tooling, the production jigs and fixtures that it takes to make what was designed repetitive and cost effective in the long run.

D2P: How many people does Profile Plastics employ, and approximately how many engineers do you have on staff?

SM: We have been between 80 and 100 in number of employees, and we're closer to 80 now than the 100. We have approximately 10 engineers.

D2P: Are they from different engineering backgrounds, like mechanical engineering and plastics engineering?

SM: Yes, those are the two most common ones: chemical engineering and mechanical engineering, and there's also an industrial engineer.

D2P: Profile also serves customers in the transportation and industrial markets, making things like truck fascia and an enclosure for programmable theater lighting. Can you tell us a little bit about your work for either of these markets?

SM: The common point, of course, is that the parts generally have to be physically large and we use the words 'highly cosmetic' because that generally leads it to pressure forming and molded-in color and a significant amount of molding detail that add to the 'value added' of the design. We don't do automotive exterior parts for obvious reasons; it's way too high a volume. But for heavy truck and industrial applications, the industrial people are the last ones to go from the metal boxes to all the benefits, appearance wise, of plastic covers, some because a lot of industrial equipment's in pretty rugged use, where it's exposed to bumps or bruises or chemical environments, or high temperature, that type of thing. But as plastics get better and better in paneling for high temperature and harsh environments, those applications are converting over to plastic covers as well.

It seems that there's a general need for a higher level of appearance in something as simple as a mold chiller, a functional product that you wouldn't think would have to be too high design, but there are a lot of companies that see that as the way to differentiate their product from another product. So using plastic design is one way to do that.

D2P: How do you see the future direction of Profile Plastics taking shape?

SM: Well, I think the market niche is geared by sort of structural things, like, injection molding needs two tools, and some process reasons. Whether the niche will grow largely depends on the U.S. industrial base because we make parts for other people. We used to make a lot of exercise equipment and, maybe five years after we made parts and shipped them to assembly plants in the Midwest, we started making parts and they would be shipped to China.

Now, the whole machine comes in a box from China, so there is no assembly in Chicago anymore and, as a result, we don't make parts and send them to China. They can make their own parts and bring it all in in a box. So how significant is that trend, and will that trend slow down? Your guess is as good as mine. We'd like to think it will, but it's got a pretty good head start.

But I think our type of products will be some of the last ones. As for exercise equipment, actually, another thing happened on the way to the ball. Exercise equipment got to be very big business, so it no longer was a thousand or 2,000 a year; it was 10,000 a year. Well, that changes the economics. We would not be doing that part today because the volume is so high. That's the normal evolution of our applications. We have to deal with things that are physically large and relatively low volume, and if they become very popular and get very large volume-wise, they go to more efficient processes.

This technical information has been contributed by
Profile Plastics

Click here to find suppliers

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