Pressure Forming with Molded-in Color

This white paper is based on a speech that Profile Plastics gave at the 2001 Spartech Technical Conference. We’re sharing this content now in recognition of the recent retirement of Eric Lattanner, Spartech’s business development manager, who received a Lifetime Achievement Award during the SPE Thermoforming Division’s October 2023 conference in Cleveland, Ohio. Profile Plastics salutes Eric for his service, especially his support of Royalite®sheets for pressure-formed parts with molded-in color.

Getting Started with Pressure Forming

Nearly 50 years ago, Profile Plastics pressure-formed its first part on a used 5’ x 10’ unit from Brown Machinery, which is now known as BMG Solutions. This “true” pressure- forming machine was built in 1972 and designed originally to vacuum-form bass fishing boats. According to Brown folklore, only six of these massive machines with bayonet locks were ever built.

Because these units featured a hydraulic squeeze for die cutting, they were well-suited for pressure forming long before this thermoforming method became popular. The market for plastic pressure forming grew slowly at first, but it accounted for approximately half of Profile Plastics’ business by the time we gave our 2001 speech. Yet that involved overcoming a major obstacle: tooling.

Tooling and Other Considerations

With our Brown machine, molds needed to leave their wooden 2×4 legs, adopt a negative instead of a positive design, and become vessels capable of withstanding 50 to 80 pounds of pressure per square inch (psi). Mold construction was easy, but these changes increased tooling costs by as much as $5,000. That undercut the economic justification for using pressure forming in the first place.

Profile also needed to address challenges with part attachment, color, texture, and function. Typically, pressure-formed parts require some method of attachment. If they don’t have consistent dimensions, however, parts mating and fastening are challenging. All of the points of attachment, including the secondary ones, need to work reliably. The pressure formed parts need to look good as well.

Pressure Formed Part Colors and Textures

Unlike injection molding, the tooling for pressure forming readily supports undercuts. That’s an important advantage for attachment, but color and texture are also key considerations. Pre-colored plastic sheets were available during pressure forming’s early days, and it had been a standard practice to share color chips with vacuum forming customers. But pressure-forming customers wanted more.

Some wanted sheets in custom colors that matched their company’s brand. Others wanted to color-match different parts, including non-plastic components. Textures were also important. At first, customers preferred heavy textures that could hide any imperfections in the tool. Finer textures were possible but required parts painting. As tool-making techniques improved, molds with finer features became possible.

Run-to-Run Color Matching and Royalite Sheets

Run-to-run color matching was critical, and top covers from a first run need to match the back covers from the next run. That’s also true of injection molding, but plastic pressure forming has different design considerations, including depth of draw. Plus, the gauge for adjoining parts is often different. Heavier gauges require a longer heat soak, and that increases the potential for sheet discoloration.

Painting can cover up imperfections, but it adds costs and extends project timelines. For molded-in color, Royalite sheets proved to be very resistant to color shifts, especially compared to competitor offerings. Today, the Royalite brand is owned by Spartech, the company from which Eric Lattanner recently retired.

Pressure Forming’s Second Decade

As pressure forming entered the 1980s, OEMs who made expensive equipment wanted to replace their sheet metal parts with lighter weight, less expensive plastic ones. Typically, the part volumes were 50 to 250 per series. Pressure forming provided a cosmetic and functional alternative that was both quick and cost-effective.

The business environment could be challenging. Sometimes, OEMs who faced potential plant closures, relocations, or outsourcing would present us with urgent projects for half-finished equipment. Many of these jobs were unprofitable and required upfront engineering and overtime that we couldn’t recapture. Profile learned from these experiences, which were the exception rather than the rule.

Fitting, Fastening, and Color Matching

For OEMs, pressure forming’s formed-in undercuts were attractive because they solved fit and function challenges. Generally, designers specified looser-fitting parts since pressure forming used lower-cost tooling. Yet this created the cosmetic challenge of hiding the witness lines from a mold’s moving sections. Fortunately, painting could cover witness lines with just a little sanding and filling.

Eventually, however, the way that parts came together became an issue. They needed to match each other in appearance and also fasten together in a way that was cosmetically pleasing. Hand-trimming highly visible parts was challenging, so Profile Plastics purchased a 5-axis Thermwood electric router in 1979. To say that this technology was still in its early stages was, in retrospect, an understatement.

Early Automatic Trimming: Pros and Cons

Profile’s 5-axis Thermwood electric router could trim features that were difficult or impossible to hand fixture. This 1970s-era machine could also trim very large parts that were difficult to trim by hand. Yet setting up jobs and programming parts was difficult. Plus, the repeatability was poor. Therefore, the electric router needed continuous adjustments and tweaking.

Although this machine was like an extension of an expert craftsman and a programmer, it didn’t meet our expectations for decreased production times and reduced skilled labor inputs. Too often, the finished parts neither looked good nor fit well together. Fortunately, we had enough customers with the right type of applications to support this form of automatic trimming, despite its challenges.

Molded-In Color vs. Parts Painting

During the early days of pressure forming, most pressure formers didn’t have especially high expectations for sheet materials. However, Midwestern thermoformers didn’t want to paint parts. Painting isn’t a clean process, and it poses problems with odors and exposure to carcinogens. The prep work is dusty, dust removal requires air handling, and HVAC energy costs can be significant because of our winters.

Midwestern thermoformers also preferred pre-colored parts because of the influence of the automotive industry. To reduce costs, the automotive supply chain wanted material suppliers to develop colored sheets for parts that would be ready right out of the mold. That would eliminate or reduce the need for parts painting, but it would also require close collaboration with material suppliers.

Building a Business Around Royalite Custom Color Matched Sheets

To avoid parts parting, Profile Plastics developed a strong relationship with Royalite, an Indiana-based division of Uniroyal that was later acquired by Spartech. Royalite’s color-matching technique supported the production of custom-colored sheets in lower volumes – and with predictable costs and lead times. Although these lead times were still relatively long, most of Profile’s customers preferred molded-in color.

Without Royalite sheets, painting would have remained the primary way to produce pressure-formed parts with color. Yet painting’s higher costs would have limited the growth of the pressure-forming industry. The freight costs associated with outside painters and the time that painting adds to manufacturing are problematic, especially among customers who want to accelerate time-to-market.

Material Costs and Manual Trimming

When Profile Plastics addressed the Spartech Technical Conference back in 2001, the cost of thermoplastic sheeting was three times greater than the cost of the materials used in injection molding. More significantly, pressure forming was working to overcome its higher reject rates because of the lower-tech molds that were used at the time. To make parts functional, secondary trimming was required.

Unfortunately, the variations in hand trimming were too great to meet customer requirements. Therefore, Profile pursued quality by culling unacceptable parts. Yet we also labored with inefficient designs that were based on injection molding and used stands-offs and bosses instead of through holes or undercuts for attachment. Our employees had to learn new skills, including precision bonding, to support this.

Part Measurements and Reject Rates

Measuring close-tolerance parts was another challenge. For example, a part with 45 minutes of CNC trimming needed 2.5 hours to measure all of its critical dimensions. Every time this job was set up, it required time-consuming adjustments before production could begin. Meanwhile, our reject rates ranged from 10 to 25%. Some sheets were sent back to Royalite, but at least they could be recycled into feedstock.

The cost of part rejects is an area of disagreement between thermoformers that prefer painting to molded-in colors. Painted parts aren’t easily recycled into non-virgin feedstock, but they can be sent through the paint shop again, which reduces the load on landfills. At Profile, substantial equipment investments have enabled us to optimize our high-volume pressure forming with molded-in colors.

From Low-Volume to High-Volume Pressure Forming

Back in 2001, Profile’s reject rates ranged from less than 1% to as high as 4%, depending on the part. As we explained in our speech to Spartech, this reduced our need for painting and cut our direct labor costs from 20% to 12%. It also strengthened our relationship with Royalite. Now that Profile could consistently produce tens of thousands of parts per year, we could pursue higher-volume applications.

Originally, Profile had asked Royalite for low volumes of custom-colored sheets with close color matching. This enabled us to break into many low-volume applications, but now we needed less expensive sheets so we could keep jobs as volumes grew and injection molding became more appealing. Yet sheet prices weren’t the only obstacle to high-volume pressure forming.

Tooling for Automation

For high-volume pressure forming, Profile needed tooling that supported automation. By using machine control to reliably cycle a mold’s moving sections, we could run our rotary equipment 24/7 – and without rejects. We also needed faster ways to program and trim a job’s first parts, and CNC machines and fixtures that could position and trim subsequent parts quickly and reliably.

In addition, Profile needed to work closely with designers to eliminate the bonded-on features that some designs required. Through progress in all of these areas, the costs of pressure-formed parts would continue to fall and we could produce higher volumes economically. Profile Plastics has made tremendous strides since our Spartech speech of 2001, which also addressed what was then our next thermoforming frontier.

Twin Sheet Thermoforming Arrives

Twin sheet thermoforming wasn’t new when the twenty-first century began, but Profile Plastics was mainly a vacuum former and pressure former at the time. Today, it’s a service that we offer for great-performing hollow and lightweight plastic parts. The process, which uses a clamshell technique of molding two sheets in one frame, was used originally to produce boats and then pallets and shipping containers.

The rise of twin sheet thermoforming dates back to the 1980s, when GE Plastics pioneered a technique called large part blow molding, or engineered blow molding to stimulate demand for its materials. Designers and molders liked what they heard, but they didn’t like how the parts looked. Excessive die lines required painting, and hand trimming was difficult. Plus, blow molding machines were expensive. In addition, GE targeted applications for its highly engineered resins, which were more expensive.

Engineered Blow Molding vs. Twin Sheet Thermoforming

During the 1990s, engineered blow molding developed a specialized but significant market. With the exception of polyethylene parts, however, blowing molding doesn’t have a cost advantage over twin sheet forming, which is also capable of specialized applications. For example, when Exxon’s Greg Wilson addressed the Spartech Technical Conference in 2000, he envisioned a market opportunity for twin-sheet thermoforming fuel tanks that were better than blow-molded ones.

Today, twin-sheet thermoforming has lower tooling costs than blow molding and advantages that include faster turnaround and lower part costs than rotational molding can achieve. Highly detailed cosmetic parts are readily achievable, and twin-sheet forming makes it possible to obtain more difficult draw ratios than other plastics manufacturing methods can achieve. To learn more about Profile Plastics’ capabilities and how we can help you succeed with your next project, contact us.

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Multi-part enclosure for panoramic dental x-ray unit.

Exceptional cosmetics have opened great opportunities for thermoforming, but satisfying high volume applications was a problem. Profile Plastics has built a business around high volume consistent, pressure forming, which has greatly expanded the market for all.

Pressure forming has proven itself as a great method for getting complex parts to market quickly without the high tooling costs and long lead times needed for injection molding. Unfortunately, because of the high per part costs and the artistic nature of the manufacturing process, pressure forming has most often been targeted to applications that require a lot less than 1,000 parts per year…Until now that is.

Profile Plastics of Lake Bluff, IL has spent the past ten years quietly perfecting a process that allows them to produce more than 10,000 of each part per year, consistently, and more importantly, cost effectively. They are now ready to reveal that they are the lowest cost manufacturer in the US for highly cosmetic, close tolerance, thermoformed parts, and that they have proven their process by consistently meeting the needs of customers who require tens of thousands of parts per year, year after year.

Who is Profile Plastics?

John Grundy, a pioneer in the thermoforming industry, founded Profile Plastics in 1960. Through his contributions to the growth of the thermoforming industry, John was chosen as Thermoformer of the Year in 1993. The company has a reputation for strong customer service and award-winning parts.

Profile Plastics' Thermoformed Medical Waste SystemThis Medical Waste System won thee 2023 SPE Thermoforming Award Winner for Pressure Form, Gold People’s Choice Award Healthcare. Throughout the years, Profile has remained on the cutting edge of technology and have been innovators in the commercial development and use of the thermoforming and pressure forming processes.

The company is currently led by Steve Murrill, whose mission is to create an organization and facility that allows Profile to anticipate and meet customer needs while opening up new high­ volume markets for pressure forming.

The entire Profile organization is structured around a team approach that is geared toward efficient,  continuous production. By having the best people organized into logical teams, Profile minimizes downtimes and creates efficiencies that reduce the total cost of operation.

To achieve highly detailed products using pressure forming, there is often a lot of hand finish work, which drives up the per-part price and makes it difficult to get consistent quality over a large number of parts. Traditionally, pressure forming has been almost more art than science. Each operator would get different results.

This meant that one shift would produce great parts while the next shift’s production would need to be reworked, deviated, or worse, scrapped. If key production went on vacation, some parts might not have been made at all. Inconsistent quality, high reject rates, excessive trimming time, slow production, and too much hand-labor per part were all obstacles that had to be overcome on the road to high-volume thermoforming.

The Profile Process for High Volume

Profile has developed a facility, an organizational structure, and a manufacturing process that allows them to consistently produce tens of thousands of each part per year. The process is as follows:

Sales Engineering.

Preparing for high volume starts with Profile’s direct sales people. Each project is unique, and the sales engineer’s job is to help the customer understand the right process for each application. Profile works to make sure that the customer understands what is possible and what is not possible with thermoforming. Many great sales opportunities are handed off to alternative processes that are a better “fit.”

Engineering.

Profile Plastics, Inc -thermoformed highly detailed cosmetic partsMuch of the cost of pressure formed parts comes from the CNC router trimming time and the manual labor needed to bond on blocks, hand trim out special areas, paint and so forth. Profile has always used molded-in color, which they believe provides a better end result and reduces production cycle time.

To reduce the other post­ production expenses, Profile spends a little more time during the engineering phase to prepare not only for the usage of the product, but also for the production process. In many cases, they are able to mold in features or eliminate blocks. By molding in these features, they reduce the time to make the part, lower the cost, and provide consistent quality.

Tooling/Process Development.

Profile engineers work to create accurate, robust, detailed production tooling, resulting in part cosmetics that are in many cases superior to injection molding. For higher volume projects, spending a little more on the mold tooling can have a dramatic effect on the consistence of production and the per-part cost. In order to take the skill of any particular operator out of the equation, Profile engineers also spend time upfront to create process check fixtures that allow the operator to regularly and precisely make sure they are making good parts. In this way, most prob­lems are caught before more than a handful of parts are made.

High Volume Production.

Custom Thermoforming PressOnce the tools are designed properly, the burden passes to production. As pressure forming has grown over the past 25 years, many of the manufacturing machines and processes were invented or modified by plant engineers as needed. This meant that each machine was a little bit different than the others. Most parts were tooled and set up to run on one particular machine. If that machine was down or busy, the part was delayed.

To get away from that restriction, Profile took advantage of a plant move and expansion to install multiple computer- controlled machines that allow for effective redundancy. If one machine is down or busy, production can be set up on an identical machine without any major problems. In addition, with more sophisticated process controls, the equipment can automatically alert the operator if something has changed. Profile runs multiple shifts on their state-of-the-art equipment, and they have developed their own quality control procedures that provide more consistent results, regardless of the operator. In fact, over the past ten years, Profile has reduced its reject rate by more than 75%. This reduces the high overhead of inspectors and rework artists, all of which result in lower costs.

Just in Time.

Traditionally, a thermoformer gets an order, makes the order, ships the order, and then waits. This approach means that there is a built-in delay in fulfilling each new order, and there can be a lot of uncertainty and downtime for the plant. Profile has implemented a different sort of “Just in Time” system.

Instead of waiting for an order, they work with each customer to understand his/her needs over time. They will then schedule production before they get an order, so that when the rush order comes in, they can meet the customer’s initial needs immediately, while they both ramp up for repeat production.

Profile also sizes the production runs to be the most efficient. They base the production run size on the customer demand, the degree of difficulty of the setup, and the physical size of the part, rather than arbitrarily stopping when the customer’s current requirements have been met. Of course, it is possible for Profile to get burned if they have parts on hand without an order and the parts are then discontinued or modified.

But Profile reports that by getting close to the customer and understanding the customer’s usage patterns, Profile can create production schedules that provide the parts right when the customers need them. This keeps the plant running more consistently and often lets Profile “be the hero” when a customer needs parts in a hurry. Over the past ten years, very few parts have been scrapped due to unauthorized overruns.

Customer Service.

While Profile has worked hard to develop a facility and a process that makes high volume production possible, company president Steve Murrill says that these actions alone are not enough. “For us, the key to transforming pressure forming into a consistent, high-volume process is an unswerving focus to customer needs. We have found that a close working relationship isn’t just a nice way to keep clients happy. It is what makes us successful. It is not enough to react to customer needs. We have to anticipate them. We combine knowledge of our process with knowledge of their needs in order to think on their behalf.”

Pressure Formed Exercise BikeBy creating a state-of-the-art facility, by helping clients design not only the part usage, but also to the production process, and by working to anticipate client needs, Profile has been able to break the volume ceiling for pressure forming. They routinely produce many parts in excess of 10,000 pieces per year. the panels for the Life Fitness Exercise Bike illustrates just this. Over 70,000 were produced using Profile’s “Just in Time” strategy.

Early Profile Plastics, Inc.'s Pressure Formed Color Printer Covers for KodakAnd over 5,000 multiple-part Electronic Printer Housings were produced in a matter of months to satisfy a rapidly developing market. Profile prides itself on complex part designs that have been recognized for excellence year after year at the annual Thermoforming Conference. Their motto, “Parts Under Pressure” is really a rallying cry to their employees to never let down and take anything for granted. The pressure is always on their parts and on their operations to maintain a high level of customer satisfaction.

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Let’s talk about how to make your part right.

Our guiding principle for doing business is simple but powerful: We’ll make it right.

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