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The terms “plastic thermoforming”, “pressure forming”, and “vacuum forming” are all used to describe plastic forming processes. While similar, there are subtle and important differences in these terms and processes that may not be well known outside of the plastic manufacturing industry.
Here is a brief breakdown to get you talking thermoforming like a pro in less than a minute:
Plastic Thermoforming is the generic broad label given to the plastic manufacturing process that heats thermoplastic sheet material (thermo) and then applies pressure or vacuum to form into a 3-dimensional shape (forming).
Pressure and Vacuum Forming are the 2 most common plastic thermoforming manufacturing techniques, under the umbrella of plastic thermoforming. They differ primarily in the method of applying pressure/vacuum to transform the heated plastic sheet into the desired 3-dimensional shape.
Pressure Forming Process |
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Vacuum Forming Process |
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Plastic Thermoforming | ||
Pressure Forming | Vacuum Forming | |
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| Process Description | Sheet thermoplastic material is heated until pliable. Positive pressure is then applied above the heated sheet, pressing the material into the surface of a mold to create the desired 3-dimensional part shape. Full Disclosure – The air under the sheet is also evacuated to assist in stretching the material over the mold, but the positive pressure applied is up to 5x greater. | Sheet thermoplastic material is heated until pliable and placed over a mold. The air is then evacuated between the heated sheet and mold creating a vacuum that pulls the material onto the surface of the mold to create the desired 3-dimensional part shape.
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| Key Benefits |
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| Tooling | Negative tooling | Positive tooling (typically) |
| Primary Part Surface (Dimensional & Aesthetic)
| Outside (part surface contacting the tool) | Inside (part surface contacting the tool) |
| Application Examples |
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In addition to pressure forming and vacuum forming, there are other methods, such as twin sheet thermoforming (to be covered in a future post), that give plastic thermoforming a vast portfolio of manufacturing capabilities that offer product solutions to a wide range of industries and applications. Plastic thermoforming often outperforms other processes and materials such as fiberglass (FRP) , metal, or injection molding.
Want to learn more about which plastic thermoforming process is the right solution for your project?
Please contact us.
The heavy gauge plastic thermoforming process can produce a very versatile range of highly detailed, durable, and tight tolerance parts with almost limitless design possibilities. The process is fast, cost effective, and ideally suited for a large list of markets and applications. However, like all manufacturing processes, plastic thermoforming requires technical expertise, detailed operating procedures, engineered tooling design and construction, and a comprehensive quality management system to ensure the consistent production of the most cost-effective solutions at the desired level of quality.
As such, not every plastic thermoforming processor is equally capable. Contract manufacturers with poor tooling, processing and quality controls can end up delaying your project or OEM product and increase costs. Productive Plastics recommends asking the following questions to gauge if a custom plastic manufacturer will be able to consistently produce parts at your required level of quality and dimension tolerances.
Ensuring that your manufacturer has adopted an accredited quality control program, such as ISO 9001, will indicate that the company has an active quality control process in place that has been evaluated and certified by an industry recognized third party. The accreditation documentation, often available on the manufacturer’s website, will give you detailed information on what aspects of the company have been certified and supporting quality documentation can often be requested from the processor.
This may seem like a trivial point, but it can be a key indicator 
to a company’s commitment to quality. A company with a well-organized manufacturing floor is much more likely to take quality, efficiency, process improvement, and safety seriously. If you are not offered a tour of the facility, ask for ne and witness firsthand the quality control measures in action. Cleanliness and organization are vital since thermoforming is an “open mold process” meaning airborne dirt could end up as an inclusion in the finished part and become a cosmetic flaw.
Lean Manufacturing practices are focused on the removal of inefficient practices in manufacturing, management, and administration operations and part of the methodology is the regular evaluation of current processes with emphasis on continual improvement. Companies that are committed to following Lean Manufacturing techniques often have a very efficient manufacturing operation, state of the art equipment, and produce quality parts with a low rejection rate.
Properly designed and constructed tooling is the foundation of plastic thermoforming and is essential to producing a high quality consistent product. Poorly engineered tooling can result in part dimension variations, surface abnormalities, and other defects. See 6 Common Thermoforming Quality Issues Actually Caused by Improper Tooling.
This collaboration innovation technique sets the stage for a smooth product development which is more likely to meet performance and delivery expectations.
Ultimately, each project is unique. A commodity type part will likely not require the same level of quality in detail and precision as a multi-part medical device assembly. However, finding a reliable custom manufacturer that can produce your parts consistently, efficiently, and to your specification is a paramount factor to the success of any product.
Have more questions about the role of quality manufacturing for your parts and components? Interested in exploring plastic thermoforming solutions for your OEM product?
Please contact us.
The manufacturing supply chain can be long and complex. Managing independent suppliers for design, tooling construction, assembly, part painting, and more can be challenging, and each has an influence on the quality, timing, and cost of the finished product.
For custom plastic thermoforming, post-production part painting is a key link in this supply chain. That is why Productive Plastics decided to bring our own painting operation under the same roof as our manufacturing facility.
Our cutting edge painting and finishing facility is solely dedicated to meeting the surface finishing needs of custom heavy gauge thermoformed parts manufactured by Productive Plastics.
What are the Benefits to Our Customers?
Reduced Risk
If a supply chain is only as strong as its weakest link, then strengthening or removing that link reduces the risk of a break. Consolidating the painting and manufacturing operation at Productive Plastics means that there is one fewer supplier to manage and monitor.
Reduced Cost
In-house facilities and complete control over the painting process reduces or eliminates the logistical and quality control costs associated with an off-site supplier.
Reduced Lead Time
The painting facility is located a mere 100 feet from the manufacturing floor which means that parts can be painted, cured, and ready for shipping or assembly in the same day that they are manufactured.
Increased Process and Quality Control
Incorporating a painting facility into the operation at Productive Plastics allowed us direct control of the painting process and quality management. We implemented the same lean manufacturing techniques, proven processes, and quality controls that we have been evolving on the manufacturing floor for over 6 decades.
Strategically consolidating the manufacturing supply chain is just one of the ways Productive Plastics is constantly improving our ability to contribute to your product’s success. Contact us and give us the opportunity to show you how we can provide much more than a high quality plastic part.
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At the 2018 Plastic Thermoforming Product Development 
Summit, hosted by Productive Plastics, you will learn about every aspect of developing a new product or converting an existing project to the plastic thermoforming manufacturing process.You will gain insights about the entire development process, from design to finished assembly, as you engage with industry leaders from each link in the production supply chain.
Wednesday
June 20th 2018
8:00am – 3:00pm
Natick Boston-Metro West
Courtyard by Marriott Boston Natick
342 Speen Street
Natick, MA 01760
508-655-6100
$50 Registration
Included:
Chance to win a 3D printer
Continental Breakfast/Coffee
Catered Lunch
| Custom Plastic ThermoformingJohn Zerillo VP Sales | Principal Productive Plastics
| Extrusion Process and Material Selection Eric B. Lattanner Business Development Manager Spartech
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| Design for Thermoforming Key ConsiderationsScott Ryan, IDSA President Brownlie Design | Tooling Development Fritz Borke Borke Mold and Bay State Cast Products
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| Industrial Finishing John Snyder PPG Paints
| Structural Adhesives and Tapes John Petrauskas Ellsworth Adhesives (ITW)
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When comparing a part manufactured with the heavy gauge plastic thermoforming process and the injection molding process, next to production volume, the largest factor that can impact the cost and even process feasibility is the size of the part.
Essentially, the larger the part is, the more expensive it becomes to produce with injection molding. Comparatively, part size has a very minimal cost effect on plastic thermoformed parts. The breakeven point on cost between the two manufacturing processes, with respect to annual production volume (Deciding Between Plastic Thermoforming and Injection Molding – The Choice is Not Always Obvious), increases as part size increases to approximately 5,000 parts or higher depending greatly on how large the part is.
The injection molding process requires a very large initial capital investment in the tooling and equipment needed to produce a part. This is because the nature of the process involves a very highly engineered 2-sided mold to create a part by feeding thermoplastic resin into a heated barrel with a rotating screw. The screw delivers the raw material forward collecting under pressure the amount required to fill the mold cavity and then injecting into the mold at high pressure and velocity. This action requires highly structured molds and equipment capable of withstanding very high clamping pressure.
As part size and dimensions increase, the complexity of design, engineering, and calibration required to construct, install, and process this 2-sided mold results in a significant increase in the cost of equipment, tooling and setup. The per-part production cost and lead time may also see an appreciable increase as the part size increases requiring much more robust molds and equipment. These increased capital expenditures will result in greater investment and overhead costs calculated in the piece price. Injection molding machines have a limited total mold size capability but can often accommodate multiple parts within the construction of a mold. Smaller part sizes equate to a higher number of parts manufactured per mold and machinery cycle. Larger part sizes decrease the number of parts that can be manufactured per mold and cycle.
Think of a muffin tray with 3-inch diameter muffin molds. Now take that same size tray but with 6 or even 10-inch diameter 
muffin molds and you imagine the impact on production and cost. In fact, most standard injection molding machines can only accommodate a maximum part size of 4’ x 4’. Larger machinery is available but is also drastically more expensive.
The heavy gauge plastic thermoforming process, on the other hand, involves considerably less pressure and most applications only require a single one-sided tool to produce a part. Additionally, only one part is formed per cycle in heavy gauge thermoforming applications. Consequently, the initial tooling investment is drastically reduced. While an increase in part size will still increase the tooling investment, the impact on cost is substantially less when compared to injection molding. Heavy gauge thermoforming equipment has oven zoning and variable sheet size capabilities which allow for a wide range of part sizes to be efficiently formed from the same equipment investment. The nature of the thermoforming process and flexible capacity capabilities makes scaling production for larger part sizes a relatively easy process. Since most heavy gauge thermoforming operations utilize cell-based manufacturing and CNC part trimming, a larger part can be produced with little impact, other than increased material, on per part cost, cycle time, and lead time. Thermoforming machinery can also manufacture part sizes as large as 10’ x 18’ providing a much larger part size capacity than injection molding.
Both injection molding and plastic thermoforming have widespread uses in a long list of industries. Each process has some unique features and benefits that are often advantageous for a specific application. In these instances, the choice to manufacture with plastic thermoforming or injection molding may be very obvious. This is most apparent in production volume. Low to mid volume tends to favor thermoforming, while high volume is usually more cost effective with injection molding.
However, a product’s needs and the capabilities of these two processes sometimes overlap. A part’s geometry may seem better suited for injection molding, but in a limited production run, but it may be drastically more cost effective to manufacture it with plastic thermoforming. This is just one example of an application where deciding between injection molding and plastic thermoforming may not be a clear choice. Selecting the right method in these situations requires a deeper appraisal of the features, benefits, and costs associated with each process.
The Clear Choice
As mentioned above, there are some instances when the type and specifications of an application drastically favor one or the other plastic manufacturing process when the choice is between injection molding or plastic thermoforming.
Injection Molding
Injection molding offers the key benefit of cost effectiveness at the mass production scale. When an application requires the production of more than 3,000-5,000 Estimated Annual Usage (EAU) identical parts with uniform wall thicknesses, injection molding often is the clear choice. This can be attributed to a high upfront tooling investment that is gradually offset by a generally low per unit manufacturing cost. The volume range of 3,000 – 5,000 is due to a variation on part cost in respect to part size. Smaller parts are generally cheaper to manufacture than larger.
Plastic Thermoforming
Plastic thermoforming, on the other hand, has a substantially lower tooling investment and a slightly higher per unit 
manufacturing cost. This equates to a much lower total part cost at low to moderate part volumes. Plastic thermoforming becomes the clear choice when the volume of manufacturing is less than 3,000 – 5,000 parts per estimated annual usage. This process also has the capability to produce single parts with very large dimensions, whereas the injection molding process is limited to single part sizes of about 4 feet x 4 feet.
Considerations When the Process Choice Is Not Clear
If your part or project doesn’t require a uniform wall thickness, large single part dimension, or has a volume requirement that is in the mid thousands, then you have landed in an area where the capabilities of plastic thermoforming and injection molding may overlap, and your process choice is not so obvious.
The good news is that you are now no longer handcuffed to a process that, while cost or size necessary, may not have the most comprehensive scope of benefits that would contribute the greatest to the success of your project.
Here are some points to consider for each process that can be taken advantage of or avoided now that you are free to choose a manufacturing method better suited to your project’s needs.
Plastic Thermoforming:
Injection Molding:
Want More Information?
What you see above is just the tip of the iceberg when it comes to comparing these manufacturing processes. For more information and for assistance in choosing the right process for your project, please contact Productive Plastics and connect with our industry experts and engineers to see how we can put over 62 years of manufacturing experience to work contributing to your project’s success.
Productive Plastics covered many topics last year on the features, benefits, and capabilities of utilizing the plastic thermoforming process to manufacture custom parts and enclosures for your projects. If you missed any, here is a quick recap, with links to content and data, that we hope you will find informative and useful.
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Productive Plastics has been around for 62 years. In over six decades of heavy gauge plastic thermoforming, one of the many lessons we’ve learned is that helping a customer’s project achieve success means a commitment to the constant evolution of every facet of our business. It’s one of our core values.
This year we invested in numerous upgrades. We expanded our resources, expertise, technology, and machinery, all designed to move us further down our technology roadmap as we implement industry 4.0 solutions and capabilities. And we continue to bring you dynamic and comprehensive heavy gauge plastic thermoforming solutions of the highest quality.
Investments at Productive Plastics This Year:
Left to right: Bryan Alicea, Don Stiger, Skip Grant, Dan Govender, Bob Cardona
John Zerillo
Yordano Alicea
This year was about laying the foundations for taking our manufacturing processes and value-added capabilities to the next level, to Industry 4.0 and beyond. New machinery, more automation, moving critical processes in-house, advances in technology, and expanded expertise were all added this year to increase our ability to contribute to your project’s success.
We invite you to contact us and schedule a time to tour our facility. We would like the opportunity to show you just how we can contribute to your project’s success and how we can provide much more than a high quality plastic part.
ISO 9001:2015
