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Deciding Between Plastic Thermoforming and Injection Molding – The Choice is Not Always Obvious

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.

  • Part production volumes > 3,000- 5,000
  • Uniform part wall thickness required

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.

  • Single part dimensions > 4’x4’
  • Part production volumes < 3,000 – 5,000 EAU

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:

  • Large single part capability (maximum dimensions approximately 10’ x 18’)
  • Short lead time ( 6-12 weeks )
  • Able to reproduce injection molded level detail
  • Smaller investment in tooling
  • Lower equipment capital investment leads to lower set up and machine time costs
  • Can produce thinner wall parts than injection molding, resulting in weight savings
  • Greater options for part surface finishing (textures, patterns, distortion printing, painting, etc.) that can be accomplished in the mold.
  • Multi material structures for cosmetic and engineering structure options (e.g. Acrylic/ABS)
  • Variable part wall thickness depending on depth of draw
  • Improved cost effectiveness at lower to mid volumes (< 3,000-5,000)
  • Lighter part weight compared to injection molding for most applications
  • Less molded in stress than injection molding
  • Twin sheet capability for hollow parts and added structure

Injection Molding:

  • Longer lead time (22-24 weeks)
  • Large investment in tooling
  • Cost effective at high volumes ( > 3,000 – 5,000)
  • Efficient material use
  • High level of precise part detail
  • Limited single part size capability (maximum dimensions approximately 4’ x 4’)
  • Finished parts often require post processing painting or finishing
  • Greater design freedom on single wall parts

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.

Please contact Productive Plastics for more information on the thermoforming process
Please download our complimentary thermoforming design guide for more information on the thermoforming process

Thermoplastics in Transit Interiors – Weighing the Advantages

Mass Transportation’s (mass transit buses, railcars and aerospace) design and manufacturing processes have been trending towards requirements for greater fuel efficiency, providing a luxury riding experience, and the need for enhanced safety.  Using buses as an example, design teams and OEMs have replaced steel and aluminum components with thermoplastics and thermoplastic composite materials.  Upgrading to thermoplastic components on average offers 55% weight savings and meets the static loading requirements of the American Public Transportation Association.  Thermoplastics are growing in popularity, offering industry focused material options that are rigid, and durable, and a manufacturing process that enhances design capability, lead time, and look and feel.

Why Reduce Weight?

As more mass equals more fuel consumption, utilizing materials that reduce the overall weight of the passenger buses, railcars, and aircrafts leads to decreased energy consumption, less brake and tire wear, and lowered emissions. Cutting vehicle weight by 110 pounds reduces 5 g of carbon dioxide emissions per kilometer and increases fuel economy by two percent. (Source: “Vehicle Weight Reduction for Optimal Performance” – DuPont

Modern transportation vehicles are becoming lightweight and fuel-efficient because of the use of thermoplastics for many interior components. Door, wall, and ceiling panels, dashboard surrounds, window masks or shrouds, seatback shells, armrest shells, bulkhead components, luggage racks, and display housings are just a few of the interior components that can be manufactured with the heavy gauge thermoforming process. While the materials industry as a whole has focused on lightweight solutions, thermoplastics offer a complete answer through a combination of strength, rigidity, and low density. For example, thermoforming produces components that weigh 30% less than comparable components made from fiberglass and 250% less than aluminum components. Interior components made from thermoplastics may make up nearly half of the volume of an automobile. However, those same, now lightweight components, contribute less than 10 percent to the weight of the vehicle. (Source: “A Lighter Future with Thermoplastic Solutions”, Lightweighting World.)

Industry-Compliant Thermoplastics with Emphasis on the Environment

The benefits of thermoplastics go beyond light weighting.  Interiors for aircraft, coach and city buses, trucks, and passenger rail cars require the use of FST (Flame Smoke and Toxicity) compliant materials.  All coach and city buses in the United States must meet the U.S. Department of Transportation Docket 90 safety specification for flame spread and smoke emissions. Motor Vehicle Safety Standard 302 Fire Test requirements apply to interior trim parts used for trucks.  One example of a material now commonly used for interior aircraft components and interior rail applications is amorphous polyetherimide (PEI-Ultem) which complies with FST standards while providing strength and aesthetic appeal. Along with meeting compliance standards, PEI thermoplastics also resist damage caused by exposure to halogenated hydrocarbons, alcohols, and aqueous solutions.  In addition, PEI thermoplastics resist warpage when exposed to heat for long durations because of a heat distortion temperature (HDT) rating of 350o F (176o C).

The manufacturing process for fiberglass emits high levels of volatile organic compounds (VOCs).  In contrast, the use of very long fiber-reinforced polypropylene (PP VLF) thermoplastic compounds reduces levels of VOCs to compliance with the open air and enclosed application specifications set by international legislation and automotive OEMs. In addition, the PP VLF thermoplastics meet or surpass standards for odor and fogging.

Parts manufactured from fiberglass cannot be recycled.  However, parts made from PP VLF thermoplastics can be recycled, have a lower life-cycle energy footprint and a lower life-cycle greenhouse gas emission. Manufacturers of mass transportation components use PP VLF thermoplastics for instrument panels, overhead and center consoles, seating, and storage bins.

Aesthetic Appeal: On-Time and Within Budget

Thermoplastics can improve the aesthetic design features of interior components used for mass transportation vehicles at a fraction of the cost required to obtain the same level of complex designs with other manufacturing processes. Low or high gloss surface finishes, custom surface texturing, complex geometric part design, and coloration are all capable, cost feasible, and can be manufactured quickly with the thermoforming process.

In-mold design and decorating enables the manufacturing of these high-level design features, resulting in part construction with consistency, precision, and a negligible impact on part cycle time. While in-mold texturing and pre-textured plastic may require a slightly higher initial investment than a simple design, the process ensures consistent part-to-part aesthetic detailing and minimizes cost by eliminating additional labor or processing.  As a result, in-mold design can produce complex designs and custom surface finishes with a minimal impact on cost and lead time.

The use of thermoplastics in component production also provides the option of producing plastics with coloration that resist stains, graffiti, and chemicals and that do not chip or vary in tone or color.  Moreover, using integral colored plastic eliminates the added cost and lead time of post-production painting. Coloration allows manufacturers to achieve a desired color finish and precise color matching along with durability.  You can also have thermoplastic components that have specialty finishes, such as wood grain or metallic patterns and overlays, capturing design intent.

Aesthetic appeal also is achieved through geometry and a seamless appearance.  Manufacturers can take advantage of the thermoforming process to build complex geometric designs with precise part mating and give the appearance of nearly seamless multi-part assemblies.  With complex designs being accounted for within the part’s tooling, the high level of quality has a minimal impact on cost or lead time.

Productive Plastics is a heavy gauge thermoforming custom components manufacturer, with vast experience with thermoplastic manufacturing for transportation applications. Contact us for more information.

Please contact Productive Plastics for more information on the thermoforming process
Please download our complimentary thermoforming design guide for more information on the thermoforming process

Plastic Thermoforming for Transportation Interiors

If you have traveled within North America on mass transportation in the last 3 to 4 decades, specifically on rail or bus, then you are familiar with the typical outdated interior layout and design of most transportation vehicles in the USA.

Many have off-white or beige-colored fiberglass wall paneling, seating, and window masking, likely chipped or cracked at many corners or high traffic areas. Some of these components may be constructed from scratched and dented sheet metal with exposed fasteners and attachment points. The design features are lacking aesthetic appeal or any integrated technology. Boxy, straight-lined components cover the interior with large gaps between mated parts. This is all standard fare for commuter mass transit, railcar, or passenger bus interiors and has been for the past 30 years or more.

Most of the transportation interiors in the USA with the exception for aerospace were designed and manufactured in the mid to later part of the last century. These interior components were mostly manufactured from fiberglass and sheet metal. The old parts are heavy, require frequent maintenance, and lack modern design aesthetics. In short, the time has arrived for major updates and upgrades in this market.

Over the past few years, upgrading the passenger experience has started as a byproduct of industry and environmental compliance standards demand ask for more efficient vehicles through lightweight. Rail, bus, and other mass transit manufacturers are now looking to take advantage of available new processes and innovations to develop the next generation of transportation interiors.

Thermoplastic materials and the plastic thermoforming process are uniquely suited to the emerging needs of the transportation interiors industry, offering extremely lightweight and durable materials that meet industry standards such as FST, Doc 90, and FMVSS 302. The thermoforming process enables a higher design flexibility for interior components at a favorable cost. The ability to do undercuts and texture tooling surfaces allow complex geometric parts, closely mated component assemblies, surface texturing, and a wide variety of paint free pre-colored material options available to designers and engineers. Such benefits are not achievable or cost prohibitive with many other manufacturing processes.

This blog and our email newsletters will take a deeper look into plastic thermoforming and its applications for the transportation interiors industry over the next few months.

Also, if you haven’t already done so, please download our Fiberglass to Plastic Thermoforming Comparison and Conversion Guide, Metal to Plastic Thermoforming Comparison and Conversion Guide, or Heavy Gauge Plastic Thermoforming Process and Design Guide for more comprehensive information on plastic thermoforming capabilities and solutions.

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Download Metal vs. Plastic Thermoforming - Comparision and Conversion Guide from Productive Plastics

Should You Upgrade Your Sheet Metal Parts and Enclosures to Plastic Thermoforming?

The heavy gauge thermoforming process offers key advantages as an upgraded replacement for many parts currently manufactured from metal. Weight reduction is a key advantage – plastic parts are lighter than metal. Further, custom plastic thermoforming can be used to produce complex geometric part shapes that are not possible with sheet metal at a feasible cost, allowing greater design freedom. This versatility gives manufacturers faster design and production cycles, while also providing the opportunity for innovation with structure and design. Additionally, thermoforming can eliminate the need for secondary part finishing. The industrial market demands lightweight and durable products and high levels of customization, with an eye towards environmental concerns about the use of recyclable materials. Custom heavy gauge thermoforming meets these demands better than sheet metal.

The Impact of Thermoplastics on Industries

Thermoforming can present a substantial upgrade over traditional sheet metal fabrication, metal stamping, metal spinning, and metal casting manufacturing processes and materials. Although sheet metal fabrication exists as a low-cost method for producing parts, the use of sheet metal sacrifices flexibility in design, capabilities, and application. Complex parts manufactured with sheet metal require secondary processes that can involve cutting, bending, welding, and bolting. Producing the same part with thermoforming can eliminate these secondary processes by easily incorporating complex 3D part designs, mating points, and various surface finishes and branding directly into the part’s tooling.

Medical Device with Plastic Thermoformed Enclosure
Large medical device with plastic thermoformed enclosure. Complex shape design and continuous design lines spanning over multiple parts.

The same differences become apparent when comparing metal stamping, metal spinning, and metal die-casting with thermoforming. Manufacturers use bending and stamping to produce low-cost parts that have a simple geometry. Any attempt to add complexity to a part requires additional assembly steps and cost. The unique process of metal spinning forms complex shapes from aluminum, steel, alloys, and other metals. Rotating a disc or tube of metal at high speeds produces axially symmetric parts and improves the tensile strength of the metal. Metal die-casting produces parts that have high heat resistance, high strength and stiffness, and low thermal expansion qualities.

In contrast, thermoforming provides higher rates of production with a level of detail and complexity that greatly exceeds the capabilities of metal processes. For example, the application of plastic thermoformed enclosures, housings, and covers for medical diagnostic equipment shortens the development and production cycles. Moreover, the use of thermoformed materials establishes lower cost tooling for applications that must comply with global safety standards.

Weight Considerations – Plastic Thermoforming vs. Metal

Plastic thermoforming allows manufacturers to use materials that have a lower density and thinner walls. Both qualities allow weight-conscious industries such as automotive and aerospace manufacturing to achieve significant weight reduction while retaining strength and durability. The use of thermoplastics improves fuel economy and reduces emissions with decreased weight and lowered friction losses in the powertrain. Reducing the weight of gears causes a reduction in inertia and an increase in automotive efficiency. The use of thermoplastics also reduces noise and vibration levels.

For electrical components, the capability to produce strong, lightweight parts also promotes the production of lightweight, wall-mounted or pole-mounted enclosures. Using thermoformed plastics for the electrical enclosures allows easier lifting than seen with aluminum or steel enclosures. When comparing the weights of thermoformed objects to metal objects, noticeable differences exist. With two same-sized objects constructed from polycarbonate and fiberglass, the polycarbonate object weighs approximately ½ pound less. An aluminum same-sized object will weigh twice the amount, an object made from steel will weigh more than six times as much.

The following chart depicts the differences in specific gravity density for different types of thermoplastic and metal materials. Specific gravity equals the ratio of density of the material to the density of water at 39°F. Because the thermoplastics shown in the chart have superior strength-to-weight ratios than the metals, the lighter thermoplastics have equivalent strength and stiffness.

Material Specific Gravity
High-impact ABS 1.03
Polycarbonate 1.19
Acetal copolymer 1.41
Aluminum 2.55 – 2.80
Cast Iron 7.03 – 7.13
Titanium 4.5
Cast Rolled Brass 8.4 – 8.7
Stainless Steel 7.7
Copper 8.89
Carbon Steel 7.8
Tool Steel 7.70 – 7.73
Tungsten Carbide 14.29

Durability Comparisons – Plastic Thermoforming vs. Metal Manufacturing

Polycarbonate has become a popular alternative for enclosures because of its strength and durability. The durability and impact resistance of polycarbonate allows the use of enclosures in all types of weather and environmental conditions in industries such as oil exploration, agricultural irrigation, wind turbines, and maritime. A polycarbonate enclosure has a tensile strength of 900 pounds per square inch and has a high impact resistance. In addition, polycarbonate enclosures resist damage caused by ultraviolet rays and have high NEMA ratings for dust and moisture protection.

Time and Cost Savings Achieved with Thermoplastics

Medical Device with plastic thermoformed enclosure
Medical device enclosure manufactured and assembled from multiple plastic thermoformed parts

While a stainless steel enclosure offers the same resistance, stainless steel costs three times more than polycarbonate. The cost comparison between thermoplastics and metals goes beyond direct monetary costs and includes indirect costs such as time. Again, using polycarbonate enclosures as an example, thermoplastics offer the advantage of easy modification. Machining a stainless-steel enclosure requires special tools and additional time.

The weight reduction seen with a polycarbonate enclosure also factors into time and cost savings. Rather than requiring two installers for the attachment of an outdoor stainless steel enclosure, the installation of a polycarbonate enclosure requires only one installer. In addition, the shipping costs for lighter weight polycarbonate enclosures are lower than the shipping costs for metal enclosures.

Direct cost savings with thermoplastics occur through repeatable manufacturing processes that produce less scrap. Given the durability of thermoplastic materials, tools and parts have a much longer service life. Manufacturing costs also decrease because of the design flexibility to consolidate parts and to produce complex mechanisms without secondary processes. Because of the numerous thermoplastic options, manufactures can carefully select materials that optimize manufacturing to production ratios and reduce lead times.

Summary

Thermoplastics have replaced the use of carbon steel, stainless steel, titanium, aluminum, magnesium, brass, and bronze in many industrial applications. Along with weight reduction, thermoplastics offer enhanced performance, greater design freedom, and decreased total system costs. Enhanced performance occurs through corrosion resistance, lower friction, increased fuel efficiency, and the capability to handle large loads at higher speeds in harsh environments.

Thermoplastics have become standard materials for parts such as medical diagnostics equipment components, enclosures, fender wells, rear bumpers, seating and interior trim components, window masks, wall paneling, decorative signs, and construction cab interiors.  Heavy gauge thermoforming eases the process of manufacturing those components by forming a two-dimensional rigid sheet of thermoplastic into a three-dimensional shape that fits industrial needs and standards.  Intricate designs with molded colors and textures occur at lower costs and with faster production cycles.

Productive Plastics is top contract manufacturer for heavy gauge thermoforming, including vacuum forming and pressure forming. Contact us or request our complimentary thermoforming design guide for more information.

Please contact Productive Plastics for more information on the thermoforming process
Please download our complimentary thermoforming design guide for more information on the thermoforming process

5 Key Points in the Process of Upgrading Parts from Fiberglass to Plastic Thermoforming

Transitioning your product manufacturing process from fiberglass to plastic thermoforming can allow you to capitalize on some major upgrades, benefits, and cost savings for your project. (See some of the advantages of plastic thermoforming vs. fiberglass in a previous post).

However, the process of transitioning from one manufacturing material and process to another, and doing it correctly, may be more complex than simply handing over the existing design and tooling. Below are the basic steps and considerations for the transition process that Productive Plastics has found to help ensure you get the best results from the conversion.

  1. Choosing the right plastic thermoforming manufacturer and process
    1. Plastic thermoforming encompasses a number of sub processes such as vacuum and pressure forming. Consult with your thermoformer to aid in selecting the ideal process for your application. Visit our thermoforming process pages for more information on each process.
    2. Select a thermoforming contract manufacturer experienced in processing a wide variety of material options with a strong understanding of those material properties.
    3. Choose a manufacturer with experience in converting applications from fiberglass to plastic thermoforming to avoid common pitfalls that can delay or increase the cost of the transition.
    4. Strong consideration should be given to a manufacturer with in house design engineers. The onsite expertise will help to ensure a smooth technical transition from fiberglass to plastic thermoforming.
    5. Select a manufacturer that is up to date with best practice methodology such as ISO, Lean Manufacturing, Six Sigma, etc.
  2. Adapting your existing product design to the plastic thermoforming process
    1. Manufacturing techniques, process capabilities, and material properties differ from fiberglass to plastic thermoforming. This is a good thing. The differences are what motivated you to consider converting your product in the first place. These differences will, more than likely, necessitate modifications to your existing design and tooling to meet your product’s needs and to maximize the advantages available with the thermoforming process.
    2. A design engineer, with plastic thermoforming experience, can adapt your product’s design to harness the benefits of the thermoforming process. (Productive Plastics utilizes our experienced in-house design engineers to help our customers with process conversions).
      1. Tighter part tolerances
      2. Reduction in part wall thickness
      3. Complex or aesthetic design enhancements unachievable or not cost effective with fiberglass
      4. Textured surface finish
      5. Lighter weight than FRP
      6. Consistent surface gloss
  1. Material selection
    1. An important consideration when manufacturing a thermoformed plastic part is the selection of appropriate material. There are a multitude of different types of plastic materials, each with their own specific characteristics, properties, strengths, and weaknesses. Communicating your product’s requirements and industry material standards early in the conversion process will allow your thermoformer to assist in selecting the ideal material for the application. Learn more about thermoforming material considerations and options.
  2. Tooling
    1. Properly designed and constructed tooling sets the foundation for tight tolerances and a high quality part. This becomes increasingly more important for complex and multi-part designs. Having your existing tooling evaluated by your thermoforming contract manufacturer as early in the transition process as possible can have a large impact on the lead time of your first part run.
    2. Choose a thermoforming contract manufacturer experienced with tooling materials options and processes to assure the right tool choice for your application and product life.
  3. Prototype testing
    1. Prototype development should be considered with a testing plan that includes dimensional as well as properties evaluation. Engaging in early involvement, support, and collaboration with a thermoforming manufacturer, like Productive Plastics, can aid in creating a successful verification plan.

Productive Plastics is top contract manufacturer for heavy gauge thermoforming, including vacuum forming and pressure forming. Contact us or request our complimentary thermoforming design guide for more information.

Please contact Productive Plastics for more information on the thermoforming process
Please download our complimentary thermoforming design guide for more information on the thermoforming process

Thermoforming Material Selection: 5 Ways Thermoplastic Materials Can Influence Product Appearance

The facade or exterior enclosure is often the first impression a customer or operator has of your product. This is also your first chance to impact how your product is perceived. While this is certainly not a new concept, it is a worthy reminder that look, style, and appearance are important. Selecting a thermoforming material with the right properties can provide shape, finish, and cosmetic capabilities that are unique to the thermoforming process and customizable to your company’s brand and product design needs.

Here are 5 ways thermoplastic material can influence the exterior look of your next project.

1. Geometry – Creating a product design with excellent and highly appealing part geometry may only be limited by creativity and inspiration. However, it is one thing to render an image of a flawlessly designed part or product, it can be quite another to manufacture such a design economically with the same elegant geometry, continuity of parts, and seamless assembly.

Producing this design physically will, to a certain degree, be subject to the manufacturing process selected, but will also be heavily dependent on the capabilities of the material selected. Thermoplastic materials require relatively lower heat and pressure to shape resulting in lower tooling and capital equipment costs than competing process materials.

For more information on how part geometry with thermoforming can shape your product and brand, check out this previous Productive Ideas blog post: Geometry and Mating Points.

2. Color – With many other materials, the only way to achieve a desired color finish, is to paint the material post production. Yes, this is also an option for most thermoplastic. However, many thermoplastic providers also produce integral colored plastic material (plastic with coloration). These materials can eliminate the extra time and cost associated with the additional process of painting your components as well as avoid the inherent maintenance issues with paint such as chipping. Many suppliers also have material products with integral patterns such as wood grain, carbon fiber, and metallic replications. See some integral color plastic and pattern examples here from one of our partnered suppliers. Silk screening and distortion printing overlays are also options with most thermoplastic material for more complex branding and surface designs. Molded-in color can provide product branding, safety awareness, color fast durability, color coordination and more.

The Perception of Color

While color match to a provided sample color chip is available for thermoforming materials there are many variables that come into play during application that may affect the perception of match. Reflection and absorption of light will be different on metals, composites, wood, plastic and other materials. Varying lighting conditions will change appearance of a color. Other physical characteristics of the objects such as surface finish, part geometry, and angle of view as well as the manufacturing process affect the color range of the sample and the finished product. This can result in a visual color difference to the observer and must be taken into consideration for design and color match considerations.

3. Gloss – High gloss finishes present a very high quality visual perception and are often desirable in markets such as medical device, recreation, food service and many other OEM markets. This look is easily achievable on most thermoplastic material by either the addition of a high gloss color film capped material or by applying a high gloss paint which is then buffed to the desired level of gloss. High gloss metal flake or pearlescent capped materials are also available as additional high gloss visual options.

4. Texture – The addition of surface texture on a thermoformed part can be accomplished via two methods.

In the first method, in-mold texturing, the texture is produced by casting, peening, or etching the texture designs directly into the tooling used in the part’s production. This method is more reliant on the design, mold construction, and forming process than it is on the thermoforming material. In mold texturing enables the manufacturer to form areas with and without texture in the component design for achieving a non-slip surface or contrasting finishes.

The second method utilizes pre-textured plastic sheet material to produce thermoformed parts with a textured finish. To avoid “texture wash”, this method is compatible for designs with relatively low depth of draw features

View additional features and benefits of textured surfaces using the thermoforming process.

5. Weatherability – Most materials have a tendency to eventually fade when exposed to prolonged UV radiation from sunlight. While thermoplastic is no exception, there are many formulations of plastic available that have either an inherent or designed high resistance to fading or discoloration from UV radiation.

Accelerated Weathering (Ref Q-Lab) is a standardized industry test used to evaluate the color fade of a material in relation to time and UV exposure. Reference the chart below for a comparison of the accelerated weathering performance of common thermoplastic materials.

Weatherability Performance of Thermoforming Materials

Thermoplastic Material Industry Abbreviation UV Resistance
     
Polyether-Block-Amide (PEBA) Excellent
Thermoplastic Polyimide (TPI)
Polyphenylene Sulfide (PPS)
Polyether-Ester Block Copolymer (TEEE)
Acrylic (PMMA)
Polyetheretherketone (PEEK)
Polyetherketone (PEK)
Perfluoroalkoxy (PFA)
Ethylene Tetrafluoroethylene (ETFE)
Polyvinylidene Fluoride (PVDF)
Liquid Crystal Polymer (LCP)
Polyetherketoneetherketoneketone (PEKEKK)
Polyetherketoneketone (PEKK)
     
Polypropylene (PP) Fair/Good
Nylon 6 (PA 6)
Nylon 6/10 (PA 6/10)
Nylon 11 (PA 11)
Nylon 6/12 (PA 6/12)
Amorphous Nylon (PA)
Nylon 12 (PA 12)
Impact-Modified Nylon 6/6 (PA 6/6)
Polycarbonate (PC)
Low Density Polyethylene (LDPE)
Polysulfone (PSU)
Polybutylene Terephthalate (PBT)
Polyethylene Terephthalate (PET)
Polyethersulfone (PES)
Modified Polyphenylene Oxide (PPO)
Polycarbonate/Acrylic Alloy (PC/PMMA)
Polyetherimide (PEI)
Polycarbonate/ABS Alloy (PC/ABS)
Thermoplastic Vulcanizate (TPV)
Polymethylpentene (PMP)
Polyphthalamide (PPA)
Polysulfone/Polycarbonate Alloy (PSU/PC)
High Temperature Nylon (HTN)
Syndiotactic Polystyrene (SPS)
Polytrimethylene Terephthalate (PTT)
     
Nylon 6/6 (PA 6/6) Poor
Polystyrene (PS)
Styrene Acrylonitrile (SAN)
Acrylonitrile Butadiene Styrene (ABS)
High Density Polyethylene (HDPE)
Acetal (POM)
Ester-based Thermoplastic (TPUR)
Ether-based Thermoplastic (TPUR)
Rigid Thermoplastic Polyurethane (RTPU)
Styreflex™ Styrenic Block Copolymer Thermoplastic Elastomer (SBC)
Fluorinated Ethylene Propylene (FEP)

View the full list of plastic abbreviations and acronyms.

Productive Plastics is a top contract manufacturer for heavy gauge thermoforming, including vacuum forming and pressure forming. Contact us or request our complimentary thermoforming design guide for more information.

Please contact Productive Plastics for more information on the thermoforming process
Please download our complimentary thermoforming design guide for more information on the thermoforming process

Is Your Material Tougher than Thermoplastic?

Whether it’s luggage or shopping cart impact, physical stress caused by operator or passenger mishandling, or the wear and tear of constant load bearing, it can be a rough world out there for the components of your product or application. Want to know which thermoplastic material can handle the abuse? Take a look at the following considerations and mechanical properties of today’s common thermoforming plastic materials.

How do thermoplastic mechanical properties factor into the material selection process?

The plastic materials used in thermoforming undergo extensive testing to determine their performance capabilities. See Thermoforming Material Selection (Material Testing and Datasheets Decoded) for more information on industry testing standards, their definitions, and practical uses for each test in regards to material selection. Material manufacturers generally provide the results of these industry tests in data sheets online.

When determining if a plastic material has the mechanical strength performance and toughness for the structural needs of your product or application, there is no one test that gives a definitive answer. Instead to determine the general impact strength and damage resistance of a plastic material, take a combined look at the results of these common material tests:

  • Stiffness (Flexural Modulus) – Provides design criteria to determine the necessary thickness required for a given load and a measure of stiffness
  • Tensile strength – Tells how much a material stretches before failure; force necessary to pull the specimen apart
  • Hardness – Material resistance to abrasion, chipping, and cracking
  • Notched Izod impact strength – Pendulum style impact test on a notched sample that’s good for comparison of similar materials

The relationship between strength and weight is also important in industries where the reduction of weight is desirable so the following should also be considered:

  • Density – how much a given volume of the material weighs
  • Specific gravityindication of material density. Like density, it provides a quick reference to the relative weights of different objects that have the same volume

Mechanical property advantages of thermoformed parts with thermoplastic materials:

Lightweight – In most cases, thermoplastic offers material options that are substantially lighter than comparable optional materials

Resistance to impact damage – Due to the flexible nature of thermoplastic it is less likely to dent like metal or crack like FRP

Strength to weight ratio – (also known as specific strength) Short fiber reinforced thermoplastics can often have equal to or greater strength characteristics than metals like aluminum and steel at a fraction of the weight

Corrosion resistance – Thermoplastics do not oxidize or rust like aluminum and steel therefore providing an environmentally stable material

Recyclability – Fiberglass is not recyclable while thermoplastics are

Reduced maintenance and replacement costs – Thermoplastic as a whole is more durable than materials such as metal or fiberglass, requiring less maintenance with a longer service life

Available thermoplastic options regarding impact resistance and toughness

As discussed in previous posts on material selection, when it comes to plastic material options, there are many choices and each has different thermal and mechanical performance properties. The information below will give you a general understanding of the mechanical properties of the common plastic material options available.

Note: The options listed are generic plastic material formulations. Many plastic material companies have specific plastic material products formulated and designed to meet the demands of a wide range of industry requirements. For information on the thermal performance of these specialty thremoplastic products, visit our material supplier datasheet page.

Thermoforming Material Impact Resistance and Mechanical Property Comparison Chart (Sorted by Tensile Strength)

Thermoplastic Material Tensile Strength (psi) Flexural Modulus (psi) Hardness IZOD Notched Impact (ft-lbs/in) Specific Gravity
Continuous Glass Thermoplastics (C-glass) 60/40 36,900 1,500,000 ~1.48
Continuous Glass Thermoplastics (C-glass) 70/30 35,100 1,395,000 15.7 ~1.48
PPS 17,000 1,000,000 M95, R125, Shore D 85 5.2 1.35
PEEK 14,000 590,000 M105, R126, Shore D 85 1.6 1.32
Nylon 12,400 410,000 M85, R121, Shore D 80 1.2 1.14
PSU 10,200 390,000 M75, R125, Shore D 80 1.3 1.24
PPSU 10,100 350,000 M80, R120, Shore D 80 13 1.4
Acetal 10,000 420,000 M89, R121, Shore D 83 1.5 1.42
Acrylic 10,000 480,000 M95, R90 0.4 1.19
Polycarbonate 9,500 375,000 M70, R118, Shore D 80 16 1.2
NORYL (PPO, PPE, & Polystyrene blend) 9,200 370,000   3.5 1.08
PBT 8,690 330,000 M72 1.5 1.3
TPO (22% strand glass fiber filled) 8,500 600,000 5.2 1.03
ECTFE (film 5-20 mil thick) 8,300 261,000 Shore D 73 R93 No break 1.68
PVC 8,000 400,000 Shore D 80 2.5 1.4
PETG 7,700 310,000 R115 1.7 1.27
PVDF 3,500 – 7,200 170,000 – 1,200,000 M75, R100, Shore D 77 2.5 1.78
TPE 1,000 – 7,000 5,000 – 800,000 Up to 85 Shore D 2.5 -No break 0.95
CAB 7,000 230,000 R105 4.4 1.2
ETFE (film 5-20 mil thick) 6,100 145,000 Shore D 67 R85 No break 1.7
ABS 6,000 320,000 R102 7.7 1.04
PCTFE (film) 5,710 243,000 Shore D 90 3.5 2.11
Polypropylene 5,400 225,000 Shore D 75, R92 1.9 0.91
TPO 4,400 170,000 Shore D 74 6 0.9
FEP (Teflon film) 4,350 95,000 Shore D 55 No break 2.12
HDPE 4,000 200,000 Shore D 69 No break 0.96

View the full list of plastic abbreviations and acronyms.

Productive Plastics is a top contract manufacturer for heavy gauge thermoforming, including vacuum forming and pressure forming. Contact us or request our complimentary thermoforming design guide for more information.

Please contact Productive Plastics for more information on the thermoforming process
Please download our complimentary thermoforming design guide for more information on the thermoforming process

Temperature Considerations in Plastic Thermoforming Material Selection

If you’ve ever microwaved last night’s leftovers in the typical plastic to go container, you’ve witnessed the effect that high heat can have on thermoplastic. The plastic begins to soften and lose its stiffness as the material temperature increases and if you heat it long enough or exceed the limit of its operational temperature range, it will begin to distort. Worst case scenario, when you open the microwave door to enjoy your meal, you are presented with something that can be quite unrecognizable from what you put in.

While this example may not be relevant in all cases, it does demonstrate the importance of selecting a plastic thermoforming material with the appropriate temperature properties for your application’s operating environment. Imagine a similar scenario on an essential safety, structural, or functional component for a medical, transportation, or industrial application. Loss of stiffness (flexural modulus) and material distortion (heat deflection) are just a few of the factors to account for when addressing the temperature requirements of a project.

Material considerations for prolonged exposure to excessive temperatures

Most of the effects of temperature to thermoplastic occur at high heat levels, although excessively low temperatures can have an impact as well. Mechanical properties, chemical resistance, electrical conductivity, material fatigue, and many other attributes can be affected by increased temperatures. Below is a list of the most common considerations.

Note: The exact temperature thresholds and performance will vary for each different plastic material. In addition, factors like part geometry and material thickness will also affect material properties under extreme temperatures both high and low. The considerations below are just a general behavior characteristic of plastic in relation to temperature. (reference our article on material testing and data sheets for more information on standard testing of a material’s temperature performance)

Distortion

  1. Exceeding a material’s approximate heat deflection temperature can cause the material to distort.
  2. Prolonged exposure to heat while subjected to a load or force can also cause plastic to deform or “creep” over time.
  3. Most thermoplastic materials have a heat distortion temperature (HDT) of less than 500 degrees F
  4. HDT is a good comparative specification of how different materials respond to the HDT test conditions but provides little information regarding the long term effects of continuous high temperature exposure on their physical, mechanical, thermal, and electrical properties.

Softening

  1. As temperature increases, material stiffness (flexural modulus) will decrease.

Expansion

  1. As with most materials, plastic expands as temperature increases (coefficient of thermal expansion – CTE). This can be a consideration when the plastic is mated with another material, such as metal, that may have conflicting thermal expansion rates.
  2. If the dimensional change is obstructed, stresses can be induced in the plastic part due to excessive tensile, shear, or compressive stress loads that could result in unexpected failure.

Service Life

  1. Thermal Degradation – Plastic materials subjected to prolonged exposure to high temperatures will lose strength and toughness, becoming more prone to cracking, chipping, and breaking, at a rate in proportion to the temperature and time of exposure. Materials exposed to higher heat for longer duration will wear substantially faster than those exposed to more moderate temperatures and exposure times.
  2. The Continuous Use Temperature Rating is based on a thermal aging test that predicts the temperature at which a 50% loss of the original mechanical properties will occur after 100,000 hours of continuous exposure at that temperature. (see table below)Continuous Use Temperature Thermoplatic Chart

Thermal Conductivity

  1. The quantity of heat that passes through a cube of the material in a certain period of time when the difference in temperature between the two surfaces becomes one degree.
  2. Plastic materials generally have a much lower Thermal Conductivity than metals. This makes them excellent replacement materials when thermal insulation is important.

Some questions to consider to determine your application’s temperature profile and ideal material candidates

During the product development process, Productive Plastics uses the following questions to zero in on the plastic material options that will be temperature compatible for a customer’s application:

  1. What environmental temperature range (high and low) will the part be exposed to operationally?
  2. What dimensional and stiffness (flexural modulus) tolerances are required of the part at the high, mid, and low points of its expected temperature range?
  3. What loads or forces are expected on the part at the high end of its temperature range?
  4. What is the time/temperature relationship? A low temperature for a long time can result in comparable properties damage as a high temperature for a short time.
  5. What is the projected service life of the application?
  6. Will the plastic part be mated to any other material types, such as metal, as part of the application design?
  7. What are the specified (FST) flame, smoke & toxicity requirements?

Available thermoplastic options and temperature performance

As discussed in previous posts on material selection, when it comes to plastic material options, there are many choices and each has different thermal and mechanical performance properties. The information below will give you a general understanding of the operating thermal ranges of the common plastic material options available.

Note: The options listed are generic plastic material formulations. Many plastic material companies have specific plastic material products formulated and designed to meet the demands of a wide range of industry requirements. For information on the thermal performance of these products, visit our material supplier datasheet page or our thermofoming materials page.

Thermoplastic Material Heat Performance

Click here for a full list of plastic abbreviations and acronyms.

Productive Plastics is top contract manufacturer for heavy gauge thermoforming, including vacuum forming and pressure forming. Contact us or request our complimentary thermoforming design guide for more information.

Please contact Productive Plastics for more information on the thermoforming process
Please download our complimentary thermoforming design guide for more information on the thermoforming process

Thermoforming Material Selection (Material Testing and Datasheets Decoded)

When it comes to plastic thermoforming materials, one of the greatest advantages is that they can be manipulated and alloyed at the polymer level as well as being co-extruded to produce a multitude of variations. The result is a large list of available and even customizable plastic material products, each with its own unique properties and often formulated to meet the requirements of a particular industry.

The task of comparing and selecting the appropriate thermoforming material can therefore be daunting. To make the selection process easier, plastic material manufacturers have their material products independently tested to provide potential users with general characteristic and performance data, which is then presented via material product datasheets. These data sheets are excellent for material property comparisons but not always a exact indicator of field performance due to test sample preparation.

See some examples of thermoforming material datasheets here.

This data can give the end user an indication on how that material will behave once thermoformed into a finished component and if it is compatible with their application.

Measuring Plastic Thermoforming Material Properties:

Below is a list of the common tests that are performed on each plastic thermoforming material product, a description of what is measured, and how it should be used to assist in material selection.

Note – The data from raw material testing may not be exactly representative of how a material will perform on your finished product and in the field. Testing performed on material samples is done in a very controlled environment, at a uniform thickness, and as a flat extruded sheet of plastic or often injection molded. Your component, once thermoformed and assembled into a finished product, will likely have complex geometry, varying part thickness, and environmental factors such as temperature that are unique to your application and unaccounted for in standard material testing. For example, a raw material test may indicate a heat deflection (material distortion) of 200 degrees. However, once that same material is thermoformed and assembled on your finished product, it may have a heat deflection of only 190 degrees. So, ultimately, while testing will give you a ballpark indication on how your product will perform, keep in mind that results may vary. For more accurate data, conduct product testing on a finished and fully assembled prototype.

Physical Property Testing

Notched Izod Impact Strength (Ref ASTM D256)

Test definition: Pendulum style impact test of a notched sample subjected to a shock force. Typically used on more notch sensitive materials such as HIPS and ABS. The force absorbed by the notchedsample is measured and the type of failure is described

Material selection application:

  • Good comparison test between similar materials
  • Not a direct indicator of field performance

Specific Gravity (Ref ASTM D792)


Test definition: The ratio of the density of any substance to the density of an equal volume of water. Because Specific Gravity is a ratio it is a unitless quantity.

Material selection application:

  • The Specific Gravity of plastic materials are an indication of their density
  • Higher Specific Gravity will result in heavier material so caution must be taken when estimating and comparing part weights with varied materials

Chemical Resistance (Ref ASTM D543)


Test definition: Evaluation of plastic materials for resistance to chemical reagents (ex. lubricants, cleaning agents, inks, foods) The test includes provisions for reporting changes in weight, dimensions, appearance and strength properties.

Material selection application:

  • The published chemical resistance properties are a good guideline for material selection. However since variable factors can affect chemical resistance one should always test under their own conditions
  • Chemicals can affect strength, flexibility, color, surface appearance, and dimensions of plastics.
  • Plastics often fail even under very low stress when in contact with some chemical agents. This is called environmental stress cracking and is of great importance in material selection

Stiffness (Flexural Modulus) (Ref ASTM D790)


Test definition: Rigidity of material / a measure of stiffness

Material selection application:

  • Provides design criteria to determine the necessary thickness required for a given load
  • Good for comparison of different materials

Hardness (Ref ASTM D2240)

Test definition: A measure of how resistant a material is to various kinds of permanent shape change when a compressive force from a harder body is applied

Material selection application:

  • This is a good measure of resistance to wear by friction or erosion
  • Material resistance to abrasion, chipping, and cracking

Tensile strength (Ref ASTM D638)

Test definition: Resistance to being pulled apart

Material selection application:

  • Tells how material stretches before breaking
  • Provides an indication of overall toughness
  • The most important indication of strength of the material

Dielectric Strength

Test definition: Electrical insulation- the maximum voltage that can be applied to a material without it breaking down

Material selection application:

  • Plastics are generally considered insulators but they can transmit some electrical energy at high frequency
  • Many variables such as material fillers and additives, part thickness, and environmental conditions will affect the plastic’s dielectric constant

Thermal Property Testing

Thermal Conductivity (Ref ASTM E1530)

Test definition: A measure of the ability of a material to transfer heat.

Material selection application:

  • Most plastics are insulators and not good conductors of heat

Coefficient of Thermal Expansion (CTE) (Ref ASTM E831, ASTM D696, and ISO11359)


Test definition: Amount of expansion and contraction at a given temperature

Material selection application:

  • Impact relating to very narrow dimensional tolerances
  • Potential interference and fitment issues when plastic components are combined in assembly with dissimilar material components
  • Tooling and process design considerations are affected by CTE
  • Strict control of temperature during forming, post forming, trimming, and QC processes must be understood and maintained

Heat Deflection (Ref ASTM D648)

Test definition: The temperature at which the material will distort

Material selection application:

  • Usually listed at 2 loading values (264 psi and 66 psi)
  • Lower heat distortion materials will require a greater processing time
  • The temperature up to which rigidity for mechanical loads is retained

Flammability

Test definition: Extent to which a material will support combustion

Material selection application:

  • Plastics made up of organic chemical materials can have violent oxidation reactions in the presence of air at elevated temperatures like any other organic materials such as wood, paper and textiles.
  • Many plastics are now available compounded with flame, smoke and toxicity suppressant ingredients
  • In many applications, government mandated standards will dictate the required testing (See FST testing)

Fire, Smoke, and Toxicity (FST) Property Testing

In industries such as aviation and mass/rail transit, there are very strict regulations on the fire, smoke, and toxicity properties of utilized materials. Many thermoplastic suppliers produce material variations that are specifically designed to meet U.S. and international regulatory requirements. These very industry specific thermoforming material products will typically list the particular industry regulation directly on the material’s data sheet.

Some common industry regulations:

FAR25.853a

FAR25.853d iv & v

ADB-0031

D6-51377

DIN 5510

ASTM E662 & E162

Look & Appearance Property Testing

Accelerated Weathering (Ref Q-Lab)

Test definition: Provides a simulated exposure sequence to ultra violet radiation that allows weatherability to be categorized

Material selection application:

  • The advantage of thermoforming and the use of coextruded material stands out here with the ability to form parts subject to ultraviolet radiation on the outside with a coextruded material that has high weatherability coextruded with a lower cost rigid substrate material
  • Evaluation of color fade relating to time and UV exposure

Scratch & Mar (Ref Taber Method)

Test definition: Provides a measurement of the scratch or mar resistance of plastic sheet

Material selection application:

  • The visual appearance of a scratch or mar normally involves changes in surface topography, color or brightness
  • Some plastic materials have elastic recovery properties that occur after removal of the applied stress

References:

Click here for more detailed information on the testing of thermoplastic properties. (Society of Plastics Engineers – Thermoforming Quarterly 2015 Q1)

For additional information on ASTM standards of material testing, visit the official ASTM website.

You can also visit our Plastic Thermoforming Materials page for more in depth information.

Productive Plastics is top contract manufacturer for heavy gauge thermoforming, including vacuum forming and pressure forming. Contact us or request our complimentary thermoforming design guide for more information.

Please contact Productive Plastics for more information on the thermoforming process
Please download our complimentary thermoforming design guide for more information on the thermoforming process

Lean Principles in Plastic Thermoforming Design

Most people familiar with the manufacturing industry associate the words “Lean” and “Process Improvement” with operations directly on the manufacturing floor. However, a manufacturer that strives to be a Lean Enterprise incorporates the practice of perpetual improvement and reducing waste (resources or time spent on non-value added functions) to every facet of their business.

One of the processes that is both critical to a project’s success and an ideal candidate for lean practices is the design engineering process. This is where customer designs are matched and adapted to the appropriate thermoforming technique, material selections are made, and proper tooling is assessed or engineered, setting the stage for a successful part run. This is a process with many variables that can have a large impact on quality, lead time, and cost.

What are the benefits of working with a manufacturer that utilizes Lean practices in the design process?

  • Working with a manufacturer that has standard operating procedures and practices documented and employed to take your project from design to production as quick as possible while avoiding common pitfalls and any non-value added endeavors
  • Design assistance for a seamless transition from the client’s required design specifications to a thermoforming process ready design
  • Savings in cost and time
  • Increased part quality and lower part defect rate

How does Productive Plastics apply lean principles to the design process?

As an example of how lean principles and process improvements can be applied to design practices in the thermoforming process, reference the chart below for functions we have identified as actual or potential waste, the actions we have implemented to eliminate or mitigate waste, and the results.

Identified Waste Process Improvement Result
Waiting

 

• Late tooling and assembly component quotes and delivery from suppliers

• Incomplete/inaccurate data

• Concurrent Engineering

 

• Gantt Chart Development

• Standard Operating Procedures & Guidelines

• Reduced lead time

 

• Reduction in resource utilization

Unnecessary/Incorrect Processing

 

• Incorrect material or process selection

• Incorrect manufacturing technique

• Early involvement and collaboration with client in part design

 

• Value Engineering Review

• Reduced lead time

 

• Maximize part consolidation and weight reduction

• Reduced defect rate

• Potential cost savings

Unnecessary Movement

 

• Development and design process requires revision due to inaccurate information

• Standardized Contract and Scope Review

 

• Standardized Design Review and collaboration with client engineering

• Define & discover collaboration

• Reduced lead time

 

• Reduction in resource utilization

Defects • Standardized Design Review and collaboration with client engineering

 

• ISO Certification

• Reduced lead time

 

• Reduced defect rate

• Potential cost savings

Unused Team Resources

 

• Losing time, ideas, skills, and improvements by not engaging employees

• Investment in people and company culture

 

• Company core values

• Collaborative planning, goals, and accountability

• Maximize employee engagement

 

• Reduced lead time

• Expertise and professional development within employee group

Productive Plastics is top contract manufacturer for heavy gauge thermoforming, including vacuum forming and pressure forming. Contact us or request our complimentary thermoforming design guide for more information.

Please contact Productive Plastics for more information on the thermoforming process
Please download our complimentary thermoforming design guide for more information on the thermoforming process

Terminology Note

Productive Plastics and the plastics industry typically use the terms "vacuum forming" and "vacuum thermoforming" interchangeably. Misspellings include "vacuumforming" and "vacuumthermoforming".

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