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 gravity – indication 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|
|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|
|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|
|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|
|ETFE (film 5-20 mil thick)||6,100||145,000||Shore D 67 R85||No break||1.7|
|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|
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.