Knowledge Hub — Materials

Thermoforming Materials Guide

Forming temperatures, shrinkage rates, mechanical properties, and application tables for ABS, HDPE, PP, PC, PETG, ABS/PMMA, HIPS, TPO, and PET — the 9 materials that account for over 95% of all thermoforming production worldwide.

9 materials covered Forming temperatures & shrinkage Application selection guide

Which plastics can be thermoformed?

Almost any thermoplastic can be thermoformed. The most common materials are ABS, HDPE, PP, PC, PETG, ABS/PMMA co-extrusion, HIPS, TPO, TPE, and PET. The choice depends on forming temperature, shrinkage rate, mechanical requirements, surface finish, and whether food contact or UV resistance is needed.

Thermoforming works by heating a thermoplastic sheet above its glass transition temperature (for amorphous materials) or melting point (for semi-crystalline materials) until it becomes pliable, then forming it over a mould using vacuum, pressure, or mechanical force. Any material that softens and flows within a workable temperature range — without degrading — can be thermoformed.

The key parameters for material selection are: forming temperature (determines heater power and cycle time), shrinkage rate (determines tooling dimensions), forming window (narrow for PP, wide for ABS), and maximum draw ratio (how deep a part can be formed relative to its width).

ABS

Acrylonitrile Butadiene Styrene

Heavy gauge

Forming Temp

150 – 180 °C

Shrinkage

0.4 – 0.7%

Thickness Range

2 – 10 mm

Density

1.03 – 1.06 g/cm³

ABS is the most widely used material in heavy gauge thermoforming. Its combination of impact resistance, surface quality, and processability makes it the default choice for automotive and industrial applications. ABS/PMMA co-extrusion adds UV stability and gloss for exterior applications.

Advantages

  • ✓ Excellent impact resistance
  • ✓ Good surface finish
  • ✓ Easy to paint and bond
  • ✓ Wide colour availability
  • ✓ Dimensionally stable

Limitations

  • ✗ UV sensitive (yellows outdoors)
  • ✗ Not food-safe alone
  • ✗ Moderate chemical resistance

Common Applications

Automotive interior panelsVehicle roofs & bonnetsAgricultural equipment coversBus & truck body partsIndustrial enclosuresBathtubs & sanitary ware

HDPE

High-Density Polyethylene

Heavy gauge

Forming Temp

160 – 190 °C

Shrinkage

1.5 – 3.0%

Thickness Range

3 – 12 mm

Density

0.94 – 0.97 g/cm³

HDPE's high shrinkage rate (up to 3%) means tooling must be oversized by 1.5–3% to achieve target dimensions. Machinecraft's PF1-X closed-chamber design with pre-blow bubble formation compensates for HDPE's tendency to sag during heating, enabling uniform wall thickness even at 10–12mm gauge.

Advantages

  • ✓ Exceptional impact resistance
  • ✓ Chemical and moisture resistant
  • ✓ Food-safe (FDA approved)
  • ✓ Recyclable
  • ✓ Low cost

Limitations

  • ✗ High shrinkage (requires oversized tooling)
  • ✗ Difficult to paint or bond
  • ✗ Lower stiffness than ABS
  • ✗ Prone to warping if cooled unevenly

Common Applications

Pickup truck bedlinersPortable toilet panelsRoof panels for electric vehiclesChemical storage tanksAgricultural traysPlayground equipment

Recommended Machines

PF1-X Series ATF Series

PP

Polypropylene

Heavy & light gauge

Forming Temp

160 – 175 °C

Shrinkage

1.0 – 2.5%

Thickness Range

2 – 8 mm

Density

0.90 – 0.91 g/cm³

PP has the narrowest forming window of all common thermoforming materials — it transitions from solid to liquid very quickly. Machinecraft's zone-controlled ceramic heaters maintain ±3°C uniformity across the sheet, which is critical for consistent PP forming. PP is the preferred material for food-contact applications due to its FDA approval and chemical inertness.

Advantages

  • ✓ Excellent chemical resistance
  • ✓ Living hinge capability
  • ✓ Food-safe
  • ✓ Lightweight (lowest density)
  • ✓ Good fatigue resistance

Limitations

  • ✗ Narrow forming window (sags quickly)
  • ✗ Poor UV resistance
  • ✗ Difficult to bond
  • ✗ High shrinkage

Common Applications

Automotive wheel archesFood packaging traysCommercial vehicle separatorsMedical device housingsBattery trays for EVsDisposable plates & bowls

Recommended Machines

PF1-X Series FCS Series

PC

Polycarbonate

Heavy gauge

Forming Temp

175 – 200 °C

Shrinkage

0.5 – 0.7%

Thickness Range

1 – 6 mm

Density

1.20 – 1.22 g/cm³

PC must be dried at 120°C for 4–6 hours before forming to prevent hydrolytic degradation (moisture causes bubbles and reduced impact strength). The high forming temperature (175–200°C) requires machines with powerful, precisely controlled heating systems. Machinecraft's PF1-X with 30–40 kW ceramic heater banks handles PC reliably.

Advantages

  • ✓ Optical clarity (88% light transmission)
  • ✓ Very high impact resistance
  • ✓ Excellent heat resistance (HDT 130°C)
  • ✓ Dimensionally stable
  • ✓ Flame retardant grades available

Limitations

  • ✗ Moisture sensitive (must be pre-dried)
  • ✗ Susceptible to stress cracking with solvents
  • ✗ Higher cost
  • ✗ Requires higher forming temperatures

Common Applications

Headlight lenses & light coversSafety shields & machine guardsMedical device housingsGreenhouse panelsAircraft interior components

Recommended Machines

PF1-X Series PF1-C Classic

PETG

Polyethylene Terephthalate Glycol

Light & medium gauge

Forming Temp

130 – 160 °C

Shrinkage

0.2 – 0.5%

Thickness Range

0.5 – 5 mm

Density

1.27 g/cm³

PETG is the easiest material to thermoform — its low forming temperature (130–160°C) and wide processing window make it forgiving for new operators. Its very low shrinkage (0.2–0.5%) means tooling dimensions translate almost directly to part dimensions. PETG is the preferred material for food-contact packaging in the EU and North America.

Advantages

  • ✓ Lowest forming temperature
  • ✓ Excellent clarity
  • ✓ Food-safe (FDA, EU approved)
  • ✓ Very low shrinkage
  • ✓ Easy to thermoform

Limitations

  • ✗ Lower heat resistance than PC
  • ✗ Absorbs moisture (pre-drying recommended)
  • ✗ Not suitable for high-temperature applications

Common Applications

Fresh produce packaging traysRetail display standsMedical blister packsCosmetic packagingPoint-of-sale displays

Recommended Machines

FCS Series PF1-UL Lab

ABS/PMMA

ABS + Acrylic Co-extrusion

Heavy gauge

Forming Temp

155 – 185 °C

Shrinkage

0.4 – 0.7%

Thickness Range

2 – 8 mm

Density

1.08 – 1.12 g/cm³

ABS/PMMA co-extrusion combines the structural strength of ABS with the UV stability and gloss of PMMA (acrylic). The PMMA cap layer is typically 0.3–0.8mm thick. This material is the standard for automotive exterior applications where Class A surface finish and 10-year UV stability are required. Machinecraft supplies ABS/PMMA sheets through its material supply network.

Advantages

  • ✓ High gloss PMMA surface (Class A finish)
  • ✓ UV stable (10+ year outdoor rating)
  • ✓ ABS structural backing
  • ✓ Scratch resistant surface
  • ✓ Wide colour range including metallic

Limitations

  • ✗ Higher cost than plain ABS
  • ✗ Requires careful temperature control
  • ✗ PMMA layer can crack if over-stretched

Common Applications

Automotive exterior panelsBus & truck exterior body partsAgricultural equipment hoodsOutdoor signageBathtubs & shower trays

Recommended Machines

PF1-X Series AM-V Series

HIPS

High-Impact Polystyrene

Light gauge

Forming Temp

140 – 165 °C

Shrinkage

0.3 – 0.6%

Thickness Range

0.3 – 3 mm

Density

1.04 – 1.08 g/cm³

HIPS is the dominant material for high-volume light gauge thermoforming (packaging, disposables). Its low cost, easy processability, and good surface detail make it ideal for FCS roll-fed machines producing millions of parts per year. Note that HIPS is not food-safe for direct food contact due to residual styrene monomer — use PETG or PP for food-contact applications.

Advantages

  • ✓ Very low cost
  • ✓ Good surface detail
  • ✓ Easy to form and trim
  • ✓ Printable surface
  • ✓ Good stiffness at low thickness

Limitations

  • ✗ Brittle at low temperatures
  • ✗ Not food-safe (styrene migration)
  • ✗ Poor chemical resistance
  • ✗ Not recyclable in most streams

Common Applications

Disposable food containers (non-food-contact)Refrigerator inner linersToy packagingPoint-of-sale displaysMedical device trays

Recommended Machines

FCS Series

TPO / TPE

Thermoplastic Polyolefin / Elastomer

Heavy gauge

Forming Temp

160 – 190 °C

Shrinkage

1.5 – 2.5%

Thickness Range

2 – 5 mm

Density

0.88 – 0.92 g/cm³

TPO is the standard material for automotive interior skin applications, replacing PVC due to its recyclability and lower VOC emissions. Thermoforming TPO requires precise temperature control — too hot causes surface defects, too cool causes tearing. Machinecraft's PF1-X with independent zone heating handles TPO reliably for automotive OEM applications.

Advantages

  • ✓ Flexible & soft-touch surface
  • ✓ Excellent UV resistance
  • ✓ Paintable without primer
  • ✓ Recyclable
  • ✓ Low density (weight saving)

Limitations

  • ✗ Lower stiffness
  • ✗ High shrinkage
  • ✗ Requires precise temperature control
  • ✗ More expensive than PP

Common Applications

Automotive instrument panel skinsDoor panel skinsAirbag coversSoft-touch interior trimsBumper fascias

Recommended Machines

PF1-X Series AM-V Series

PET

Polyethylene Terephthalate

Light gauge

Forming Temp

130 – 160 °C

Shrinkage

0.2 – 0.4%

Thickness Range

0.2 – 2 mm

Density

1.33 – 1.38 g/cm³

PET for thermoforming is always amorphous (A-PET or PETG), not the semi-crystalline PET used in bottles. A-PET must be cooled quickly after forming to prevent crystallisation (which causes opacity). PET is the most widely recycled plastic globally, making it the preferred choice for sustainable food packaging applications.

Advantages

  • ✓ Excellent clarity
  • ✓ High tensile strength
  • ✓ Food-safe (FDA, EU)
  • ✓ Recyclable (widely accepted)
  • ✓ Barrier properties (O₂, CO₂)

Limitations

  • ✗ Crystallises if cooled too slowly (becomes opaque)
  • ✗ Moisture sensitive
  • ✗ Narrow forming window for amorphous PET

Common Applications

Fresh produce traysBakery packagingMeat & poultry traysPharmaceutical blister packsDeli containers

Recommended Machines

FCS Series

Full material comparison table

ABS has the best balance of properties for heavy gauge thermoforming. PETG and PET are easiest to form (lowest temperature). HDPE has the highest shrinkage. PC requires the highest forming temperature. PP has the narrowest forming window.

Thermoforming Materials Comparison Table
MaterialForming Temp (°C)Shrinkage (%)Tensile (MPa)HDT (°C)Density (g/cm³)Food SafeUV StableGauge
ABS150–1800.4–0.740–5088–1001.03–1.06✗✗ (use ABS/PMMA)Heavy
HDPE160–1901.5–3.022–3160–800.94–0.97✓✗Heavy
PP160–1751.0–2.530–40100–1150.90–0.91✓✗Heavy/Light
PC175–2000.5–0.755–75130–1401.20–1.22✗✓ (UV grades)Heavy
PETG130–1600.2–0.548–5370–801.27✓✗Light/Medium
ABS/PMMA155–1850.4–0.745–5585–951.08–1.12✗✓ (10+ yr)Heavy
HIPS140–1650.3–0.625–3570–851.04–1.08✗✗Light
TPO160–1901.5–2.515–2550–700.88–0.92✗✓Heavy
PET130–1600.2–0.450–8065–801.33–1.38✓✗Light

Sources: Plastics Technology, Omnexus Material Database, Machinecraft process data

Material selection guide by application

Automotive exterior → ABS/PMMA. Automotive interior skins → TPO. Bedliners & outdoor structural → HDPE. Food packaging → PETG or PET. High-volume disposables → HIPS or PP. Optical/safety shields → PC. General heavy gauge → ABS.

Automotive Exterior

ABS/PMMA co-extrusion

Class A surface finish, UV stable 10+ years, structural strength

Automotive Interior Skins

TPO or TPE

Soft-touch, paintable without primer, recyclable, low VOC

Food Packaging

PETG or PET

FDA/EU food-safe, excellent clarity, recyclable, low forming temp

High-Volume Disposables

HIPS or PP

Lowest cost (HIPS) or food-safe (PP), high-speed FCS forming

Industrial Enclosures

ABS

Best balance of impact resistance, surface finish, and cost

Outdoor Structural Parts

HDPE

Chemical resistance, UV resistance, impact resistance, food-safe

Optical / Safety Shields

PC

88% light transmission, highest impact resistance, HDT 130°C

Medical Devices

PC or PETG

Sterilisable (PC), food-safe (PETG), excellent clarity, dimensional stability

Frequently asked questions

What is the most commonly used material for heavy gauge thermoforming?

ABS (Acrylonitrile Butadiene Styrene) is the most widely used material in heavy gauge thermoforming, accounting for approximately 40% of all heavy gauge applications. It offers the best balance of impact resistance, surface quality, processability, and cost. For outdoor applications requiring UV stability, ABS/PMMA co-extrusion is used instead.

What temperature is needed to thermoform ABS?

ABS is typically thermoformed at 150–180°C sheet surface temperature. The oven temperature is set higher (usually 200–240°C) to achieve this surface temperature within a reasonable cycle time. Machinecraft's PF1-X machines with ceramic zone heaters maintain ±3°C uniformity across the ABS sheet.

Can HDPE be thermoformed?

Yes, HDPE can be thermoformed, but it requires careful process control due to its high shrinkage rate (1.5–3.0%) and tendency to sag during heating. Machinecraft's closed-chamber design with pre-blow bubble formation compensates for HDPE sag, enabling uniform wall thickness at gauges up to 12mm. Tooling must be oversized by 1.5–3% to account for shrinkage.

What is the difference between ABS and HDPE for thermoforming?

ABS offers better surface finish, dimensional stability (0.4–0.7% shrinkage vs 1.5–3.0% for HDPE), and paintability. HDPE offers better impact resistance, chemical resistance, food safety, and lower cost. ABS is preferred for automotive and industrial applications requiring appearance. HDPE is preferred for structural applications like bedliners, tanks, and outdoor panels where chemical resistance matters more than surface finish.

Which thermoforming materials are food-safe?

Food-safe thermoforming materials include: PETG (easiest to form, lowest temperature), PET/A-PET (food packaging standard), PP (excellent chemical resistance, microwave-safe grades available), and HDPE (FDA approved, used for cutting boards and food containers). ABS, HIPS, and PC are not recommended for direct food contact.

What is the forming temperature for PP (polypropylene)?

PP is thermoformed at 160–175°C sheet surface temperature. PP has the narrowest forming window of common thermoforming materials — it transitions from solid to liquid very quickly, making precise temperature control critical. Machinecraft's zone-controlled ceramic heaters maintain ±3°C uniformity, which is essential for consistent PP forming.

Why does HDPE have such high shrinkage in thermoforming?

HDPE's high shrinkage (1.5–3.0%) is due to its semi-crystalline structure. When heated above its crystalline melting point (~130°C), the crystalline regions melt and the polymer chains relax. Upon cooling, the chains re-crystallise and contract significantly. This is much higher than amorphous materials like ABS (0.4–0.7%) or PC (0.5–0.7%). Tooling must be designed with oversized dimensions to compensate.

What material should I use for automotive exterior panels?

ABS/PMMA co-extrusion is the standard for automotive exterior panels requiring Class A surface finish and UV stability. The PMMA cap layer (0.3–0.8mm) provides 10+ year UV resistance and high gloss, while the ABS backing provides structural strength. For flexible exterior applications like bumper fascias, TPO is preferred due to its paintability without primer and recyclability.