PET · grade · default condition
PET Unfilled
Properties of the Unfilled condition, compared with the other PET grades.
Default choice for machined precision parts, wear strips and bushings where stiffness, dimensional stability and good machinability matter.
What is PET Unfilled?
PET Unfilled is PET in the Unfilled grade — default choice for machined precision parts, wear strips and bushings where stiffness, dimensional stability and good machinability matter. PET Unfilled has a yield strength of 80 MPa (11.6 ksi) and a tensile strength of 82 MPa (11.9 ksi) — stronger than 87% of polymer grades. Elongation at break is 20% and the elastic modulus is 3.1 GPa (0.45 Msi). PET Unfilled has a density of 1.39 g/cm³ (0.0502 lb/in³), heavier than 77% of polymer grades. Its glass-transition temperature is 79°C (174 °F).
Advantages
- Tough — resists crack growth — 4 MPa·√m (3.64 ksi·√in), better than 91% of polymer grades
- High strength — 80 MPa (11.6 ksi), better than 87% of polymer grades
- Low embodied carbon — 2.8 kg CO₂/kg, better than 87% of polymer grades
- Easy to machine — 78/100, better than 80% of polymer grades
- Low moisture uptake — 0.11%, better than 75% of polymer grades
Limitations
- High mold shrinkage — 2%, worse than 81% of polymer grades
- Needs corrosion protection — 70/100, worse than 80% of polymer grades
- Heavy — 1.39 g/cm³ (0.0502 lb/in³), worse than 77% of polymer grades
PET Unfilled properties
Typical room-temperature values for PET Unfilled — 13 properties are specific to this condition; the rest are grade-level values shared by every PET grade. Each bar shows where the value sits among the polymer grades in FabDigit's library — further right is higher.
Physical7
PET Unfilled has a density of 1.39 g/cm³ (0.0502 lb/in³), heavier than 77% of polymer grades. Its glass-transition temperature is 79°C (174 °F).
Mechanical17
PET Unfilled has a yield strength of 80 MPa (11.6 ksi) and a tensile strength of 82 MPa (11.9 ksi) — stronger than 87% of polymer grades. Elongation at break is 20% and the elastic modulus is 3.1 GPa (0.45 Msi).
Thermal11
PET Unfilled is rated for continuous service to 100°C (212 °F). It conducts heat at 0.25 W/m·K (0.144 BTU/hr·ft·°F), better than 71% of polymer grades. Thermal expansion is 65 µm/m·K (36.1 µin/in·°F).
Electrical7
PET Unfilled is an electrical insulator with a dielectric strength of 22 kV/mm (558.8 V/mil) and a resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (70/100), worse than 80% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of PET Unfilled takes about 82 MJ of energy and emits 2.8 kg of CO₂ — less than 83% of polymer grades. Typical recycled content is 25%.
Manufacturability7
PET Unfilled's machinability is very good (78/100, better than 80% of polymer grades); weldability fair (45/100); formability fair (50/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other PET grades and fills
PET is also supplied in 8 other conditions. The full side-by-side table is on the PET overview.
- UnfilledDefaultDefault choice for machined precision parts, wear strips and bushings where stiffness, dimensional stability and good machinability matter.82 MPa tensile
- CF30PET compounded with 30 wt% chopped carbon fiber for very high stiffness, low creep, low mold shrinkage and static-dissipative/conductive behavior.200 MPa tensile
- GF45For maximum stiffness and creep resistance in thin-wall metal-replacement parts; brittle and abrasive to tooling.185 MPa tensile
- GF30Use for stiff, dimensionally stable structural mouldings needing 200 °C-class heat resistance (housings, connectors, under-hood brackets).160 MPa tensile
- FRChoose where a UL 94 V-0 rating at 0.8–1.6 mm is mandatory, e.g. electrical connectors, coil bobbins and switch bodies.135 MPa tensile
- IMUse when snap-fits, clips or impact-loaded housings need toughness that plain or glass-filled PET cannot supply.105 MPa tensile
- Solid Lubricant Filled (TX)Pick for unlubricated sliding: bushings, wear pads and guides where low friction and long wear life beat maximum strength.60 MPa tensile
- rPETCost- and footprint-driven choice for sheet, strapping, fiber and non-critical mouldings; IV and colour vary batch to batch.60 MPa tensile
Working with PET Unfilled
Is PET easy to machine?
Machines like a free-cutting engineering plastic: sharp positive-rake carbide, high speed, light finishing passes and air/mist cooling give excellent surface finish and tight tolerances; watch for stress relief in thick stock (anneal before finish cuts).
Can PET be welded?
No solvent bonding — join by ultrasonic, hot-plate, IR or laser welding, or use cyanoacrylate/epoxy after abrasion/plasma treatment; mechanical fastening and self-tapping screws work well.
Can PET be formed, bent or molded?
Dry pellets to <0.02 % moisture (150 °C, 4 h desiccant) to avoid hydrolytic IV loss; melt 265–295 °C with hot mold 100–145 °C for full crystallization, or chilled mold/copolyester for clear amorphous APET sheet that thermoforms readily.
What surface finishes work on PET?
Takes machining, printing, hot stamping and vacuum metallizing well after corona/flame or plasma pre-treatment; can be laser-marked, but paint adhesion needs a primer and no plating/anodizing applies.
PET chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| isophthalic acid / CHDM comonomerin bottle/APET copolyester grades to suppress crystallization | 0 – 3 | 1.5 |
| glass fiber0 in default unfilled grade; 15–45 % in GF variants | 0 – 45 | 0 |
| solid lubricant (PTFE/other)TX bearing grades | 0 – 20 | 0 |
| flame retardant + synergistFR V-0 grades | 0 – 20 | 0 |
| nucleant / heat stabilizer / mold releasstandard additive package | 0 – 3 | 0.5 |
| ethylene terephthalate repeat unit (–C10polycondensate of purified terephthalic acid (PTA) or DMT with mono-ethylene glycol; Sb/Ti/Ge catalyst residues at ppm level | balance | — |
PET Unfilled — frequently asked
What is PET Unfilled used for?
PET Unfilled is typically used for precision machined mechanical components, slide bearings and wear strips, pump and valve parts, electronic structural parts, beverage bottles and food packaging film. In short: durable industrial PET.
What is the yield strength of PET Unfilled?
PET Unfilled has a typical yield strength of 80 MPa (11.6 ksi) and a tensile strength of 82 MPa (11.9 ksi) — stronger than 87% of polymer grades. Strength varies by condition: see the 9 listed tempers.
Is PET Unfilled easy to machine?
Yes — machinability is rated very good (78/100, better than 80% of polymer grades). Machines like a free-cutting engineering plastic: sharp positive-rake carbide, high speed, light finishing passes and air/mist cooling give excellent surface finish and tight tolerances; watch for stress relief in thick stock (anneal before finish cuts).
Can PET Unfilled be welded?
With care — weldability is rated fair (45/100). No solvent bonding — join by ultrasonic, hot-plate, IR or laser welding, or use cyanoacrylate/epoxy after abrasion/plasma treatment; mechanical fastening and self-tapping screws work well.
What surface finishes work on PET Unfilled?
Takes machining, printing, hot stamping and vacuum metallizing well after corona/flame or plasma pre-treatment; can be laser-marked, but paint adhesion needs a primer and no plating/anodizing applies.
Can PET Unfilled be formed, bent or molded?
Dry pellets to <0.02 % moisture (150 °C, 4 h desiccant) to avoid hydrolytic IV loss; melt 265–295 °C with hot mold 100–145 °C for full crystallization, or chilled mold/copolyester for clear amorphous APET sheet that thermoforms readily.
What is the maximum service temperature of PET Unfilled?
PET Unfilled is rated for continuous use to about 100°C (212 °F), and briefly to 150°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in PET Unfilled?
Yes — PET Unfilled is available for CNC machining, sheet metal and injection molding with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- Ertalyte / Ertalyte TX PET-P stock shapes datasheet — Mitsubishi Chemical Advanced Materials (Quadrant) (2022)
- Rynite PET thermoplastic polyester resin product & molding guide — DuPont / Celanese (2021)
- Arnite A (PET) grade datasheets — Envalior / DSM Engineering Materials (2023)
- CAMPUS plastics database — PET unfilled and GF grades — CWFG / CAMPUS consortium (2024)
- Engineered Materials Handbook Vol. 2: Engineering Plastics — ASM International (1988)
- ASTM D5927 — Standard Specification for Thermoplastic Polyester (TPES) Molding and Extrusion Materials — ASTM (2021)
- ISO 7792-1/-2 — Plastics, thermoplastic polyester (TP) moulding and extrusion materials — ISO (2012)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.