Thermal Expansion: Dimensional Control and Accuracy

Thermal Stability and Precision: A Challenge for Technical Systems

Industrial environments subject to temperature variations demand stable, precise materials. Low thermal expansion is essential to guarantee dimensional stability, assembly reliability and component life.

Why is the Coefficient of Thermal Expansion critical?

The CTE (Coefficient of Thermal Expansion), expressed in µm/m-°C, determines how a material expands under heat. A high CTE can cause :

  • Deformation and loss of tolerance
  • Cracks, excessive play or unwanted tightening
  • Contact or sealing defects

Low CTE HPPs are ideal for technical assemblies exposed to heat.
 

DEMGY selection: Low CTE HPP polymers

Product

 

CTE (µm/m-°C)

 

Continuous temp.

 

Specifications

 

Applications

 

Torlon® 4203 (PAI)

 

~18

 

260°C

 

Excellent stability

 

Bearings, mechanical

 

PEEK GF30/CF30

 

~15-25

 

260°C

 

Loaded glass/carbon

 

Connectors, auto

 

Vespel® SCP-5000 (PI)

 

~18

 

320°C

 

Space vacuum resistant

 

Space, cryogenics

 

PPS GF40 (Ryton® R4)

 

~18-20

 

220°C

 

Glass-reinforced

 

Electronics, precision

 

PVDF (Kynar® 1000 HD)

 

~120

 

140°C

 

Less stable

 

Fluids, coatings

 

PTFE (Teflon® FEP-9302)

 

~125

 

200°C

 

Inert, but not very stable

 

Seals, insulation

 

Fiber-reinforced grades (GF/CF) greatly reduce expansion.

Standard plastics & metals: where are the limits?

Material

 

Typical CTE

 

Problems

 

Standard plastics (PA6, POM)

 

70-150

 

Large deformations

 

Aluminum

 

~23

 

Good, but heavy

 

Steel

 

~12

 

Stable, but dense

 

Reinforced HPP

 

15-25

 

Low density + high precision

 
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Applications sensitive to thermal expansion

Aerospace

  • Structural components, connectors, insulators
  • Vespel® SCP-5000: functional from -200 to +300°C

Precision mechanics

  • Guide rings, polymer bearings
  • Torlon® 4203: rigid, precise, stable

Electronics & connectors

  • Circuit supports, housings
  • PEEK GF30 / PPS GF40 : thermal compatibility with substrates

Automotive & mobility

  • Engine and gearbox components
  • Thermal resistance + stability = long-term reliability

DEMGY expertise for your thermal needs

Targeted material advice

  • Selection based on CTE, temperature, required rigidity
  • Recommended reinforcements (carbon, glass, mineral)

Controlled processing

  • Heat-compensated machining & injection
  • High-stability additive manufacturing

Dimensional validation

  • Cyclic temperature testing
  • Shrinkage control, internal voltage
     

Conclusion

Controlling thermal expansion is an essential lever for the functional performance, geometric precision and reliability of technical parts. Thanks to their low CTE and structural stability when hot, the HPPs selected by DEMGY meet the most demanding requirements.

Associated products