How to improve dimensional stability?

The three biggest factors are:

• Moisture & humidity: Different plastics absorb varying amounts of moisture at different rates. Over time, this moisture can influence the plastic’s mechanical strength, electrical properties (such as the dielectric loss factor), and physical dimensions.
• Temperature: Plastics generally have higher thermal expansion coefficients compared to metals, causing them to change size more significantly in response to heat. For complex or tightly-packed configurations operating in extreme temperatures, it's crucial to choose plastics with low thermal expansion coefficients.
• Mechanical stress: Compression, wear, and other stresses can cause plastics to distort over time. This distortion can occur both during the application of pressure and persist afterward, preventing the plastic from returning to its original shape.