PEEK (polyetheretherketone) is a high-performance semi-crystalline engineering plastic with exceptional heat resistance, mechanical strength, and chemical stability. Due to its high melting point and sensitivity to thermal degradation, precise temperature control during injection molding is critical for producing parts with stable dimensions, good appearance, and reliable performance. This article provides standardized temperature settings and processing guidelines for PEEK injection molding.

Raw Material Drying Temperature

Although PEEK has low moisture absorption, even small amounts of water can cause silver streaks, bubbles, and molecular degradation under high-temperature processing. Thorough drying is therefore essential.

Recommended drying temperature: 150℃ – 160℃Drying time: 4 – 6 hoursFor recycled material, extend drying time to 6 – 8 hours. A dehumidifying dryer with a dew point below -40℃ is preferred. After drying, the material should be kept sealed and insulated to prevent reabsorption of moisture.

Barrel Temperature Settings

PEEK melts at approximately 343℃ and decomposes above 400℃. Barrel temperatures should be set in a gradually increasing pattern from rear to front.

Rear zone: 330℃ – 350℃

Center zone: 360℃ – 380℃

Front zone: 370℃ – 390℃

Nozzle: 370℃ – 390℃

The melt temperature must not exceed 400℃ to avoid thermal degradation.

Mold Temperature

Mold temperature directly determines crystallinity, internal stress, and dimensional stability.

Standard parts: 160℃ – 180℃

High-precision or high-performance parts: 190℃ – 210℃

A high-temperature oil heater is required; water-type temperature controllers are not suitable. The mold must be preheated to the set temperature and stabilized before production.

Adjustments for Different Part Structures

For thin-walled parts (less than 1mm), increase barrel and mold temperatures slightly to improve flow. For thick parts (over 6mm), reduce barrel temperature and extend cooling time to prevent sink marks and voids.

Startup, Shutdown and Production Interruption

Start by heating the mold first, then the barrel. During production interruptions over 10 minutes, lower the barrel temperature to below 320℃. Before shutdown, clean the barrel with purging material to prevent carbonization.

Temperature-Related Defects and Solutions

Silver streaks, bubbles, or discoloration usually indicate overheating or excessive residence time. Insufficient filling or poor welding often results from low melt or mold temperature. Warpage is commonly caused by low mold temperature or uneven cooling.

Conclusion

PEEK injection molding relies on strict control of drying, barrel, nozzle, and mold temperatures. Stable, high-quality parts can be consistently produced by following standardized temperature settings, proper preheating and cooling procedures, and timely adjustments based on part structure and equipment conditions.