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Molds & Tooling 1 views

PBT Draft Angle and Forced Demolding

Problem Phenomenon
The product is scratched during demolding, or forced demolding of pure PBT parts with undercut structures fails
Cause Analysis
Pure PBT can reach an elongation of 200%, and smaller undercuts can be forcibly demolded; but after glass fiber filling, the elongation drops greatly and forced demolding is not possible; the core draft angle must be at least 0.5°
Solution
①Core draft angle ≥0.5°, main runner draft ≥3°; ②Pure material with small undercuts can be forcibly demolded; ③Forced demolding is forbidden for glass fiber filled parts; after adjustment, take samples continuously to verify the effect, and resume mass production only after confirming stability
Key Takeaway
PBT demolding design is differentiated according to whether it is filled or not; the forced demolding capability of pure material no longer exists in glass fiber grades; after confirming effectiveness, solidify the parameters and practices into the work instruction to prevent recurrence
PBT; draft angle; forced demolding; elongation; glass fiber

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