Thermoforming
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Air Entrapment Blistering When LCP Thin Wall Fills into Thick Sections
Problem Phenomenon
【Problem Phenomenon】When the latter part of a thin-wall flow path enters a thicker region, bubbles or internal voids appear at the thick wall, visible by X-ray inspection
Cause Analysis
LCP has extremely high fluidity and crystallizes rapidly; when thin-wall high-speed filling enters a thick-wall region, the melt front folds and entrains air, and the gas is sealed by the rapidly crystallizing skin layer and cannot escape; the thin-wall-filling-thick structure is a typical blistering scenario recorded in Vectra Tech Tips
Solution
Optimize the gate position so that the melt fills from thick to thin, or reduce the injection speed in that section to let the gas escape through the vents; add vent grooves in the thickened area, and add venting on the parting line if necessary
Key Takeaway
Thin wall entering thick wall easily entrains air; adjusting flow direction and venting is more effective than simply raising temperature; after confirming effectiveness, solidify the parameters and practices into the work instruction to prevent recurrence; include this case in the defect archive as a troubleshooting reference for subsequent similar problems
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