CUSTOMER SUCCESS STORY
From frequent ejection scratches and underfilled undercuts, to zero-defect mass production. The full story of AMII's process transformation.
|
98%+ Mold Release Yield Improvement |
Zero Ejection Scratch Defects |
40%↓ Mold Setup Cycle Reduction |
100% Thread & Undercut Fill Rate |
AMII is a plastic injection molding manufacturer specializing in plastic bottle caps, with products widely used across food & beverage, personal care, and industrial packaging sectors. Their components are held to strict standards for seal integrity, surface appearance, and dimensional consistency.
As market demand grew for high-precision caps with complex geometries — including internal undercuts and multi-start thread profiles — AMII's existing mold tooling began revealing systemic limitations, placing simultaneous pressure on both production capacity and quality output.
Before engaging Senlan, AMII's production engineering team was persistently held back by four critical pain points:
Difficult Undercut Demolding
Complex internal undercut geometry required excessive ejection force, frequently causing product deformation or tearing during release.
Ejection Scratch Damage
Abnormal friction between the mold and part wall during ejection produced batch-level surface scratches, severely reducing yield rates.
Incomplete Thread & Undercut Fill
Uneven injection pressure distribution left thread roots and undercut detail zones underfilled, leading to seal failures.
Poor Machining Precision
Controlling stock allowances in internal undercut cavities was unreliable, resulting in poor dimensional consistency and lengthy mold setup times.
Following a detailed analysis of AMII's product geometry and existing tooling condition, Senlan Precision Parts Co., Ltd. engineered a tailored Collapsible Core solution — fundamentally redesigning the mold mechanism to address all four pain points systematically.
-
01
Collapsible Core Mechanism Replaces Traditional Split Cavity
A multi-segment collapsible core collapses radially inward at mold opening, completely eliminating the axial pull-out force required for undercut release — enabling damage-free ejection every cycle.
-
02
High-Precision Segment Machining + Integrated Lapping
Each collapsible core segment was CNC machined individually to tight tolerances, then lapped together as an assembly. Mold closing precision was achieved at ≤0.01 mm, eliminating dimensional inconsistency in undercut zones.
-
03
Runner System & Pressure Distribution Re-optimization
Gate locations and hot runner balancing were redesigned in coordination with the collapsible core layout, ensuring uniform melt flow into thread roots and undercut detail areas for complete fill.
-
04
Surface Treatment & DLC Coating Upgrade
DLC (Diamond-Like Carbon) coating was applied to all ejection contact surfaces, reducing the friction coefficient by 60% and permanently eliminating ejection scratch defects.
After implementation, AMII's production line achieved a step-change improvement in both quality and efficiency within a short timeframe:
|
Zero Scratches Ejection scratch defects have been fully eliminated |
Yield +98% Mold release yield rate dramatically improved |
Cycle -40% Mold setup and adjustment cycle shortened |
|
100% Fill Thread & undercut complete fill rate achieved |
Cost ↓ Significantly Rework and scrap losses reduced |
Stable Consistency Batch dimensional consistency has greatly improved |
“Before this solution, every batch of undercut caps coming off the mold made us nervous. Ejection scratches and underfill were consuming enormous amounts of rework time. After the Collapsible Core solution was implemented, those problems virtually disappeared overnight. The mold precision and product consistency exceeded our expectations, and the pressure on our production team has been dramatically reduced.”
|
Customer |
AMII Plastic Injection Molding Manufacturer |
|
Industry |
Plastic Packaging / Injection Molding |
|
Product |
Plastic Bottle Caps (with Internal Undercut Structures) |
|
Solution Provider |
Senlan Precision Parts Co., Ltd. |
|
Solution Applied |
Collapsible Core Mold Design |
Facing similar internal undercut molding challenges?
Senlan's Collapsible Core solution has been proven across multiple industries. Con
Contact us for a complimentary mold diagnostic assessment.



