Mold Unit with Protrusion Crushing to Prevent Recessed Defects
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Solution Overview
Problem
In injection blow molding, recessed portions as molding defects often form in thick portions of intermediate molding products due to differing volume shrinkage rates during cooling, leading to potential defects in the final product, and extending holding pressure time to mitigate this issue prolongs the molding cycle.
Innovation Solution
A mold unit design where a first mold forms protrusions on the inner surface of thick portions during injection molding, and a second mold crushes these protrusions during blow molding to smooth the surface, preventing recessed defects without extending holding pressure time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If holding pressure time is extended to prevent recessed portions in thick portions, then manufacturing precision is improved, but productivity deteriorates
Solution Approach 1:
The first mold forms protrusions on the inner surface of thick portions during injection molding as a preliminary action. These protrusions are then crushed by the second mold during blow molding, preventing recessed defects without requiring extended holding pressure time, thus resolving the contradiction between manufacturing precision and productivity
2Manufacturing precision
If protrusions are formed on inner surface of thick portions during injection molding, then recessed defects are prevented, but device complexity increases
Solution Approach 1:
The invention merges the functions of the first mold (injection molding) and the second mold (blow molding) to work cooperatively. The first mold forms protrusions and the second mold crushes them, achieving surface quality improvement without requiring complex additional equipment, as the existing two-stage molding process is utilized
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The mold unit effectively prevents recessed defects by smoothing the inner surface of intermediate molding products, ensuring high accuracy in final products without prolonging the molding cycle.
Implementation Method 1
a first mold that performs injection molding for molding an intermediate molding product molds a protrusion on an inner surface of a thick portion of the intermediate molding product
Implementation Method 2
when the intermediate molding product is fitted to a second mold in order to perform blow molding for molding a final molding product from the intermediate molding product, the second mold crushes the protrusion from an inside of the intermediate molding product
Implementation Method 3
the second mold may crush the protrusion while sliding on an inner surface of the intermediate molding product
Data Source
AI summary
A mold unit in which a first mold that performs injection molding for molding an intermediate molding product molds a protrusion on an inner surface of a thick portion of the intermediate molding product, and when the intermediate molding product is fitted to a second mold in order to perform blow molding for molding a final molding product from the intermediate molding product, the second mold crushes the protrusion from an inside of the intermediate molding product.