Wedge-Lock System for Injection Molds with Floating Pucks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing injection molds face challenges in maintaining concentricity and consistent wall thickness due to breathing gaps at the parting line caused by high injection pressures, which leads to uneven thermal expansion and galling issues with traditional wedge locking systems.
Innovation Solution
A wedge-lock system that uses sets of wedges with compressible attachment means and floating pucks to self-adjust and maintain core and cavity halves' centering, allowing for thermal expansion compensation and preventing galling by applying clamping force only during mold closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If larger wedge angles (7°-20°) are used to provide sufficient clamping force, then the locking force is improved, but gaps between wedges increase causing loss of concentricity and inconsistent wall thickness
Solution Approach 1:
The wedge locking system is divided into multiple independent wedge sets (typically 4 or more) distributed around the mold perimeter. Each wedge set independently compensates for local breathing gaps and thermal expansion, collectively maintaining overall concentricity and preventing galling through distributed load bearing.
2Manufacturing precision
If smaller wedge angles (3° or 1° or less) are used to reduce gaps and maintain concentricity, then manufacturing precision is improved, but thermal expansion control becomes difficult and wedges tend to gall and seize
Solution Approach 1:
The floating puck mechanism enables the wedge assembly to automatically self-adjust and self-center during mold operation. The compressible attachment means allows the core wedge piece to float and self-align with the cavity wedge, maintaining optimal contact and preventing galling without requiring external adjustment mechanisms.
3Manufacturing precision
If shimming is used to restore concentricity, then manufacturing precision is temporarily improved, but the solution is time consuming and only temporary since processing conditions continuously cause shifting
Solution Approach 1:
The wedge locking system transitions from a static fixed-position design to a dynamic floating adjustment mechanism. The core wedge piece can move laterally on the floating puck, allowing continuous real-time adaptation to changing processing conditions, thermal expansion, and breathing gaps throughout the injection molding cycle.
4Manufacturing precision
If tighter tolerances are used to build the mold and maintain concentricity, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The system changes the operational parameters of the wedge locking mechanism by introducing controlled movement and compression capabilities. The floating puck and compressible attachment means allow the wedges to operate with larger tolerances while maintaining precise concentricity through dynamic adjustment, eliminating the need for extremely tight manufacturing tolerances.
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 system effectively maintains concentricity and consistent wall thickness by reducing gaps between wedges, preventing galling, and allowing for precise control of thermal expansions, thus improving mold performance and reducing costs.
Implementation Method 1
a core wedge assembly including a core wedge piece positioned adjacent the first side of the protrusion and being connected by compressible attachment means which extends laterally through said protrusion to at least one floating puck
Implementation Method 2
a second cavity wedge secured to the cavity block having a mating angled surface to the angled side of the protrusion, which in said closed position, engages the angled side of said protrusion and urges said laterally outwardly extending at least one floating puck inwardly to compress said compressible attachment means and thereby urge said core wedge piece into firm contact with said first cavity wedge
Data Source
AI summary
A wedge-lock system for injection molds, using a protrusion on one side of the mold and a mating opening and sets of wedges which act together upon mold closing to provide and maintain accurate centering of the core and cavity halves in reference to each other, to prevent core shifts and compensate for uneven thermal expansion of mold components.