Distributed Compression Tooling for Thin-Wall Case Warpage
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Solution Overview
Problem
Injection molding of computer peripheral device cases with thin walls often results in warpage due to uneven solidification of molten material, which conventional pressurized gas methods fail to adequately address.
Innovation Solution
A molding apparatus with compressing rods and channels that adjust the volume of a compressing recess within the mold cavity to pressurize the molten material, ensuring uniform solidification and reducing warpage by maintaining pressure during the molding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pressurized gas is injected into the mold cavity to maintain pressure during solidification, then warpage is reduced, but gas bubbles become entrapped in the solidified material
Solution Approach 1:
The patent replaces the pneumatic system (pressurized gas) with a mechanical system (piston and diaphragm assembly). The piston mechanically pushes the diaphragm to apply pressure to the molten material, eliminating gas bubble entrapment while maintaining the necessary pressure for uniform solidification and warpage reduction.
Solution Approach 2:
The diaphragm acts as an intermediary between the piston and the molten material. It transfers the mechanical force from the piston to the molten material while preventing direct contact between the piston and material, allowing for effective pressure application without contamination or bubble entrapment.
2Ease of manufacture
If conventional injection molding is used for thin-walled cases, then manufacturing is simple, but uneven solidification causes warpage
Solution Approach 1:
The patent applies pressure to the molten material during the injection and solidification phases before the material fully solidifies. This preliminary pressurization ensures uniform density and prevents warpage from developing during cooling, while still allowing for relatively simple manufacturing processes.
3Manufacturing precision
If pressure is maintained during solidification to ensure uniform density, then warpage is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent divides the mold into two halves, with the movable diaphragm assembly integrated into one half. This segmentation allows the pressurization function to be added to the molding apparatus without requiring complete redesign, maintaining relative simplicity while achieving uniform density and warpage reduction.
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 solution effectively alleviates warpage in molded components by solidifying the material under pressure, ensuring uniform density and alignment of features like buttons on the device case.
Implementation Method 1
actuating the one or more compressing rods with a driving force to push the molten material received in the compressing recess back into the mold cavity; maintaining a pressure on the molten material in the mold cavity by maintaining the driving force applied on the one or more compressing rods
Implementation Method 2
solidifying the molten material in the mold cavity for a predetermined time
Data Source
AI summary
A molding apparatus is proposed for manufacturing a molded component. The molding apparatus may include an upper half mold and a lower half mold cooperatively coupled with each other. A mold cavity is defined between the upper half mold and the lower half mold. The molding apparatus further includes one or more compressing channels formed in the lower half mold and in fluid communication with the mold cavity; and one or more compressing rods, wherein each of the one or more compressing rods is slidably received in a respective one of the one or more compressing channels, wherein a top surface of each of the one or more compressing rods defines a compressing recess within the respective one of the one or more compressing channels.