Method of manufacturing an outer shell of a dispenser part
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Solution Overview
Problem
Conventional dispenser outer shells face issues with distortion and weak seams, particularly due to overflow of plastic material during the injection molding process, which can result in ridges or protrusions on the inner surface, compromising the smooth dispensing of products.
Innovation Solution
The solution involves retaining the first component part in the mould using protrusions that form recesses in the component part, preventing displacement and overflow during the injection of the second component part, thereby ensuring a smooth inner surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the first component part is retained in the mould using protrusions forming recesses, then overflow of plastic material is prevented and inner surface smoothness is improved, but the device complexity increases due to additional mould features
Solution Approach 1:
The protrusions are incorporated into the mould design from the beginning to preliminarily position and retain the first component part during the injection molding process. This preliminary action prevents displacement and overflow before they can occur, ensuring a smooth inner surface without requiring post-processing or additional retention mechanisms.
Solution Approach 2:
The mould is segmented into multiple cavities (first cavity for the first component part, second cavity for the second component part) with protrusions in the first cavity to retain the first component part. This segmentation allows independent control and retention of each component part, preventing overflow at the seam while maintaining manufacturing efficiency.
2Strength
If double injection molding process is used to join component parts in one mould, then seam strength is increased and distortion is reduced, but overflow of plastic material occurs beyond the seam
Solution Approach 1:
The first component part is preliminarily formed and retained in the first cavity of the mould using protrusions before the second component part is injected. This preliminary retention action prevents the first component part from displacing during the second injection, thereby preventing overflow of the second component plastic material beyond the seam while maintaining strong bonding.
Solution Approach 2:
The injection molding process is segmented into two distinct stages: first, forming and retaining the first component part in the first cavity; second, forming the second component part in the second cavity. This segmentation allows precise control of each injection phase, preventing overflow while ensuring strong seam formation through the mating surfaces.
3Ease of manufacture
If the first component part is transferred from first cavity to second cavity, then the outer shell can be formed with two component parts, but distortion occurs due to movement and shrinking
Solution Approach 1:
The outer shell manufacturing process is segmented into two independent injection molding operations in separate cavities. The first component part is formed in the first cavity and retained there, while the second component part is formed in the second cavity. This segmentation eliminates the need to transfer the first component part, preventing distortion from movement and shrinking while still achieving a complete outer shell with two component parts.
Solution Approach 2:
The first component part is preliminarily formed and retained in the first cavity with protrusions before the second component part is injected in the second cavity. This preliminary retention prevents any subsequent movement or distortion of the first component part, ensuring shape stability while completing the outer shell formation process.
Data Source
AI summary
An outer shell for a dispenser and a method for making same are provided, the outer shell including first and second injection molded plastic component parts. The first and second component parts each include an outer surface and an inner surface, with the first component part having a first mating surface directed to the outer surface of the first component part and the second component part having a second mating surface directed to an inner surface of the second component part. The first and second component parts are joined to each other along a seam by mating the first mating surface and the second mating surface during injection moulding. A plurality of recesses is formed in the inner surface of the first component part along the seam and/or on a gate protrusion extending away from a free end of the first mating surface of the first component part.