Outer shell for a dispenser and method for producing such an outer shell
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Solution Overview
Problem
Existing dispenser outer shells face issues with distortion and weak seams due to overflow of plastic material during injection moulding, leading to potential cracking and the need for a smooth inner surface to prevent product damage.
Innovation Solution
The outer shell is manufactured using a method where the first component part is retained in the mould with protrusions to prevent displacement and overflow, featuring recesses and protrusions with specific angles and arrangements to secure the part in place, ensuring a strong and smooth seam during the injection moulding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the first component part is not retained in the mould during injection moulding, then the manufacturing process is simpler, but the plastic material overflows and creates ridges on the inner surface
Solution Approach 1:
The mould is designed with protrusions that engage with recesses in the first component part before the injection of the second component material. This preliminary positioning action prevents displacement and overflow during the subsequent injection process, ensuring a smooth inner surface without requiring complex retention mechanisms.
2Manufacturing precision
If the first component part is retained in the mould with protrusions, then overflow is prevented and inner surface smoothness is improved, but the mould design becomes more complex
Solution Approach 1:
Instead of making the entire mould complex, protrusions are added only at specific locations where the first component part needs to be retained. These localized protrusions engage with corresponding recesses in the first component part, providing precise retention only where needed while keeping the rest of the mould design simple.
3Strength
If the seam is made with local reinforcements, then the strength is improved, but distortion of the component parts increases
Solution Approach 1:
The first component part is preliminarily positioned and retained in the mould using protrusions and recesses before the second component material is injected. This preliminary action ensures accurate alignment and prevents distortion during the joining process, allowing the seam to achieve sufficient strength without requiring excessive local reinforcements that would cause distortion.
Data Source
Figure 1A~2
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AI summary
The present disclosure relates to an outer shell for a dispenser, the outer shell comprising: a first injection moulded plastic component part and a second injection moulded plastic component part, wherein the first and second component parts each comprise an outer surface and an inner surface, wherein the first component part has a first mating surface directed to the outer surface of the first component part and the second component part has a second mating surface directed to an inner surface of the second component part, wherein the first and second component parts are joined to each other along a seam by mating said first mating surface and said second mating surface during injection moulding, wherein a plurality of recesses is formed in the inner surface of the first component part along at least a part of the seam and/or on a gate protrusion extending away from a free end of the first mating surface of the first component part. The present disclosure also relates to a method for producing such an outer shell in a double injection moulding process in a single mould.