Interdental Cleaning Tool Molding to Prevent Shaft Breakage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The shaft portion of interdental cleaning tools is prone to damage during the ejection from the mold due to excessive loads applied when the base portion is pulled out, particularly when the grip portion is gripped.
Innovation Solution
The manufacturing method involves using molds with acute angles between spaced-apart portions and connection portions to reduce the force applied to the shaft portion during ejection, forming an inwardly convex shape at the boundary of the shaft's circumferential surface to prevent breakage and suppress relative rotation between the cleaning and shaft portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the base portion is ejected from the mold by pulling the grip portion, then the base portion can be removed from the mold, but excessive load is applied to the shaft portion causing it to break
Solution Approach 1:
The patent changes the geometric parameters of the mold, specifically setting the separation plane to encompass the shaft portion axis and designing spaced-apart portions with acute angles. This parameter modification allows the ejection force to be distributed more favorably, reducing the load concentration on the shaft portion while maintaining effective ejection of the base portion.
Solution Approach 2:
The mold is segmented into spaced-apart portions that are separated by the separation plane encompassing the shaft axis. This segmentation allows independent movement and force application on different parts of the base portion during ejection, enabling the grip portion to be pulled while the shaft portion is supported by the mold structure, thereby preventing breakage.
2Reliability
If the separation plane encompasses the shaft portion axis, then the mold can be separated without damaging the shaft, but the ejection process becomes more complex
Solution Approach 1:
The separation plane is positioned asymmetrically to encompass the shaft portion axis rather than being centered or offset. This asymmetric arrangement allows the shaft to be supported during ejection while the base portion is removed. The spaced-apart portions are also designed with asymmetric acute angles relative to the separation plane, creating a favorable stress distribution that protects the shaft without requiring complex additional mold components.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In order to prevent shaft portion from being broken in ejection of base portion from mold, method for manufacturing interdental cleaning tool includes: base portion forming step of forming base portion by filling first space of primary mold (50) with synthetic resin, which includes first and second mold members (50A, 50B); and cleaning portion forming step of forming cleaning portion around shaft portion by filling second space of secondary mold with elastomer. Base portion forming step uses first and second mold members (50A, 50B). First and second molds include: first and second contact surfaces (51A, 51B); pair of first and second spaced-apart portions (54A, 54B); and first and second connection portions (52A, 52B), angle (θ) between each of first and second spaced-apart portions (54A, 54B) and separation plane being acute.