Biaxially Drawn Resin Bottle Handle Pinhole Detection
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Solution Overview
Problem
The existing process for biaxial drawing and blow molding of synthetic resin bottles with handles fitted using an insert molding process faces challenges in detecting pinholes near the stoppers, as the resin may break or become thin, leading to undetected pinholes due to the resin being broken or molten in these areas.
Innovation Solution
A synthetic resin bottle with a recessed portion and a handle fitted in an undercut engagement, featuring a ridge or groove that extends rearward from the stopper base, creating spaces for air release, allowing pinholes to be detected reliably through pressurized air inspection, even if they develop near the stoppers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the handle is fitted firmly in the undercut engagement using stoppers in the insert molding process, then the fitting strength is improved, but the resin may be broken or become thin in the vicinities of the stoppers, leading to pinhole development that cannot be detected
Solution Approach 1:
The inspection area is segmented into two parts: the sealed inspection area (excluding the vicinity of stoppers) and the non-sealed area (including the vicinity of stoppers). The ridge structure creates a physical boundary that separates these areas, allowing the inspection to focus on the sealed portion while the non-sealed portion naturally vents to atmosphere.
Solution Approach 2:
The ridge structure acts as an intermediary element between the stopper and the bottle wall. It provides a controlled interface that allows the resin to flow around the stopper while maintaining a defined boundary for pressure application during inspection, preventing resin breakage near the stopper.
2Measurement precision
If pressurized air inspection is performed under neck-sealed condition, then the inspection precision is improved, but pinholes near the stoppers cannot be detected because the resin becomes molten and contacts the stopper surface
Solution Approach 1:
The bottle surface is divided into a sealed inspection area and a non-sealed area. The sealed area excludes the vicinity of stoppers where resin may become molten, allowing pressure to be applied only to areas where pinholes can be reliably detected. The non-sealed area naturally vents to atmosphere and is excluded from pressure application.
Solution Approach 2:
Instead of trying to inspect the entire surface including areas near stoppers, the invention inverts the approach by deliberately excluding the problematic areas (vicinity of stoppers) from the sealed inspection zone. This allows reliable inspection of the remaining sealed area while accepting that areas near stoppers cannot be inspected under pressure.
3Ease of manufacture
If the resin is drawn and becomes thin in the vicinities of the stoppers, then the insert molding process can be completed, but pinholes may develop and remain undetected
Solution Approach 1:
The inspection process is segmented to apply pressure only to the sealed area that excludes the vicinity of stoppers. This allows the manufacturing process to proceed normally with the handle fitted using stoppers, while the inspection focuses only on areas where the resin thickness is sufficient and pinholes can be reliably detected.
Solution Approach 2:
Different areas of the bottle surface are assigned different inspection qualities: the sealed area (excluding stopper vicinity) is subjected to pressurized air inspection, while the non-sealed area (including stopper vicinity) is excluded from pressure application. This local differentiation allows inspection where reliable while accepting limitations where resin becomes too thin.
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 ensures reliable detection of pinholes by forming connecting passages along the ridge or groove, maintaining a sealed neck and allowing air release, thus enhancing the inspection precision and preventing rattling during blow molding.
Implementation Method 1
a connecting passage or passages for air release is/are formed along the ridge or through the groove, by utilizing a space or spaces formed between a body wall and the ridge or groove
Implementation Method 2
allowing pinholes to be detected reliably through pressurized air inspection
Data Source
AI summary
Pinhole detection is achieved when pinholes happen to develop near stoppers used to fit a handle. A biaxially drawn synthetic resin bottle has a recessed portion, and a synthetic resin handle, fitted in an undercut engagement to the recessed portion by insert molding. The handle comprises upper and lower fitting arms disposed at a grip in a vertically long plate shape. Both arms extend forward from the grip. A stopper extends upward from a front end of the upper fitting arm, and a stopper extends upward and/or downward from a front end of the lower fitting arm. A ridge or groove is formed extending rearward of a stopper of either arm, along a top surface of the upper fitting arm or along a top surface and/or an underside surface of the lower fitting arm. A connecting passage for air release is formed along the ridge/groove.