Perforated Top Curl for Plastic Container Lip Formation
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Solution Overview
Problem
Existing plastic container manufacturing methods require significant heat and force to form the upper lip, leading to residual heat issues, excess lubricant coating, and uneven cross-sectional shapes due to stiff side seams, resulting in unpredictable and misshapen containers.
Innovation Solution
A plastic container design featuring a perforated line with slits and uncut portions at the top edge, allowing for reduced force and heat usage during lip formation, and a method of manufacturing using a single blank of plastic material where the marginal edge portions are wrapped to form a side seam, creating a double wall thickness that reduces the force required for curling the lip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If significant heat is applied to soften the plastic sidewall material during lip formation, then the amount of force required for curling the lip is reduced, but residual heat remains in the sidewall making it difficult to handle
Solution Approach 1:
The perforated line is formed in the blank before the lip curling operation. This preliminary action creates predetermined weak points that guide the deformation during lip formation, allowing the material to bend more easily without requiring excessive heat softening, thereby reducing residual heat in the finished product
2Ease of manufacture
If a lubricant such as mineral oil is used to lubricate the interface between the sidewall and die during lip curling, then the curling process is facilitated, but excess lubricant remains coated on the sidewall
Solution Approach 1:
The perforated line is created in advance on the blank, providing a predetermined deformation path that reduces friction and resistance during the lip curling operation. This preliminary structuring allows the process to proceed with minimal lubricant application, preventing excess lubricant from coating the sidewall
3Ease of manufacture
If the blank is wrapped to form a side seam with overlapping edges, then the container is formed from a single blank, but a thickened region is created in the lip that is relatively stiff and requires increased force during curling
Solution Approach 1:
The perforated line incorporates localized features at the side seam region, including adjusted slit patterns or spacing specifically at the overlapping edge area. This local modification compensates for the increased thickness and stiffness, ensuring uniform force distribution and consistent lip formation across the entire circumference
4Strength
If significant force is applied to form the lip, then the lip is successfully formed, but the cross-sectional shape of the upper portion becomes unpredictable and misshapen
Solution Approach 1:
The blank is divided into multiple segments by the perforated line with spaced slits, creating a series of connected but flexible sections. This segmentation allows the material to deform in a controlled, progressive manner during lip formation, maintaining uniform cross-sectional shape while still achieving the desired lip structure
Solution Approach 2:
The perforated line pattern is predetermined on the blank before forming, establishing a template for uniform deformation. This preliminary patterning ensures that when force is applied during lip curling, the material responds uniformly throughout, producing consistent cross-sectional geometry
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 enables the formation of a plastic container with a uniform and desired shape, reducing the amount of force, heat, and lubricant needed, while minimizing residual heat and excess lubricant, resulting in a more manageable and uniformly shaped container.
Implementation Method 1
The perforated line includes uncut portions of material between the slits. The slits and uncut portions may be of uniform widths and may each be between about 0.016'' and about 0.25'' wide.
Implementation Method 2
During the formation of the upper lip, a significant amount of heat is typically applied adjacent the lip region in order to soften the plastic sidewall material, thereby reducing the amount of force required for curling the lip.
Implementation Method 3
In cases where the sidewall is constructed of a flat sheet of plastic material that is wrapped to form a cylinder, an overlapping side seam is formed. The overlapping side seam results in a thickened region in the lip that is relatively stiff and requires an increased amount of force during the curling process.
Data Source
AI summary
A plastic container is provided having a sidewall, a downwardly extending upper lip, and a perforated line defined at a top edge of the container where the lip and sidewall are joined. The sidewall and lip may be formed from a container body constructed of a single sheet of material that is wrapped such that marginal edge portions of the blank are brought together in overlapping fashion to form a side seam. When the sidewall and lip are formed from such a blank of material, the perforated line is formed a specified distance below a top edge of such blank. The perforated line reduces the amount of force, heat and lubricant required in order to form (e.g., curl, roll, fold or bend) the upper lip of the container. The slits of the perforated line may extend across a width of the blank in either a uniform or variable fashion.