Composite Can Lid Joining with Inductive Heating
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Solution Overview
Problem
The existing methods for manufacturing can lids, particularly those composed of composite materials like aluminum or tin plate and plastic, are complex and costly, lacking an efficient and simple process for joining these materials while ensuring a strong and reliable connection.
Innovation Solution
The method involves using inductive heating to melt the plastic part, creating a material continuity with the sheet metal part, and applying a bonding agent of the same plastic to enhance adhesion, with a press and hollow conductor apparatus for efficient heating and joining, allowing for a single-step process that saves energy and simplifies the manufacturing of reclosable can lids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If existing methods are used to join plastic and sheet metal parts, then a join connection is achieved, but the manufacturing process is complex and costly
Solution Approach 1:
The patent combines multiple joining operations into a single integrated process step where the plastic part is heated and molded directly onto the sheet metal part in one operation, eliminating the need for separate heating, bonding, and cooling steps that characterize existing methods
Solution Approach 2:
The patent replaces complex mechanical joining systems with a simplified thermal-molding process where heat and pressure are applied through a mold to directly form the plastic part onto the sheet metal part, eliminating the need for complex clamping and bonding mechanisms
2Use of energy by moving object
If existing joining methods are used, then plastic and metal parts are connected, but energy consumption is high
Solution Approach 1:
The patent applies heat locally only to the specific region of the plastic part that contacts the sheet metal part, rather than heating the entire plastic component or using prolonged heating cycles, thereby minimizing energy consumption while achieving sufficient melting and bonding
Solution Approach 2:
The plastic part is pre-heated to a temperature close to its melting point before contact with the sheet metal part, reducing the additional energy required during the actual joining process and allowing for faster, more energy-efficient bonding
3Manufacturing precision
If plastic part is directly heated, then melting and joining occurs, but the plastic part may deform excessively
Solution Approach 1:
The sheet metal part serves as an intermediary heat transfer medium between the heat source and the plastic part, distributing heat evenly across the contact surface and preventing localized overheating and deformation of the plastic part
Solution Approach 2:
The patent employs dynamic control of heating parameters and pressing force during the joining process, adjusting the intensity and duration of heat application based on the plastic part's melting characteristics to achieve complete bonding while maintaining dimensional accuracy
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
This approach results in a strong, energy-efficient, and cost-effective join connection for can lids, enabling fast and simple production with reduced energy consumption and improved adhesion, while ensuring a firm bond between the metal and plastic components.
Implementation Method 1
inductive heating has the advantage here that only the sheet metal part is directly heated since eddy currents can be generated only in the sheet melt part due to the induction
Implementation Method 2
eddy currents can be generated only in the sheet melt part due to the induction
Implementation Method 3
only the sheet metal part is directly heated since eddy currents can be generated only in the sheet melt part due to the induction
Implementation Method 4
the plastic part is indirectly heated by the metal part, whereby the side of the plastic part contacting the sheet metal part is in particular partly melted
Implementation Method 5
The plastic part is partly melted by the inductive heating and is thereby connected to the sheet metal part with material continuity
Data Source
AI summary
A method of manufacturing a can lid composed of a composite material comprising at least one sheet metal part, in particular an aluminum part or a tin plate part, and at least one plastic part, in particular composed of polypropylene or polyethylene terephthalate, wherein the plastic material and the sheet metal part are joined together by pressing together and by inductive heating to effect a stable connection with an effort and a manufacturing time that are as small as possible.