Selective Thermoforming Grid and Profile Plate Heat Management
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Solution Overview
Problem
Existing selective thermoforming processes face challenges in maintaining uniform heating of polymeric materials due to premature heat loss from the mold surface, which can distort unformed areas with printed or artistic content, and require improvements in mold interaction and energy distribution.
Innovation Solution
A grid support system with springs and alignment pins keeps the polymeric material separated from the mold initially, using profile plates with cut-outs or through-holes to apply heat uniformly, and a non-stick coating to prevent heat transfer and printing distortion, allowing for controlled thermoforming without premature contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the polymeric material is placed in contact with the mold surface for thermoforming, then the forming process can proceed, but the mold surface acts as a heat sink drawing heat from the material and causing non-uniform heating
Solution Approach 1:
A Teflon-coated mesh screen is introduced as an intermediary layer between the polymeric material and the mold surface. This mesh allows heat to pass through to the material while preventing direct contact between the material and the cool mold surface, thereby eliminating the heat sink effect and achieving uniform heating across the entire material surface.
2Manufacturing precision
If the polymeric material is heated uniformly across the entire surface, then forming can occur, but printed or artistic content on unformed areas becomes distorted
Solution Approach 1:
The heating process is segmented into two distinct phases: first, uniform heating of the entire polymeric material surface through the mesh screen to prepare it for forming; second, selective heating of only those areas that require forming while leaving areas with printed content at lower temperatures. This segmentation allows precise control over which regions are heated and formed, preserving the integrity of printed content.
3Device complexity
If the mold surface is used directly for heating, then the process is simple, but the heat sink effect disrupts process consistency
Solution Approach 1:
The Teflon-coated mesh screen serves as a simple yet effective intermediary component that resolves the heat sink problem without significantly complicating the apparatus. The mesh is easily installed over the mold surface and maintains consistent thermal behavior throughout the forming process, thereby improving reliability while adding minimal complexity.
4Temperature
If profile plates with through-holes are used for heat application, then heat can reach the material, but printing transfer may occur between the plate and material
Solution Approach 1:
The invention employs disposable or easily replaceable profile plates with Teflon coating. The Teflon coating prevents printing transfer by creating a non-stick barrier between the plate and the polymeric material. If the coating becomes compromised or printing transfer occurs, the profile plate can be replaced with a new one, maintaining process quality without requiring complex repair or refurbishment procedures.
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 solution enhances the uniform heating and forming process, maintaining the integrity of printed or artistic content and improving the presentation of thermoformed products by preventing heat sink effects and reducing the risk of printing transfer.
Implementation Method 1
The grid may be supported by springs or other biasing mechanisms and accepted by a receiver groove or recesses in the mold. When compressed by vacuum pressure and the force of the clamps, the grid may retract flush into the mold.
Implementation Method 2
Energy sinks such as profile plates with cut-outs similar to the heat sinks of the Shanley, IV application also may be employed in connection with the present invention. Heat may then be applied to the upper side of the profile plate (i.e. the side away from the sheet), passing through the cut-outs to heat selected areas of the sheet.
Implementation Method 3
When compressed by vacuum pressure and the force of the clamps, the grid may retract flush into the mold.
Data Source
AI summary
Thermoforming apparatus and methods are described. To-be-formed polymeric material may be separated initially from a mold surface by a grid or support rail, avoiding the mold surface from drawing heat away from the material while it is being heated to forming temperatures. The grid may retract into the mold when no longer needed to support the material. Plugs or inserts about which material is formed may include skirts, allowing the formed material to be shaped so as to guide coins or other objects into cavities in which the coins or objects are held for presentation or display. Profile plates associated with the molds may include non-stick material on their sides intended to abut to-be-formed polymeric sheets in order to reduce possibility of transfer of printing from the sheets to the plates and reduce undesired transfer of heat from the plates to the sheets.