Fluid Cooling Passages Replace Metal Ridges in Plastic Profile Extrusion
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Solution Overview
Problem
Current plastic profile extrusion calibration methods face challenges in efficiently cooling complex profiles, leading to increased drag and reduced output rates due to the reliance on metal ridges for heat transfer, which results in uneven cooling and potential distortion of the plastic parts.
Innovation Solution
The calibration device replaces metal ridges in strategic locations with fluid cooling passages, allowing high-velocity cooling media to efficiently cool the interior sections of complex plastic profiles, thereby controlling the shape and dimensions by selectively cooling the inside of channels faster than the outside surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If metal ridges are used for heat transfer in calibration devices, then the plastic profile can be cooled and frozen to maintain shape, but the cooling efficiency is reduced and drag increases
Solution Approach 1:
The patent replaces metal ridges with fluid cooling passages that allow high-velocity cooling media to flow directly through the calibration device. This hydraulic cooling system efficiently removes heat from the plastic profile, enabling faster cooling rates and higher output rates without the drag problems associated with metal ridge contact.
Solution Approach 2:
The invention substitutes the mechanical heat transfer mechanism (metal ridges in contact with plastic) with a fluid-based thermal exchange system. The cooling media flows through passages to conductively cool the plastic profile, replacing the mechanical contact method with a more efficient thermal exchange process.
2Shape
If metal ridges are used to hold interior channels open, then the shape can be maintained, but uneven cooling and distortion occur
Solution Approach 1:
The patent implements different cooling strategies for different regions of the plastic profile. Fluid cooling passages are strategically positioned to provide targeted cooling to interior channels and other specific areas that require uniform cooling, while allowing different cooling rates in other regions. This local differentiation of cooling quality prevents distortion while maintaining shape.
Solution Approach 2:
By using fluid cooling passages instead of metal ridges, the system achieves uniform cooling throughout the plastic profile including interior channels. The high-velocity cooling media efficiently extracts heat from all regions, preventing the uneven cooling and distortion that occurs with metal ridge-based systems.
3Reliability
If stainless steel is used for calibrator plates, then wear resistance is improved, but heat transfer efficiency is reduced
Solution Approach 1:
The patent replaces the stainless steel plate structure with fluid cooling passages that allow direct thermal exchange between the cooling media and the plastic profile. This eliminates the need for thick stainless steel plates, achieving both wear resistance (by removing the contact surface) and superior heat transfer (through direct fluid-to-plastic cooling).
Solution Approach 2:
The invention substitutes the mechanical stainless steel plate structure with a fluid-based cooling system. This replacement simultaneously solves the conflicting requirements of wear resistance and heat transfer efficiency by eliminating mechanical contact while maximizing thermal exchange through direct fluid cooling.
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 enhances cooling efficiency, reduces drag, and allows for higher linear manufacturing rates by ensuring uniform cooling and maintaining the desired dimensions of complex plastic profiles, overcoming the limitations of traditional metal ridge-based calibration systems.
Implementation Method 1
The calibration device includes a fluid cooling passage formed in the calibration body and having a portion that communicates with the longitudinal cavity, exposing a surface of the unfrozen plastic profile with cooling fluid to freeze the surface of the profile
Implementation Method 2
Contact with the metal of the calibrator conducts heat from the plastic profile into the metal calibrator
Implementation Method 3
The hot, fluid plastic exiting the extrusion die must be captured by some sort of calibration device to hold the soft, unfrozen material in the desired shape as it continuously moves down the extrusion line and is cooled to below the plastic material melt temperature or glass-transition temperature (Tg) and freezes to become solid
Implementation Method 4
The primary function of the calibration tooling is to conductively cool the plastic as it holds the size and shape of the profile
Data Source
AI summary
Plastic profile extrusion system includes an extrusion die that pre-forms a hot, unfrozen plastic profile shape. Cooled calibration device receives the hot plastic in a longitudinal cavity through the calibration device to conductively cool the plastic as it holds the plastic profile to size and dimensions. For plastic parts with channels, inside corners, or other difficult to cool sections, the calibration device would require a metal ridge to hold the shape of that channel or corner as the heat is conducted from the hot plastic through the metal ridge into the body of the calibration device. This invention replaces metal ridges that hold the shape of the plastic profile during cooling in at least part of the calibration device with fluid cooling passages that communicates with the moving portion of the plastic profile and cooling medium to fill the flow passages to extract heat from the plastic material.