Blank Holder Dynamics for Composite Punching and Injection
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Solution Overview
Problem
Existing methods for producing multilayer elements with composite materials face challenges such as imprecise punching, fiber slippage, and increased costs due to the use of multiple tools, which affect the integrity and rigidity of the material.
Innovation Solution
A device and method that utilize a single tool to punch and inject a layer into a composite material sheet, employing a blank holder that maintains the sheet's integrity by blocking fiber slippage and allowing for simultaneous punching and layer injection, with the blank holder retracting during injection to ensure precise molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If two distinct tools are used for punching and injection molding, then the punching precision can be improved, but the production cost and cycle time increase
Solution Approach 1:
The patent combines the punching operation and injection molding operation into a single integrated tool. The tool includes a punch, die, and blank holder that work together to perform both punching and molding in one cycle, eliminating the need for two separate tools and reducing production time while maintaining precision through the blank holder's fiber-blocking capability
2Manufacturing precision
If the sheet is held during punching in a single tool, then the punching precision is improved, but the sheet may move during injection molding
Solution Approach 1:
The blank holder is designed to be movable between two positions: a low holding position during punching where it clamps the sheet to prevent fiber slippage, and a high molding position during injection where it retracts to allow proper layer formation. This dynamic positioning resolves the contradiction between needing the sheet held for precision punching and needing it free to move for proper injection molding
3Stability of the object's composition
If the blank holder remains in the low holding position during injection, then the sheet stability is maintained, but the injection molding quality deteriorates
Solution Approach 1:
The blank holder transitions from the low holding position to the high molding position during the injection phase. This movement allows the injection mold to properly form the layer around the punched hole without interference from the blank holder, ensuring high injection molding quality while the blank holder had previously maintained sheet stability during punching
4Productivity
If a single tool is used for both punching and injection, then the production cost decreases, but the sheet integrity may be compromised due to fiber slippage
Solution Approach 1:
The blank holder acts as an intermediary element between the punch/die and the sheet during punching. It applies localized pressure to block fiber slippage at the punching zone without interfering with the overall sheet integrity or the subsequent injection molding process, thereby maintaining sheet integrity while enabling efficient single-tool production
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 ensures accurate punching and maintains the integrity of the composite material web, preventing fiber slippage and reducing production costs by using a single tool, while ensuring the sheet remains stable during both punching and injection processes.
Implementation Method 1
the elastic support means comprise a spring positioned in the cavity and configured to exert a force on the blank holder, to cause the blank holder to pass from the high molding position to the low holding position
Implementation Method 2
the elastic support means comprise a hydraulic control member positioned in the cavity and configured to exert a force on the blank holder, so as to move the blank holder between the upper molding position and the position sustain bass
Implementation Method 3
the injection pressure of the layer exerted in the notch can make it possible to retract the blank holder
Data Source
Figure 1~2
Figure 3
Figure 4~6
AI summary
Device (1) for producing a multilayer element comprising at least one layer (7) of composite material and one layer (8) of plastic material and having at least one punching hole through the layer (7) and surrounded by the layer (8).The device (1) comprises (i) a die (3) having at least one opening (31) and (ii) an upper frame (11), the upper frame (11) having at least one blank holder (4) movable between a low holding position and a high molding position, intended to come opposite the opening (31), and (iii) at least one punch (2) movable between a retracted position and a deployed position in which the punch (2) is configured to slide in the opening and punch the sheet (7) interposed between the die (3) and the blank holder (4), and define a core for the injection of the layer (8), the blank holder (4) being configured to hold the sheet (7) positioned on the die (3), in its low holding position, during punching by the punch (2) and to form a molding impression with the punch (2) delimiting the layer (8), in its high molding position.