Fiber Forming Mold Screen Shaping With Nested Punch Stages
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Solution Overview
Problem
Existing methods for forming screens for molded fiber parts often result in damage, wrinkles, and distortion, leading to inferior quality and potential failure points in the molded products due to the deformation process.
Innovation Solution
A multi-stage nested punch unit is used to deform the screen progressively, with each stage maintaining pressure on previously deformed portions to prevent stretching and ensure accurate shaping, utilizing a series of punches and springs to control the deformation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a screen is deformed using conventional single-stage pressing methods, then the deformation process is simple and quick, but the screen develops wrinkles, distortion, and damage leading to inferior quality
Solution Approach 1:
The deformation process is divided into multiple sequential stages using a nested punch unit with inner, intermediate, and outer punches. Each punch stage deforms a specific portion of the screen progressively, preventing wrinkles and distortion that occur with single-stage pressing. The inner punch deforms the central portion first, followed by intermediate punches, and finally the outer punch deforms the peripheral portions.
Solution Approach 2:
The nested punch unit employs a hierarchical structure where the inner punch is positioned within the intermediate punch, which is in turn positioned within the outer punch. This nested configuration allows multiple deformation actions to occur in sequence from the center outward, enabling precise control over the screen deformation process while maintaining a compact tool structure.
2Manufacturing precision
If pressure is applied uniformly across the screen during deformation, then the process is simple, but the screen material stretches and distorts reducing integrity
Solution Approach 1:
Different portions of the screen receive different pressure levels at different times during the deformation process. The inner punch applies pressure to the central portion first, followed by intermediate punches applying pressure to middle sections, and finally the outer punch applies pressure to peripheral sections. This localized, sequential pressure application prevents uniform stretching and maintains screen integrity.
Solution Approach 2:
The deformation process begins with the inner punch deforming the central portion of the screen before outer portions are deformed. This preliminary deformation of the inner area creates a controlled progression that prevents sudden stretching and distortion when outer portions are subsequently deformed, maintaining overall screen integrity.
Data Source
AI summary
A method of forming a forming mold screen including providing a die plate defining a plate contour and a die center point. A screen is disposed on the die plate. A retainer plate secured to the die plate defines an opening having a retainer center point substantially aligned with the die center point. The screen is disposed between the die plate and the retainer plate and substantially defines a plane. A nested punch unit inserted into the opening includes an inner punch and an outer punch disposed around the inner punch. The inner punch and the outer punch are aligned along an axis substantially aligned with the retainer center point. The screen pressed with the nested punch unit includes pressing the screen with the inner punch followed by pressing the screen with the outer punch.