Full-Form Flat-Knitted Helmet Preforms for Low-Waste Production
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Solution Overview
Problem
The production process of textile composite helmet preforms suffers from low production efficiency, high processing cost, material waste, and poor dimensional stability due to manual cutting and layering, leading to residual stresses and uneven distribution of impact resistance.
Innovation Solution
A method involving longitudinal and transverse knitting with reinforced yarns on a flat knitting machine to create a full-form flat-knitted helmet shell preform, eliminating cutting and splicing, and using a vacuum-assisted resin injection to form a helmet shell with improved dimensional stability and impact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If manual cutting and laying is used to prepare helmet shell preforms, then the production process is simple, but the production efficiency is low and processing cost is high
Solution Approach 1:
The patent applies preliminary action by knitting the helmet shell preform in its final three-dimensional shape directly during the knitting process, rather than cutting and assembling flat pieces afterward. The computer-controlled knitting machine pre-forms the shell with integrated reinforcement layers, eliminating subsequent cutting and laying operations, thus significantly improving production efficiency while reducing processing complexity
Solution Approach 2:
The patent merges multiple operations into a single knitting process. The reinforcement layers and shell structure are combined into one integrated knitted preform, eliminating the need for separate cutting and assembly steps. This consolidation of operations directly addresses the contradiction by improving productivity without adding processing complexity
2Manufacturing precision
If flat fabric is cut and laid and then extruded into helmet shell shape, then the shell can be formed, but the fibers and yarns are stretched and squeezed causing large residual stress and poor dimensional stability
Solution Approach 1:
The patent applies preliminary action by forming the shell in its final shape during the knitting process itself, rather than extruding it afterward. The three-dimensional structure is created as the fabric is knitted, preventing subsequent stretching and squeezing that would generate residual stresses, thus improving dimensional stability
Solution Approach 2:
The patent changes the fundamental parameter of how the shell is formed - from post-knitting extrusion to in-process three-dimensional knitting. This parameter change eliminates the mechanical deformation that causes residual stress, directly resolving the contradiction between manufacturing precision and stress levels
3Loss of substance
If cutting method is used on expensive high-performance fibers, then the preform can be shaped, but valuable materials are wasted which is not environmentally friendly
Solution Approach 1:
The patent applies preliminary action by shaping the preform during the knitting process itself, rather than cutting it afterward. The computer-controlled knitting machine creates the exact three-dimensional shape needed, eliminating material waste from cutting operations while maintaining full shaping capability
Solution Approach 2:
The patent replaces the mechanical cutting system with a computer-controlled knitting system that shapes the preform during fabrication. This substitution eliminates material waste while maintaining shaping capability, directly resolving the contradiction between reducing substance loss and preserving ease of manufacture
4Productivity
If traditional knitting is used, then the production process is simple, but it cannot produce full-form helmet shells without cutting and splicing
Solution Approach 1:
The patent applies dynamics by using a computer-controlled knitting machine that can dynamically adjust knitting parameters, needle selection, and yarn feeding during the knitting process. This dynamic control enables the machine to knit complex three-dimensional helmet shell shapes without cutting and splicing, improving productivity while managing complexity through automation
Solution Approach 2:
The patent changes the knitting process parameters from traditional fixed patterns to computer-controlled variable patterns. This allows the knitting machine to produce full-form helmet shells with complex geometries in a single continuous process, significantly improving production efficiency while the automation manages the increased process complexity
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
Enhances production efficiency, reduces material waste, and improves dimensional stability and impact resistance by eliminating residual stresses and uneven distribution, resulting in a more robust and efficient helmet shell production process.
Implementation Method 1
The invention belongs to the technical field of helmet materials, and particularly relates to a full-form flat-knitted helmet shell preform, a preparation method and a helmet shell thereof
Implementation Method 2
using a vacuum-assisted resin injection to form a helmet shell
Data Source
AI summary
Disclosed are s full-form flat-knitted helmet shell preform, the preparation method, and the helmet shell, which belong to the field of helmet material technology. Two different knitting directions of the helmet shell preforms are prepared by means of longitudinal knitting and transverse knitting combined with partial knitting respectively; Meanwhile, reinforced yarn is added during the knitting process of the preforms to obtain the transversely and longitudinally knitted helmet shell preforms with reinforced yarn. The fabric structure of the preforms disclosed in this invention is a flat-knitted three-dimensional fabric with reinforced yarns, which solves the problem of low tensile strength and high elongation of flat-knitted fabrics, and solves the poor impact resistance caused by poor bonding strength between layers of helmet shells to some extent. Moreover, the method of preparing helmet shells from preforms improves production efficiency, reduces material waste, and solves the problem of poor dimensional stability.