Knitting Machine Stitch-Length Control for Consistent Garment Sizing
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Solution Overview
Problem
Knitting machines face challenges in producing consistent garment sizes, especially when switching between yarn colors, leading to significant wastage in smaller production runs due to the reliance on trial and error for determining stitch lengths and tensions.
Innovation Solution
A method and system for controllably varying stitch lengths based on pattern density, using a multivariate model to determine stitch lengths and tensions, allowing for precise control of yarn tension on a stitch-by-stitch basis, enabling consistent and predictable fabric dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If trial and error methods are used to calibrate stitch length and tension, then the desired garment dimensions can be achieved, but production time is significantly increased and waste is generated
Solution Approach 1:
The patent applies preliminary action by pre-calculating the optimal stitch length for each stitch based on the pattern design before knitting begins. The system analyzes the pattern data to determine swap locations and calculates appropriate stitch lengths in advance, eliminating the need for trial-and-error calibration during production. This allows the knitting machine to directly produce garments with consistent desired dimensions without time-consuming adjustments.
2Manufacturing precision
If trial and error methods are used to calibrate stitch length and tension, then the desired garment dimensions can be achieved, but material waste increases due to rejected samples
Solution Approach 1:
The system performs preliminary calculation of stitch lengths based on pattern analysis before knitting starts. By determining the optimal stitch length for each stitch in advance based on swap density and pattern requirements, the system ensures that the first garment produced meets dimensional specifications, eliminating waste from rejected trial samples.
3Ease of manufacture
If consistent stitch length is used across all stitches, then the knitting process is simple, but the final garment dimensions vary due to pattern density variations
Solution Approach 1:
The patent applies local quality by varying the stitch length locally based on the specific requirements of each stitch position in the pattern. The system calculates different stitch lengths for different stitches based on pattern density, swap locations, and color changes. This allows regions with high swap density to have shorter stitches while maintaining overall garment dimensional consistency, resolving the contradiction between process simplicity and dimension precision.
4Device complexity
If yarn tension is not controlled, then the knitting machine operates without complex control systems, but the stitch length varies leading to inconsistent garment size
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the stitch length parameter based on pattern analysis. The system calculates optimal stitch lengths considering yarn tension, pattern density, and swap requirements. By varying this critical parameter according to local pattern conditions rather than using a fixed value, the system achieves consistent stitch length and garment dimensions while maintaining reasonable control system complexity.
Data Source
AI summary
Disclosed is a method and apparatus for knitting a fabric using a knitting machine. The knitting machine is arranged to knit with a plurality of yarns using a corresponding plurality of knitting needles, each knitting needle being arranged during knitting of a stitch to connect with and knit with one of the plurality of yarns. The method controllably varies the stitch length for each stitch in dependence on the pattern to be knitted.