CAD/CAM features for knitting
system
Jimmy Lam
Institute of Textiles & Clothing
Learning Objectives
Principle of electronic control in knitting
 Numerical and computer control system
 Modern control elements in knitting machine

Circular Machine

CAD/CAM are mainly used for jacquard single or double jersey knitting on large
diameter circular knitting machines. The content of CAM in piece goods are:

* The memory of the controller
– The very large memory of the machine built in computer can hold up a few different patterns,
which can be called up at any time, or mixing of patterns during knitting. The preparation of
jacquard patterns are normally done on CAD units and the final patterns are stored in the data
carriers for the knitting machine to read.
* Shifting of colours on jacquard fabric.
– Before knitting, colour yarns are placed on the machine in specified orderlike
» feeder no
12345678
» yam colour
AB C DAB C D
– If the same pattern has to be knitted with different combination of colour such as;
» feeder no
1 2 3 4 5 6 7 8 and yarn colour B C DJ A B C D or
» feeder no
1 2 3 4 5 6 7 8 and yam colour C D A B C D A B or
» feeder no
1 2 3 4 5 6 7 8 and yam colour D A B C D A B C

Principle


2. Computer
» The flexibility of making decision, process data (yes or no)
make it ideas for counted loop sequence, branching or
jumping operation.
» ie. Electronically controlled knitting pattern preparation and
needle selection
3. Computer Hardware and software
– Hardware : electronic, magnetic and mechanical device
– Software : programme and documentation for the system

4.
–
–
–

Main Sections of Computer
CPU;
Memory;
Peripheral Interface
5.
Input & output device
– Input: sensors on knitting machine; keyboards, light-pen; tapes
and discs.
– Output : actuators on knitting machine, light; digital and
graphic display; tapes and printer.

6. Memory: ROM and RAM
»
»
Read only memory (ROM), non-voltaile, cannot be erased.
Hold important program and is programmed in
manufacturing.
»
Others: PROM and EPROM

Read and Write Memory (RAM)
–
Is voltaile and data can be erased.
–
Use to store data and programme during processing.
–
Two types: Static RAM and Dynamic RAM

7) Knitting machine program and control
–
Electronic machine eliminates all punch cards, chains, rack wheel, peg
drum, element but which are expensive and bulky.
– Interactive computer graphics enable designer draws pictures and display
on the screen. Colour can be added/changed immediately. Pattern can be
rotated, stretch, mirror and scale.

Designer can freely explore his/her ideas using the
computer tools
Modern V-bed Knitting Machine
Control
Machine Control

The modern V-bed m/cs abandoned the
pasteboard card control because:
 The electronic parts are cheaper to produce than the
mechanical parts;
 Numerical is more accurate and very fast in
response;
 Programs are easy to file or store;
– Easy to duplicate the programs
Two control methods
Numerical and computer control
Numerical Control

They are the simple control for non-jacquard
knitting. It contains a control panel with function
keys and control knobs for data input. The major
advantages is that no pasteboard card and hole
punching is needed.
Computer Control

Computer Control
– The numerical control is only good for simple knit collars, rib
straps and body panels without pattern. Once individual needle
selection is involved, computer control must be used.

Modern electronic V-bed m/c has :
– Central Processing Unit: The brain of m/c control with data like
pattern, machine control, economizer, pattern development.
– Keyboard : This is used for giving command or make
modification.
– Tape/Floppy reader : The pattern and data input device
– Visual Display Unit : A monitor to display all information of the
knitting machine.
Example :Shima Seika

The modern electronic V-bed m/c (says, Shima
Seika), divided the systems into 6 sections, namely
 Control tape;
 Pattern tape;
 Pattern development tape;
 Stitch tape;
 Economize tape; and
 Yarn carrier tape
Shima Seika Control System

1
–

2.
–

3.
–
Control tape
Similar to punch card in mechanical machine, it is a one inch
paper tape with 8 row holes. The tape is divided into block, one
block is the same as one punch tape.
Pattern tape
This sector contains all the pattern details. The design is normally
created in a CAD system and is now transferred as a series of holes
in the punch tape. The length of tape will depend on the pattern
size, the longer the design, the longer will be the tape.
Pattern development tape
This is to control the location of the pattern onto the fabric. It can
be mirror the design or repeat the design horizontal/vertically etc.
See Figure
Shima Seika Control System

4.
–

5.
–

6.
–
–
Stitch tape
This is used to control the stitch length (loop length) of the fabric. Modern Vbed m/c could have over 30 different setting in the memory for different material
and structure design.
Economizer tape
The economizer on the mechanical V-bed is to use the minimum number of
pasteboard cards for sweater panel. For the electronic machine with computer
control, the system can memorize all the repeat structure and sort out the
necessary cards or blocks in the design automatically.
Yarn Carrier tape
In cut and sewn panel, the yarn carriers are set at fixed places about 2 to 4 cm
away from fabric selvedge. For fully fashioning panel (or intersia), the knitting
width is changing all the time, the yarn carriers must stop in varies position.
The stopping of yarn carriers is controlled by the computer which is either
changes the location of the carrier stoppers on the rails or commands the cam
carriage to release the working yarn carriers at specific location above the needle
Discussion
Discuss the different between numerical and
computer control system
 List out the five control systems found in Shima
Seika Electronic knitting machine
