Shamima Akter Smriti, Senior Lecturer, Department of Textile Engineering, Daffodil International University and Professor Dr. It is submitted only in partial satisfaction of the requirement of Bachelor of Science in Textile Engineering degree of Daffodil International University and we also remain responsible for inadequacies and errors. Shamima Akter Smriti, Senior Lecturer, Department of Textile Engineering, Daffodil International University for her productive guidance, criticism, constant inspiration and providing all necessary support for the completion of this thesis.
Mahbubul Haque, Head, Department of Textile Engineering, Daffodil International University, for giving us the opportunity to carry out this report. Subject: Submission of the thesis on 'Investigation on break time in various circular weft knitting machines'. With due respect, we as students at Daffodil International University have prepared our thesis on 'Study on stop time in different circular weft knitting machines'.
We have done our best to follow your procedures in all parts of planning this thesis. So this thesis will help to understand the stopping time of classy knitted products.
Objectives of this thesis
Literature review
Theoretical Background
Fabric
- Weaving
- Knitting
Course per inch: The number of course in one inch is called course per inch CPI. Walis per inch: The amount of walis in one inch in the fabric is called walis per inch WPI.
Classification of knitted fabrics
Classification of knitting machine
- Weft knitting machine
In weft knit structure, the loops of horizontal directions can be made using one thread and they run in the same horizontal directions. These are the types of knitting machines, but we mostly use Circular knitting machine in weft knitting, which are mainly two types.
Single jersey Circular knitting machine
- Needle
- Types of knitting needle
- Sinker
- Cam
Due to its effectiveness as a self-shaping needle, it has individual movement and control over stitch length. Made of a thin sheet of metal with a separate action, operating at approximately right angles to the hook of the needle bed, between the following needles. It helps hold the yarn even when there is no loop shape.
It is the devices which transfer the rotary motion drive into a suitable reciprocating motion for needles, sinkers and other elements. It is angular and acts directly on the tip of the needle or sinker or other elements.
Some important elements of circular knitting machine
- Machine parts
VDQ pulley: It is used to control and maintain the stitch length followed by the G.S.M of the fabric. Take-off roller: After the knitting is completed, this roller is used to take off and wrap into a steel roll. Positive Feeder: Positive feed device is used to remove slip of yarn during yarn feeding.
On most of the circular knitting machinery, the dial and cylinder rotate where cams, yarn feeder and guides remain inactive. In the case of a double jersey circular knitting machine, the link needle holds its motion for looping through its butt which eventually covers in a cam track. All through the rotation of the dial and the cylinder of the cylinder needle is transferred vertically and the dial is horizontal.
The circular double knitting machine can produce the tops of socks, sleeves, cuffs, ribbing of clothes. All parts are similar to the circular knitting machine except that in double knitting there is no sink to support the knitting.
Knitting action of double jersey circular knitting machine
Some important term and definitions
Efficiency
- Time efficiency
In addition to the above reasons, there are some other reasons that stop the machine, such as converter failure, improper lubrication, etc.
Machine
Total number of machines used to collect data for this work. Here in this work, 16 machines are monitored to collect the data. Their specifications are given below, Table 4.1: Knitting machine specification.
Stop watch
The data collected from the machines is given below, Table 4.2: Specification of machine no.1. Reasons with time Total Strike time Time period Thread break Cone change Needle brake Cleaning Roll change Tension loose Other Worker idle time. Total downtime for cone change = 7.75 min Total downtime for needle break = 0 min Total downtime for cleaning = 3.75 min Total downtime for roll change = 3.47 min Total downtime for tension release = 0.62 min. Total downtime for worker idle time = 3.37 min Now,.
M/C No Thread Break Cone Change Cleaning Spindle Change Loose Tension Needle Break Workshop Spindle Timing Others Inverter Failure Lycra Break L Pack Change Cone Drop.
Results and discussions
From graph 3 it was observed that in double Lacoste machine time loss percentage in 14,15 and 16 no. Time period Reasons for the time Total Stop time Yarn break Cone change Needle brake Cleaning Roll change Tension loose Other Workers idle time. Time Period Reasons for Time Total Stop Time Yarn Break Cone Change Cone Drop Cleaning Roll Change Tension Loose Other Workers Idle Time.
Reasons for Time Total Stop Time Time Period Yarn Break Cone Change Needle Brake Cleaning Roll Change Lycra Break L Package Change Worker's Idle Time. Time Period Reasons for Time Total Stop Time Yarn Break Cone Change Inverter Error Cleaning Roll Change Tension Loose Other Worker Idle Time.
Yarn break Cone change Cone drop Cleaning Change roll Tension loose Other Idle worker. Yarn breakage Cone change Needle brake Cleaning Roll change Tension loose Other Worker idle time. Time Period Yarn Break Cone Change Needle Brake Cleaning Roll Change Lycra Interruption L Package Change Worker Idle Time.
