Tricot Warp Knitting Machine.

Experiment Name: - Study on the Tricot warp knitting machine. 

Introduction:

The warp knitting machine is a knitting m/c where the loops are formed in course wise direction and the fabric produced is in open width form. In Tricot warp knitting m/c compound needles are used. The warp yarns are feed to the needles through guide bars using shogging and swinging motion.

Objectives:

      To identify with tricot Warp knitting machine.

      To know the machine specification.

      To learn the feature of this machine.

      To know the different parts of this machine.

      To know the machine mechanism.

      To learn the knitting actions of this machine.

M/C specification:

Brand: LIBA

Origin: W. Germany

Manufacturing Company: MASCHINEN FABRIK, NAILA.

Manufacturing Year: 1991

Width: 84 inch/ 213 cm

Type: COP 2K

Gauge: 28

Features of tricot machine:

1)    Tricot machines have a gauge expressed in needle per inch.

2)    Chain link numbering 0, 1, 2, 3, 4 …………etc.

3)    Generally with three links per course.

4)    Their sinker are joined to each other at the front and back, never move clear of the needles as they combine the functions of holding down, knocking over, and supporting the fabric loops.

5)    The fabric is drawn-away towards the batching roller almost at right angles to the needle bar.

6)    The warp beams are accommodated in an inclined arc toward the back of the machine, with the top beam supplying the front guide bar and the bottom beam supplying the back guide bar.

7)    The warp sheets pass over the top of the guide rocker shaft to their tension rails situated at the front of the machine.

8)    The machines have a simple construction and a short yarn path from the beams.

9)    Mechanical attention to the knitting elements is carried out at the front of the machine as the warp beams prevent access to the back.

10) The entire warp sheets are drawn over the rocker shaft to the front of the machine it is easier to thread up the guide bars connecting with the back bar; otherwise the front warp will obscure this operation.

11) The guide bars are therefore numbered from the back towards the front of the machine because of this threading sequence.

12) The conventional tricot beam arrangement generally restricts the maximum number of beam and guide bars to four, but this is not of major importance as the majority of tricot machines employ only two guide bars.

13) The small angle of fabric take away and the type of knitting action produce a gentle and low tension on the structure being knitted.

14) This is ideal for high speed production.

15) It is a simple, fine gauge (28-44), close knitted, p[lain and patterned structures, particularity for lingerie and apparel, specially using two guide bar structures with both bar over lapping and under lapping.

16) In the past, the two guide bar tricot or lock knit machine proved most particular in E28 and E32 gauge, with knitting widths of 84 and 168 inches (213 and 426 cm) using 40 denier nylon.

17) It is possible to knit from 10 denier nylon up to 1/20’s cotton count. Machine gauges can range from E10 for coarse staple fiber yarn to E20-E24 for textured yarn fabrics and E36-E44 gauge for fine fabrics, in knitting widths up to 260 inches (660 cm).

18) The needles, like the sinkers and guides, may be cast in leads or they may be individually cranked to fit into the needle bar.

Fig: Tricot warp knitting machine.

Knitting Action:

1. The rest position: The needles have risen to 2/3 of their full height from knock-over and have their hooks towards the back of the m/c. The latch bar is in downward position and the guides are at the front of the m/c with the sinkers forward, holding the old overlaps in their throats so that they are maintained in the correct height on the needle stems.

2. Needle rise and guide bar swing: With the sinkers forward holding down the fabric, the hooks and tongues rise, with the hook rising faster, until the head of the latter is level with the guide holes and is open. The guides then swing through to the back of the m/c.

3. The overlap and return swing: The guide’s shog for the overlap and swing to the front of the m/c immediately. The hooks and the tongues start to descend with the tongues descending more slowly, thus closing the hook.

4. Hook closing: The hooks and the tongues start to descend with the tongues descending more slowly, thus closing the hook

5. Landing: The sinkers start to withdraw as the needles descend so that the old loop is landed onto the closed hook. Thus the landing is occurred.

6. Knock-over and under lap: The sinkers start to withdraw as the needles descend so that the old loop is landed onto the closed hook and then knocked over as it descends below the sinker belly. At this point the under lap occurs before the needles begin their upward rise and sinker move forward to hold down the fabric.

7. Go to rest position: The sinkers now move forward to hold down the fabric loops and push them away from the ascending needles, which are rising to the rest position.

Conclusion:

The knitting action of the Tricot warp knitting m/c is done by the needles, its sliding latches and the guide bars. The main work of feeding the thread around the needle is done by guides with their shogging and swinging motions. By this experiment we learned about the knitting action of a tricot warp knitting machine. This experience will help us in our future career.