In yarn dyeing process; yarns are batched like the batching section of knit dyeing. The activities of yarn dyeing and knit dyeing batching section are almost similar but the process is different. Here grey yarns are the raw materials for yarn dyeing which is supplied from the soft winding section.
Batching is the second important section after soft winding and before bleaching as well as dyeing process. It is the process to make a batch for dyeing. During batch preparation some points are considered. If some fault occurs during batch preparation then it affects the shade of the yarn package.
Steps in Batching: In batching section; spring tubes are pressed by the pressing machine. This is a steps work, in batching section bathing is done as the following:
Soft package from soft winding section
Enter the package into the spindle of the carrier
Pressing by press machine/manually
Prepared for dyeing
Pressing Machine: Pressing machine is used for pressed the spring tube which contains yarn for dyeing. By this machine, cap is fitted on the top of each spindle. During pressing, yarn package density keeps in controlled. Otherwise imbalanced density occur shade problems in dyeing process.
Machine Description: Different types of pressing machines are used for yarn package pressing. One of the most used pressing machine is FONG’S which is manufactured by FONG’S NATIONAL ENGINEERING (SHENZEN) CO. LTD. Its origin country is China.
Parts of Pressing Machine: Followings are the parts of a pressing machine:
- Punching head
- Tray(box)/Carrier head
- Cap plate tray
- Operator carrier
Advantages of Pressing machine: Pressing machine gives the following facilities over manual pressing:
- It gives uniform pressure on the entire package.
- Low pressure variation.
- Cap is fitted by the machine.
Disadvantages: Although pressing machine has some limitation. Followings are some disadvantage:
1. Only spring package can be pressed.
2. Need more times than manual pressing.
Points need to consider during batching: Various points are considered during batching and pressing. They are as follow:
- Every package in batch carrier should have uniform softness or hardness.
- Batch operator should be aware about lot mixing and count mixing package.
- Operator should feed minimum package and should not feed over range package in a carrier.
- Tube should be neat and clean. If any tube loss its original shape then it should replace by original one. Uneven shade is occurred for tube fault.
- During tube setting big tube part should feed first then small tube part, because it facilities easy remove of package.
- Pressing should be less than 20%.
So, during batching we have to consider the yarn count, yarn lot number and pressing parameters for better dyeing performance.