Last updated on August 25th, 2023 at 11:04 pm
Dyeing is the most technical part of the Textile Industries. Because you need to match the pre-production sample and production samples shade with buyers approved sample shade and it’s not an easy job. In some cases shade doesn’t match and you need to re-dye the whole batch and in some cases, the following dyeing faults occur:
- Due to improper pretreatment.
- Very rapid addition of dyes and chemicals.
- Lack of controlling dyeing parameters.
- Check addition of dyes and chemicals are at a steadily increasing rate.
- Proper pretreatments.
- Check the rope turnover time.
- Proper washing after dyeing.
- Machine loading is higher.
- Running at lower nozzle pressure.
- High bath draining temperature.
- Proper cycle time should be ensured.
- Nozzle pressure should be accurate.
- The bath draining temperature should be moderate.
- Excessive loading of fabric during dyeing.
- Sudden change in temperature during cooling.
- Due to lack of synchronization of winch speed and pump pressure.
- Follow the temperature gradation during the whole cycle of dyeing.
- Fabric must be loaded according to loop length.
- Maintaining the proper synchronization between the winch speed and pump pressure.
- Due to the presence of traces of Fe+ and Cu+ ions in the process bath.
- If soda dosing is done at a high temperature then in presence of an oxygen pinhole is created.
- Inadequate amount of stabilizer H2O2 bleaching.
- The water used in dyeing should be free from water hardness.
- Soda dosing should be done at a low temperature (not more than 600C)
- Improper mixing and dissolving of dyestuff.
- Dye bath hardness.
- Mixing and dosing of dyestuffs should be done properly.
- The water of the dye bath should hardness free.
- If soaping start before wash
- CaCO3 or MgCO3 in soaping bath
- Quick soda dosing
- Soda particles should be dissolved properly.
- After pre-treatment and dyeing, proper neutralization should be done.
Fly Dye Stains
- If dye is mixed in the dyeing floor then flying dust particles may come in contact with the dissolved dyestuffs.
- If the dyeing floor is too dirty.
- Dyes should be dissolved in a separate drum and in a separate room.
- The dyeing floor must be neat and clean.
Trims Shade does not match with the body
- Different types of yarns are used in fabric and trims.
- The dye lot is different for trims and bodies.
- Improper recipe setting for trims and fabric.
- The same type of yarn, dye lot, recipe, nozzle pressure, uniform distribution to each nozzle etc. should be used for both fabric and trims.
- If pH is not maintained
- Poor emulsification of softener applied
- Inferior quality of softener
- Ensure that the softener is uniformly dissolved in the water
- Use the right softener and the correct procedure for the application.
- Maintain the correct pH.
- High yarn tension
- Count variation
- Mixing of the yarn lots
- Ensure uniform yarn tension to all the feeders.
- Ensure that the yarn being used for knitting is from the same lot.
- This is because dye class is not the same for all ropes in a batch or when collar/cuff is dyed using dyes from one lot and body fabric is dyed using dyes from different lots.
- To overcome this, one has to choose the same dye class which will give the same shade at least under a primary and secondary light source.
Hand Feel Problem
- Use of harsh metal chemicals for processing.
- Insufficient softeners application in dyeing machine.
- It can be easily reduced by demineralization and can be improved by the addition of a softener.
You may also like: Working Flowchart of Knit Dyeing
Common dyeing problems and remedies video: