Standard Operating Procedures (SOP) For Dyeing Process

Dyeing needs consistency in its process for getting accurate results. So that sop of dyeing or standard operating procedure for dyeing process is so important in the textile industry. Dyeing is a repeating procedure. We need to do the same work several times a day. This is the full dyeing operating process (sop) from knitted gray fabric to finish fabric. The dyeing process sop depends on the type of fabric. That means is it knitted fabric or oven fabric?. This is the sop of the complete knit dyeing process.

SOP Of dyeing process:

The Batch section receives fabric from the grey fabric store.

Prepare the batch according to the dyeing machine capacity, color, lot, etc & provide a batch number for further follow-ups up to finishing.

Batching QC team cross-checks the batching procedure & ensures the batching whether it is done properly or not. They check the quality & quantity of the batch before sending it to the next process.

Batched fabric is sent for singeing for removing the hairiness of the fabric. Heat setting is done at 190-200 °C temperature.

The dyeing section receives the fabric & starts the pretreatment process i.e demineralization, scouring, bleaching for removing the impurities of the fabric at a certain temperature.

The dyeing machine operator operates the machine & completes the process of dying by dosing dyes & chemicals as per instruction. Dyeing online QA concern randomly checks the parameters of dyeing.

Unload the batch after treatment

Complete the whole finishing process with one roll (first roll). If pass follows the parameter for the whole batch. If not ok then reprocess that roll to correction

After dyeing, Finishing Section receives the fabric, fabric is opened by a slitting machine following the needle mark.

Fabric is dried at center/dryer machine to adjust the dia & GSM of the fabric by giving specific pressure, temperature & overfeed at a specific speed. Softener is added for giving the fabric a smooth hand feel.

For fleece fabric, the fabric is sent to the brush & peach finish machine. This process is to be done as per buyer requirements.

For readjustment of dia & GSM after peach, brush process the fabric is sent to stenter machine as per work instruction.

Finally, the fabric is finished in compacting machine by controlling dia & GSM.

Online quality controller checks all types of process parameters & quality of the fabric during the production process.

Offline quality controller inspects finish fabric with 4 point inspection system & check the Dia, GSM of the fabric. GPQ team gives a decision for offline inspected fabric on the basis of lab test report as per work instruction.

QC team arrange physical tests (Shrinkage, Spirality, Bursting, Rubbing, Pilling, etc.) and chemical tests (colorfastness, phenolic yellowing, PH, etc.) through lab & GPQ team assess the QC & Lab report.

Pass fabrics are sent to the finished fabric store with a QC pass sticker. The temporarily rejected fabrics are sent for reprocess & the rejected fabrics are sent to the permanent reject zone.

End

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