Defects & Remedies in Terry Towel Processing

Defective pieces: Defective pieces are those pieces, which contain above defects and are separated for alteration during checking.

Measurement of defect

Quantitative measure of defect there are two measuring units as below.

a) Defect per hundred units

b) Percent defectives

List of defects (Table 1)

Table 1:

Classification of defect

A. Man related defect

B. Machine related defect

C. Material related defect

A. Man related defect: The man related defects mean due to improper handling of materials the defect occurs are like stains, yellow pen marking, colors stains, patchy dyeing, length and cross cut, selvedge cut etc.

B. Machine related defect: The machine related defects are like shearing, bowing, missing end, pile pulling, cracks, half pieces, reverse terry, lining, etc.

C. Material related defect: The material related defect is like contamination, lintting, etc.

Causes of defect and their remedies

Defect in Dyeing department [4].

Stain: Stains are classified in five types.

a) Soil or mud stain

b) Rust and bit stain

c) Oil stain

d) Contamination stain

e) Softener stain

f) Color stain

a) Soil or mud stains

Causes Soil or mud stains:

i. Improper material handling by workers.

ii. Material in contact with dust present part of machine, trolley, etc.

Remedies Soil or mud stains:

i. Care must be taken during material handling by workers.

ii. To avoid material in contact with dusty part of machine, trolley etc.

b) Rust and bit stains (Figure 1)

Figure 1:Defect of rust and bit stains.

Causes rust and bit stains:

i. Unloading of dyed material in without cover trolley (uncover) and transferring it to next process.

ii. This is occurring when material is in contact with rust present roller on rope opener, shearing machine and trolleys.

iii. Bit stain occurs due to sparrows present in the plant (Figure 2A & 2B).

Remedies rust and bit stains:

Figure 2A:Causes of rust and bit stains.

Figure 2B:Causes of rust and bit stains.

i. Loading or unloading the material in full polypropylene sheet covered trolley and then transfer to next process.

ii. Proper cleaning and washing of rope opener and shearing machine and trolleys etc.

Figure 3A:remedies of rust and bit stains.

iii. Material must be properly covered with polythene before transfer to next process (Figure 3A & 3B).

Figure 3B:Causes of rust and bit stains.

c) Oil stain

Causes of oil stain:

i. Oil stains may be occurring from weaving on selvedge of terry towel due to temple and cutter.

ii. Due to use of excessive oil in dyeing section.

iii. Excessive oil use in stitching machine also causes to oil mark on terry towel (Figure 4).

Figure 4:Defect of oil stain.

Remedies of oil stain:

i. Daily checking the part of weaving machine and properly clean the machine.

ii. Material should be handle carefully from oily part of machine, trolley etc.

iii. Material should be handle carefully by workers on stitching machine and machine must be clean properly.

Figure 5:Remedies of oil stain.

iv. Check grey Material coming from weaving before pretreatment (Figure 5).

d) Contamination

Causes of Contamination:

i. This stain occurs due to impurities present in row cotton material and it remains as it is up to yarn stage.

Remedies of Contamination:

i. Use impurity less row material of cotton.

e) Softener spot (Figure 6)

Figure 6:Defects of softener spot.

Causes of softener spot:

i. Improper softener dissolving in the addition tank with water.

ii. Improper dosing and poor emulsification of softener applied.

iii. Foam present on material may causes softener spot.

iv. Inferior quality of softener.

v. If pH is not maintaining.

Remedies of softener spot:

i. Proper or uniformly dissolving of softener in addition tank with water

ii. Proper dosing of softener.

iii. Foam completely removes from fabric.

iv. Use right softener and the correct procedure of application.

v. Maintain pH.

f) Color spot or stain (Figure 7)

Figure 7:Defects of color Spot.

Causes of color spot:

i. Improper machine cleaning (hydro extractor, rope opener)

ii. Improper material handling by workers.

iii. Improper mixing and dissolving of dyestuff.

iv. Dye bath hardness.

Remedies of color spot:

i. Proper machine cleaning.

ii. Proper material handling by worker with hand gloze.

iii. Mixing and dosing of dyestuff should be properly.

iv. Water of dye bath should hardness free (Figure 8A & 8B).

Figure 8A:Remedies of color spot.Defects of color Spot.

Figure 8B:Remedies of color spot.

Dyeing hole defect (Figure 9):

Figure 9:Defect of dyeing hole.

Causes of dyeing hole:

i. Improper scouring and bleaching.

ii. Improper peroxide and caustic dosing.

iii. Due to over bleach.

iv. Improper material handling may causes hole on the fabric.

Remedies of dyeing hole:

i. Enzyme should be done carefully.

ii. Caustic dosing must be slow.

iii. Avoided over bleach of material.

Linttin defect (Figure 10):

Figure 10:Linttin defect.

Causes of Linttin defect:

i. Improper sizing.

ii. Also due to use of low twist yarn in terry weaving

Remedies of Linttin defect:

i. Only minor floats can be rectified.

Defect of bowing (Figure 11):

Figure 11:Defect of bowing.

Causes of bowing defects:

i. Improper speed of dryer Cylinder.

Remedies of bowing defects:

i. Set proper speed for particular GMS of terry towel.

Shearing (Figure 12):

Figure 12:Defect of shearing.

Causes of Shearing:

i. Improper distance between spiral blade of shearing machine and material.

ii. Mechanical problem.

iii. Operator problem.

Remedies of Shearing:

i. Set proper distance between spiral blade and material.

ii. Operator should be trained and must be careful.

Uneven dyeing (Patchy) (Figure 13):

Figure 13:Defect of uneven dyeing (Patchy).

Causes of uneven dyeing (Patchy):

i. Uneven pretreatment (desizing, scouring and bleaching).

ii. Very rapid addition of dyes and chemicals.

iii. Lack of controlling dyeing parameters.

Remedies of uneven dyeing (Patchy):

i. By ensuring pretreatment.

ii. Proper addition of dyes and chemicals.

iii. Controlling all dyeing parameters.

Process control parameters to avoided uneven dyeing: pH, Time, Temperature, Liquor ratio, Water hardness, Chemical dosing time, H2O2 killing.

Factors and benefits (Table 2)

Table 2:

Before trial (Figure 14)

Figure 14:

After trial (Figure 15)

Figure 15:

Percent defects in all departments (Figure 16,17)

Figure 16:Defect of percentage in all departments.

Figure 17:Defect of percentage in all departments.

Percentage of processing defect before trial (25 Days) (Table 3)

Table 3:

Graphical representation

Before trial result of defect in processing department (Figure 18):

Figure 18:

Percentage of processing defect after trial (25 Days) (Table 4):

Table 4:

Graphical representation

After trial result defect in processing department (Figure 19):

Figure 19:

Defect in processing before trial and after trial (Table 5 &Figure 20):

Figure 20:

Table 5:

In this project we try to minimize the dyeing defect arising in the processing department. For this work first we study and analyze that which defects are occurs in terry towel production and their quantity by collecting back month data of downgrade in overall terry towel production [5]. After this we calculate % wise defectives in various department.

Then we focus on defect arising in processing department. By our above analysis processing defect was found in 0.7% of total CTN packing (Pcs) in which stain was found in large quantity 19.7%, Shearing 4.5%, Lintting 1.9% [6], Bowing 0.5%, uneven dyeing(patchy) 0.3% and holes found 7.2% Near by one month we are continue this work and then after discussion with our industrial mentor we try to goes towards the origin of defect and suggest the remedies for defect occurs in processing department [7,8]. After taking corrective action by implementation of our remedies we start work for minimization of defect near by one month. After completion of work we analyze again quantity of defect in processing department which is slightly minimize than before trial defect percent in which stain was found 13.5%, shearing 2.5%, bowing 0.06%, patchy dyeing 0.2% and holes 5.5%. After comparing it with previous data of defect our project work minimizes the processing defect from 0.7% to 0.3% i.e we minimize 0.4% defect in processing department [9,10].

In this project from our above analysis the defect coming from processing department was minimize as follow:

i. In conventional process of industry stains was coming 19.7% and after our project work and implementation of our suggested remedies it is minimize to 13.5%.

ii. Shearing was coming 4.5% and after implementation of remedies it is minimize to 2.5%.

iii. Bowing was coming 0.5% and after implementation remedies it is minimized to 0.06%.

iv. Uneven dyeing (patchy) was coming 0.3% and after implementation of remedies it is minimize to 0.2%.

v. In conventional industrial process of industry, a hole is coming 7.2% and after our studies and action taken it is minimized to 5.5%.

From our above report we concluded that before taking corrective action overall percentage of processing defect was 0.7%. After taking corrective action in processing department by implementation of our remedies, defect coming from over all processing department was 0.3%. Defect arising in processing department were under controlled and minimizing by 0.4% differences. In this project it was also concluded that most of the processing defect were coming due to manual operation during unloading and loading processing.

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