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Practical Garment Production Process – A Case Study

End-to-End detailed garment production process

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This project work deals with the productivity and quality enhancement in a garment manufacturing unit through a practical study conducted in the stitching department.

Abstract

In today’s fast-changing world each customer is expecting high-quality garments with product variety. This project work deals with the productivity and quality enhancement in a garment manufacturing unit through a practical study conducted in the stitching department. The use of this project work will improve the efficiency of the production line for bottleneck operations, shows better utilization of available resources, reduce process variations & maintain consistency in the quality of the process output. The project result shows that the industry can achieve higher productivity and profitability with improved quality products by minimizing reworks activities. It also minimizes cost and improves internal throughput time. Initial reading before trial shows that DHU% is going out of control due to various reasons after necessary corrective action, the DHU% is decreased from 30.63% to 25.90%.

In every garment manufacturing, a number of rejected garments are found after product delivery. Some of the organizations considered these garments to be rejected because those garments have no more use by any means. But doing the Reworks in the garments industry for rejected pieces can hamper the smooth production rate and focus on poor quality products having an impact on the overall factory economy. There is no ready-made solution that can reduce rejection percentage overnight. Each order is unique. But this rework suggests how to handle such problems and bring down the rejection rate to a minimum with quality production. Minimization of reworks is a must in quality and productivity improvement. But this project works is suggesting how to handle such types of issues and bring down rejection rate to a minimum. Fabric defects are a very important issue that affects both buyer and supplier so the basic needs for productivity and quality improvement are to control defects rate during various activities of the sewing department. We have to control the productivity by supervising & strict operating conditions to be followed.

Method

In this project, we have collected 15-day DHU to analyze before and after the study. The standard method is to measure DHU of any process is to collect the data regarding the total pieces checked and the number of total defects is detected in the inspected garments. It is noted that it is a number of defects, not the defective garments. One defective garment may have more than one defect. At the time of inspection, a checker found different defects like a broken stitch, hole, raw edges, etc. Once you have a record of the following information of a lot you can measure DHU of that lot using a formula.

Table 1.1 Before Trial Data

Before Trial
Serial No Defects Total No of Defects Total DHU%
1 Bottom Hem (Broken stitch, overlock) 6689 7.89%
2 Waistband (Down stitch, Broken stitch) 2814 3.32
3 Tacking (Missing) 1699 2.00%
4 Trimming/Damage 2126 2.50
Total 13,328 15.73%

 

Chart 1.1-Analyses of Defects

 

Chart 1.2 – Analysis of Top defects by Pareto Diagram

 

Before Trial
Serial No Defects Total No of Defects Total DHU%
1 Bottom Hem (Broken stitch, overlock) 6689 7.89%
2 Waistband (Down stitch, Broken stitch) 2814 3.32
3 Tacking (Missing) 1699 2.00%
4 Trimming/Damage 2126 2.50
Total 13,328 15.73%

Table 1.2

Chart 1.3- Top Defects Analysis

 

Root causes Analysis

A cause and effect diagram is a chart that identifies the potential causes for a particular quality problem.

This problem is related to the machine workers, measurement, supplier, material and many other aspects of the production process. This study has considered the causes. This study has considered the causes related to ‘4 M’ (man, machine, material, and method)

Root causes Analysis of waistband Down stitch

Fig 1.1

 

Fig 1.2

Solution

  • The solution was found by analyzing the defects by 5 Why’s and the ways the process can fail.
  • The solution was also found with the help of Poka-Yoke.
  • It ensures that the right conditions exist before a process step is executed and thus preventing defects from occurring in the first place.

Implementation of 5 Why’s

 

BOTTOM

Q) Why are problems occurring at the Bottom (Broken Stitch, Open Bottom)?

  • Due to improper machine setup.

Q) Why are the machines not properly set up?

  • Due to untrained operators not having knowledge of setting machines.

Q) Why are the operators not having knowledge of setting machines?

  • Due to No training provided

WAISTBAND

Q) Why are problems occurring at the waistband (Down stitch)?

  • Due to uneven stitches near the fusing present near the waistband.
  • Due to handling problems during down stitch.
  • Due to improper setting of the pressure foot.

Q) Why are uneven stitches, handling problems, improper setting of pressure foot present?

  • Due to unskilled operators/No training provided.

Solution Implementation

  • The training was provided to the checkers about their roles and about how to carry out their checking.
  • Training provided to the Operators about:
    1. Different types of defects, their causes, and remedies.
    2. Different factors affect stitching, defects, their causes, and remedies.

Checker’s Training Module

To control the quality of products of a factory, a checker should follow the following approaches:

  1. Have the proper approach toward operators.
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    • Approach operator with the defective garment.
    • Ask the operator kindly to stop the work and pay attention.
    • Explain the defect found and ask if she understands why the garment is defective.
    • Make sure the operator understands why it is defective.
    • Try to find out why the defect was created or why it was not detected at the workstation.
    • Ask the operator to inspect the current bundle for more defective parts and then repair all parts that are out of tolerance including the one found by the inspector. This should be done immediately.
  1. Train operators to sew with good quality from the beginning.
  2. Know quality specifications and tolerances.
    • Be sure to understand what constitutes good and poor quality.
  3. Be consistent in the decisions toward quality.
  4. Comment on both good and bad quality.
  5. Be sure to check each operator’s work daily. The number of defects found should govern the number of inspections performed. Vary inspection times and inspection sequence. Check into the middle of the bundle. Do not always look at only the top garments. 

Job Role of In-line Checker

  •  Responsible for doing inline inspections on all operations/operators in a day.
  • Responsible for generating all reports relating to inline inspection.
  • Responsible for ensuring that during inline inspection standard quality specifications for each operation are being met at all the operation points.
  • Responsible for communicating any quality discrepancy during inline inspection to the Quality Assurance Head and bringing the same to the immediate notice of the Line In-charge

Job Role of End-line Checker

  • Responsible for doing the final inspection on all end-of-line sewn garments.
  • Responsible for generating all reports relating to final inspection.
  • Responsible for ensuring that standard quality specifications are met for all sewn garments.
  • Responsible for communicating any quality discrepancy during final inspection to the Q.A. head and bringing the same to the immediate notice of the line in charge for taking corrective action.

Purpose of End-Line Inspection

The purpose of the End-Line Inspection is to check the quality of the final stitched garments for the following:

  • Labeling
  • Style
  • Material
  • Colour
  • Accessories
  • Defects
  • Size measurement etc.

The inspection procedure can be started in the following way:

  •  The inspection table should have an even surface with the required slant surface and good lighting.
  • At least 2 bins should be kept to keep good and defective garments separately.
  • The fit sample, spec sheets, trim cards, etc should be ready for reference.
  • Accessories like measuring tape, audit forms, pencils, etc should be carried.
  • Lay garment on the table, front up.
  • Flip garment over to the back.
  • Turn the garment inside out and check the wrong side.
  • Most Important of all the steps- Do not worsen the defect.

Job Role in End Line Inspection

Step Task Responsibility
1 Lay the garment flat on the table. Check the finished garment for overall stitch quality and material defects. Quality checker
2 Check each part of the garment in a sequence. Flatten the seams. Quality checker
3 Turn the garment inside out and check for the stitching inside. Send for repairs if defects are found Quality checker
4 Mark the defects found on the garment with clearly visible stickers. Quality checker
5 Check the garment for measurements, which should be within the tolerance limit. Quality checker
6 Give the bundle to the concerned section supervisor to carry out repairs. Enter the defects onto the repair list. Also, enter the bundle number and the time when it was collected. Operator
7 Return the repairs to the operator Supervisor
8 Return the repair bundles to the original checker. Fill out the time when the pieces were returned. Operator
9 Recheck the bundle Quality checker
10 Select or reject as in step 2 of 3 Quality checker

Table 1.3 Job Role in End Line Inspection

Pilot Run

  • Pilot run comprises once an order is into production and no more than the first 30 pieces have come out of the line.
  • There is a statistical quality inspection procedure applicable at this stage.
  • This is done to identify the initial problems in the garment manufacture and solve them at the initial stage.

 

Step Task Responsibility
1 All fabric, lining, trims and accessories must be checked for quantities to ensure production schedules are met standards against the approved sample. Quality checker
2 Check each sewing operation for defects(random pieces) and suggest any attachments, folders that may benefit the operation. Quality checker
3 Check for proper follow up of the recommended QA process and relevant forms such as:1. In-Process Inspection2. End Line Inspection3. Quality Audit Quality checker
4 Check for the inspection points within the line and suggest additions/improvements wherever necessary. Quality checker
5 Inquire for any specific problems Quality checker, Supervisor
6 Advise and discuss the nature and magnitude of the problems and try and correct the problem along with the supervisor. Quality checker, Supervisor
7 Record findings. Quality checker

Table 1.4 Pilot Run

Operator’s Training

  • Pre-sewing activities
    • Before sewing a garment, the sewing machine operator should
      • Check that equipment is safe and set up in readiness for use
      • Perform a machine, needle and spool check. Do samples run to check thread tension?
      • Check that the materials to be used are free from faults
      • Go through all the materials required for constructing the garment. Do fabric, thread and trims checking before sewing.
      • Ensure the materials used meet the specification matching
  • Go through the spec sheet and make sure the materials meet the specifications provided by the buyer

Factors affecting stitching

Fault Causes Remedies
The sewing machine stops during sewing The sewing machine has been run at a low speed for an extended period of time. To prevent overheating, motor power is automatically turned off. Turn the power off and wait about 20 minutes. The safety device will reset, and the machine will be ready to operate.
The needle will not move. The pressure foot is up. Bobbin Winder shaft in winding position. Lower pressure foot. Move bobbin winder shaft back fully to left.
Upper thread breaks The threading is not correct. Threading has a knot in it. The thread tension is too high. The needle is of the wrong size. Correctly thread the machine. Remove knot. Correct thread Tension. Insert Correct needle.
Bobbin thread breaks Bobbin has not been fully inserted in the bobbin case. Bobbin has been incorrectly threaded. Lint in the bobbin case. Securely install bobbin in the bobbin case. Correctly thread bobbin case. Clean bobbin case and shuttle.
Needle breaking Incorrect size of needle for thread and fabric. Needle bent. The pressure foot is incorrectly set. Crossing a thick seam using a too-small needle. Place correct size of needle for thread and fabric. Change the needle Set the pressure foot properly.
Material not feeding correctly Dirt under needle plate near feed dog. Incorrect pressure foot pressure. Bent pressure foot. Clean the feed dog and the lower side of the needle plate. Check the pressure foot and its pressure.

Table 1.5 Factors affecting stitching

Reporting Defects

Defect Causes Remedies
Skipped stitches The thread tension is too tight. The needle is bent or blunt. The needle is the wrong size. Needle and thread do not match. The thread take-up lever has not been threaded. Light pressure on pressure foot. Incorrect setting of needle Correct thread tension. Replace the needle with the correct size. Use proper thread or needle. Check threading order.
increase pressure on pressure foot. Reset Needle
Irregular stitch. Incorrect size needle. Improper threading. Loose upper thread tension. Light pressure on pressure foot. Less pressure on the pressure foot Choose the Correct size needle for thread and fabric. Rethread machine. Tighten upper thread tension. Increase pressure on pressure foot.
Fabric Puckering Tensions are too high. Machine speed is too high for the material being sewn. Blunt needle Check for the tension. Reduce the machine speed. Change the needle
Idle stitching The Knotting Point of thread is formed without sewing product. Adjust proper tension. Properly adjust the bobbin or looper.
Needle mark Hole in the fabric due to needle due to resewing, basting etc. Avoid seam ripping
Staggered Stitches Less pressure on pressure foot. Take up spring weak, broken or missing. Check the pressure on the pressure foot. Check for taking up spring.

Table 1.6 Reporting Defects

Fig1.4- Training to the checkers

 

Fig 1.6-Tacking SOP

 

Before Trial After Trial
Serial No Date Total No of Defects Total Check Pieces Total DHU% Date Total No of Defects Total Check Pieces Total DHU%
Day 1 13/06/19 1796 6130 29.30 10/7/19 1789 7791 22.96
Day 2 15/06/19 1227 4143 29.62 11/7/19 2154 8534 25.24
Day 3 16/06/19 1500 4561 32.89 13/7/19 2350 8573 27.41
Day 4 17/06/19 1197 4440 26.96 14/7/19 2190 9436 23.21
Day 5 18/06/19 1963 4910 39.98 15/7/19 1835 6711 27.34
Day 6 19/06/19 1335 4335 30.80 16/7/19 2380 8117 29.32
Day 7 20/06/19 1260 3572 35.27 17/7/19 2341 8113 28.85
Day 8 22/6/19 1486 4708 31.56 18/7/19 1642 6972 23.55
Day 9 23/6/19 1822 5745 31.71 20/7/19 2015 7872 25.60
Day 10 24/6/19 2493 8935 27.90 21/7/19 1922 7057 27.24
Day 11 25/6/19 1898 6496 29.22 22/7/19 2359 8106 29.10
Day 12 26/6/19 1705 6398 26.65 23/7/19 1677 6735 24.90
Day 13 27/6/19 2062 6245 33.02 24/7/19 1956 8296 23.58
Day 14 29/6/19 2335 7298 32.00 25/7/19 2140 8057 26.56
Day 15 30/6/19 1878 6808 27.59 27/7/19 2088 8658 24.12
Total 25957 84724 30838 119028
Average 1730.46 5648.26 30.63 2055.86 7935.2 25.90

Table 1.7 Before and After Data Analysis

Chart 1.4-Before and After Data Analysis

 

Chart 1.5–Before and After Data Analysis

 

Improvement in Top 4 defects

Before Trial After Trial
Serial No Defects Total No of Defects Total DHU% Total No of Defects Total DHU%
1 Bottom Hem (Broken stitch, overlock) 6689 7.89% 8345 7.01%
2 Waistband (Down stitch, Broken stitch) 2814 3.32 3190 2.68%
3 Tacking (Missing) 1699 2.00% 1876 1.57%
4 Trimming/Damage 2126 2.50 2380 1.99%
Total 13,328 15.73% 15791 13.26%

Table 1.8 Before And After Data Analysis

Chart 1.6- Before and After Data Analysis of Top 4 Defects

 

Cost-Benefit Analysis

  • The project helped in reducing the manpower from 9 to 7.
  • Wages of 1 Worker Rs 91728/Year
  • And hence saving a total of Rs 183456/Year.

Conclusion

  • Quality is improved by minimizing the DHU % from 30.63% to 25.9%.
  • Elimination of defects like Bottom(Broken Stitch, Open Bottom), Waistband (Down stitch), Tacking(Missing) in sewing lines itself.
  • Proper training is provided to quality checkers.
  • Proper training is provided to operators.
  • Proper checking of garments in the finishing department.
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