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Resolving bottlenecks of garment sewing floor in possible ways

Abstract

This project is on “Solving bottleneck of a sewing line in possible way”. The selected method for this purpose focuses on cycle time reduction and cost reduction by solving bottleneck, at first a discussion session was arranged with the production and IE team in order to set potential area for improvement. Then we identified the workable area by time study & capacity graph. We analyzed the micro motion by video capturing of bottleneck process, workstation layout analysis, and machine controlling. Then we introduced the motion economy and point kaizen concept with the related department to improve the method and arranged a training session for the workers. We implemented the improved method to the selected workstations. At last the follow up responsibility was handed over to the responsible authority. The order we’ve worked on for this project is from the brand CRAGOPPHERS. The order quantity was 2200pcs. Method development study & cost savings calculation is attached as Annex-4. We were able to reduce 430sec of cycle time which results in saving a total BDT 11,640/- in that particular line. The factory consists of 42 sewing line. The improved method is applicable in any sewing method. If they roll out within 42 sewing lines then the expected cost savings would be BDT 4,88,880/-.

Keywords: Bottleneck, Point Kaizen, Motion Economy, Work standardization, Cost saving

  1. Introduction:

The lowest output point in the production line is called bottleneck. That is bottleneck area, where supply gathered and production goes under capacity.There are so many reasons to arise a bottleneck in the production line and it is described below.

Pre-Production Stage:

  1. Sub Standard issue supply or supply in delay from store. .
  2. Substandard cut panel supply from cutting
  • Wrong pattern supplied from CAD, etc.

Production Stage:

  1. Worker selection wrong.
  2. Wrong works flow / sequence of works.
  • Non-balance allocation of elements.
  1. Machine disturbances / out of order.
  2. Non-serial supplies forward from workers.
  3. Quality problem.

Diagnostic character of bottleneck:

  1. Direct Observing Method: Those areas are bottleneck areas where pile of supply is observed.
  2. Hourly Production Report: Supervisors use to record hourly production report of each worker. The record shows the bottleneck point.
  3. Time Study Method: – By performing cycle check we can realize bottleneck from different of time. We can realize bottleneck at a glance by making graph and it is a best and scientific way to find out the real bottleneck.

How to reduce bottleneck in apparel industry:

A bottleneck can be solved by increasing the process capacity or adjusting the production level in the sequence where the bottleneck is happening. Following 4 M methodology, this can be solved by:

Man:

  • Selecting right person at right process
  • Prior skill need assessment and train in advance
  • Train worker based on Motion Economy
  • Workers must be trained on self-inspection
  • Workers must be trained in basic troubleshooting of machine

Machine

  • Selecting proposer machine to perform the job
  • Ensure disturbance free machine.
  • Preventive maintenance to ensure availability

Material

  • Ensure standard input to the process from previous process
  • Supply material is orientation as per process need
  • No Sub-standard material should be allowed in process

Method

  • Introduced zig-pattern-fixture to reduce defect generation
  • Improve work station layout to reduce micro-motion
  • Continuous improvement of work method to reduce non-value added work.
  • Balance the work as per worker’s capacity
  • No backward flow should be allowed in line
  1. Objective:

2.1. General Objective:

The general objective of the study is to solve bottleneck, enhance productivity through lean manufacturing tools at TEAM Group, BD.

2.2. Specific Objectives:

To meet customer demand on time by eliminating non value added (NVA) work from the manufacturing process,

  • To reduce operation cycle time ,
  • To improve productivity, and
  • To save manufacturing cost.
  1. Methodology

In conducting a study, appropriate instruments of data collection tools should be employed, decided and explained briefly together with the reasons why they are selected. There are different data gathering tools and or techniques used in conducting a study. In this study, direct observation and time study is used. Kaizen is a concept referring to business activities that continuously improve all functions and involve all employees from the CEO to the assembly line workers.

Types of kaizen:

  1. Point kaizen
  2. System kaizen
  3. Line kaizen
  4. Plane kaizen
  5. Cube kaizen

Here, we have followed Point Kaizen. It is a quick improvement targeting a specific workstation which helps to get the low hanging fruit in very shorter time period. As soon as an error is predicted or is detected in the work process, a solution is implemented. Measures for point kaizen are usually small and easy to implement. Also, they can be connected or not to the whole chain, and can have a huge impact.

In manufacturing, Point Kaizen mostly follows the motion economy principles. Motion economy refers to the manner in which human energy is conserved while performing a task. The objective in all areas of the dental office, clinical, business or laboratory setting should be to minimize the number and magnitude of motions and conserve energy while working.

The principles of motion economy form a set of rules and suggestions to improve the manual work in manufacturing and reduce fatigue and unnecessary movements by the worker, which can lead to the reduction in the work related trauma.

The principles of motion economy can be classified into four groups:

  • Principles related to the use of human body,
  • Principles related to the arrangement of the work place,
  • Principles related to the design of tools and equipment.
  • Principles related to time conservation.

Principle 1 & 2 are used for this project which are,

Use of Human Body:

  1. The two hands should begin motions at the same time.
  2. The two hands should not be idle at the same time except during rest periods.
  3. Motions of the arms should be made in opposite and symmetrical directions and should be made simultaneously
  4. Hand motions should be confined to the lowest classification with which it is possible to perform the work satisfactorily:
  • Finger motions
  • Wrist motions
  • Forearm motions
  • Upper arm motions
  • Shoulder motions
  1. Momentum should be employed to assist the worker whenever possible, and it should be reduced to a minimum if it must be overcome by muscular effort.
  2. Smooth continuous motions of the hands are preferable to zigzag motions or straight-line motions involving sudden and sharp changes in direction.
  3. Ballistic (i.e. free swinging) movements are faster, easier and more accurate than restricted or controlled movements.

Arrangement of the Work Place:

  1. There should be a definite and fixed place for all tools and materials.
  2. Tools, materials, and controls should be located close in and directly in front of the operator.
  3. Drop delivers should be used whenever possible.
  4. Materials and tools should be located to permit the best sequence of motions.
  5. Arrange the height of the workplace and chair for alternate sitting and standing, when possible.
  6. Provide a chair of the type and height to permit good posture.

3.1. Direct observation and Time-study

Observation is the process of recognizing and recording the behavior of people, objects and events. Time study is a structured process of directly observing measuring (using a stop-watch device) human work in order to establish the time required for completion of the work by a qualified worker when working at a defined level of performance. Also, direct observation of the existing manufacturing process can serve as an instrument for collecting data related to the study problem.

Within the garment industry time variation is a must since the garments are made by different machine operators. For this reason, emphasizes the need to set a standard target for different prod-ucts, thereby making time and motion studies mandatory.

 

  1. Result and discussion

4.1. Calculations

In this study, both primary and secondary data was used for the analysis. It starts by time study, capacity graph preparation and ends in Method improvement and cost saving.

Capacity graph (Before):

Capacity graph (After):

4.2. Time study for making capacity graph

In order to find bottlenecks in the sewing line as well as the efficiency of the line, at first a detailed work and time study was carried out to prepare a capacity graph. The following basic steps were followed to prepare a capacity graph-

Step 1: Define objective of the study.

Step 2: Observe the cycle time of every operation of both operator and helper by a stopwatch. In this case there were 48 operators and 4 helpers in that line.

Step 3: Calculate the capacity of every workstation from the observed cycle time.

Step 4: Prepare a graph with those data. In this case the capacity graph was prepared with the help of Microsoft excel.

Step 5:      Identify the bottlenecks from the capacity graph.

4.3. Method Improvement

Method improvement involves the practice of identifying, analyzing and improving existing methods to optimize performance, meet best practice standards or simply improve quality and the user experience for customers and end-users.

What did we do:

Workstation-1: Front & back yoke join

What did we do: Trained the operator to sew steady from needle point to ending point grabbed by the hand to reduce bursts.

Before-There were a total 14 sewing bursts at the process for which the cycle time of the process was 170.

After- Sewing bursts were reduced to 8 from 14 as a result the cycle time was reduced to 98.

 

Workstation-7: Quilting at Front part

What did we do: We increased the machine speed from 1900 to 2600

Before- Process cycle time was 112

After- Process cycle time was 82

 

Workstation-9: Quilting at sleeve

What did we do: We increased the machine speed from 1900 to 2600

Before- Process cycle time was 172

After- Process cycle time was 145

 

Workstation-5: Basting at Front & Back side panel

What did we do: Trained the operator to sew steady from needle point to ending point grabbed by the hand to reduce bursts.

Before- Sewing bursts were 32 times and process cycle time was 132

After- Sewing bursts were reduced 24 times and process cycle time was 110

 

Workstation-26: Front side panel & pocket bag join (1*2)

What did we do: Instructed her to mark the pocket bag joining point at the front side panel before sewing them.

Before- Pocket bag joining seam alteration & process cycle time was 317

After- No alteration & process cycle time was 239

 

Workstation- 25: Lining front part & yoke join

What did we do: Trained her to match both fabric part with their cut mark position and then sew steadily.

Before- Process cycle time was 93

After- Process cycle time was 59

 

Workstation-10: Quilting at hood

What did we do: Trained the operator to sew steady from needle point to ending point grabbed by the hand to reduce bursts.

Before- Sewing burst was 20 times and process cycle time was 108

After- Sewing burst was reduced to 15 times and cycle time was 97

 

Workstation-36: Shell lining join at center front

What did we do: Trained the operator to sew steady from needle point to ending point grabbed by the hand to reduce sewing bursts as much as possible.

Before- Sewing bursts were 18 times and process cycle time was 266

After- Sewing bursts were reduced to 12 times and process cycle time was 192

 

4.4. Cost saving calculation

Here,

Worker salary per month = 9500TK

Working day in a month = 26 day

Working time in a day = 8 hours

So, worker payment per second (W.P.P.S) = 9500÷26÷8÷60 =0.013tk per sec

Order quantity (O.Q) = 2200pcs

 

 

Process Cycle time Cycle time saved Implemented stations (I.S) Cost saved per sec {(Saved C.T×W.P.P.S) × I.S ×O.Q }
Before After
FRONT & BACK PANEL BASTING (1*4) 132 110 22 1 629.2
QUILTING AT SLEEVE 172 145 27 2 1544.4
SHELL LINING JOIN AT CENTER FRONT 266 192 74 2 4233
QUILTING AT HOOD (1*2) 108 97 11 1 315
LINING FRONT PART & YOKE JOIN 93 59 34 1 972.4
FRONT SIDE PANEL & POCKET BAG JOIN (1*2) 317 239 78 1 2230.8
QUILTING AT FRT 112 82 30 2 1716

 

So, Total cost saved= BDT 11640

 

  1. Conclusion

We implemented motion economy principles 1&2 to solve bottleneck which does not requires any extra cost and time. It only requires engagement of associated persons, some training and follow up the improvements to achieve the desired output. As this method does not requires any extra cost, further study can be carried out to find the impact of other two principles.  Our expectation from this project was to reduce manufacturing cost & increase productivity which is fulfilled. So, we can say that if we follow these steps to all the sewing line of the factory, the result will be remarkable.

 

Acknowledgement

The author thanks the management of Textile Today, TEAM Group, BD and specially Mr. Tarek Amin for this type of effective initiation & Mr. Abdullah al Rana Farhad for his co-operation and participation in this project.

If anyone has any feedback or input regarding the published news, please contact: info@textiletoday.com.bd

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