Know What You Wear

Wednesday, November 22, 2017

Production System in Garment Industry

The garment production systems are a combination of production processes, materials handling, personnel and equipment that direct workflow and produce finished garments. It is a system that depicts how the two-dimensional fabric is transformed into a three-dimensional garment in a manufacturing system. The names of the production systems are based on the various factors like utilization of a number of machines to assemble a garment, layout of machines, total number of operators involved to produce a garment and number of pieces moving in a production line during the production of a garment.

Each garment production system needs a suitable management philosophy, materials handling procedures, plant layout for garments spreading and worker training. The garment industry could combine various production systems to achieve their specific garments’ production needs like utilizing only one production system or a combination of different systems for one product style. Designing production system ensures the coordination of various production activities. There is no particular production system that is universally accepted, yet there are different types of production systems followed by different organizations as discussed in the following section.

Production systems used in apparel manufacturing:
The objectives of garment production systems are:

  1. Examine the features of different kinds of garment production systems
  2. Compare and contrast the different production systems
  3. Assess and critically relate the merits and demerits of utilization of different production systems in various circumstances
Types of garment production systems:
The different types of production systems are distinct and require different conditions for working. However, they should meet the two basic objectives, that is, to meet the specification of the final product and to be cost-effective in nature. The main aim of any production system is to achieve a minimum possible total production time. This automatically reduces in-process inventory and its cost. The subassembly system reduces temporary storage time to zero by combining temporary storage time with transportation time.

Any production system has four primary factors that make up the system.

Processing time + Transportation time + Temporary storage time + Inspection time = Total Production Time.

Processing time is the sum total of working time of all operations involved in manufacturing a garment. Transportation time involves the time taken to transport semi finished or finished garments from one department to another or from one operation/machine to another. Temporary storage time is the time during which the garment/bundle is idle as it waits for the next operation or for completion of certain parts. Inspection time is time taken for inspecting semi finished garments for any defects during manufacturing or inspecting fully finished garments before packing.

In the apparel industry, the most commonly used production systems are make through, modular production and assembly line production systems.

Make through System:
It is the conventional method of production line where an operator assembles a single piece of garment at a time by carrying out all the sewing processes necessary to assemble a garment. After completion of assembling one garment, the operator will start assembling the next one and so on. In this system, an operator would be provided with a bundle of cut work pieces and would continue to assemble them based on his or her own method of work. This type of system is efficient when a huge category of garment styles has to be produced in very few quantities.

The benefits of implementing the make through system are:

  • Quick throughput time
  • Easy to supervise
The shortcomings of the make through system are:
  • Low productivity
  • High labor cost
  • It necessitates an experienced operator for assembling
  • This system is limited to couture and sample making
Group system - Section or Process system:
This is a development of the individual system, with the difference that the operators specialize in one major component and sew it from beginning to end. For example, an operator specializing in backs would assemble the back and yoke, label attaching, etc., and performs all the operations required to finish that particular component.

The sewing room would have a number of sections, each containing multi-talented operators capable of performing all the operations required for a specific component. The sections shown in Figure-1 are built according to the average garment produced, and include:

  • Collar preparation
  • Sleeve preparation
  • Front preparation
  • Back preparation
  • Assembling operations (closing, setting collars and sleeves, etc.)
  • Finishing operations (buttonholes, blind-stitching, etc.)
Group system garment production
Figure-1: Group system garment production
All in all, this is a very efficient system for producing a variety of styles in reasonable quantities. Figure-1 shows a typical layout and work flow for this type of system.

Advantages of group system in clothing industry:

  1. The labour cost is lower and productivity is higher compared to the make through system as operators of various levels of skill and specialized machines are utilised in this system.
  2. This system is very efficient for producing a variety of styles in reasonable quantities.
  3. Automation and specialization can be done.
  4. Breakdown of machines and absenteeism will not cause serious problems.
Disadvantages of group system:
  • The garment quality should be strictly maintained as all levels of operators are involved in the work.
  • Highly skilled operators are necessary to do simple operations within the section.
  • The inventory cost is high due to high work-in-process (WIP), which is necessary in this system as a group of people are involved in each section.
  • As the cut pieces are not bundled as in the case of a bundling system, there could be a chance for a lot of mix up, shade variation and sizes.
Whole garment production system:
There are two types of whole garment production systems: (1) Complete whole garment and (2) Departmental whole garment. In the whole garment system an individual makes the entire garment from cutting the cloth to sewing and pressing the garment. The garment is ready for dispatch once the operator completes the final operation. This type of system is used in few places, which are engaged in custom-whole sale; they are normally high priced and exclusively made for a particular customer. They are limited in number and distribution; normally about 10–20 garments are made.

The departmental whole garment system is also used by custom wholesale manufacturers as well as high price or better dress manufacturers. In the departmental whole garment system one individual does all the work with the equipment allocated to a department. For example on person does all the cutting work in cutting department, second person does all the sewing work in sewing department, third person does the pressing and packing work. The workers in this system may use more than one equipment to complete his/her job.

Advantages of
whole garment production system:
  1. This system is more effective when a very large variety of garments have to be produced in extremely small quantities.
  2. In individual piece rate system the operators will do with full involvement. To finish more pieces, to earn more money.
  3. Operator will be specialized in his own working area.
  4. As the pay depends upon the complication of the operation, the operator tries to finish the complicated operation without any difficulties.
  5. The work in progress (WIP) is reduced, at a time one cut garment to one operator and so the amount as inventory is reduced.
Disadvantages of whole garment production system:
  1. Labor cost is higher due to the utilization of highly skilled laborers for the particular job.
  2. The operator is more concerned on the number of pieces finished rather than the quality of work.
  3. Productivity is less due to lack of specialization.
  4. For long run/bulk quantity of same style is not effective in this system.
Assembly line system for apparel production:
In this kind of garment production system, each operator is allocated to carry out only one job/operation repeatedly. Some of the characteristics of this system are

  • The bundled cut garment pieces are moved successively from one job to another job.
  • One bundle comprises all cut components that are necessary to finish the complete garment.
  • Bundle tickets contain a master list of jobs for the particular garment style and corresponding coupons for each job.
  • A ticket number will be allotted to each bundle which represents style, size and shade of the garment.
The two main types of assembly line production system followed in the industries are:
  1. Progressive bundle systems (PBS)
  2. Unit production system
Bundle system and PBS for garments production:
Most apparel manufacturers believe that the best way to be efficient and achieve economy of scale is by mass production. The bundle system enables manufacturers to gain economies of scale. The bundle system, often referred to as the traditional garment production system, has been widely used by garment manufacturers for several decades. The bundle system is a dedicated system comprising cut parts, tied into bundles, to complete one or more sections of an apparel product.

The bundle system of apparel production consists of garment parts needed to complete a specific operation or garment component. Bundles of garments are assembled in the cutting room where cut parts are matched up with corresponding parts and bundle tickets. The bundles are moved to the sewing room and given to the garment operator who is scheduled to complete the operation.

PBS is a variation to the bundle system. The main characteristics of the systems are one worker with a single skill at a single operation, no interaction between operations, piece rate compensation, maximization of productivity of individual operators, need for extra spaces for material storage, straight lined equipment layout, and manual material movement in large batches. The system helps operators to make more units of garments at faster speeds, with high productivity but with more quality problems. To stabilize the workflow, higher levels of WIP add to production costs, not value, and lead to longer lead times. In these systems, the difference between actual run time and total manufacturing throughput time is significant. The success of PBS depends on how the production system is set up and used in a plant.

Advantages of the PBS of garment production:

  1. This production system may allow better utilization of specialized garment production machines, as output from one special purpose automated garment machine may be able to supply several garment machine operators for the next operation.
  2. Small garment bundles will allow faster throughput until and unless there are any bottlenecks or long lead times within operations.
Disadvantages of PBS of garment production:
  1. The PBS is cost-efficient for individual garment operations. As the garment operators perform the operation on a daily basis it allows them to increase their speed and productivity, and as a result they are not willing to learn a new garment operation because it reduces their efficiency and earnings.
  2. Operators working in a PBS of garment production are independent of other operators and the final product.
  3. Absenteeism, machine failure, and slow processing are also some major bottlenecks in this system.
  4. WIP is seen in large quantities in this production system, which leads to longer lead times.
  5. Poor quality of garments are seen in bundles, which were hidden because of large inventories in the work process.
  6. Leads to extra handling and difficulty in controlling inventory in the garment industry.
  7. Line balancing becomes difficult most of the time.
  8. Proper planning is requires for each batch and for each style, which takes a lot of time.
  9. Improper planning leads to poor labor turnover, poor quality and less production.
  10. Variety of styles of lesser quantity are not effective in this system.
Straight line or ‘Synchro’ production system:
This kind of production system is based on a harmonised or synchronised flow of work in each stage of the garment production process. Synchronisation of time is a critical factor of this system as synchronisation of workflow could not be done if more variations in standard time (SAM) of particular operations are present.

Assume if one operation has a SAM of 1.7 minutes, then all the other operations in the particular production line should have the same, or closer SAM value. Balancing of standard time for each operator could result in irrational combinations of whole or part operations which could minimise the efficiency of individual operators. The layout of a synchro-system for the manufacture of a full sleeve shirt is shown in Figure-2.

Layout for full sleeve shirt
Figure-2: Layout of a synchro-system for the manufacture of a full sleeve shirt
PBS Synchro straight line system:
The PBS synchro system is not a flexible system and liable to frequent breakdown of machines and more absenteeism. The standby machines and operators should be made available to avoid bottleneck processes every time. Further, this system needs an adequate quantity of similar styles of garments for continuous operation of the line.

Unit production system (UPS) for garments production:
Unit production system or UPS is a response to competitive pressure because of consumer demands and increasing global competition. This system requires an automated overhead transporter system to move individual units from one operation to another instead of human handling of materials in the bundle system.

Though this production system has been in use for several years, major progress was made when computers were utilized for production planning, production controlling and regulating the work flow in the production line.

The important features of this production system are:

  • It is mainly concerned with a single garment and not bundles.
  • As per the predetermined sequence of processes, the cut garment pieces are transported automatically from one work station to another.
  • The work stations are so constructed such that the cut components are accessible as near as possible to the operator to reduce the time taken for taking the component and positions the same for sewing.
The operational principles of a unit production system (UPS) are as follows:
  • All the cut panels for one garment are loaded into a carrier at a workstation specially designed for this specific job. The carrier is divided into several sections, each having a quick-release clamplike system to avoid falling out of cut panels during transportation through the system.
  • When a particular batch of cut panels of the garments has been fixed into carriers, they are fed past an electronic device. This device counts and records the number of the carrier and addresses it to its first destination.
  • The loaded carriers are then moved onto the main powered line, which is circulated between the rows of machines continually. Each workstation is connected to the mainline by means of junctions, which open automatically if the work on a particular carrier is addressed to that particular work station.
  • The carrier is moving toward the left side of the operator and waits along with the other carriers in the work station. When the operator has completed the particular work on one carrier, he or she has to press a push button, which is positioned at the side of the sewing machine, to activate a mechanism that transports the carrier back to the main line so that another carrier will be fed automatically to take its place.
  • A data collection system records when the carrier left the station and then it is addressed to its next destination.
Unit production system
Figure -3: Work station and carrier arrangement in the UPS system
The work station and carrier arrangement in the UPS system is shown in Figure -3.

Advantages of the UPS of garment production:
  1. Bundle handling system is completely eliminated.
  2. Time involved in the pick up and drop is reduced to a minimum.
  3. Output is automatically recorded, eliminates the operator to register the work.
  4. Computerized systems in this UPS automatically balance the work between two work stations.
  5. Up to 40 styles can be produced simultaneously on one system.
Disadvantages of the UPS of garment production:
  1. UPS requires high investments where the payback period is long.
  2. Planning needs to be effective every time.
  3. Sometimes the orderly and controlled flow of work via computerized control of the whole production process becomes difficult to measure.
Comparison between the PBS and the UPS:
In garment manufacturing companies various types of sewing systems are installed. The owner of an apparel manufacturing unit buys these systems depending on the production volume, product variety, and the cost involved in buying and maintaining these machines. Among them the PBS is the mostly installed sewing system to date. In this system, the bundles of cut pieces are moved manually on the feeding line by the helpers. The operators drag the bundles on their own, finish their required operation, and move forward to the next operator. With advancement in technology, mechanical material transport systems are bought in. An overhead transport system, UPS, is the one that transports cut pieces hanged in hangers (one hanger for one piece) by an automated system. It reduces manual transport and handling and has many other benefits over the PBS.

Modular production system for apparel manufacturing:
The modular system of production is basically obtained from the Japanese auto manufacturing and is regarded as one way to meet the flexibility in demands required in the apparel industry. The modular system, although dates back to the 1980s, is one of the newest production systems in the apparel industry. This system is also called a team or cellular system. Pressure from increased market segmentation and the need for shortened production development cycles and greater operating flexibility, plus intense competition in standardized product lines from low-wage countries, have forced apparel manufacturers to experiment with this new production system. Modules use a cross-training technique, which requires multi skilled workers and a small set of machines to produce a finished garment. The key principle here is operator/worker involvement and team work, which requires important changes in the industry’s human resource (HR) department. In this system the workers are responsible for quality. The main features of the modular system are groups of workers with multiple skills in one module, group piece rate or hourly rate compensation, U-shaped module, and single piece hand offs; this system is called Group Technology or cellular manufacturing. Less material handling drastically reduces inventory levels and throughput time, which saves the cost of inventory and material handling.

Features of a modular production system:

  • Unconstrained to work with the operators.
  • In one workstation, the workers/operators should be able to perform the operations in different sewing machines in a highly skilled manner.
  • In this modular production system, in-line inspection locations are constructed into the production line so that the inspector could be able to return the defective garment panel to the concerned operator through the system.
  • Productivity is high in this production system since the operator handles the garment only once for several operations, instead of handling it for every operation.
  • Only a few garments will be processed in the particular production line as the throughput time is less in this system.
  • A modular production system module could have up to eight work stations positioned around the transport system.
Advantages of a modular garment production system:
  1. High flexibility
  2. Fast throughput times
  3. Low wastages
  4. Reduced absenteeism
  5. Reduced repetitive motion ailments
  6. Operator ownership of the production process is high
  7. Empowered employees
  8. Improved quality of product
Disadvantages of a modular garments production system:
  • A high capital investment in equipment
  • High investment in initial training
  • High cost incurred in continued training
Evaluation of garments production systems:
The evaluation of garment production systems can be done by taking into consideration four primary factors such as

  1. Processing time: It is the total working time of all the processes involved in assembling a garment.
  2. Transportation time: It is the total time consumed for movement of semi finished or finished garments from one workstation or department to another.
  3. Waiting time of unfinished garments: It is the idle time of a work bundle when it waits for the next operation.
  4. Inspection time: It is time taken for in-process inspection of semi finished garments or final inspection of finished garments before packing.
The choice of best apparel production system will depend on the product and policies of the company and on the capacities of manpower. The main goal of all the production systems is to decrease the total production time which leads to reduction in inventory cost. The appropriate selection of a suitable garment production system for an industry is influenced by the product style and policies of the industry and on the labour capacity. The cost of inventory decides the choice of a production system in most circumstances in an apparel industry. When material, labor, space and interest costs are high, a synchronized subassembly system, which gives the minimum possible in-process inventory, is more suitable.

References:

  1. http://www.indiantextilejournal.com/articles/FAdetails.asp?id=28
  2. Industrial engineering in apparel production by V Ramesh Babu
  3. Apparel Manufacturing Technology by T. Karthik, P. Ganesan, D. Gopalakrishnan
  4. Garment Manufacturing Technology Edited by Rajkishore Nayak and Rajiv Padhye