Production System

Production systems What is a production system? An apparel production system is an integration of material handling production process, personnel and the equipment that directs work flow and generates finished products. Different types of production systems are • Progressive bundle system • Unit production system • Modular production system Each system requires an appropriate management philosophy, materials handling methods, floor layout, and Employee training. Firms may combine or adapt these systems to meet their specific production needs.
Firms may use only one system, a combination of systems for one Product line, or different systems for different product lines in the same plant. Progressive Bundle System The progressive bundle system (PBS) gets its name from the bundles of garment parts that are moved sequentially from operation to operation. This system, often referred to as the traditional production system, has been widely used by apparel manufacturers for several decades and still is today. The expert says that use of bundle systems would decrease as firms seek more flexibility in their production systems [pic]
Work flow in progressive bundle system Bundles consist of garment parts needed to complete a specific operation or garment component. For example, an operation bundle for pocket setting might include shirt fronts and pockets that are to be attached. Bundle sizes may range from two to a hundred parts. Some firms operate with a standard bundle size, while other firms vary bundle sizes according to cutting orders, fabric shading, size of the pieces in the bundle, and the operation that is to be completed. Bundles are assembled in the cutting room where cut parts are matched up with corresponding parts and bundle tickets.

Bundles of cut parts are transported to the sewing room and given to the operator scheduled to complete the operation. One operator is expected to perform the same operation on all the pieces in the bundle, retie the bundle, process coupon, and set it aside until it is picked up and moved to the next operation. A progressive bundle system may require a high volume of work in process cause of the number of units in the bundles and the large buffer of backup that is needed to ensure a continuous work flow for all operators. [pic] The progressive bundle system
The progressive bundle system may be used with a skill center or line layout depending on the order that bundles are advanced through production. Each style may have different processing requirements and thus different routing. Routing identifies basic operations, sequence of production, and the skill centers where those operations are to be performed. Some operations are common to many styles, and at those operations, work may build up waiting to be processed. Advantages and disadvantages of using progressive bundle system Advantages
The success of a bundle system may depend on how the system is set up and used in a plant. This system may allow better utilization of specialized machines, as output from one special purpose automated machine may be able to supply several operators for the next operation. Small bundles allow faster throughput unless there are bottlenecks and extensive waiting between operations. Disadvantages: The progressive bundle system is driven by cost efficiency for individual operations. Operators perform the same operation on a continuing basis, which allows them to increase their speed and productivity.
Operators who are compensated by piece rates become extremely efficient at one operation and may not be willing to learn a new operation because it reduces their efficiency and earnings. Individual operators that work in a progressive bundle system are independent of other operators and the final product. Slow processing, absenteeism, and equipment failure may also cause major bottlenecks within the system. Large quantities of work in process are often characteristic of this type of production system.
This may lead to longer throughput time, poor quality concealed by bundles, large inventory, extra handling, and difficulty in controlling inventory Unit production system A unit production system (UPS) is a type of line layout that uses an overhead transporter system to move garment components from work station to work station for Assembly [pic] Work flow of unit production All the parts for a single garment are advanced through the production line together by means of a hanging carrier that travels along an overhead conveyor.
The overhead rail system consists of the main conveyor and accumulating rails for each work station. The overhead conveyor operates much like a railroad track. Carriers are moved along the main conveyor and switched to an accumulating rail at the work station where an operation is to be performed. At the completion of an operation the operator presses a button, and the carrier moves on to the next operation. Most unit production systems are linked to a computer control center that routes and tracks production and provides up-to-the-minute data for management decisions. The utomatic control of work flow sorts work, balances the line, and reduces claims of favouritism in bundle distribution. Electronic data collection provides payroll and inventory data, immediate tracking of styles, and costing and performance data for prompt decisions. Processing begins at a staging area in the sewing room. Cut parts for one unit of a single style are grouped and loaded directly from the staging area to a hanging carrier. Loading is carefully planned so minimal handling is required to deliver garment parts in precisely the order and manner that they will be sewn.
When possible, operations are completed without removing the parts from the carrier. Varied sizes and types of hanging carriers are available for different types of products. Automated materials handling replaces the traditional system of bundling, tying and untying, and manually moving garment parts. Unit production systems eliminate most of the lifting and turning needed to handle bundles and garment parts. The need for bundle tickets and processing operator coupons is also eliminated when an integrated computer system monitors the work of each operator.
Individual bar codes or electronic devices are embedded in the carriers and read by a bar code scanner at each workstation and control points. Any data that are needed for sorting and processing such as style number, color shade, and lot can be included. Integrated systems have on-line terminals located at each work station to collect data on each operation. Each operator may advance completed units, reroute units that need repair or processing to a different station, and check their efficiencies and earnings Operator may signal for more inventory or call for a supervisor if assistance is needed.
The terminals at each station enables central control center to track each unit at any given moment and provide management with data to make immediate decisions on routing and scheduling. Operators of the UPS control center can determine sequences of orders and colors to keep operators supplied with work and to minimize change in equipment, operations, and thread colors. A unit production system can control multiple routes and simultaneous production of multiple styles without restructuring production lines. The control center may perform routing and automatic balancing of work flow, which reduces bottlenecks and work stoppages.
Each operator as well as the control center is able to monitor individual work history. individual unit, number of units completed, the operator who worked on each unit, and the piece rate earned for each unit. The system will calculate the earnings per hour, per day, and the efficiency rate of each operator. Advantages: Benefits of a unit production system depend on how a system is used and the effectiveness of management. Throughput time in the sewing room can be drastically reduced when compared to the progressive bundle system because works in process levels are reduced.
Operator productivity increases. Direct labor costs are reduced because of propositioned parts in the carriers and elimination of bundle processing. Indirect labor costs may be reduced by elimination of bundle handling and requiring fewer supervisors. Quality is improved because of accountability of all operators and immediate visibility of problems that are no longer concealed in bundles for extended periods of time. The central control system makes it possible to immediately track a quality problem to the operator that completed the operation.
Other benefits that are realized are improved attendance and employee turnover and reduced space utilization. Disadvantages: Considerations for installing a UPS include costs of buying equipment, cost of installing, specialized training for the system, and prevention of downtime. Down time is a potential problem with any of the systems, but the low work in process that is maintained makes UPS especially vulnerable. Modular Production System A modular production system is a contained, manageable work unit that includes an empowered work team, equipment, and work to be executed.
Modules frequently operate as minifactories with teams responsible for group goals and self-management. The number of teams in a plant varies with the size and needs of the firm and product line. Teams can have a niche function as long as there are orders for that type of product, but the success of this type of operation is in the flexibility of being able to produce a wide variety of products in small quantities. The numbers of employees on a team, usually 4 to 15, vary with the product mix. A general rule of thumb is to determine the average number of operations required for a style being produced and divide by three.
Team members cross-trained and interchangeable among tasks within the group. Incentive compensation is based on group pay and bonuses for meeting team goals for output and quality. Individual incentive compensation is not appropriate for team-based production. Teams may be used to perform all the operations or a certain portion of the assembly operations depending on the organization of the module and processes required. Before a firm can establish a modular production system, it must prioritize its goals and make decisions that reflect the needs of the firm.
With a team-based system operators are given the responsibility for operating their module to meet goals for throughput and quality. The team is responsible for maintaining a smooth work flow, meeting production goals, maintaining a specified quality level, and handling motivational support for the team. Team members develop an interdependency to improve the process and accomplish their goals. Interdependency is the relationship among team members that utilizes everyone’s strengths for the betterment of the team. Work flow in modular production system [pic]
A Modular Production System operates as a Pull System, with demand for work coming from the next operator in line to process the garment. Wastage is normal, and workflow is continuous and does not wait ahead of each operation. This increases the potentials for flexibility of styles and quantities of products that can be produced. Teams usually operate as ‘Stand-up’ or ‘Sit-down’ units A module may be divided into several work zones based on the sequence of operations and the time required for each operation. A work zone consists of a group of sequential operations. Operators are trained to perform the operations in their work zone and djacent operations in adjoining work zones so they can move freely from one operation to another as the garment progresses Work flow within a module may be with a Single-piece hand-off, Kanban, or Bump- back system. If a single-piece hand-off is used, machines are arranged in a very tight configuration. As soon as an operation is completed the part is handed to the next operator for processing. Operations need to be well balanced as there is usually only one garment component between each operation. Some modules may operate with a buffer or small bundle of up to ten pieces of work between operators.
If a small bundle is used, an operator will complete the operation on the entire bundle and carry the bundle to the next operation. An operator may follow a component or bundle for as many operations as they have been trained or until the adjacent operator is ready to assume work on the bundle Advantages of a Modular Production System are: 1. ) High flexibility 2. ) Fast throughput times 3. ) Low wastages 4. ) Reduced Absenteeism 5. ) Reduced Repetitive Motion Ailments 6. ) Increased employee ownership of the production process 7. ) Empowered employees 8. ) Improved Quality
Disadvantages of Modular Production System: 1. ) A high capital investment in equipment. 2. ) High investment in initial training. 3. ) High cost incurred in continued training Combinations of Production Systems Some firms may use the progressive bundle system for producing small parts Combined with modular production for garment assembly. This reduces the investment in specialized equipment and reduces the team size needed. Some industry consultants believe that a modular system combined with a unit production system provides the most flexibility, fastest throughput, and most consistent quality.
This would be particularly useful for large items such as coveralls or heavy coats. The UPS would move the garment instead of the operators. Each manufacturer needs to determine what is best for its product line and production requirements. The another major and oldest production system followed in industry is TOYOTA PRODUCTION SYSTEM (TPS) Toyota production system [pic] History of (TPS) The production system developed by Toyota Motor Corporation to provide best quality, lowest cost, and shortest lead time through the elimination of waste.
Development of TPS is credited to Taiichi Ohno, Toyota’s chief of production in post-WWII period. Beginning in machining operation and spreading from there, Ohno led the development of TPS at Toyota throughout the 1950’s and 1960’s and the dissemination to the supply base through the 1960’s and 1970’s. Toyota Motor Corporation’s vehicle production system is a way of “making things” that is sometimes referred to as a “lean manufacturing system” or a “Just-in-Time (JIT) system,” and has come to be well known and studied worldwide.
Then, in 1924, Sakichi invented the world’s first automatic loom, called the “Type-G Toyoda Automatic Loom (with non-stop shuttle-change motion)” which could change shuttles without stopping operation. The Toyota term “jido” is applied to a machine with a built-in device for making judgments, whereas the regular Japanese term “jido” (automation) is simply applied to a machine that moves on its own. Jidoka refers to “automation with a human touch,” as opposed to a machine that simply moves under the monitoring and supervision of an operator. Since the loom stopped when a problem arose, no defective products were produced. This meant that a single operator could be put in charge of numerous looms, resulting in a tremendous improvement in productivity. [pic] Just in time `Just-in-time’ is a management philosophy and not a technique.
Just-in-Time” means making only “what is needed, when it is needed, and in the amount needed. ” To efficiently produce a large number of products such as automobiles, which are comprised of some 30,000 parts, it is necessary to create a detailed production plan that includes parts procurement, for example. Supplying “what is needed, when it is needed, and in the amount needed” according to this production plan can eliminate waste, inconsistencies, and unreasonable requirements, resulting in improved productivity. Kanban system [pic] Kanban is a production system… its a part of toyato production or lean manufacturing system… Kanban is a Japanese word which means signal cards…. These cards are hung where ever required… o only when this card indicated that the particular space is empty; the products are filled back in the tray… This is a simple concept, but very effective. Kanban mainly focus on the reduction of overproduction. The is also interlinked with the Toyota production system In the TPS, a unique production control method called the “Kanban system” plays an important role. The Kanban system has also been called the “Supermarket method” because the idea behind it was borrowed from supermarkets. Supermarkets and mass merchandizing stores use product control cards on which product-related information, such as product name, product code, and storage location, is entered.
Because Toyota employed Kanban signs in place of the cards for use in production processes, the method came to be called the “Kanban system. ” At Toyota, when a process goes to the preceding process to retrieve parts, it uses a Kanban to communicate what parts have been used. Here a Kanban system is used [pic] There are two kinds of Kanban • Production instruction Kanban • Parts retrieval kanban Cellular manufacturing What is cellular manufacturing? Cellular manufacturing, sometimes called cellular or cell production, arranges factory floor labor into semi-autonomous and multi-skilled teams, or work cells, who manufacture complete products or complex components.
Properly trained and implemented cells are more flexible and responsive than the traditional mass-production line, and can manage processes, defects, scheduling, equipment maintenance, and other manufacturing issues more efficiently [pic] History Cellular manufacturing is a fairly new application of group technology, although the Portsmouth Block Mills offers what by definition constitutes an early example of cellular manufacturing. By 1808, using machinery designed by Marc Isambard Brunel and constructed by Henry Maudslay, the Block Mills were producting 130,000 blocks (pulleys) for the Royal Navy per year in single unit lots, with 10 men operating 42 machines arranged in three production flow lines. This installation apparently reduced manpower requirements by 90% (from 110 to 10), reduced cost substantially and greatly improved block consistency and quality.
Group Technology is a management strategy with long term goals of staying in business, growing, and making profits. Companies are under relentless pressure to reduce costs while meeting the high quality expectations of the customer to maintain a competitive advantage. Successfully implementing Cellular manufacturing allows companies to achieve cost savings and quality improvements, especially when combined with the other aspects of lean manufacturing. Cell manufacturing systems are currently used to manufacture anything from hydraulic and engine pumps used in aircraft to plastic packaging components made using injection molding. Goals of cellular manufacturing
The goal of cellular manufacturing is having the flexibility to produce a high variety of low demand products, while maintaining the high productivity of large scale production. Cell designers achieve this through modularity in both process design and product design. Process design The division of the entire production process into discrete segments, and the assignment of each segment to a work cell, introduces the modularity of processes. If any segment of the process needs to be changed, only the particular cell would be affected, not the entire production line. For example, if a particular component was prone to defects, and this could be solved by upgrading the equipment, a new work cell could be designed and prepared while the obsolete cell continued production.
Once the new cell is tested and ready for production, the incoming parts to and outgoing parts from the old cell will simply be rerouted to the new cell without having to disrupt the entire production line. In this way, work cells enable the flexibility to upgrade processes and make variations to products to better suit customer demands while largely reducing or eliminating the costs of stoppages. Product Design Product modularity must match the modularity of processes. Even though the entire production system becomes more flexible, each individual cell is still optimised for a relatively narrow range of tasks, in order to take advantage of the mass-production efficiencies of specialisation and scale.
To the extent that a large variety of products can be designed to be assembled from a small number of modular parts, both high product variety and high productivity can be achieved. For example, a varied range of automobiles may be designed to use the same chassis, a small number of engine configurations, and a moderate variety of car bodies, each available in a range of colors. In this way, a large variety of automobiles, with different performances and appearances and functions, can be produced by combining the outputs from a more limited number of work cells. In combination, each modular part is designed for a particular work cell, or dedicated clusters of machines or manufacturing processes.
Cells are usually bigger than typical conventional workstations, but smaller than a complete conventional department. After conversion, a cellular manufacturing layout usually requires less floor space as a result of the optimized production processes. Each cell is responsible for its own internal control of quality, scheduling, ordering, and record keeping. The idea is to place the responsibility of these tasks on those who are most familiar with the situation and most able to quickly fix any problems. The middle management no longer has to monitor the outputs and interrelationships of every single worker, and instead only has to monitor a smaller number of work cells and the flow of materials between them, often achieved using a system of kanbans