Introduction

The manufacturing system model shows how subsystems interact. This model helps in making decisions on how to improve the system. To make the manufacturing system work, people do jobs that contribute to system operation. The jobs in a manufacturing system include-- designing, planning, operating and controlling. Each of these jobs represent a series of planned activities. Of course, since they are all part of the system they are interrelated. Managers are responsible for coordinating the activities so they are often referred to as managed activities.

Designing

In research and development departments, people search for new ideas which will contribute to the  product line of the company. Scientists and engineers work in teams to invent new products, materials, and processes. They also explore ways to improve existing products.

The research team use basic and applied research to gain knowledge to improve products, materials and, processes. Basic research is a process used to gain new knowledge. Applied research looks for practical applications of knowledge.

Development is a process that involves testing and improving new or existing products. During the development phase, prototypes are constructed. Prototypes are full size or scaled models of the product. These models are tested to determine how well products work and how long they will last (life cycle). Tests are also done to determine whether they are safe to use and if the product or the processes used to fabricate the product will harm the environment.

There are many new products that never make it to the market. Some product designs are too hard to produce. Others just simply won't sell because people don't need or want them. Before production begins, market researchers analyze the target population and the distribution network. Is the product designed for children, teenagers, young adults or adult populations? Is the market local, national or international? These questions are answered by surveying potential customers and test marketing.

Designers must determine if the product is  marketable. They must identify the processes needed to produce the product, the type of tools needed, the number of workers, and the cost of production. This information is combined with market research to determine selling price and profit margin.

 

Product Design and Engineering Activities   Define the Problem/Identify Need   Invent New or Improve Existing Product(s)   Develop and Test Prototype   Conduct Market Research   Estimate Profit Margin   Construct Working Drawings

Production Planning

Once a product is designed, an efficient way to produce it must be planned. Production planning involves designing the system for making the product. Production and mechanical engineers work closely to plan the sequence of operations needed to make each part. Special tooling is designed for each machine so processes can be performed quickly and safely.

Now that the tools and processes have been identified, it is time to study each workstation and design ways to reduce time and increase accuracy and safety of each operation. Time and motion studies are used to analyze workstation design. The purpose of conducting studies is to eliminate wasted motion. The process involves observing motion, collecting time data, identifying wasted motion, implementing solutions and testing. To achieve the most efficient work cell design, motion to perform the operation can be divided into the slightest movement and studied. Environmental factors such as lighting, temperature, color and sound are often studied to improve the work place.

Depending on the the type of product and potential market, the best way to set up production must be decided. There are four types of production systems: job, batch, continuous and Just -In-Time (JIT) manufacturing.

With job production, products are manufactured by individuals or groups. Usually the product remains stationary and the material, equipment and labor are brought to the work. With this system, several different products can be produced at the same time. This system is also flexible because it is easy to retool for different products. It is often used for special orders of one product or for large items such as ships or airplanes. The disadvantage of job production is that it takes more time to produce each product so costs are high.

The batch system is designed to fabricate products in groups or lots. Parts are moved to workstations where machines that perform similar operations are grouped. For example, group of parts may move to the milling department, then to the drilling department, then to the paint department, and finally to the assembly department. This type of production system is good when there is a moderate demand for a product. One hundred or One thousand products can be made an then the line can be changed to produce a different product.

The third system is the continuous system. With this system, machines are arranged by the processes that are needed to make the product. Continuous production is sometimes referred to as line production because often machines are arranged in a line. When a very large market exists, this is the most efficient system. Products can be made faster and at a reduced cost. However, continuous systems are not as flexible as the others. It takes more time to change product lines.

JIT manufacturing requires a 'systems" look at the product variety being manufactured and/or assembled, process capabilities, purchased materials, and competitive advantage. This system of manufacturing is sometimes referred to as 'stockless production' or 'kanban' and can be applied to all the other manufacturing techniques, whether they are traditional or automated. JIT is designed in a way to increase profitability in companies by making them more competitive. The idea behind JIT manufacturing is that sub assemblies are completed just in time to be made into finished products and these products are delivered just in time to be sold, likewise raw materials are bought just in time to be used. The idea behind JIT is to reduce production cycle time while getting rid of waste.

The choice of the type of system to use depends on customer demand. Low demand would warrant a system which is flexible-- job or batch. With high customer demand, the continuous system would be best. Sometimes a combination of systems are used. For example, parts are batch processed then assembled on a continuous flow system.

The information on the sequence of operations, tooling,  and types of system is analyzed to determine the best layout for machines in the plant. Engineers design the plant layout so the flow of materials through the system is efficient.  All of this information is carefully documented so supervisors and workers can perform their jobs.

Safety engineering is an important part of the planning process. When processing materials there are many hazards. Tools, machines and exposure to hazardous materials can cause injury. Safety engineers study the risks involved in each production step and design special guards for machines, material handling safeguards, and safe work areas to minimize risk. Compliance with the National Institute for Occupational Safety and Health (NIOSH) and federal and state Occupational Safety and Health Association standards help protect the worker and minimize the risk of accidents and injuries.

Upon successful completion of  production planning a pilot run is conducted to prove that the activities are meeting expectations. During the trial run, each phase of production is analyzed to determine shortfalls or inefficiencies that need to be corrected .  Any part of the production system can be broken down and reengineered to maximize productivity before full production begins.

 

Production Planning Activities   Specify Equipment and Operations   Design Tooling and Program CNC Equipment   Identify Type of System   Develop Plant Layout (plant capacity, line balance etc.)   Design Safety System   Conduct Pilot Run

Operating

Operating the manufacturing system involves making the parts, assembling the product, packaging and shipping. While the product is being made, the production system design is really being tested. The process must be monitored to determine if the system is operating properly. Information about the flow of material through the production line is recorded. Quality is measured at several points in the process. This data is used to control and improve the system.

Maintenance is another important part of operating a manufacturing system. Maintenance personnel repair machines and maintain all the equipment to reduce machine down time and insure safe working conditions. The maintenance department is also responsible for maintaining the building. Building maintenance insures that the structure is kept in good shape and the heating and electrical systems work well. Fire extinguishers and other safety systems are also maintained by this department.

The operating economics involve controlling the flow of money. Income from the sale of products is used to maintain inventory and  pay employees. The income and cost are monitored to determine the profit.

 

Operating Activities   Fabricate Product   Maintain Database   Maintain Facilities   Maintain Inventory (operation economics)   Administer Employee Wages and Benefits

Controlling

It would be great if all product designs and production plans were perfect from the start, but in the real world of manufacturing this is not the case. Each of the managed activities must be continually monitored and improved. As you learned in section ___, the feedback and control cycle involve data collecting, analyzing, reporting and modifying.

As shown in figure 2, these activities are continually performed for each of the managed activities. In a way, controlling is a communication process that ties all the functions of manufacturing together. Information about the design is reported to the production engineer who in turn offers design changes which will improve the production process. Operation data is reported to production engineers who change tooling designs to improve operations.

(Figure 2)

The quality of information communicated between departments is important for continual improvement of the system. Computers play an important role in helping managers update the system. Computers can be used to collect data, analyze data and generate a report. Computer networks can connect each department so valuable information is always available.