Specialization of operations

1. Specialization of operations. The first strategy involves the use of special-purpose

equipment designed to perform one operation with the greatest possible efficiency.

This is analogous to the specialization of labor, which is employed to improve labor

productivity.

2. Combined operations. Production occurs as a sequence of operations. Complex

parts may require dozens or even hundreds of processing steps. The strategy

of combined operations involves reducing the number of distinct production

machines or workstations through which the part must be routed. This is accomplished by performing more than one operation at a given machine, thereby

reducing the number of separate machines needed. Since each machine typically

involves a setup, setup time can usually be saved by this strategy. Material handling effort, nonoperation time, waiting time, and manufacturing lead time are all

reduced.

3. Simultaneous operations. A logical extension of the combined operations strategy is

to simultaneously perform the operations that are combined at one workstation. In

effect, two or more processing (or assembly) operations are being performed simultaneously on the same work part, thus reducing total processing time.

4. Integration of operations. This strategy involves linking several workstations together into a single integrated mechanism, using automated work handling devices

to transfer parts between stations. In effect, this reduces the number of separate

work centers through which the product must be scheduled. With more than one

workstation, several parts can be processed simultaneously, thereby increasing the

overall output of the system.

5. Increased flexibility. This strategy attempts to achieve maximum utilization of equipment for job shop and medium-volume situations by using the same equipment for

a variety of parts or products. It involves the use of programmable or flexible automation (Section 1.2.1). Prime objectives are to reduce setup time and programming

time for the production machine. This normally translates into lower manufacturing

lead time and less work-in-process.

6. Improved material handling and storage. A great opportunity for reducing nonproductive time exists in the use of automated material handling and storage systems. Typical benefits include reduced work-in-process, shorter manufacturing lead

times, and lower labor costs.

7. On-line inspection. Inspection for quality of work is traditionally performed after

the process is completed. This means that any poor-quality product has already

been produced by the time it is inspected. Incorporating inspection into the manufacturing process permits corrections to the process as the product is being made.

This reduces scrap and brings the overall quality of the product closer to the nominal specifications intended by the designer.

8. Process control and optimization. This includes a wide range of control schemes

intended to operate the individual processes and associated equipment more efficiently. By this strategy, the individual process times can be reduced and product

quality can be improved

Plant operations control. Whereas the previous strategy is concerned with the control of individual manufacturing processes, this strategy is concerned with control

at the plant level. It attempts to manage and coordinate the aggregate operations

in the plant more efficiently. Its implementation involves a high level of computer

networking within the factory.

10. Computer-integrated manufacturing (CIM). Taking the previous strategy one level

higher, CIM involves extensive use of computer systems, databases, and networks

throughout the enterprise to integrate the factory operations and business functions.

The ten strategies constitute a checklist of possibilities for improving the production

system through automation or simplification. They should not be considered mutually exclusive. For most situations, multiple strategies can be implemented in one improvement

project. The reader will see these strategies implemented in the many systems discussed

throughout the book.

1.4.3 Automation Migration Strategy

Owing to competitive pressures in the marketplace, a company often needs to introduce a

new product in the shortest possible time. As mentioned previously, the easiest and least

expensive way to accomplish this objective is to design a manual production method,

using a sequence of workstations operating independently. The tooling for a manual

method can be fabricated quickly and at low cost. If more than a single set of workstations is required to make the product in sufficient quantities, as is often the case, then the

manual cell is replicated as many times as needed to meet demand. If the product turns

out to be successful, and high future demand is anticipated, then it makes sense for the

company to automate production. The improvements are often carried out in phases.

Many companies have an automation migration strategy, that is, a formalized plan for

evolving the manufacturing systems used to produce new products as demand grows. A

typical automation migration strategy is the following:

Phase 1: Manual production using single-station manned cells operating independently. This is used for introduction of the new product for reasons already mentioned: quick and low-cost tooling to get started.

Phase 2: Automated production using single-station automated cells operating

independently. As demand for the product grows, and it becomes clear

that automation can be justified, then the single stations are automated

to reduce labor and increase production rate. Work units are still moved

between workstations manually.

Phase 3: Automated integrated production using a multi-station automated system with serial operations and automated transfer of work units between

stations. When the company is certain that the product will be produced

in mass quantities and for several years, then integration of the singlestation automated cells is warranted to further reduce labor and increase

production rate.

This strategy is illustrated in Figure 1.6. Details of the automation migration strategy vary from company to company, depending on the types of products they make and

the manufacturing processes they perform. But well-managed manufacturing companies