Productivity and Quality improvements due to CAD/CAM:
The effects of an important new technology such as CAD/CAM extend to many functions in an organization resulting in productivity and quality improvements beyond simply those in manufacturing. The following, some of them items we have already touched on, is a partial list of such effects.
1. Engineering design: Initial design considers more alternatives, is more efficiently done, and results is better designs. Calculations of areas, volume, weight, stress, and the like are best done on a computer. CAD systems can either perform such calculations directly or prepare the data for computation on mainframe computers.
2. Drafting: Parts with recurring features or parts that are frequently updated can be maintained more efficiently with CAD.
3. Bills of material: These can easily be produced from data stored in a CAD system.
4. Cost estimating: CAD systems can correlate, store, and recall graphical and text data for each part for cost estimating purposes.
5. Order entry: Some manufacturers have integrated order entry with CAD when orders are tied to specific engineering drawings.
6. Manufacturing: Process planning can be shortened or eliminated through the CAD/CAM coupling. Many commercial systems provide software for producing NC programming tapes and other information used in preparing an order for production.
Applications and Economics of FMS:
Flexible manufacturing was pioneered in the United States, but the Japanese are far ahead in the installation of such systems. To date, US manufacturers have brought only a few of these systems, illustrated by GE’s electric meter plant in New Hampshire, which produces 2000 different versions of a meter on the same flexible manufacturing equipment with a total output of more than a million meters per year. Another showcase system in the United States is Deere & Company’s $1.5 billion plant in Waterloo, lows, which has an FMS for machining 1000 pound castings into finished transmission cases.
The Japanese have been much more aggressive in the installation of FMS systems. Fanuc Ltd., Japan’s premier robot producer, has a system near Mount Fuji that makes parts for robots and machine tools that is supervised by a single controller watching operations on closed circuit TV. The plant cost about $32 million, but Fanuc estimates that the investment required for a conventional plant with similar capacity requiring ten times the labor force would be $320 million. The FMS plant requires 100 employees, one employee to supervise ten machining centers and the others used for maintenance and assembly, making it about five times as labor productive as the conventional plant.
Nearby, Fanuc has an FMS facility for automatically machining and assembling 10,000 electric motors per month. The system involves 60 machining centers and 101 robots. Over 900 types and sizes of motor parts are machined in lots ranging from 20 to 1000 units. Workers perform maintenance during the day, and the robots work at night in eerie darkness.
Near Nagoya in Japan, Yamazaki Machinery Works Ltd operates a 12 worker $20 million FMS with a three day turnaround on order. They estimate that a conventional system would require 215 workers with almost four times the number of machines and a three month turnaround. Yamazaki estimates that the five year after tax profit of its FMS will be $12 million compared with only $800,000 for a conventional plant.
The showcase Yamazaki plant is a newer FMS involving 65 computer controlled machine tools and 34 robots, all linked with a CAD design center at corporate headquarters . the labor force s 215, compared to an estimates 2500 for an equivalent conventional plant. What is to be produced and the details for processing are controlled from headquarters. Obviously, with a system of such plants, the overhead cost of production planning and control can be reduced compared to the equivalent conventional capacity.
The rush toward advanced production technology has resulted in companies having programmable equipment from any different vendors, often with incompatible ways of packaging and sending information, which cripples the dream of computer integrated manufacturing systems. Individual companies, such as General Motors, have moved to offset this disadvantage by establishing a nonproprietary Manufacturing Automation Protocol (MAP), which specifies a single multi-channel coaxial cable for linking incompatible devices in a network and includes a common syntax for exchanging data between programs.