Tech Directions - October 2007 - (Page 20)

Table 4—Operations (Assembly) Chart Seat Plane stock to thickness Layout seat circumference Saw rough circumference Smooth seat edge Round seat edge Sand smooth Stain Dry Legs Mark lengths of legs Cut stock to length Form the tapers Drill two holes Sand smooth Stain Dry Supports Mark lengths of support Cut stock to length Sand smooth Stain Dry oping the best facility layout and placement of machines for efficient operation. Often, this also helps in the preparation of tooling and purchase of equipment needed for production. Implications for Manufacturing Programs Process planning clearly has benefits in terms of determining the most effective manufacturing processes and the order in which they should be performed to produce a particular part or product. Its use in the educational setting also benefits students. Through use of process planning students will be directed to work in a more systematic, organized, safe, and meaningful manner. Resulting simplification of manufacturing tasks will lead to increased productivity. Students will also experience increased structure and orderliness in the lab. The practice and implementation of process planning makes manufac- Join supports to legs Install seat Inspect stool Pack stool several factors, including required quantity, materials needed to make parts, surface finish requirements, and specified tolerances. Selecting a process without considering the influence of these factors could adversely affect the cost, quality, and ease of manufacturing the parts. These factors and their influences are listed and explained in Table 5. they make their way around a plant during processing. They contain instructions, specifying the order of the workstations the parts go to. The process chart simplifies the task Table 5—Factors Influencing Process Selection Factor Quantity Materials Surface finish requirement Specified tolerances Potential Influences Large lot sizes justify expensive tooling/process. Some materials require a different process. For example, aluminum can be cast, wood cannot. Different processes produce different finishes. A process with a better finish can help in avoiding unnecessary secondary processing. Tight tolerances require expensive tooling. turing—in the real world and in the lab—more organized, safe, attractive, fulfilling, and productive. References Meyers, F. E. (2005). Manufacturing facilities design and material handling (3rd ed.). Englewood Cliffs, NJ: Prentice Hall. Rehg, James A., & Kraebber, Henry W. (2005). Computer-integrated manufacturing (3rd ed.). Englewood Cliffs, NJ: Prentice Hall. Wright, R. T. (1990). Processes of manufacturing. South Holland, IL: Goodheart-Willcox. Uses of the Process Chart Industrial operations use the process chart for documenting and filing procedures involved in processing new and existing products. Most companies use such documents for training employees. The process chart’s time element provides valuable information related to cost estimation. When a job shop receives an order, a cost estimation is usually generated to inform the customer of the cost involved in fabricating the ordered parts. The wooden stool’s seat, for example, would cost about $45.50 in labor if it took 186 minutes to fabricate and the operator charged $15 per hour to do the job. The material and overhead costs are also added to this estimate to generate the final cost to the customer. The process chart also helps in preparing route sheets, the instruction papers attached to parts lots as of preparing the route sheet since the route sheet is a simplified version of the process chart. (The route sheet does not contain such details as processing time and set up of machines.) The process chart also helps to reveal unnecessary and time-wasting processes, which can then be eliminated, combined, or modified. In today’s highly competitive manufacturing industry, engineers use such charts to get a better picture of how their existing manufacturing systems look like compared with their target. In advanced manufacturing, this type of analysis helps in devel- 20 techdirections ◆ OCTOBER 2007

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Tech Directions - October 2007 Technically Speaking Contents Direct from Washington The News Report Technology Today Technology’s Past Mastering Computers Rock Your Classroom!—Use Subwoofers to Teach Electricity and Science Sure, They Can Build It, But. . . . Manufacturing Students Need Process Planning Skills Teach Graphic Design Basics with PowerPoint Free Teacher Resources Product Central More than Fun

Tech Directions - October 2007

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