Operations Ch2

Processes Planning and Design: This chapter discusses the selection and design of the transformation process that can deliver those factors—low cost, high quality, enhanced functionality, speed, and so on—in an efficient and effective manner.

• - Transformation system design considers alternative transformation forms and selects best one given characteristics of desired outputs.
• - Layout analysis seeks to maximize the efficiency or effectiveness of operations.

• Continuous process
• Flow shop
• Job shop
• Cellular production
• Project operations

• - Highly standardized products in large volumes —
• - Often these products have become commodities —
• - Typically these processes operate 24 hours/day seven days/week
• - Objective is to spread fixed cost over as large a volume as possible
• - Starting and stopping a continuous process can be prohibitively expensive
• - Highly automated and specialized equipment used
• - Layout follows the processing stages - Output rate controlled through equipment capacity and flow mixture rates
• - Low labor requirements
• - Often one primary input
• - Initial setup of equipment and procedures very complex

• - Similar to continuous process except discrete product is produced —
• - Heavily automated special purpose equipment —
• - High volume - low variety —
• - Both services and products can use flow shop form of processing

• - Low unit cost because...
• ◦specialized high volume equipment
• ◦bulk purchasing
• ◦lower labor rates
• ◦low in-process inventories
• ◦simplified managerial control

• - Variety of output difficult to obtain
• - Difficult to change rate of output
• -—Minor design changes may require substantial changes to the equipment -—Worker boredom and absenteeism
• -—Work not very challenging
• -Vulnerable to equipment breakdowns

• - Objective is to assign tasks to groups
• - The work assigned to each group should take about the same amount of time to complete —
• - Final assembly operations with more labor input often subdivided easier
• -Paced versus unpaced lines

• - High variety - low volume —
• - Equipment and staff grouped based on function —
• - Each output processed differently

• - Flexibility to respond to individual demands —
• - Less expensive general purpose equipment used —
• - Maintenance and installation of general purpose equipment easier
• - General purpose equipment easier to modify and therefore less susceptible to becoming obsolete
• - Pace of work not dictated by moving line
• - Less vulnerable to equipment breakdowns

• - General purpose equipment is slower
• - Higher direct labor cost —
• - High WIP inventories —
• - High material handling costs
• - Management control very difficult

• A = absolutely necessary —
• E = especially important —
• I = important —
• O = ordinary closeness OK —
• U = unimportant —
• X = undesirable

• Combines flexibility of job shop with low costs and short response times of flow shop —
• Based on group technology —
• First identify part families —
• Then form machine cells to produce part families

• Large scale —
• Finite duration —
• Nonrepetitive —
• Multiple interdependent activities

• High volume indicate automated mass production
• High variety implies use of skilled labor and general purpose equipment
• Make-to-stock versus make-to-order