operations 7 473.31 fall 2015 bruce duggan providence university college
TRANSCRIPT
Operations7
473.31
Fall 2015
Bruce Duggan
Providence University College
This Week’s Project
Vehicle Salvaging:• Process Flowchart• Precedence Graph
1Check for Spare Tire
[? min]
Is there a spare tire?
Is the tire in good shape?
yes
no
yes
no
yes
Is the rim aluminum
?
3Leave tire on
rim[? min]
2Take it out
[? min]
yes
4Put in good
tire bin[? min]
(from 3)
Summary
Many factories use a combination of layouts• workcentres for some parts
• assembly operations for others
Service businesses are in many ways similar to manufacturing businesses
Service design must consider• the high degree of personalization
often required
• the speed of delivery needed
• the direct customer contact
• the inherent variability of service encounters
6-20
Know The Answers To These Questions1. What is the difference between an “assemble to order” process and a “make to order” process?
2. How else, other than an assembly line, can a production process be organized?
3. What calculation can be used to help determine if investing in equipment for a process is worthwhile?
4. Should services be classified by degree of customer contact or by degree of labour intensity?
5. How do you determine the required “pace” (cycle time) for an assembly line and how do you determine how many people are needed to work on the line?
6. How can changing a facility layout reduce waste and increase capacity?
6-21
Organization of Production ProcessesProject layout• The product, because of its sheer volume or weight remains fixed in a location
Workcentre• A process structure suited for low-volume production of great variety of
nonstandard products
Manufacturing cell • An area where simple items that are similar in processing requirements are
produced
7-3
Organization of Production ProcessesAssembly Line• A process structure designed to make:
o discrete partso moved through a set of specifically designed workstationso at a controlled rate
Continuous process• An automated process that converts raw materials into a finished product in
one continuous process.• Similar to assembly line, but the flow is continuous, not discrete.
Product-Process Matrix
Break-Even Analysis
A standard approach to choosing among alternative processes or equipmentModel seeks to determine the point in units produced (and sold) where we will start making profit on the process or equipment Model seeks to determine the point in units produced (and sold) where total revenue and total cost are equal
7-6
Break-Even Analysis Formula
This formula can be used to find any of its components if the other parameters are known
break-even demand =
purchase cost of process or equipment
total fixed costs of process or equipment
price per unit
cost per unit
unit price to customer
variable cost per unit
Break-Even Analysis Example
Suppose you want to purchase a new computer that will cost $5,000. It will be used to process written orders from customers who will pay $25 each for the service. The cost of labour, electricity and the form used to place the order is $5 per customer. How many customers will we need to serve to permit the total revenue to break-even with our costs?
break-even demand =
total fixed costs of process or equipment $5,000
= 250 customersunit price to
customervariable cost per unit
$25 $5
Designing a Production System
Project Layout• Visualize the product as a hub of a wheel, with materials and equipment
arranged concentrically around the production point.
Workcentres• Arrange workcentres in a way that optimizes the movement of material.
Designing a Production System
Workcentre Layout
Designing a Production System
Manufacturing Cell• Group parts with common machine requirements into families. • Identify dominant flow patterns for each part family.• Machines and the associated processes are physically grouped into cells.
Designing a Production System
Manufacturing Cell
Designing a Production System
Assembly Line Layout• Assembly line layout design is for the special purpose of building a project by
going through a series of progressive steps or ‘stations’• Stations are linked by a material-handling device. • There is usually some form of pacing by which the amount of time allowed at
each station is managed.
Designing a Production System
Continuous Process Layout• Continuous or flow process is similar to an assembly line except the product
moves continuously through the process.
Classification of Services
Service systems• Generally classified according to:
o who the customer is o the service provided to them
• Customer is involved in the production process• Service systems with a high degree of customer contact are more difficult to
control than those with a low degree of customer contact
Service-System Design Matrix
Assembly Line Balancing
1. Specify the sequential relationships among tasks.2. Determine the required workstation cycle time.3. Determine the theoretical minimum number of workstations.4. Assign tasks, one a time, until the sum of the tasks is equal to the
workstation cycle time.5. Evaluate the efficiency of the balance.6. Rebalance if needed.
Assembly Steps and Times: Vortex Hybrid Sedan
Precedence Graph:Vortex Hybrid Sedan
Line Balancing Process:Vortex Hybrid Sedan
Precedence Graph:Vortex Hybrid Sedan
Possible Physical Layout of an Assembly Line
Flexible Line Layouts
End of Chapter 7