SAMENVATTING
Operations Management H4, 5, 6, 10, 11
Hanze Hogeschool Groningen
Technische Bedrijfskunde
, Samenvatting Operations Management – Technische Bedrijfskunde – Mats Molenberg
Inhoudsopgave
Hoofdstuk 4 - Capacity Planning .......................................................................................................................... 3
Capacity............................................................................................................................................................... 3
Planning Long-Term capacity ............................................................................................................................. 3
Measures of Capacity and Utilization ............................................................................................................ 3
Economies of scale ......................................................................................................................................... 4
Diseconomies of Scale.................................................................................................................................... 4
Capacity Timing and Sizing Strategies ............................................................................................................... 5
Sizing Capacity Cushion ................................................................................................................................ 5
Timing and Sizing Expansion......................................................................................................................... 5
A systematic approach to long term capacity decisions...................................................................................... 5
Step 1: Estimate Capacity Requirements........................................................................................................ 5
Step 2: Identify gaps ....................................................................................................................................... 6
Step 3: Develop alternatives ........................................................................................................................... 6
Step 4: Evaluate the alternatives ..................................................................................................................... 7
Tools for Capacity Planning ............................................................................................................................... 7
Waiting-line models ....................................................................................................................................... 7
Simulation ....................................................................................................................................................... 7
Decision Trees ................................................................................................................................................ 7
Hoofdstuk 5 - Constraint Management................................................................................................................ 8
The Theory of Constraints ................................................................................................................................... 8
Seven key principles of the Theory of Constraints (TOC) ............................................................................. 8
Practical application of the TOC involves the implementation of the following steps: ................................. 9
Managing Bottlenecks in Service Processes ....................................................................................................... 9
Managing bottlenecks in manufacturing processes ............................................................................................ 9
Identifying Bottlenecks................................................................................................................................... 9
Relieving Bottlenecks ..................................................................................................................................... 9
Drum-Buffer-Rope System (DBR) ............................................................................................................... 10
Applying the Theory of Constraints to Product Mix Decisions......................................................................... 10
Managing Constraints in Line Processes .......................................................................................................... 10
Line Balancing .............................................................................................................................................. 10
Key Equations.................................................................................................................................................... 13
Hoofdstuk 6 - Lean Systems ................................................................................................................................ 14
Continuous Improvement Using a Lean Systems Approach ............................................................................. 14
Strategic Characteristics of Lean Systems ........................................................................................................ 15
Supply Chain Considerations in Lean Systems ............................................................................................ 15
Process considerations in Lean systems ....................................................................................................... 15
Toyota Production System............................................................................................................................ 17
Designing Lean Systems Layouts ...................................................................................................................... 17
One Workers, Multiple Machines ................................................................................................................ 18
Group Technology ........................................................................................................................................ 18
The Kanban system ............................................................................................................................................ 19
General operating rules Kanban: .................................................................................................................. 19
Determining the number of containers ......................................................................................................... 20
Other Kanban Signals ................................................................................................................................... 20
Value stream mapping (VSM) ........................................................................................................................... 20
Current State Map (VSM) ............................................................................................................................ 21
1
, Samenvatting Operations Management – Technische Bedrijfskunde – Mats Molenberg
Operational Benefits and Implementation Issues .............................................................................................. 22
Organizational Considerations ..................................................................................................................... 22
Process Considerations ................................................................................................................................. 22
Inventory and Scheduling ............................................................................................................................. 22
Hoofdstuk 10 – Operations Planning and Scheduling ...................................................................................... 23
Levels in Operations Planning and Scheduling ................................................................................................ 23
Level 1: Sales and Operations Planning ....................................................................................................... 23
Level 2: Resource Planning .......................................................................................................................... 25
Level 3: Scheduling ...................................................................................................................................... 25
S&OP (Sales & Operations Plan) Supply Options ........................................................................................... 25
S&OP Strategies................................................................................................................................................ 26
Chase Strategy .............................................................................................................................................. 26
Level Strategy ............................................................................................................................................... 26
Mixed strategy .............................................................................................................................................. 26
Constraints and Costs ................................................................................................................................... 26
Backlog (achterstand) ................................................................................................................................... 26
Sales an Operations Planning as a Process ................................................................................................... 27
Spreadsheets for Sales and Operations Planning ............................................................................................. 28
Spreadsheets for a Manufacturer .................................................................................................................. 28
Spreadsheets for a Service Provider ............................................................................................................. 28
Scheduling ......................................................................................................................................................... 29
Job and Facility Scheduling .......................................................................................................................... 29
Workforce Scheduling .................................................................................................................................. 30
Sequence Jobs at a workstation .................................................................................................................... 30
Hoofdstuk 11 – Resource Planning ..................................................................................................................... 32
Material Requirements Planning ...................................................................................................................... 32
Dependent Demand ...................................................................................................................................... 32
Master Production Scheduling .......................................................................................................................... 33
Developing a Master Production Schedule .................................................................................................. 34
Available-to-Promise Quantities .................................................................................................................. 35
Reconciling the MPS with Sales and operations plans................................................................................. 35
MRP Explosion .................................................................................................................................................. 36
Bill of Materials ............................................................................................................................................ 36
Inventory Record .......................................................................................................................................... 37
Planning Factors ........................................................................................................................................... 39
Outputs from MRP............................................................................................................................................. 40
MRP and the Environment ........................................................................................................................... 41
MRP, Core Processes, and Supply Chain Linkages ..................................................................................... 41
Enterprise Resource Planning........................................................................................................................... 41
How ERP Systems Are Designed ................................................................................................................. 41
Resource Planning for Service Providers ......................................................................................................... 42
Dependent Demand for Services .................................................................................................................. 42
Bill of Resources .......................................................................................................................................... 42
2
, Samenvatting Operations Management – Technische Bedrijfskunde – Mats Molenberg
Hoofdstuk 4 - Capacity Planning
Capacity
Capacity: The maximum rate of output of a process or a system.
Wanneer de capaciteit de vraag van nu en de toekomst niet haalt zal de organisatie
kansen voor groei en winst missen.
Changing the capacity of a process will have an impact on other processes within the
firm and across the chain.
Marketing: provides demand forecasts needed to identify capacity gaps.
Human resources: focuses on hiring and training employees needed to support internal
capacity plans. So, all departments in a firm get involved with and are affected by
long-term capacity planning decisions.
Planning Long-Term capacity
Long-term capacity plans deal with investments in new facilities and equipment at the organizational level and
require top management participation and approval because they are not easily reversed.
These plans cover at least two years into the future, and long-term capacity planning is central to the success of
an organization.
Measures of Capacity and Utilization
Capacity can be expressed in one of two ways: in terms of output measures or input measures:
Output measures of capacity: Best utilized when applied to individual processes within the firm or
when the firm provides a relatively small number of standardized services and products.
Input Measures of Capacity: Generally used for low-volume, flexible processes, such as those
associated with a custom furniture maker. In this case, the furniture maker might measure capacity in
terms of inputs such as number of workstations or number of workers.
Utilization: Degree to which a resource such as equipment, space, or the workforce is currently being
used and is measured as the ratio of average output rate to maximum capacity.
3
, Samenvatting Operations Management – Technische Bedrijfskunde – Mats Molenberg
Economies of scale
Economies of scale: A concept that states that the average unit cost of a service or good can be
reduced by increasing its output rate.
Four principal reasons explain why economies of scale can drive costs down when output increases:
1) Fixed costs are spread over more units
2) Constructions costs are reduced
3) Cost of purchased materials are cut
4) Process advantages are found
Spreading fixed costs: In the short term, certain costs do not vary with changes in the output rate.
These fixed costs include heating costs, debt service, and managers salaries.
Reducing Construction Costs: Certain activities and expenses are required to build small and large
facilities alike: building permits, architects fees, and rental of building equipment. Doubling the size of
the facility usually does not double construction costs.
Cutting Costs of Purchased Materials: Higher volumes can reduce the costs of purchased materials
and services. They give the purchaser a better bargaining position and the opportunity to take
advantage of quantity discount.
Finding Process Advantages: High-volume production provides many opportunities for cost
reduction. At a higher output rate, the process shifts toward a line process, with resources dedicated to
individual products. Firms may be able to justify the expense of more efficient technology or more
specialized equipment. The benefits from dedicating resources to individual services or products may
include speeding up the learning effect, lowering inventory, improving process and job designs, and
reducing the number of changeovers.
Diseconomies of Scale
Occurs when the average per unit increases as the facilities size increases. Bigger is not always better,
however. At some point, a facility can become so large that diseconomies of scale set in; that is, the
average cost per unit increases as the facility’s size increases.
Voor en nadelen van schaalvergroting
Voordelen Nadelen
Spreiding van je vaste kosten Complexiteit
Terugdringen van gebouwkosten Verlies van focus
Snijden in de kosten van ingekochte materialen Inefficiënties
Vinden van proces voordelen
4
Operations Management H4, 5, 6, 10, 11
Hanze Hogeschool Groningen
Technische Bedrijfskunde
, Samenvatting Operations Management – Technische Bedrijfskunde – Mats Molenberg
Inhoudsopgave
Hoofdstuk 4 - Capacity Planning .......................................................................................................................... 3
Capacity............................................................................................................................................................... 3
Planning Long-Term capacity ............................................................................................................................. 3
Measures of Capacity and Utilization ............................................................................................................ 3
Economies of scale ......................................................................................................................................... 4
Diseconomies of Scale.................................................................................................................................... 4
Capacity Timing and Sizing Strategies ............................................................................................................... 5
Sizing Capacity Cushion ................................................................................................................................ 5
Timing and Sizing Expansion......................................................................................................................... 5
A systematic approach to long term capacity decisions...................................................................................... 5
Step 1: Estimate Capacity Requirements........................................................................................................ 5
Step 2: Identify gaps ....................................................................................................................................... 6
Step 3: Develop alternatives ........................................................................................................................... 6
Step 4: Evaluate the alternatives ..................................................................................................................... 7
Tools for Capacity Planning ............................................................................................................................... 7
Waiting-line models ....................................................................................................................................... 7
Simulation ....................................................................................................................................................... 7
Decision Trees ................................................................................................................................................ 7
Hoofdstuk 5 - Constraint Management................................................................................................................ 8
The Theory of Constraints ................................................................................................................................... 8
Seven key principles of the Theory of Constraints (TOC) ............................................................................. 8
Practical application of the TOC involves the implementation of the following steps: ................................. 9
Managing Bottlenecks in Service Processes ....................................................................................................... 9
Managing bottlenecks in manufacturing processes ............................................................................................ 9
Identifying Bottlenecks................................................................................................................................... 9
Relieving Bottlenecks ..................................................................................................................................... 9
Drum-Buffer-Rope System (DBR) ............................................................................................................... 10
Applying the Theory of Constraints to Product Mix Decisions......................................................................... 10
Managing Constraints in Line Processes .......................................................................................................... 10
Line Balancing .............................................................................................................................................. 10
Key Equations.................................................................................................................................................... 13
Hoofdstuk 6 - Lean Systems ................................................................................................................................ 14
Continuous Improvement Using a Lean Systems Approach ............................................................................. 14
Strategic Characteristics of Lean Systems ........................................................................................................ 15
Supply Chain Considerations in Lean Systems ............................................................................................ 15
Process considerations in Lean systems ....................................................................................................... 15
Toyota Production System............................................................................................................................ 17
Designing Lean Systems Layouts ...................................................................................................................... 17
One Workers, Multiple Machines ................................................................................................................ 18
Group Technology ........................................................................................................................................ 18
The Kanban system ............................................................................................................................................ 19
General operating rules Kanban: .................................................................................................................. 19
Determining the number of containers ......................................................................................................... 20
Other Kanban Signals ................................................................................................................................... 20
Value stream mapping (VSM) ........................................................................................................................... 20
Current State Map (VSM) ............................................................................................................................ 21
1
, Samenvatting Operations Management – Technische Bedrijfskunde – Mats Molenberg
Operational Benefits and Implementation Issues .............................................................................................. 22
Organizational Considerations ..................................................................................................................... 22
Process Considerations ................................................................................................................................. 22
Inventory and Scheduling ............................................................................................................................. 22
Hoofdstuk 10 – Operations Planning and Scheduling ...................................................................................... 23
Levels in Operations Planning and Scheduling ................................................................................................ 23
Level 1: Sales and Operations Planning ....................................................................................................... 23
Level 2: Resource Planning .......................................................................................................................... 25
Level 3: Scheduling ...................................................................................................................................... 25
S&OP (Sales & Operations Plan) Supply Options ........................................................................................... 25
S&OP Strategies................................................................................................................................................ 26
Chase Strategy .............................................................................................................................................. 26
Level Strategy ............................................................................................................................................... 26
Mixed strategy .............................................................................................................................................. 26
Constraints and Costs ................................................................................................................................... 26
Backlog (achterstand) ................................................................................................................................... 26
Sales an Operations Planning as a Process ................................................................................................... 27
Spreadsheets for Sales and Operations Planning ............................................................................................. 28
Spreadsheets for a Manufacturer .................................................................................................................. 28
Spreadsheets for a Service Provider ............................................................................................................. 28
Scheduling ......................................................................................................................................................... 29
Job and Facility Scheduling .......................................................................................................................... 29
Workforce Scheduling .................................................................................................................................. 30
Sequence Jobs at a workstation .................................................................................................................... 30
Hoofdstuk 11 – Resource Planning ..................................................................................................................... 32
Material Requirements Planning ...................................................................................................................... 32
Dependent Demand ...................................................................................................................................... 32
Master Production Scheduling .......................................................................................................................... 33
Developing a Master Production Schedule .................................................................................................. 34
Available-to-Promise Quantities .................................................................................................................. 35
Reconciling the MPS with Sales and operations plans................................................................................. 35
MRP Explosion .................................................................................................................................................. 36
Bill of Materials ............................................................................................................................................ 36
Inventory Record .......................................................................................................................................... 37
Planning Factors ........................................................................................................................................... 39
Outputs from MRP............................................................................................................................................. 40
MRP and the Environment ........................................................................................................................... 41
MRP, Core Processes, and Supply Chain Linkages ..................................................................................... 41
Enterprise Resource Planning........................................................................................................................... 41
How ERP Systems Are Designed ................................................................................................................. 41
Resource Planning for Service Providers ......................................................................................................... 42
Dependent Demand for Services .................................................................................................................. 42
Bill of Resources .......................................................................................................................................... 42
2
, Samenvatting Operations Management – Technische Bedrijfskunde – Mats Molenberg
Hoofdstuk 4 - Capacity Planning
Capacity
Capacity: The maximum rate of output of a process or a system.
Wanneer de capaciteit de vraag van nu en de toekomst niet haalt zal de organisatie
kansen voor groei en winst missen.
Changing the capacity of a process will have an impact on other processes within the
firm and across the chain.
Marketing: provides demand forecasts needed to identify capacity gaps.
Human resources: focuses on hiring and training employees needed to support internal
capacity plans. So, all departments in a firm get involved with and are affected by
long-term capacity planning decisions.
Planning Long-Term capacity
Long-term capacity plans deal with investments in new facilities and equipment at the organizational level and
require top management participation and approval because they are not easily reversed.
These plans cover at least two years into the future, and long-term capacity planning is central to the success of
an organization.
Measures of Capacity and Utilization
Capacity can be expressed in one of two ways: in terms of output measures or input measures:
Output measures of capacity: Best utilized when applied to individual processes within the firm or
when the firm provides a relatively small number of standardized services and products.
Input Measures of Capacity: Generally used for low-volume, flexible processes, such as those
associated with a custom furniture maker. In this case, the furniture maker might measure capacity in
terms of inputs such as number of workstations or number of workers.
Utilization: Degree to which a resource such as equipment, space, or the workforce is currently being
used and is measured as the ratio of average output rate to maximum capacity.
3
, Samenvatting Operations Management – Technische Bedrijfskunde – Mats Molenberg
Economies of scale
Economies of scale: A concept that states that the average unit cost of a service or good can be
reduced by increasing its output rate.
Four principal reasons explain why economies of scale can drive costs down when output increases:
1) Fixed costs are spread over more units
2) Constructions costs are reduced
3) Cost of purchased materials are cut
4) Process advantages are found
Spreading fixed costs: In the short term, certain costs do not vary with changes in the output rate.
These fixed costs include heating costs, debt service, and managers salaries.
Reducing Construction Costs: Certain activities and expenses are required to build small and large
facilities alike: building permits, architects fees, and rental of building equipment. Doubling the size of
the facility usually does not double construction costs.
Cutting Costs of Purchased Materials: Higher volumes can reduce the costs of purchased materials
and services. They give the purchaser a better bargaining position and the opportunity to take
advantage of quantity discount.
Finding Process Advantages: High-volume production provides many opportunities for cost
reduction. At a higher output rate, the process shifts toward a line process, with resources dedicated to
individual products. Firms may be able to justify the expense of more efficient technology or more
specialized equipment. The benefits from dedicating resources to individual services or products may
include speeding up the learning effect, lowering inventory, improving process and job designs, and
reducing the number of changeovers.
Diseconomies of Scale
Occurs when the average per unit increases as the facilities size increases. Bigger is not always better,
however. At some point, a facility can become so large that diseconomies of scale set in; that is, the
average cost per unit increases as the facility’s size increases.
Voor en nadelen van schaalvergroting
Voordelen Nadelen
Spreiding van je vaste kosten Complexiteit
Terugdringen van gebouwkosten Verlies van focus
Snijden in de kosten van ingekochte materialen Inefficiënties
Vinden van proces voordelen
4
