F3 Planning and controll Flashcards
Vad är operations
- The scope of operations is to match supply with
demand, while aligning with companies’ vision /
strategies. - To accomplish this scope by establishing stable
processes and measurement systems
Vad gör en planerare (operations controll) på air france
‒ Optimal flight routes
‒ Anticipate problems, e.g. pilots strikes, weather changes etc.
‒ Improve margins, i.e. maximize revenues and minimize costs, e.g. fuel consumption.
‒ All planning documents need to be ready for the flight crew, who will receive and check them before departure.
- Important elements in the planning:
‒ Frequency for each airport what routes and frequency are needed.
‒ Fleet assignment how should flights be scheduled.
‒ Banks i.e. arranging optimal transfer.
‒ Block time time from the moment a plane leaves a departure gate at an airport and arriving to its gate in the arrival airport.
‒ Planned maintenance allow for necssary inspection and maintenance.
‒ Crew planning schedule pilot and cabin crew. Maximize working hours, while reducing costs (e.g. allowances).
‒ Gate plotting schedule access to gates.
‒ Recovery account for deviations and ensure some tolerance is built-in the system.
Planning och kontroll över tidsperspektiv
Long-term planning and control
Aggregerade efterfrågeprognoser
Bestämmer resuser i aggregerad form
Mål sätts i financiell form
Medium-term planning and control
Delvis avaggregerad prognos
Bestämmer resurser och situationsfaktorer
Mål sätts i både financiella och operationella termer
Short-term planning and control¨
Fullständigt avaggregerad prognos
Gör ingripanden av resurser för att korrigera avvikelser från planen
Volume-variaty påverkan på plannering och kontroll
Consider job shops vs oil refineries, what is the
importance of planning and control for those two
process types?
* Architect Studio vs Electricity Utility.
* A Studio has normally a high variety/highly
customised projects. Can they produce in advance? Do they need planning?
* Long-term, no planning is needed. Opposite for
short-term planning.
* Electricity utility volumes are high, production is continuous, and variety non-existent. Facilities needed to produce electricity requires huge investments, increasing the need for long-term
Avvikelser
Sales and operations
Olika funktioner involverade i operations har vanligtvis olika mål
S&op integrerar kort och långsiktig planering och integrerar planeringen av nyckelfunktioner
Det är en aggregerad process som inte kollar på detaljer
Kan heta andra saker
Säker vs osäker efterfrågan
Bildäck
Nya bilar vs privatkunder vill ha nya däck
P-D ratio
Make to Order a service or a product is not produced
until an order is received.
Make to Stock anticipate demand. Manufacture in
advance
P:D ratio is low, much uncertainty is removed
(except from the production cycle).
* P:D ratio is high, uncertainty is higher and
operations and planning activities are more
speculative.
Vilka aktiviteter finns det i planning and controll
Loading
Sequencing
Scheduling
Monitoring and controll
Vad innebär loading
Hur mycket
Vad innebär sequencing
I vilken ordning ska saker göras
Vad innebär Scheduling
När ska saker göras
Vad innebär monitoring and controll
Går aktiviterna enligt planen
- Once loading, sequencing and scheduling have
been performed, each part of the operation needs
to be monitored and controlled. - Necessary to do to ensure that the planned
activities are indeed happening. - If not, any deviations of plans can be rectified.
Vilka olika typer av loading och när ska man använda de
- Finite Loading:
- Work over/above capacity is not allowed.
- Load can be limited using appointment
systems - It can be specified by safety regulations.
- Cost of limiting load is low
- Infinite Loading:
- Loading is not limited but the system tries
to cope with it. - Capacity can be flexible and adapted to
different arrival rates. - The cost of limiting the loading is high.
Exempel på saker som konsumerar up time för maskiner
Planerade perioder utan jobb
Oplanerade perioder utan jobb
Breakdowns
Långsam körning
Kvalitetsförluster
Omställning mellan körning
Maximal tillgänglig tid
Värdefull operationstid alltind < 168h/w
Olika former av sequencing
‒ Physical constraints
‒ Customer priority
‒ Due date
‒ Last in First Out (LIFO)
‒ First In First Out (FIFO)
‒ Longest Operation Time (LOT)
‒ Shortest Operation Time (SOT)
Hur utvärdera olika sequencing
‒ Meeting due date promised to customers or days of lateness.
‒ Minimize flow time (time spent in process).
‒ Minimize work in progress inventory.
‒ Minimize idle-time.
Olila typer av scheduling
Forward scheduling
Backword scheduling
Vad innebär theory of constraints
Any operating system is always limited by a small number of constraints. i.e. there is always at least one process or resource which limits the whole operating system.
These constraints, e.g. the most loaded resouces, set the pace at which the system works. These are also known as bottlenecks.
Bottlenecks determine utilization rates of processes/stations before and after the bottleneck.
Any improvement done to the system should start from its bottlenecks!
Vad innebär drum buffer rope
- A bottleneck is also called ”drum” because it
sets the beat of the following activities. Starvation appears in the following activities. - It is important bottlenecks are always
operating and to ensure this, a ”buffer”
inventory before the bottlenecks is needed or
activities in front will have to wait for the
bottleneck. - ”Rope”: communication / information sharing
is needed between the bottleneck and
preceding activities, to ensure that these do
not overproduce and flood the buffer or line
Vad innebär capaciry managment
‒ Understanding the nature of demand
and supply and thereby reduce
mismatches,
‒ Reconcile demand, customer
satisfaction and resource efficiency
Långsiktig capacity managment på enterprice nivå
Strategic capacity planning
* Horizon time of years and months
Concerns:
* Buildings, facilities and process
technology
* Long-term supply arrangements
ger constraints till undre nivåer och får feedback från de
Medium-term capacity management
- Horizon time of quarters, months
and weeks
Concerns: - Aggregate number of people
- Degree of subcontracted
resources
Constraints får ovanifrån och ger ner
Feedback: Får under och ger upp
Short-term capacity management
- Horizon time of weeks, days, hours
Concerns: - Loading activities on individual
processes and staff
Constraints får ovanifrån
Feedback: ger upp
Vilka prestationsmål har man i capacitymanangment
- Costs costs appear if capacity is over- or under- utilized.
- Revenues these are also affected when capacity does not match demand, as a consequence of changed
profits and costs. - Working Capital an increment of manufacturing capacity may lead to increase of finished product inventory.
- Quality fluctuations in capacity, e.g. hiring temporary workers, may lead to defects or similar quality concerns.
- Speed responsiveness can be affected. If capacity increases queues are avoided, reducing waiting times. At
the same time, building up inventory improves responsiveness. - Dependability when demand and supply matches perfectly, we will not be able to respond to supply
disruptions. - Flexibility if demand and capacity are in balance, the operation will not be able to respond to unexpected
changes of demand.
Capacity managment framework
SUPPLY SIDE
Measure capacity to deliver:
products and services
Consider impacts of mix,
time frame and
specification
Manage the supply side:
Determine base capacity
Select ‘level’ or ‘chase’
capacity plans
DEMAND SIDE
Measure demand for
products and services:
Select qualitative and/or
quantitative methods
to support forecasting
Manage the demand side:
Demand management
Yield management
Understand the consequences of
different capacity
management decisions:
Use predictable versus
unpredictable demand
assessment, cumulative
representations,
queuing principles, and
a longitudinal
perspective to support
decision making
Hur kan man mäta kapacitet
‒ Flow time / process time into Flow
rate / process rate.
‒ Utilization rate
‒ Service level (value adding persp.)
Skillnaden mellan input och output mått
- Activity Mix
- Time dependance
Hospital
Beds available
Number of patients treated per week
Air-conditioner plant
Machine hours available Number of units per week
Theatre
Number of seats
Number of customers entertained per week
University
Number of students Students graduated per year
Electricity company
Generator size
Megawatts of electricity generated
Retail store
Sales floor area
Number of items sold per day
Airline
Number of seats available
Number of passengers per week
Brewery
Volume of fermentation tanks
Litres per week
Skilladen mellan design kapacitet, effektiv kapacitet och verkligt output
Design capacity = the theoretical capacity of an operation based on the original design.
- Effective capacity = the capacity of an operation, excluding
planned losses. - Actual output = capacity of an operation, excluding planned and unplanned losses (e.g. sickness, employees mobility, machines breakdowns, demand changes, etc.)
Formel för utilization
Utilization = Verkligt output/ Designkapacitet
Formel för effektivitet
Effektivitet = Verkligt output / Effektiv kapacitet
Formel för overall equipment effectivness
- The capacity reduction, due to predictable and
unpredictable losses, results into ”capacity
leakage” - A popular method to assess this leakage is
the OEE (Overall Equipment Effectiveness) - OEE = a x p x q, where
‒ a = availability of a process
‒ p = performance/speed of a process
‒ q = quality of products/services created
Olika planer för supply managment
Level capacity plan
Chase capacity plan
Capacity management strategies, based on
short- versus long-term volumes
Olika planer för demand managment
‒ Price differentials: adjust prices depending on demand
(high/low season)
‒ Scheduling promotions: encourage demand during low
season.
‒ Constraining customer access: allow access only at
particular times of day/week/month
‒ Service differentials: degrade service during high
season, improve during low demand periods.
‒ Create alternative products / services: deviate demand
on available products / servcices.
‒ Yield management: study past data to understand underor
overbooking risks, change prices based on season or
capacity.
Kapacitetsstrategier
Kapacitet kan leda eller lagga efter efterfrågan
Hur upplever kunder köer
1 Unoccupied time feels longer than occupied time.
2 Pre-process waits feel longer than in-process waits.
3 Anxiety makes the wait seem longer.
4 Uncertain waits feel longer than known, finite waits.
5 Unexplained waits feel longer than explained waits.
6 Unfair waits feel longer than equitable waits.
7 The more valuable the service, the longer customer will ‘happily’ wait.
8 Solo waiting feels longer than group waiting.
9 Uncomfortable waits feel longer than comfortable waits.
10 New or infrequent users feel they wait longer than frequent users.
Vad är planning and controll
Planning and control is the reconciliation of the potential of the operation to supply products and services, and the demands of its customers on the operation. It is the set of day-to-day activities that run the operation on an ongoing basis.
A plan is a formalisation of what is intended to happen at some time in the future. Control is the process of coping with changes to the plan and the operation to which it relates. Although planning and control are theoretically separable, they are usually treated together.
The balance between planning and control changes over time. Planning dominates in the long term and is usually done on an aggregated basis. At the other extreme, in the short term, control usually operates within the resource constraints of the operation but makes interventions into the operation to cope with short-term changes in circumstances.
Vad är capacity managment
Capacity management is the activity of understanding the nature of demand for services and products, and effectively planning and controlling capacity.
Capacity decisions are taken across multiple time horizons and each level of capacity decision is made within the constraints of a higher level. In the other direction, short-term decisions provide important feedback for longer-term planning.
Vad ska en bra demand forecast göra
Good demand forecasts should:
(1) be as accurate as possible;
(2) give a clear indication of relative uncertainty;
(3) be expressed in terms that are useful for capacity management (e.g. units per hour, operatives per month, etc.).
Exempel på kvalitativa demand forecast metoder
panel, delphi, scenario plannering
Vad är capacity
The capacity of an operation is the maximum level of value-added activity over a period of time that the process can achieve under normal operating conditions.
Capacity can be measured by the availability of its input resources or by the output that is created.
Vad är demandmanagment
‘Demand management’ involves changing the pattern of demand to bring it closer to available capacity. This is achieved by either stimulating off-peak demand or constraining peak demand.
A number of methods are used to manage demand, including price differentials, scheduling promotion, constraining customer access, service differentials and creating alternative products or services.
Yield management is a common method of coping with mismatches when outputs cannot be stored.
Vad är capacity planning
Capacity planning often involves setting a base level of capacity and then planning capacity fluctuations around it. The level at which base capacity is set depends on three main factors: the relative importance of the operation’s performance objectives, the perishability of the operation’s outputs, and the degree of variability in demand or supply.
‘Level capacity’ plans involve no change in capacity and require that the operation absorb demand– capacity mismatches, usually through under- or over-utilisation of its resources, or the use of inventory.
‘Chase’ (demand) plans involve the changing of capacity to track demand as closely as possible. Methods include overtime, annualised hours, staff scheduling, varying workforce size, using part-time staff, increasing skills flexibility, subcontracting, zero hours contracting and changing the output rate.
Vilka faktorer ska man tänka på när man sätter Base capacity
Den relativa vikten av olika prestationsmål
Graden av “perishibility” av outputs
Graden av variability i demand eller supply
