Fuck Tenta Flashcards
Draw the relationship of manufacturing planning and control
The picture with all the boxes
In what stage of manufacturing planning and control is forecasting present?
All stages except the last
What step in manufacturing planning and control is part of Sales and Operations planning?
Production planning & resource planning
What step in manufacturing planning and control is part of Master production scheduling?
Master production scheduling & rough cut capacity planning
What step in manufacturing planning and control is part of Order planning?
Material planning and capacity requirements planning
What does S&OP stand for?
Sales and operations planning
What types of production flow types are there?
- V Type
- A
- T
- X
- I
How’s the relation between volume and variety and the different production layouts?
From fixed layout to Line layout, the standard image.
What is fixed position?
Airplanes
What is line layout?
Volvo
What is cell layout?
Operators goes in a loop and do certain procedures on every product. Look at figure.
What is functional layout?
Functional layout groups the machine based on type.
What are commonly used means of transport for material feeding?
- Forklifts
- Conveyors
- Tuggers and trains of tow carts
- Automated Guided Vehicles (AGVs)
Draw figure for difference between direct flow and flow via picking area for material flow in supply process?
One lite picking station in between storage and assembly station.
Give example of characteristics in regards to the context of the manufacturing company that can influence the production logistics?
It needs to be fit between the context that exists within and around the manufacturing company and the approaches used in the production logisitcs.
Eg.
- Market characteristics (required lead time, variations in demand)
- Supplier characteristics ( distance to suppliers, degree of cooperation)
- Products characteristics (complexity, degree of customization)
- Manufacturing strategy
Draw the manufacturing strategy matrix
See figure in introduction slide
What is the relationship between planning horizon and level of detail and where are the stages?
Higher level of detail the closer the planning horizon is.
Longest planning horizon & low level of detail
1. S&OP
2. Master production scheduling
3. Order planning
4. Execution and control
Shortest planning horizon and high level of detail
What is the relationship between planning horizon and level of detail and where are the stages?
Higher level of detail the closer the planning horizon is.
Longest planning horizon & low level of detail
1. S&OP
2. Master production scheduling
3. Order planning
4. Execution and control
Shortest planning horizon and high level of detail
What is the aim of S&OP and in what planning object, horizon and frequency?
Achieve a good balance between demand and supply and coordinate goals and plans in different units.
Planning object: Product group/Product
Horizon: 1-2 years
Frequency: Quarterly/monthly
What is the aim of Master Production Schedule and in what planning object, horizon and frequency?
Achieve a good balance between demand and supply and give info to sales function about what can be promised to customer.
Planning object: Product
Horizon: 0.5-1 years
Frequency: Monthly/weekly
What is the aim of Order planning and in what planning object, horizon and frequency?
Establish quantities and point in time for the orders - initiating material flows and satisfying existing requirements.
Planning object: Item
Horizon: 1-6 months
Frequency: Weekly/Daily
What is the aim of Execution and control and in what planning object, horizon and frequency?
Release orders to the shop floor - material available check and sequencing of orders
Planning object:Operation
Horizon: 1-4 weeks
Frequency: Daily
What does MPS stand for?
Master Production Schedule
What types of material flows do a manufacturing company deal with?
- Inbound flows of materials from external suppliers:
- Raw materials
- Components
Internal flows:
- Internally manufactured parts and semi-finished items being refined into finished products
Outbound flows of finished products to customers
Give a brief explanation of order planning?
Order planning comprises the administrative activities required to control material flows (inbound, internal, outbound) on an operative level.
Draw rhe re-order point system figure
Basically that you order as soon as your stock level reaches a minimum level (before it’s done on the safety stock) to always make sure that there is enough inventory.
Explain traditional push system in term of execution and control?
- Production plans are used for ordering
- Batch production
- The operators are production according to a dispatch list
- When a job is finished in one machine it is moved (pushed) to the next machine. If the next machine is busy will the batch be put in the queue.
- Priority rules are used to decide the next batch to produce
Explain traditional pull system in term of execution and control?
- Production plans are used, however not for scheduling but for capacity planning
- Small batch sizes
- No dispatch lists
- The start of an operation is initiated by a signal from the following operation
What are the advantages and disadvantages of traditional functional layout?
+ Flexibility - product mix, small volumes
- Many transports
- Difficult to plant and control
- Many planning points
- Hard to overview the flow
- Ques
- Long throughput time
- High WIP
- Splited responsibility, optimizing separate functions
What is the relationship between flow efficiency and resource efficiency?
See figure in Production Flow lecture.
What happens if there is excessive focus on resource efficiency?
- Long throughput times, ex. long waiting times generates new demand
- Handling many flow units at the same time, ex. move patients between full wards
- Many re-starts for each flow unit ex. re-book appointments.
What are the advantages of pull controlled, on-piece continuous flow?
- Builds in quality
- Created real flexibility
- Creates higher productivity (reduce non values added work)
- Frees up floor space
- Improves morale (working environment)
- Reduces cost of inventory
- Improves safety
Give example of product flow types and draw how they look
- Serial product flow
- Semi- parallel product flow
- Parallel product flow
- Combinations at different system level
- Organic product flow
Hoe can the operators work differ in regards to flow?
- Fixed on one work station
- Follow the product along the flow to many work stations
- Follow the product along the whole flow (line)
How can capacity impact throughput and WIP?
A more even capacity can generate better throughput of products and drastically reduce WIP.
Think of game of dice: 1-6 capacity vs. 3-4
How do the production cycle time influence balance loss and handling losses?
With very short cycle times it’s a high percentage of it losses. From around 3-4 minutes and more does cycle time level out and the losses are ‘equal’.
So very short cycles is not as good since a lot of time is than unnecessarily spent on losses.
How does buffers impact system loss?
No buffers result in high system losses. Having 1 buffer drastically reduce system losses and is not depending on the number of work stations.
Buffer 2,3 and 4 only have slight improvements on the system loss compared to the impact the first buffer have.
How does variation and number of work station relate to system losses?
With increasing number of work stations the bigger impact have a large variation.
Give the equation to calculate throughput time
Throughput time = (Flow units in the flow, WIP) x (Cycle time)
Can be used to calculated WIP as well.
How do you calculate takt time?
Takt time = Available working hours / Customer demands, units
Why forecast?
Required delivery lead time to customers shorter than purchasing and production lead time
- It takes time to adjust capacity
- A key input to the S&OP process and other plans
- Relates to the budget
- Input for determining batch size and order quantities
- Input to agreements with suppliers
What can cause demand uncertainty?
- Demand uncertainty can result from the increasing rat of change in the market.
- Can result from behavior in the supply chain, making demand fluctuations increase upstream (bull-whip effect)
What factors influence the forecasting process?
- Forecast data
- The length of the forecast period - eg. week, month year?
- Forecast frequency - how often we redo our forecast?
- Forecast horizon - how many periods ahead we are looking?
- Aggregation level - product, product group?
- Forecast units - pieces, meters, liters, kilogram?
What are common demand patterns and how do they look?
- Random variation
- Trend
- Seasonal variation
Can be combined and random variations are always present
What are the two general forecasting methods?
- Qualitative
- Quantitative
Explain qualitative forecasting
Based on subjective judgement and few formal calculations.
+ Up-to-date knowledge of changes and elements occurring in the environment that affect the forecast
- Short term memory, overconfidence bias (wishful thinking)
Explain quantitative forecasting
Based on calculations (more or less advanced)
+ Objective, consistent, capable of processing large amounts of data
- Only as god as the data upon which they are based. When changes occur in the data that are not incorporated in the model cannot the forecast be accurate.
What are the different qualitative forecast methods?
- Sales management method
- Grass root method
- Pyramid forecasting
Explain sales management approach/method
- Management personnel gather in meetings to forecast demand
- Consideration to sales statistics
- Forecast breakdown into regions
- Quick way to produce forecasts
- Consensus achieves among participating management
- Risk of subjective assessments
- Management deiced - rather than the individuals closet to the market
Explain the grassroots approach
- Initial assessments made by salespeople and other personnel in direct contact with the market.
- The initial forecasts are collected and processed centrally
- A common forecast is created for the whole company
- Forecasts produced by those with the most knowledge of the market
- Responsibility to realize forecast fails upon those who made them
- Forecast breakdown into regions not necessary
- Takes more than the sales management approach
- Risk of subjective assessments
Explain pyramid forecasting
- Both management and grass root participation
- Bottom up - top down
- If the grassroot forecast deviate from the managements forecasts, grassroot forecasts are proportionally adjusted
- The original proportion between e.g. regions or products areas remain
- The total equals management total
- Sales staff not tied to its own forecast
What are the quantitative forecasting methods?
- Moving average
- Exponential smoothing
- Focus forecasting
Explain moving average
It’s a quantitative method of forecasting.
It sum the actual demand of the previous x months and divide by x it for the next month forecast. The next month the previous month actually demand is added and the oldest demand removed, so again the sum of x months and than divided by x.
The number of periods (x) is decisive for how the method will operate. A large values gives a more stable demand since random variations don’t have as big of an impact. However, it reacts slowly to systematic changes in demand.
Explain exponential smoothing
F(t+1) = cD(t) + (1-c)F(t)
Using a smoothing constant, alpha, (c in the equation).
A large constant is responsive to systematic changes in demand while a small constant is stable to random variation.
Explain focus forecasting
If it worked before, it will probably work again. Using simulations for every forecast occasion to find which method have given the most accurate result previously. The best method is chosen to generate the forecast for the next period.
Takes trend and seasonal variation into consideration.
Explain forecast monitoring
Important to supplement forecasting methods with different types of forecast monitoring to avoid surprises.
- Estimate forecast error (i.e difference between the forecast for one period and the actual demand of the same period)
- Check that the forecast remains withing acceptable margins of error (e.g demand monitoring and forecast monitoring)
How can forecasting be used in the automotive industry?
- Is dependent on accurate forecast on product model level.
- This forecast is used as input to tactical planning (S&OP and MPS) but also for generating delivery schedules sent to suppliers.
- Long term forecast is always important as it takes time and consumes resources to increase and decrease manufacturing capacity.
- When demand exceeds supply the company might generate an order backlog with delivery times of several months which may reduce criticality of detailed forecast.
How can forecasting be used in the fashion industry?
- Usually has short product life cycles and needs processes that are responsive to market fluctuations
- Forecast on fabric type levels are used as input to tactical planning of manufacturing resources and supplier booking.
- Forecast on product level is used to make to stock products
How can forecasting be used in the ice cream industry?
- Forecast is used for tactical planning in the same way as automotive manufactures and manufactures of fashion clothes - to plan resources and generate deliver schedules to suppliers.
- A manufactures of ice cream usually have long product life cycles and could rely on historical sales data and quantitative methods for forecasting for tactical planning.
Seasonal demand variations.
- Likely to consider e.g. weather forecast for short term forecasting.
Communication is important for customer orders, why?
All sources of demand must be identified and considered.
- Regular customer demand
- Unexpected/rare sources of demand e.g large spare part order orders
Communication is important for customer orders, why?
All sources of demand must be identified and considered.
- Regular customer demand
- Unexpected/rare sources of demand e.g large spare part order orders
Rapid and straightforward communication with customer in case order status changes.
Explain the order process with Make-to-Stock (MTS)
- Products are manufactures without requiring any customer orders
- Prolonged delivery lead time e.g. in case of shortages in stock or order backlog
- Two types of orders: Traditional orders and call-offs
- Available-to-promise (ATP) basis for providing information about delivery lead time
- Order registration
- Picking and delivery
- Allocations removed and quantities updated
Explain available-to-promise (ATP)
ATP is the quantity of end items tat sales can promise to deliver in specified planning period without affecting other customers delivers. Generally performed by the ERP system.
Calculated in the first period and in periods with scheduled receipts.
. For the first period:
ATP (period 1) = Opening stock on hand + Scheduled receipts during first period –Allocations prior to the next inbound delivery
- For following periods:
ATP = Scheduled receipts during the period – Allocations prior to the next inbound delivery
Explain the order process with Make-to-Delivery-Schedule
Make-to-delivery-schedule: Manufacturing takes place according to a predetermined schedule, in line with an overall agreement.
Call-offs made to initiate delivery.
Explain the order process when make-to-order (MTO)
- Final product unknown, semi-finished products and purchased products unknown o some extent.
- Products must be specified before an order can be prepared.
- Available to promise calculations must consider both access to materials and access to capacity.
What is the definition of S&OP?
“Function of setting the overall level of manufacturing output and other activities to best satisfy the current planned levels of sales, while meeting general businesses objectives of profitability, productivity, competitive customer lead times etc. as expressed in the overall business plan.”
What is the aim of S&OP?
To achieve balance between supply and demand in such a way that a company’s efficiency and competitiveness are promoted.
- Demand: Forecast, Customer order
- Supply: Inventory, production capacity
- To integrating organizational functions in the process and create consensus among one set of goals and plans.
- Actual contracts may be written.
What is the S&OP process?
Input
- forecast
- restrictions
- goals
–> Activities 1-5 –>
Output
- supply vs demand
- plan integration
- marketing sales
- production
- logistics
- purchasing
- finance
What are the inputs to S&OP?
- Market and customer data, to anticipate the future demand.
- A forecast of aggregate demand covering the selected planning horizon (12-24 months)
- The current status of the system in term of workforce level, inventory level, production rate, supplier capabilities etc.
- The options available to adjust capacity
- The options available to adjust demand
What are the outputs from S&OP?
A sales plan, a delivery and a production plan: Decision for each planning period within the planning horizon about issues like:
- workforce and capacity levels
- inventory level, or customer lead-time and order backlog
- production rate
Projected costs and cash flow if the production plan was implemented - i.e an economic evaluation
“One set of numbers”
What is the difference between S&OP and budgeting?
Budgeting is a financial statement. S&OP is a long term plan for sales and production.
The sales and operations plan could be constrained by the budget and may also be an important input to the budgeting process.
What are the S&OP design parameters?
- Planning object: What does production and delivery plan refer to? Product group, product family, etc.
- Capacity unit: On what level do we consider capacity? production plants, workshops, assembly lines?
- Planning horizon
- Frequency
What are the activities in S&OP?
Step 1:
Forecast future demand
Step 2:
Prepare preliminary delivery plan
Step 3:
Prepare preliminary production plan
Step 4:
Adjust delivery plan and production plan
Step 5:
Establish delivery plan and production plan
Explain step 1 in S&OP
STEP 1: Forecast future demand
- Forecast - often from marketing/sales department: expected demand in coming period
- Should be as realistic and accurate as possible
- Does not consider potential capacity restrictions
Explain step 2 in S&OP
STEP 2: Prepare preliminary delivery plan
- Compare previous delivery plan with volumes actually delivered
- Adjustments can be made compared to the forecast
- Plan to deliver less, e.g. to phase out product
- Plan to deliver more by use of e.g. price reductions or marketing campaigns.
Establish goals for finished good inventory or order backlog (Make to Stock vs. Make to Order)
What differate MTS and MTO in a S&OP context?
MTS:
Production plans and delivery plans are balanced with changes to the inventory levels (finished good)
MTO:
Production plans delivery plans are balanced with changed to the order stock
Explain step 3 in S&OP
STEP 3: Prepare preliminary production plan
- Compare previous production plan with volumes actually produced
- Takes the preliminary delivery plan as a post of departure
- Considers the balance between delivered volumes, produced volumes and inventory/backlog
- Considers available capacity and start-up materials
Explain step 4 in S&OP
STEP 4: Adjust delivery plan and production plan
Meeting including representatives from:
- marketing/sales
- operations (i.e purchasing, production, logistics)
- finance
Make adjustments:
- delivery plan
- production plan
- inventory levels/backlog
Explain step 5 in S&OP
STEP 5: Establish delivery plan and production plan
Delivery plan and production plan are put forward to top management
Signifies and agreement within the company:
- Marketing department undertakes to sell agreed volumes
- Production and purchasing undertake to produce agreed volumes
What consideration to capacity should be taken considering S&OP?
Consideration to limited amount of capacity in terms of critical or scarce resources:
- Raw materials and components
- Production resources
- Transportation resources
- Storage space
- Supplier capacity
- …
What are the stages and categories in S&OP maturity?
STAGES
- Stage 1: No S&OP process
- Stage 2: Reactive
- Stage 3: Standard
- Stage 4: Advanced
Categories:
- Meeting & collaboration
- Organisation
- Measurements
- Information technology
- S&OP plan integration
What can lack of S&OP lead to?
- Unstable planning conditions (too much/little material and finished goods inventory, capacity, buffers, flexibility)
- Poor customer service
- Conflicting goals (no cross-functional discussions and agreements)
Give an equation for production volume
Production Volume = Volume delivered + ending inventory - starting inventory
Explain monitoring of S&OP
It’s important to monitor actual results and compare to the sales and operations plan
Act upon deviations:
- E.g if inventory is increasing beyond plan, reduce the production rate
Hire/fire staff to accommodate changes? Or use temporary staff?
- Possible to make quick and drastic changes
- .. or to distribute the changes over time
Explain planning horizon
A long planning horizon is associated with uncertainties. How long horizon is actually needed?
The horizon applied must be “long enough”:
- sufficient for budgeting
- seasonal variations and business outlook
- time to adapt capacity
- accumulated product lead-time
Explain time fences for changes in plans
It takes time to make changes, production plans cannot be changed too much too quickly.
Time fences regulate what changes are allowed with which horizon.
Example:
• Month 1 (coming month): no changes to volume allowed
• Month 2: Maximum 20% change allowed
• Month 3: Maximum 40% change allowed
• Month 4: No limitations on basis of current plan
Explain generally what master production scheduling is
- A plan that defines the specifics goods that specifics shops will produce in definite quantities at definite times over a shorter term horizon compared to S&OP, in accordance with the aggregate plan from S&OP.
- Typically stated in product specification terms (end product numbers)
- The basis for promising delivers to customers.
- ATP
- The master production schedule does not present an executable manufacturing plan, further details are needed
What is the difference between S&OP and MPS?
The primary use of the aggregate production plan from S&OP is to balance the production schedule so that the production costs are minimized, given a certain service level and to ensure capacity is available for this.
However, the output of an aggregate plan does generally not indicate individual products. This means that for more detailed planning, the aggregates plan must be dis-aggregated into individual products. The result of such a dis-aggregation is what is known as the master production schedule.
- Partly the same principle used for S&OP and MPS
- May be treated as one single planning level:
- If no reason to plan at product group level, eg. very few end items
- Required planning horizon not too long
- Stable ordering
- MPS tends to be more of calculation compare to S&OP
- MPS must consider incoming customers orders, or cancellations and sometimes deduct orders from forecast (order consume the forecast)
In which term can MPS be stated?
- End-item products
- Options or modules from which a variety of end products could be assembled
- Number of units of an “average” final product configuration
- Applicable when assemble-to-order
What is the MPS process?
Input
- S&OP
- restrictions
- customer orders
–> Activities 1-5 –>
Output
- MPS
- Delivery plan
- Input to ATP
Explain the MPS activites
Step 1:
Forecast future demand
Step 2:
Generate preliminary delivery plan
Step 3:
Generate preliminary MPS
Step 4:
Adjust delivery plan and MPS
Step 5:
Establish delivery plan and MPS
How do the MPS and S&OP differ?
- MPS basically have the same steps as in S&OP but with a shorter planning horizon and a higher level of detail.
- MPS is less of a process, more calculations.
- Fewer people and departments involved for MPS activities.
What are the MPS design parameters?
- Planning object
- The capacity unit
- Planning horizon
- Frequency
How should the planning horizon be for MPS?
Often desirable to have a planning window including several weeks of production