Automotive Production Flashcards
Master Production Scheduling
Objectives
Service-oriented Efficiency-oriented
Delivery capability Leveling
Scheduling costs in order promising Costs due to unbalanced
(e.g., discounts due to late delivery) production programs
Delivery reliability Inventory
Costs of delayed completion Costs of early
delivery (e.g., penalty payment)
Objectives:
of assembly line balancing:
WS18/19
SS18
Minimizing the number of stations for a given cycle time (1P)
Minimizing the cycle time for a given number of stations (1P)
Subject (Planning Task) of assembly line balancing:
WS18/19
SS18
Assignment of elementary work operations (1P) including the required
equipment to the productive units (stations) (1P) of a flow production
system
Introduction to Assembly Line Sequencing
Planning task
WS16/17
SS18
Objectives
Avoidance of work overload(The process times of some stations exceed or undercut the determined average time
)
Balancing of labor-intensive and less labor-intensive process steps(Example: Electric vs. manual sunroof)
Continuous material flow
A great variety of options calls for a high variety of materials and parts
Sequencing has to consider this if the individual parts shall be delivered JIT to the line
Challenges
High product variety
Mostly fixed costs
Dynamic interdependencies between production and logistics
Planning task
Determing a production sequence for multiple variants within a flow production system
Overview of planning tasks in order-driven automotiveproduction
longterm: Network Planning (Demand Forecasting & Planning)
mediumterm: Purchasing Structure and Logistics - Assembly Line Balancing - Capacity Planning - Distribution Structure and Logistics (Demand Forecasting & Planning)
shortterm:Material Requirement Planning - Order Promising and Master Production Scheduling
Inventory Management- Assembly Line Sequencing
(Distribution Planning - Order Promising)
Supplier–Purchase–Production–Distribution–Sales–dealer/ end customer
Name two planning tasks that are closely interlinked with assembly line sequencing and answer the following questions for each of them: What decisions are made within the planning task? How do these de-cisions affect assembly line sequencing?
SS18
Assembly line balancing (1 point): Within assembly line balancing the work elements are assigned to the stations of the line (1 point). Thus, the processing times of the different models/variants at the sta-tions are determined. These station times have to be considered with-in assembly line sequencing to minimize work overload. A poor line balance will generally result in many work overload situations. (2 points)
Master production scheduling (1 point): Within MPS the production quantities per day/shift for the product variants are determined (1 point). Assembly line sequencing has to create a production se-quence based on these quantitieswith the objective of minimizing work overload and/or leveled material supply.If the MPS is not care-fully planned many work overload situations will occur. (2 points)
Name and describe two events that affect the production sequence and therefore require reshuffling an initial sequence during production.
Material shortages: In the event of defects or missing parts for a certain model the production sequence cannot be produced as planned. The model has to be removed from the sequence which might require reshuffling the sequence to avoid work overload / smoothen material supply.
Machine failures: In the event of a failure of a machine that is required to perform a certain work step (e.g., handling robot to assemble a panoramic sunroof) the production sequence also has to be reshuffled.
Rush orders: In the event of rush orders the sequence has to be reshuffled to expedite the completion of the rush order.
task of capacity planning
Determine the mix of flexibility instruments that allows for the economic adjustment of production and labor capacities und stocks of an existing flow production to satisfy a given demand for multiple products.
Main challenges:
o Resources with limited flexibility (1 point)
o Fluctuating demand (1 point)
Importance of long-term planning horizon:
Long-term planning
horizon necessary since most of the flexibility instruments require a lead time (1 point). For instance, adjusting the labor capacity requires several months since qualified personnel has to be recruited (1 point).
What happens to the production plan from
Figure AP 2.1 if only two
changes of the production capacity are allowed over the whole planning horizon? Explain the effect
of this restriction on the total cost of
the production plan and the stock levels.
Effects of restricting the number of changes to two:
Total costs will increase (1 point) since capacity cannot be adjusted for each period based on the demand and therefore more expensive capacity stages with a higher capacity have to be used for a longer period of time. (1 point)
Stock levels will increase (1 point) to satisfy the demand in the last periods from stock and change into a capacity stage that leads to lower costs. (1 point)
Assumptions of SALBP
SS17
- Mass production of a homogeneous product
- All working processes are performed in a predefined form (no alternative)
- Assembly line with (fixed) cycle time corresponding to the planned demand
- No consideration of pre-assembly and parallel stations
- A well-defined precedence graph is available
- Deterministic processing times
- No assignment of secondary activities beyond the precedence graph
- One operation takes a maximum of the cycle time
- All stations can be equally equipped with machines and workers
- Sequential execution of operations (no parallel work)
Shortly explain
thefunction of nodes
, edges and edge ratings
in the context of precedence graphs.
Nodes correspond to operations; identification through number
Edges (i, j) correspond precedence relations between nodes i and j
The edge rating equals the processing time of the upstream node i
Planning Approaches
Mixed-model sequencing
Minimization of work overload by a detailed classification, which explicitly considers processing times, movements of workers and station boundaries.
Car sequencing
Minimization of work overload by an implicit consideration of the restrictions. Sequencing-rules of the type Ho:No – for No sequence positions, a maximum of Ho units with option o are permitted.
Level scheduling
Orientation at the JIT philosophy: Ideal production rates are specified and the sequence is designed to minimize the difference between ideal and real planning. The material requirements can additionally be considered.
Which type of production networkdoesthe German car manufac-turer currentlyusefor customers from all over the world? Namethetype of networkand two advantagesof thistype of network. Whichtype of production networkwould you recommendtothe company to enter the Chinesemarket? Namethe type of networkand give two argumentsfor your recommendation.
World factory (1p)
Advantages:Low production costs (1p)Economies of scale and synergies (1p)
Local production (1p)
Reasons (max. 2p)
:High local adaption requirements (1p)
High local-content-requirements resp. high transactional costs (e.g. transport, tariffs) (1p)
New model
lower opportunities for economies of scaleat existing plant(1p)(Further criteria: Image in local countries)
Typical Allocation Strategies
ss18/19
Allocation is the assignmentof a product to a location(product-plant-link)
Allocation strategy defines underlying principles of
allocation decisions in the production network
Allocation strategy determines the degree ofallocation flexibility
Solitairestrategy
Chainstrategy
„Peak breakerplant“
Totalflexibility
Chain Strategy best.
Argumentation (3P):
Need for a flexible and robust production system due to fluctuating demand
Need for an efficient production
system due to high investments
Uncorrelated demand allows for compensation of capacity utilization
between different car models that can be produced in the same plant
Name two kinds of coststhatwould still differ between the locations despite the trade agreement? Would theworldwide trade agreement reduce the relevance of model-based location and allocation planning? Briefly explainyour answer.
Max 2PLogistics costs (1P)
Labor costs (1P)Material costs (different prices in different countries because of differ-ent labor and logistics costs) (1P)
With a world-wide trade agreement, the complexityof the decision problem wouldbe lower because uncertainties in exchange rates and tariffs can be disregarded. However,it is still necessary to evaluate the material and logis-tics costs and network effects of location and allocation decisions.Material availability and costs, as wellas local demand patterns and distribution costs still have to be considered.Necessity of planning and planning effort remain high, model-based decision support remains relevant.
Location Planning und Allocation Planning
Location Planning
Planning task:
Opening and closing of plants
Definition of aggregate capacities
Characteristics High investments for new plants Challenge of demand prediction for each product More flexible equipment leads to more flexible in production Political influence regarding opening and closing of plants Local content restrictions Selected location influence material, logistics, personnel costs, as well as delivery times
Allocation Planning
Planning task:
Allocation of models/products to plants/locations
Definition of product-specific capacities
Characteristics
Product-specific equipment at each plant
Irreversible decisions about capacities at the beginning of the product life cycle
Challenge of demand prediction for each product
Depending on the selected location, allocation has great influence on material, logistics and personnel costs, as well as delivery times
Based on the mathematical optimization model given above, the ob-jective is to maximize production volume. From a business economics perspective, elaborate why this objective functio is reasonable. What kind of objective function would you choose if the model would additionally decide on the capacity level of every plant?
Explanation given obj
ective function (4P) (2P for each correct
argument):
Capacity, capabilities,
and demand are assumed to be given and thus
fixed costs are independent of model decisions (2P)
Assuming a positive contribution margin, it makes most sense to max-
imize production volume to maximize revenue and profit (2P)
New objection function if model decides on capacity level (2P):
Maximize profit, as costs are now dependent on the capacity le
vel chosen by the model and so are the revenues (because of variable production volume)
Briefly explain the differences between a “Chain” and a “Hub and Spoke” production network. Make use of the criteria “economies of scale and synergies” and “transportation and transactional costs” to explain under which conditions which network type should be preferred.
ss18/19
Chain: Different production steps are carried out at different locations. The markets are then supplied centrally from the plant with the last production step (1P)
–>Utilization of economies of scale when transaction costs to the markets hardly play a role (2P).
Hub and Spoke: Only the last production step is executed in the target country. Vehicles are completed in the target country (1P)
–>Exploiting economies of scale when transaction costs are very high (2P).
There are two different approaches Multi Variant Models
(MALBP) can be modelled. Name bothof them
SS18
SALBP with mixed precedence graph (1P)
MALBP with variant-specific processing times (1P)
Nametwo flexibility instruments of capacity adjustment. Explain
briefly how capacity adjustment
can reduce the work overload.
Overtime hours (1P) Changing number of shifts (1P) Longer/shorter shifts (1P) Labour time account (1P) Leased workers (1P) Variable cycle time (1P)
By using the flexibility instruments the capacity can be changed. With a
higher capacity per day/shift ,more cars can be produced at the same time
respectively. Therefore,
there is more capacity/time to produce one car and the work overload will be reduced. (2P)
Order Processing Strategies
order penetration point (OPP)
The order fulfillment process (also: order-to-delivery-process) comprises the set of virtual and physical activities to provide each customer with the vehicle of his or her chosen specification.
The order penetration point (OPP) separates forecast-based and order-related processes. It materializes as a stock for compensating imperfect forecasts.
Global Production Networks of the Automotive Industry
Elements: Production location Procurement market Sales market Trade Area
Relations between the elements:
Material and product flows
Trade agreements
Local content restrictions
Global production network with locations in various trade areas, different sales
markets, and interconnected material-flow relations
Assessment of SALBP
(+) Basic structuring of the decision situation
(+) Easy to use, but already NP-hard
(+) Output or standard model as a basis for adjustments
(+) Solution method - at least in broad terms - transferable
(-) Due to simplifications (rather) unrealistic
Assessment of MALBP
Still rather unrealistic
Hard to solve–>use of heuristics
Determination of the variant-specific processing times at the stations is difficult due to the high volume of data
Only time-oriented objective functions
No consideration of cash flows and investments
