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Lesson 3 Layout & Flow. Sandwich making. ' If you were making a sandwich for a friend how would you do it? ' If you were making sandwiches for a whole group of friends who were due to arrive in an hour’s time, how would your process change? ‘
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Sandwich making • 'If you were making a sandwich for a friend how would you do it? • 'If you were making sandwiches for a whole group of friends who were due to arrive in an hour’s time, how would your process change?‘ • 'If you were making 5,000 sandwiches a day for a supermarket, how would you wish to organize the production system?'
Sandwich making • Sandwich for a friend - What kind of sandwich would they want (limited only by the availability of ingredients in the kitchen), when do they want it? (it could be made to order), and how much it could be customized (more salt and pepper) • Whole group/1hour arrival (You would butter all the bread together, standardize the products to some extent, and so on). • ‘Making 5,000 sandwiches a day for a supermarket?'(would need to use an assembly line or process, etc.).
Volume & Variety • Layout and flow cannot be discussed without first considering : • The product volume and variety • The type of process to be employed • These factors are inextricably linked
Volume and variety Project process Jobbing process Batch process Mass process Continuous process Decision 1 Process type Strategic performance objectives Fixed position layout Process layout Cell layout Product layout Decision 2 Basic layout type Decision 3 The physical position of all transforming resources Detailed design of layout The flow of the operation’s transformed resources How decisions might be connected (Slack2004)
Volume & Variety • Product volume – quantity of units produced • Product Variety – is the variation in products (SKU’s) • Product volume and variety is affected by the type of business and the market demand for products
Volume-Variety Dilemma Low VOLUME High High Not possible? VARIETY Accepted continuum for processes Not viable? Low
Volume & Variety • Product volume and variety have a big influence on process design. • The two dimensions normally go together: • Low volumes operations normally have a high degree of product variety. [automotive component supplier] • High volume operations normally have a low degree of product variety.[canning plant] • The same organisation can have different parts of the operation organised differently – [large automotive OEM] • Volume/Variety is seen as having a large Influence upon the process type deployed
Volume & Variety • Process types in manufacturing are generally considered as: • Project Processes • Jobbing Processes • Batch Processes • Mass Processes • Continuous Processes • The volume/variety position points to the most appropriate process
High Project Jobbing Batch Variety Mass Contin- -uous Low Low Volume High Manufacturing Process Types Notice how process types overlap! Process types are designed to cater for the volume /variety mix
Project Processes • One-off, complex, large scale, high work content “products” e.g. construction projects • Speciallymade, every one customized i.e. a project! • Defined start and finish: time, quality and cost objectives • Many different skills have to be coordinated • Fixed position layout, resources brought to product
Jobbing Processes • Also deal with high variety / low volume • Very small quantities: “one-offs” • Speciallymade. High variety, low repetition e.g. bespoke suits • Skill requirements are usually very broad • Each job has to share resources with other jobs • Fixed position or process layout (routing decided by jobbers)
Batch Processes • Higher volumes and lower variety than for jobbing • Standard products, repeating demand. But can make specials • Specialized, narrower skills • Set-ups (changeovers) at each stage of production • Can use process or cellular layout, has a predetermined planned routing
Mass (Line)Processes • Higher volumes than Batch • Standard, repeat products • Low and/or narrow skills • No set-ups, or almost instantaneous ones • Cell or product layout: a fixed sequence of operations
Continuous Processes • Extremely high volumes and low variety: often single product • Standard, repeat products • Highly capital-intensive and automated • Few changeovers, if any, required • Difficult and expensive to start and stop the process • Product layout: usually flow along conveyors or pipes
INCREASING VARIETY INCREASING VOLUME PRODUCT CHARACTERISTICS Low volume Low standardization Low volume Multiple products Higher volume Few major products High volume High standardization Random flow (project) Custom furniture maker Jumbled flow (jobbing) Machine tool maker Disconnected line flow (batch) PROCESS CHARACTERISTICS Automobile factory Connected line flow (mass) Petro- chemical refinery Smoothflow (Continuous) The Product/Process Matrix
Volume Manufacturing operations process types Service operations process types Variety Project Professional service None More process flexibility than is needed so high cost Jobbing Service Shop Batch Less process flexibility than is needed so high cost Mass None Mass service Continuous The ‘natural’ line of fit of process to volume/variety characteristics Deviating from the ‘natural’ diagonal on the product-process matrix has consequences for cost and flexibility
Layout and F low • Layout decisions have to be carefully thought out: • Size and complexity of equipment involved • Cost • Resource and time • Disruption to production and customer service • Complex and ‘muddled’ production flows can evolve if not designed and monitored properly
Layout • Product volume and variety dictate the process type selected. • Areas of overlap exist where more than one type could be applicable – in this case operational objectives are used to make decision: cost, flexibility, known future areas of growth etc. • There are four broad layouts • Fixed position • Process • Cell • Product
Layout • It is important to note that one process type does not mean one layout type. • There are normally choices associated with jobbing processes, batch processes and mass processes.
The nature of the basic layout types Manufacturing B asic layout Service process types types process types Fixed Project processes Project processes Professional position layout services Jobbing processes Process layout Service shops Batch pro cesses Cell layout Mass services Mass processes Product layout Continuous processes
Fixed Position • Transformed resources do not move • Equipment and resources move to the product which is stationery. • Normally because product is too large, i.e. shipbuilding, aero-engine, power generators. • Or too delicate or fragile – heart transplant patient • Main problems associated with this type of operations are space and scheduling issues: • Adequate space for groups to work without interference • Storage for materials and equipment • Scheduling of material and people is key to FP success
Fixed Position Example • Case study exercise – ALSTROM • Pg 209 • In groups of 2-3 discuss the set questions. • Question 2 should be answered in relation to performance metrics - Quality, Speed, Dependability. Flexibility and Cost
Alstrom Case Study • 1. What factors at each site are likely to influence the layout? • Although the generators themselves will be relatively standard (though there are some variations) the installation of each will be slightly different where the generator interfaces with something else. The input of fuel, the output of generated electricity, and the way in which the generator is fixed to its foundations will all depend on the customer’s site. So, for example, the geometry of the site could be important. Very large pieces of the generator will have to be brought in and positioned in the site. If access to the site is restricted this may have to be done in a non-standard manner. Similarly, some of the services required by the product (compressed air, water, etc.) may not be available at the right place. These will also have to be provided.
Alstrom Case Study • 2. Parts of the product are assembled in the factory and transported to the site. What advantage does this give the company? • The advantages to the company can be classed according to our normal five performance objectives as follows. • Quality – Assembling large parts of the generator at the factory ensures that the job will be done by skilled staff who can make sure that any small problems in assembly are solved at the point where there are the appropriate facilities. Assembling parts on the site introduces more variables which may undermine the quality of the product. • Speed – It will be faster to assemble parts in the factory using an appropriate layout than trying to do the same on the site where conditions are less predictable. • Dependability – Again, the relatively predictable conditions of the factory will allow assembly to be carried out to a schedule. Assembly on site is prone to disruption from the other tasks taking place on the site. • Flexibility – Standard parts, assembled at the factory, can be used for more than one customer. So, for example, if one part, when it gets to the site, is found to be unsatisfactory another one can be rushed to it at short notice. • Cost – Making many of the same part in the factory (even if the part is fairly large) is obviously cheaper than assembling everything on site.
Process Layout • Resource types dominate layout decision • Similar process are located together – for convenience or utilisation • Parts are routed through the operation based upon their requirements • Flow patterns are different and complex • Control and visibility is also an issue • Example of use – production of aero-engine parts – many different processes involved.
Cellular Layout • Where all the required resources are available in one area to meet the processing needs. • Can be of the product or process layout type. • After completion the product may be finished or go to another cell. • Cells attempt to bring order to the product flow
Product Layout • Each product follows the same route • Can also be known as flow-line • Flow is clear predictable and therefore offers visibility and ease of control. • Products produced are standardised (although small variations are possible) – but flow route is the same. • Examples – car assembly, electronic goods etc.
Advantages and disadvantages Fixed Process Cell Product position layout layout layout layout Very high product High product and Can give good and mix flexibility. mix flexibility. compromise. Low unit costs for high volume. Product/customer Relatively robust Fast throughput. A dvantages not moved. in the case of Opportunities for disruptions. Group work can specialization of High variety of result in good equipment. tasks for staff. Easy to supervise. motivation. Can have low mix Very high unit Low utilization. Can be costly to flexibility. costs. rearrange existing Can have very layout. Not very robust to Disadvantages Scheduling space high WIP. disruption. and activities can Can need more be difficult. Complex flow. plant. Work can be very repetitive.
Next Week • No tutorial sessions on Monday 15th October • Answer SAQ for Unit 1 - Lesson 3 • Read Unit 1 lesson 4 of study guide LAYOUT DESIGN TECHNIQUES – LINE BALANCING
