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Process selection

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ContentsContents

1- What is process?1- What is process?2- Factors affecting process selection2- Factors affecting process selection3- Types of processes:-3- Types of processes:- (A) - Project.(A) - Project. (B) - Job shop.(B) - Job shop. (C )- Batch.(C )- Batch. (D) - Assembly line ( mass)(D) - Assembly line ( mass) (E) - Continuous(E) - Continuous

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1-What is 1-What is process?process?

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What is the process?What is the process? ProcessProcess (or process technology)(or process technology)

is a is a specific combinationspecific combination of of machines, operators, work machines, operators, work methods and systems, methods and systems, materials, and environmental materials, and environmental factors that togetherfactors that together convert convert inputs to outputs.inputs to outputs.

Simply Process technology Simply Process technology refers to : refers to : equipment, people, equipment, people, and systemsand systems used to produce a used to produce a firm's products and servicesfirm's products and services.

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2 -Factors 2 -Factors affecting process affecting process

selectionselection

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Factors determining process selectionFactors determining process selection The selection of a process structure is determined by many The selection of a process structure is determined by many

factors. factors. Four of the most important are these: are these: 1. The expected volume and1. The expected volume and demand pattern for the products. pattern for the products. 2. 2. The number of different products to be made by the to be made by the

system and the types of processing each requires.system and the types of processing each requires. 3. 3. The customerThe customer order type, , which defines whether the which defines whether the

product isproduct is made to stock ( (the product's characteristics are the product's characteristics are set by the producer, and the product is normal made in set by the producer, and the product is normal made in advance of orders), oradvance of orders), or made to ordermade to order ( (the product is made the product is made on receiving customer's order, and its characteristics may be on receiving customer's order, and its characteristics may be specified by the customer). specified by the customer).

4. 4. TheThe physical characteristics of the products and the and the specific technologies require to produce them.specific technologies require to produce them.

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3-Types of 3-Types of production production

systemssystems

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Types of processesTypes of processes

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Process selection in manufacturing- Types of processesProcess selection in manufacturing- Types of processes

1- Project process:1- Project process:Process that focuses on making Process that focuses on making one-of-a-kindone-of-a-kind products. products.

2- Intermittent process::2- Intermittent process::Process that produces products in Process that produces products in small lot sizessmall lot sizes (e.g., job and batch (e.g., job and batch operations)operations)

3- Line-flow process:3- Line-flow process:Continuous process that produces Continuous process that produces high high

volume, volume, highly highly standardized products standardized products

(e.g., assembly-line and continuous operations).(e.g., assembly-line and continuous operations).

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Types of production systemsTypes of production systems

Five types of process technologies are:

1- Project. 2- Job shop. 3- Batch. 4- Assembly line, and 5- Continuous. Each is more or less suited to different product/market situations,

and each has its unique operating characteristics, problems, and challenges.

As we move from project production process to continuous flow, variety decreases, and volume increases (high variety - low volume)

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(A) -Project (A) -Project

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(A) -Project(A) -Project Project technology deals with Project technology deals with one-of-a-one-of-a-

kind kind products that are tailored to the products that are tailored to the unique unique requirements of each customer (a unique and requirements of each customer (a unique and usually usually large and complex large and complex item is item is produced ).produced ).

Since the products cannot be standardized, the Since the products cannot be standardized, the conversion process must be conversion process must be flexible flexible in its in its equipment capabilities, human skills, and procedures. equipment capabilities, human skills, and procedures.

The major The major strength strength of a project-type process is of a project-type process is that it is totally that it is totally flexible flexible to meet the individual to meet the individual needs of the customerneeds of the customer

(A) -Project(A) -Project Examples here include the production of a Examples here include the production of a

movie and the construction of a skyscraper movie and the construction of a skyscraper building , and a customized car .building , and a customized car .

Highly skilled personnel are usually Highly skilled personnel are usually requiredrequired for this type of process, as they often must work for this type of process, as they often must work independently, with minimal guidance and independently, with minimal guidance and supervision. supervision.

In addition, workers here need to be well In addition, workers here need to be well trained in a variety of tasks. trained in a variety of tasks. (Labor skills and (Labor skills and costs are generally high)costs are generally high)

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(B) - Job shop(B) - Job shop

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(B) - Job shop(B) - Job shop Job-shop production processes produce a Job-shop production processes produce a widewide variety and variety and

smallsmall quantity of specialized products. quantity of specialized products. Products are generally Products are generally customizedcustomized; ; they may be produced they may be produced

by entirely different sequences of operationsby entirely different sequences of operations.. Job shops are essentially Job shops are essentially make- to order make- to order

systems, whereas continuous flow, mass, and batch systems, whereas continuous flow, mass, and batch production processes are generally production processes are generally make-to-make-to-stockstock processes. processes.

More general-purpose equipment is usedMore general-purpose equipment is used, and there is less , and there is less opportunity for specialized, automated equipment. opportunity for specialized, automated equipment.

The labor force must be highly skilled and able to The labor force must be highly skilled and able to perform perform a wide variety of tasks on different jobs. a wide variety of tasks on different jobs.

Unit production Unit production costs are highercosts are higher than for other production than for other production processes. processes.

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(B) - Job shop(B) - Job shop Job shop technology is appropriate for manufacturers of Job shop technology is appropriate for manufacturers of small small

batches of many different productsbatches of many different products (high variety - low (high variety - low

volume)volume) , , each of which is custom designed and, each of which is custom designed and, consequently, requires its own unique set of consequently, requires its own unique set of processing steps, or routing, through the production processing steps, or routing, through the production process. process.

Some prefer to Some prefer to define job shop production as a process define job shop production as a process where a specific quantity of a product is produced where a specific quantity of a product is produced only only once.once.

Each job or product is different from the others and Each job or product is different from the others and no repetition is no repetition is involvedinvolved.. Therefore, each job is individually plannedTherefore, each job is individually planned. .

- Numbered prints from a painting, programs for concerts, and T-shirts - Numbered prints from a painting, programs for concerts, and T-shirts commemorating specific events are good examples of products commemorating specific events are good examples of products made in a job shop processmade in a job shop process

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Job shop -Job shop -advantages Flexibility Flexibility to respond to individual demands to respond to individual demands

((can be adapted easily to changes in product can be adapted easily to changes in product design.( because of general purpose machines design.( because of general purpose machines and facilities variety of products can be and facilities variety of products can be produced)produced)

Less vulnerable to equipment Less vulnerable to equipment breakdowns breakdowns (a (a fault fault in one operation in one operation does does not result into completenot result into complete stoppage of the stoppage of the entire processentire process))

Less expensive Less expensive general purpose equipment general purpose equipment usedused

Operators will become more skilled Operators will become more skilled and competent, and competent, as each job gives them as each job gives them learning opportunitieslearning opportunities

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Job shop- DisadvantagesJob shop- Disadvantages

1. General-purpose equipment is usually 1. General-purpose equipment is usually less less efficient efficient at processing materials. at processing materials.

2. 2. More skilled, higher-paid employees More skilled, higher-paid employees are are needed to set up and operate general-purpose needed to set up and operate general-purpose equipment and to equipment and to modify work methods to modify work methods to make a variety of products. make a variety of products.

3. Work-in-process inventories 3. Work-in-process inventories are needed are needed to to keep the work centers operating keep the work centers operating during during equipment setupsequipment setups, as well as to provide the , as well as to provide the scheduling flexibility needed to coordinate the scheduling flexibility needed to coordinate the variety of products and job processing times. variety of products and job processing times.

4. The large in-process inventories and flexible 4. The large in-process inventories and flexible material-handling systems require material-handling systems require more more space space . .

Job shop- DisadvantagesJob shop- Disadvantages55. . Quality conformance is difficult Quality conformance is difficult because because

workers must be familiar with a wider range of quality workers must be familiar with a wider range of quality requirements, they perform more product requirements, they perform more product changeovers, and they cannot spend as much time changeovers, and they cannot spend as much time refining their work methods for anyone product. refining their work methods for anyone product.

6- The 6- The variability in process sequencingvariability in process sequencing, lot , lot sizes, and processing sizes, and processing timestimes, as well as possible , as well as possible uncertainty about order receiptsuncertainty about order receipts and due dates, make and due dates, make scheduling and coordinating jobs and equipment very scheduling and coordinating jobs and equipment very complex. These factors, along with the large in-process complex. These factors, along with the large in-process inventories, inventories, result in long throughput times. result in long throughput times.

7- Much time is spent waiting for 7- Much time is spent waiting for access to access to equipmentequipment; some equipment is ; some equipment is overloadedoverloaded while other equipment is while other equipment is idle,idle, depending upon the depending upon the mix of jobs at hand.mix of jobs at hand.

Speed of work is slow and unit costs are high.Speed of work is slow and unit costs are high.

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(C) -Batch(C) -Batch

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(C)-Batch(C)-Batch Batch technology is a step up from job shop Batch technology is a step up from job shop

technology in terms of product technology in terms of product standardization,standardization, but it is not as but it is not as standardized as assembly line technology. standardized as assembly line technology.

Within the wide range of products in the batch Within the wide range of products in the batch facility, facility, several are demanded several are demanded repeatedlyrepeatedly and in large volumesand in large volumes..

These few dominant products These few dominant products differentiate differentiate batch facilities from job shopsbatch facilities from job shops..

Consequently, like job shops, batch facilities Consequently, like job shops, batch facilities produce a produce a wide wide variety of products in a variety of products in a widewide variety of volumes. variety of volumes.

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(C)-Batch(C)-Batch Batch production processes are used for producing Batch production processes are used for producing small lots small lots

of similar products. of similar products. The products are made in batches with short production runs, and The products are made in batches with short production runs, and

the the same sequence of operations is generally followedsame sequence of operations is generally followed. . Such processes usually Such processes usually differ from massdiffer from mass production in the production in the

materials used, machine setups, and layout. materials used, machine setups, and layout. More labor skills are necessary to set up machines and perform a More labor skills are necessary to set up machines and perform a

wider variety of tasks during production. wider variety of tasks during production. These These differences increase unit costs. differences increase unit costs.

Each batch contains identical items but every batch is different Each batch contains identical items but every batch is different from the others. from the others.

A particular operation on a batch is performed by one group and A particular operation on a batch is performed by one group and then it is then it is passed passed on to other groups for subsequent operations.on to other groups for subsequent operations.

Batch production is popular in bakeries and in the manufacture of Batch production is popular in bakeries and in the manufacture of shoes, pharmaceutical ingredients, inks, paints and adhesives.shoes, pharmaceutical ingredients, inks, paints and adhesives.

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Batch – advantages Batch – advantages Some degree of Some degree of specialization specialization is possible and capital is possible and capital

investment is comparatively low .investment is comparatively low . The batch method can be an advantage for businesses that The batch method can be an advantage for businesses that

produce a produce a range of products. range of products. It is It is cheaper to produce a number of each item cheaper to produce a number of each item

in one go in one go because machines can be used more effectively, the because machines can be used more effectively, the materials can be bought in bulk and the workers can specialize in materials can be bought in bulk and the workers can specialize in that task. that task.

It can It can reduce initial capitalreduce initial capital outlay because outlay because a single a single production line can be used to produce several production line can be used to produce several products .products .

Batch production can be Batch production can be useful for useful for small businesses small businesses who cannot afford to run continuous production lines. who cannot afford to run continuous production lines.

Batch production is useful for a factory that makes Batch production is useful for a factory that makes seasonal seasonal items or products for which it is difficult to items or products for which it is difficult to forecast demandforecast demand

Cost per unit is lower as compared to job shop Cost per unit is lower as compared to job shop productionproduction

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Batch- disadvantagesBatch- disadvantages The main problem in batch production is the The main problem in batch production is the idle time idle time between one between one

operation and the other. operation and the other. The work has to wait The work has to wait until a until a particular operation is carried out on the whole batchparticular operation is carried out on the whole batch ( (machines and machines and workers may be idle while waiting for a whole batch to finish its previous workers may be idle while waiting for a whole batch to finish its previous operation)operation)

Work-in-progress inventory is highWork-in-progress inventory is high, and large storage space , and large storage space is required. (Money is tied up in work-in-progress since an order cannot is required. (Money is tied up in work-in-progress since an order cannot be dispatched until the whole batch has been completed)be dispatched until the whole batch has been completed)

Due to frequent changes in product design Due to frequent changes in product design no standard sequence of no standard sequence of operations can be used. operations can be used.

Machine set-ups and tooling arrangements have to be Machine set-ups and tooling arrangements have to be changed frequentlychanged frequently. Often machinery must be . Often machinery must be cleaned and cleaned and adjustedadjusted and this takes time. and this takes time.

The workforce tend to be The workforce tend to be specialized specialized so they may be less motivated so they may be less motivated as they as they have to repeat operations have to repeat operations on every item in the batch so on every item in the batch so quality may be effectedquality may be effected..

If batches areIf batches are small small then unit then unit cost cost will remain relatively will remain relatively high.high. Production planning & control is Production planning & control is complexcomplex Material handling is Material handling is complexcomplex because of irregular and longer flowsbecause of irregular and longer flows

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(D) - Assembly (D) - Assembly lineline

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(D) - Assembly line(D) - Assembly line (Mass production)(Mass production)

Assembly line (or simply line) technology is for facilities that Assembly line (or simply line) technology is for facilities that produce produce a narrow range of standardized products.a narrow range of standardized products.

Since the Since the product designs are relatively stableproduct designs are relatively stable, , specialized specialized equipment, human skills, and management equipment, human skills, and management systems systems can be developedcan be developed and dedicated to the limited range and dedicated to the limited range of products and volumes. Beyond this range, the system is of products and volumes. Beyond this range, the system is inflexible.inflexible.

Assembly-line, (or mass) production processes are used for Assembly-line, (or mass) production processes are used for high-volume production of high-volume production of discrete discrete partsparts. Usually . Usually only a only a small variety of different products are small variety of different products are produced. produced.

As with continuous- flow production processes, As with continuous- flow production processes, specialized specialized equipment and automation are common. equipment and automation are common.

Machine setups are infrequentMachine setups are infrequent, , labor skill requirements are labor skill requirements are low,low, and as a result, unit costs also are low; and as a result, unit costs also are low;

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(D) - Assembly line(D) - Assembly line (Mass production)(Mass production)Mass production is used under the following Mass production is used under the following

circumstancescircumstances::

Standardization of product and process Standardization of product and process sequencessequences

Dedicated special purpose machines Dedicated special purpose machines Large volume of product.Large volume of product. Shorter cycle time of productionShorter cycle time of production Perfectly balanced production linesPerfectly balanced production lines Flow of material , components and parts is Flow of material , components and parts is

continuous and without any back trackingcontinuous and without any back tracking Material handling can be completely automatic.Material handling can be completely automatic.

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Mass production Mass production advantagesadvantages Production planning and control is easyProduction planning and control is easy

Material handling can be completely Material handling can be completely automatic.automatic.

Higher rate of production with reduced Higher rate of production with reduced cycle timecycle time

Higher capacity utilization due to line Higher capacity utilization due to line balancingbalancing

Less skilled operators are requiredLess skilled operators are required Low WIP inventory Low WIP inventory Manufacturing cost per unit is low.Manufacturing cost per unit is low.

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Mass production Mass production disadvantagesdisadvantages

Breakdown of one machine will Breakdown of one machine will stop an entire production line.stop an entire production line.

Line layout needs major change Line layout needs major change with the changes in the product with the changes in the product design.design.

High investment in production High investment in production facilitiesfacilities

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(E) -Continuous(E) -Continuous

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(E) - Continuous(E) - Continuous Continuous production processes are characterized Continuous production processes are characterized

by:by: HighHigh production volume and a production volume and a highhigh degree of product degree of product

standardization. standardization. Such processes useSuch processes use highly specialized highly specialized and dedicatedand dedicated

equipment andequipment and often a high degree ofoften a high degree of automation. automation. (Special (Special purpose automatic machines are used to perform purpose automatic machines are used to perform standardized operations.)standardized operations.)

Since the equipment is highly specializedSince the equipment is highly specialized, , there is little need there is little need to change machine setupsto change machine setups for different productsfor different products or for a or for a highly skilled work forcehighly skilled work force..

Because of the high volumeBecause of the high volume, , unit costs are generally low.unit costs are generally low.

Goods are produced in anticipation of Goods are produced in anticipation of demanddemand..

The productThe product designdesign, , the conversion process, the conversion process, and the and the operationsoperations sequencesequence are are standardized,standardized,

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Continuous - advantagesContinuous - advantages

The main advantage of continuous system is that work-in-progress inventory is minimum. As the processing of material is continuous and progressive, there is no waiting period.

Each work is passed to the next stage immediately after the previous operation is complete without waiting for the completion of work on the total batch.

As a result costs of materials handling are minimized and full use can be made of automation.

Few job instructions are needed and less storage space is required. Cost per unit can be minimized by investing in specialized equipments. The quality of output is kept uniform because each stage develops skill through

repetition of work. Handling of materials is reduced due to the set pattern of production line. Control over materials, costs and output is simplified. The repetitive nature of processes make

production control easier. There is quick return on capital employed Standardization of product and process sequence. Higher rate of production with reduced cycle time Higher capacity utilization due to line balancing Manpower is not required for material handling as it is completely automatic. Unit cost is lower due to high volume of production 24 hours-365 days

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Continuous - disadvantagesContinuous - disadvantages

Flexibility to accommodate Flexibility to accommodate and process number of and process number of products products does not existdoes not exist

Very high investment for Very high investment for setting flow linessetting flow lines

Product differentiation is Product differentiation is limited.limited.