Assembly Line ProductionIntroduction

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SNS COLLEGE OF ENGINEERINGKurumbapalayam (Po), Coimbatore – 641 107

AN AUTONOMOUS INSTITUTIONAccredited by NBA – AICTE and Accredited by NAAC – UGC with ‘A’ GradeApproved by AICTE, New Delhi & Affiliated to Anna University, Chennai

Definition-Assembly• Assembly - The process of putting

together a number of parts( to make amachine or other product).

- The act of combining components

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Definition - Line• Line – Is the Path and has direction

,length and thickness.

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Definition - Production• Production –The processes and methods

used to transform tangible inputs (rawmaterials,semi-finishedgoods, subassemblies)and intangible inputs (ideas, information,knowledge) into goods or services.

• Tangible - real , able to be shown, touched, or experienced.• Intangible - unable to be touched, not having physical

presence.

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Definition• Assembly Line Production

–is a manufacturing process in whichparts are added as the semi-finished assemblymoves from workstation to workstation where theparts are added in sequence until the finalassembly is produced.

- is a production process that breaksthe manufacture of a good into steps that arecompleted in a pre-defined sequence.

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PrincipleAssembly Line Production

The principle of an assembly line is that each worker isassigned one very specific task, which he or she simply repeats,and then the process moves to the next worker who does his orher task, until the task is completed and the product is made.

It is a way to mass produce goods quickly andefficiently.

All workers do not have to be human; robotic workers can make up an assembly line as well.

Note:

Principle - a basic idea or rule that explains or controls howsomething happens or works

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Advantages –Assembly Line Production

• Speed & Mass Production• Fair Product Cost• Affordable• Uniformity of finished products• Ease of repair• Standardized Parts

Employee• Specialization (in a specific task)• Average Skill level sufficient• Ease of job rotation• Able to share Improvements in Process, Product

etc

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Dis advantages –Assembly Line Production

• Higher initial capital investment• Inflexible Production facility• Need of specialized machines• Significant Space is required

Employee• Monotonous Work (Repetitive Work)• Missing of unique craftsmanship(Luxury items).• Motivational problems exists• Skill level balancing will be a problem• Overconfidence

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Production & Productivity

• Production - the volume of output irrespective ofthe quantity or quality of resources used to attainthat level of output. Refers only to quantityproduced. Measure of produced goods.

• Productivity -If we put in it element of efficiencywith which the resources are employed, we enterthe area of productivity.(How much is producedusing what with its quantity,quality)

Measure of efficiency or rate of production. (Output/Input)

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Production & Productivity• For Example consider Current Situation.

Engines Produced(Nos) Manpower utilized(Nos) Productivity =50Engines/50Men

= 50 Engines=50 Men=1Engine/1Men

Case 1:If we increase Engines produced to 60Nos and Manpower to 60Nos.Production has increased =from 50engines to 60 engines. Productivity remains Same.

That is 60Engines/60Men=1Engine/1Men

Case 2:If we increase Engine produced to 60Nos and Manpower remains sameat 50 Men. Here Production and Productivity both got increased. Production increase = from 50 Engines to 60Engines Productivity =60Engines/50 Men=1.2Engines/Men

Case 3:If we keep engines produced same at 50Engines and reduce manpower to 40Men.Production remains same.Productivity increase =50 Engines/40Men=1.25Engines/men

Case 4:If we increase engines produced to 68 Engines and increase manpower to 56 Men.Production has increased =from 50 engines to 68Engines. Productivity increase =68 Engines/56Men=1.21Engines/Men

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Standard Time

Standard time - is the time required by anaverage skilled operator, working at anormal pace, to perform a specified taskusing a prescribed method.

Standard time = Normal Time + Total Allowances

Note:Normal time = {(Time worked) / (Number of units produced)}*(Performance rating)

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Standard Time

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Line Balancing

Line Balancing - is leveling the workloadacross all processes in a cell or value streamto remove bottlenecks and excess capacity.Everyone is doing the same amount of work.No one is waiting.No one is overburdened.Variation is smoothed.

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Bottle Neck

Bottleneck - is one process in a chain ofprocesses, such that its limited capacityreduces the capacity of the whole chain.

Has Maximum Stage Time.Significantly slows down production.(Impacts the output).Have More WIP(work in process)The station that consumes more cycle time.Limits the capacity of the system.

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Bottle Neck

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How to reduce Bottle Neck

1. Possibility to Increase manpower.2. Possibility to increase machine/tools.3. Possibility to split the task and assign to

prior stage/Later stage.4. Outsourcing-Partial/Full.5. Automation-Semi/Full.6. Process improvement.7.Reduce Setup time.Eg- SMED Note:SMED

– Single -Minute Exchange ofDies.

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Assembly Line Balancing

Assembly line balancing - is a productionstrategy that sets an intended rate ofproduction to produce a particular productwithin a particular time frame.

That is “the work is divided in to series of elementary tasks with short durations”.

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Need- Assembly Line Balancing

To meet customer demand.To determine the speed of the assembly line.To determine the number of stages or number of workstations.To identify the bottleneck stage/operation.To equalize the workload among the employees.To reduce production cost.

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Models - Assembly Line Balancing

Model 1Tries to determine the minimum

workforce required to achieve a given desiredproduction rate.Model 2

Tries to determine the maximumproduction rate which can be achieved with agiven workforce.

Note:Once the Takt time is determined we

need to relate takt time with Man time,Machine Time & Setup time.

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Time StudyTime Study - a work measurement technique

consisting of careful time measurement of the task with atime measuring instrument to establish the time requiredfor completion of the task by a qualified worker whenworking at a defined level of performance.It will be adjusted for any observed variance from normal effort or

pace and to allow adequate time for such items as foreign elements,unavoidable or machine delays, rest to overcome fatigue, andpersonal needs.

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Motion Study

Motion Study -Motion study is asystematic way of determining the bestmethod of doing the work.

Systematic recording and criticalexamination of existing and proposed waysof doing work as a means of developingand applying easier and more effectivemethod and thereby reducing cost.

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Predetermined Motion Time System (PMTS)

PMTS - a procedure that analyzes any manualactivity in terms of basic or fundamental motionsrequired to perform it. Each of these motions isassigned a previously established standard timevalue and then the timings for the individualmotions are synthesized to obtain the total timeneeded for performing the activity.

Example for PMTS –MTM,MOST, etcMTM – Method Time MeasurementMOST - Maynard Operation Sequence Technique

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Lean Manufacturing

Lean manufacturing or lean production,often simply a systematic"lean", is method for waste minimization /elimination (“Muda”) within amanufacturing system withoutsacrificing productivity.

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Seven wastes - Lean Manufacturing1. Waste of overproduction (more than what the customer wanted)

2. Waste of rework (Defective product).3. Waste of waiting (the units should flow from one process to the

next and ultimately, to the customer without any waiting)

4. Waste of inventory (make it to order and invoice it - inventory has no

real value - a sale does!)

5. Waste of transport (reduce floor space , shrink the factory, reduce lead times)

6. Waste of motion (unnecessary movements - human)

7. Waste from the process(Over processing).

In modern times, 2 new wastes have been added

Waste of a human being (an example is a machine watcher) Waste of natural resources (save the planet)

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Six Sigma(6σ)Six Sigma is a disciplined, statistical-based, data-driven approach andcontinuous improvement methodology foreliminating defects /reducing variation ina product, process or service.

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Six Sigma(6σ) -Methodologies

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5’S’

5S - is used to organize the workplacewell so that it motivates people to performwell.

1. SEIRI-Sort Out(Segregate)2. SEITON-Set in order(Arrange& Identify)3. SEISO-Shine(Wipe & Clean)4. SEIKETSU-Standardize5. SHITSUKE-Sustain(Discipline)

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7 QC Tools

1. Check Sheet2. Cause & Effect Diagram3. Control Chart4. Histogram5. Pareto Diagram6. Scatter Diagram7. StratificationNote : We need to identify the right tool for

the problem.

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Kaizen

Kaizen – Japanese word means Continuousimprovement.

Kaizen – is small improvementssystematically carried out on a continualbasis by all employees.

Principle:Very large number of small improvements (Value) = Large Improvement (Value)

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POKA-YOKE

Poka-Yoke a Japanese word is nothing but Mistake Proofing. It is a scientific technique used to prevent problems due to error.

Mistakes can happen if not prevented. Poka-Yoke removes the possibility of

mistakes being done. Poka-Yoke detects an error, gives a

warning and can shut down the process.

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FMEA – Failure Mode & Effect Analysis

FMEA is(1)Anticipation of potential failure modes and its effects. (2)Identifying causes for that failure modes.(3)Identify & recommend corrective / preventive actions to

reduce/eliminate risks due to failures.(4)Put all controls in place.

Risk Priority Number(RPN)=Severity*Occurrence*Detection(SOD)

RPN is used for prioritization

Types of FMEA

System FMEA Design FMEA Process FMEA

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Thank You

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