UNIT III

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UNIT III:

UNIT III OPERATIONS MANAGEMENT

PLANT LOCATION :

PLANT LOCATION

NEED FOR SELECTION:

NEED FOR SELECTION When the business is newly started The existing business expansion Establishment of branches Land lease expires Other reasons

PowerPoint Presentation:

Plant location involves two major activities To select a proper geographic region Selecting a specific site with in the region

PLANT LOCATION:

PLANT LOCATION Meaning-the establishment of an industry at a particular place. It is of 2 types- Localization /centralization-means concentration of similar type of industries at some particular place. E.g. textile in Mumbai. Delocalization /Decentralization-means spreading of similar type of industries at different places. E.g. banking industries.

Factors affecting location & site decisions:

Factors affecting location & site decisions Availability of raw materials Proximity to market Integration with other parts of orgn Availability of labor and skills Availability of Amenities Transport & communication facilities

Factors affecting location & site decisions (contd…):

Factors affecting location & site decisions (contd…) 7. Suitability of climate 8. Availability of services 9. Regional regulations 10. Room for expansion 11. Safety requirements 12. Others like low interest on loans, special grants, living standards

Plant layout:

Plant layout Meaning- Plant layout is the physical arrangement of industrial facilities. It involves the allocation of space & the arrangement of equipment in such a manner that overall operating costs are minimized.

Factors affecting plant layout:

Factors affecting plant layout Management Policy Manufacturing process Nature of product Volume of production Type of Equipment

Factors affecting plant layout (contd…):

Factors affecting plant layout (contd…) 6. Type of building 7. Availability of Total floor area 8. Arrangement of Material Handling Equipment 9. Service facilities 10. Possibility of future expansion

METHODS OF PRODUCTION:

METHODS OF PRODUCTION The methods of production can be of the following types: Intermittent or interrupted production Job Production Batch Production Mass and flow line production

JOB PRODUCTION:

JOB PRODUCTION In this type of production, every job is different from the other in terms of type, cost, efforts, consumption of materials or specifications.

PowerPoint Presentation:

ADVANTAGES Reaching the target customer’s requirements Special training to labor Best suitable for pull system of demand DISADVANTAGES Time taking Large scale economies cannot be realised Costliest Division of labor is not possible

BATCH PRODUCTION:

BATCH PRODUCTION All the products manufactured under a batch are similar in terms of type, cost, efforts, consumption of materials or specifications.

PowerPoint Presentation:

ADVANTAGES cost of product design per unit is low Economies of production Flow of materials can be continuous Automation and mechanization DISADVANTAGES Varying customer demands Not appropriate for pull system

MASS PRODUCTION:

MASS PRODUCTION This is also called flow production. The production can be undertaken on large and specialized machines and processes.

PowerPoint Presentation:

ADVANTAGES Mechanization and division of labour Large – scale economies Minimum material handling costs DISADVANTAGES Special care Idle machinery may result in wastage of resources Bottle necks

Types of plant layout:

Types of plant layout Product layout Process layout Fixed Position/ Stationary layout Combination lay out

Product layout:

Product layout Layout that uses standardized processing operations to achieve smooth, rapid, high-volume flow Here machines are arranged acc. to the needs of product & in the same sequence as the operations are necessary for manufacture. E.g. ‘back office’ of services such as banks and insurance companies.

Product Layout (contd…):

Raw materials or customer Finished item Station 2 Station 3 Station 4 Material and/or labor Station 1 Material and/or labor Material and/or labor Material and/or labor Used for Repetitive or Continuous Processing Product Layout (contd…)

Product Layout (contd…):

Work Station 1 Work Station 2 Work Station 3 Product Layout (sequential) Used for Repetitive Processing Repetitive or Continuous Product Layout (contd…)

Advantages of Product Layout:

High rate of output Low unit cost Labor specialization Low material handling cost High utilization of labor and equipment Established routing and scheduling Short processing time Advantages of Product Layout

Disadvantages of Product Layout:

Creates dull, repetitive jobs Poorly skilled workers may not maintain equipment or quality of output Fairly inflexible to changes in volume Highly susceptible to shutdowns Needs preventive maintenance Require large capital investment Disadvantages of Product Layout

PowerPoint Presentation:

Process layout Layout that can handle varied processing requirements Here all machines performing similar type of operations are grouped together at one location in the process layout. Thus here facilities are grouped together acc. To their functions. E.g. all drilling machines are located at one place known as drilling section.

PowerPoint Presentation:

Dept. A Dept. B Dept. D Dept. C Dept. F Dept. E Used for Intermittent processing Job Shop or Batch Process Layout (functional)

Advantages of Process Layouts:

Can handle a variety of processing requirements Machines breakdown doesn’t result in shutdown. Equipment used is less costly Wide flexibility in production facilities. Each production unit of system works independently. High utilization of facilities Variety makes the job interesting. Advantages of Process Layouts

Disadvantages of Process Layouts:

In-process inventory costs can be high Challenging routing and scheduling Equipment utilization rates are low Material handling is slow and inefficient & is more. More space is required Longer processing time Back tracking may occur. Disadvantages of Process Layouts

Comparison of product & process layout:

Comparison of product & process layout factors Product layout Process layout 1. nature Sequence of facilities Similar aregp2gether 2. Machines utilization Not to full capacity Better utilization 3. product standardized diversified 4. Processing time less more 5. Material handling less more 6. inventory High WIP Low WIP 7. breakdown Can’t tolerate Can tolerate 8. Production centre simple complex 9.flexibilty low high 10. floor space Requires less more 11. investment high low

FIXED POSITION LAYOUT:

FIXED POSITION LAYOUT Layout by fixed position of the product is inherent in ship building, aircraft manufacture .

ADVANTAGES:

ADVANTAGES It is possible to assign one or more skilled workers to a project from start to finish in order to ensure continuity of work It involves least movement of materials A number of quite different projects can be taken with the same layout

DISADVANTAGES:

DISADVANTAGES There appears to be low utilization of labor and equipment It involves high equipment handling costs

COMBINATION LAYOUT:

COMBINATION LAYOUT A combination of process and product layouts combines the advantages of the both types of layouts. A combination layout is possible where an item is being made in different types and sizes. examples: wood saws, files etc

WORK STUDY:

WORK STUDY Work study is defined as that body of knowledge concerned with the analysis of the work methods and the equipment used in performing a job, the design of an optimum work method and the standardization of proposed work methods.

Objectives of Work Study:

Objectives of Work Study To analyze the present method of doing a job, systematically in order to develop a new and better method. To measure the work content of a job by measuring the time required to do the job for a qualified worker and hence to establish standard time. To increase the productivity by ensuring the best possible use of human, machine and material resources and to achieve best quality product/service at minimum possible cost. To improve operational efficiency.

PowerPoint Presentation:

WORK STUDY METHOD STUDY WORK MEASUREMENT MOTION STUDY TIME STUDY

BASIC WORK STUDY PROCEDURE:

BASIC WORK STUDY PROCEDURE Select the job or process or the operation to be studied. Record all relevant facts about the job or process or operation using suitable charting techniques. Examine critically all the recorded facts, questioning the purpose, place, sequence, person and the means of doing the job/process/operation. Develop the new method.

RECORDING SYMBOLS:

RECORDING SYMBOLS Standard Symbol Name of Activity Operation Transportation/Movement Inspection Delay/ Temporary storage Storage Combined Activity

PROCESS CHARTS:

PROCESS CHARTS Outline Process Chart Operation Process Chart Flow Process Chart Two handed Process Chart Multiple Activity Chart Man – Machine Chart Flow Diagram String Diagram SIMO Chart

PRIMARY QUESTIONS :

PRIMARY QUESTIONS The PURPOSE for which The PLACE at which The SEQUENCE in which The PERSON by whom The MEANS by which

PowerPoint Presentation:

ELIMINIATING COMBINING REARRANGING OR SIMPLIFING those activities With a view to

SECONDARY QUESTIONS :

SECONDARY QUESTIONS The secondary questions cover the second stage of the questioning technique, during which the answers to the primary questions are subjected to further query to determine whether possible alternatives of place, sequence, persons and means are practicable and preferred as a means of improvement upon the existing method .

PowerPoint Presentation:

PURPOSE: what is done? why is it done? what else might be done? what should be done? PLACE : where is it done? Why is it done there? Where else might it is done? Where should it be done?

PowerPoint Presentation:

SEQUENCE: When is it done? Why is it done? When might it be done? When should it be done? PERSON: who does it? Why does that person do it? Who else might do it? Who should do it? MEANS: How is it done? Why is it done that way? How else might it be done? How should it be done ?

Procedure (contd…):

Procedure (contd…) 5. Measure the work content and establish the standard time using an appropriate work measurement technique. 6. Define the new method. 7. Install the new method as standard practice. 8. Maintain the new method for the job/process/operation

THE TECHNIQUES OF WORK MEASUREMENT :

THE TECHNIQUES OF WORK MEASUREMENT 1.  Direct Time study 2.  Synthesis Method 3. Analytical Estimating 4. Predetermined Motion Time System (PMTS) 5. Work Sampling / Activity Sampling / Ratio Delay Method

METHOD STUDY:

METHOD STUDY Work methods analysis or Method Study is a scientific technique of observing, recording and critically examining the present method of performing a task or job or operation with the aim of improving the present method and developing a new and cheaper method.

MOTION STUDY:

MOTION STUDY Motion Study is the science of eliminating wastefulness, resulting from using unnecessary; ill – directed and inefficient motion. The aim of motion study is to find and perpetuate the scheme of the least waste methods of labor.

OBJECTIVES OF MOTION STUDY:

OBJECTIVES OF MOTION STUDY To study the existing method To develop an improved method To reduce excessive materials handling To improve utilization of resources To eliminate wasteful and inefficient motions To standardize work methods or processes.

TYPES OF MOTION STUDY:

TYPES OF MOTION STUDY 1. Micro motion Study Take motion picture of the operations Analyze the film The film is analyzed by breaking the job cycle into micro motions or therbligs. Therbligs indicate the basic motions consisting of three parts i) When the motion begins ii) The nature of the motion iii) When the motion ends. Ex: Search – Sr; Select – St; Transport empty – TE etc Prepare a SIMO chart

TYPES OF MOTION STUDY:

TYPES OF MOTION STUDY 2. Memomotion Study It is a special form of motion study in which motion pictures are taken at slow speed using a motion picture camera.

WORK MEASUREMENT:

WORK MEASUREMENT It is defined as the application of techniques designed to establish the work content of a specified task by determining the time required for carrying out the task at a defined standard of performance by a qualified worker.

THE QUALIFIED WORKER :

A qualified worker is one who is accepted as having the necessary physical attributes, who possess the required intelligence and education and who has acquired the necessary skill and knowledge to carry out the work in hand to satisfactory standards of safety, quantity and quality. THE QUALIFIED WORKER

OBJECTIVES OF WORK MEASUREMENT:

OBJECTIVES OF WORK MEASUREMENT Improved planning and control of activities or operations. More efficient manning of the plant Reliable ideas for labor performance Reliable basis for labor cost control Basis for sound incentive schemes

WORK MEASUREMENT PROCEDURE:

WORK MEASUREMENT PROCEDURE Break the job into elements Record the observed time for each element Establish elemental time values by extending observed time into normal time by applying a rating factor Assess relaxation allowances Determine the frequency of occurrences of each element in the job, multiply the work content by its frequency to arrive at work content of the job

THE TECHNIQUES OF WORK MEASUREMENT :

THE TECHNIQUES OF WORK MEASUREMENT 1.  Direct Time study 2.  Synthesis Method 3. Analytical Estimating 4. Predetermined Motion Time System (PMTS) 5. Work Sampling / Activity Sampling / Ratio Delay method

DIRECT TIME STUDY:

DIRECT TIME STUDY Time study is concerned with the determination of the amount of time required to perform a unit of work. The main objective is to determine by direct observation, the quantity of human work in a specified task and hence to establish the standard time, within which an average worker working at a normal pace should complete the task using a specified method.

PROCEDURE OF TIME STUDY:

PROCEDURE OF TIME STUDY a.  Obtaining and recording all available information about the job, operator and the surrounding conditions likely to affect the execution of the work b.  Recording the complete description of the method, breaking down the operation into 'elements' c.  Measuring with a stopwatch and recording the time taken by the operator to perform each 'element' of the operation. i) Non – fly back ii) Fly Back iii) Split hand

PowerPoint Presentation:

d. Assessing the rating using rating scale e.    Extending observed time to ‘basic times’ = Observed time * Rating factor Where, RF = Rating of observed worker/Rating of Qualified Worker f.    Determining the allowances to be made over and above the basic time for the operation g. Determining the 'standard time' for the operation.

SYNTHESIS METHOD:

SYNTHESIS METHOD Synthesis is a technique of work measurement for building up the time required to do a job at a defined level of performance by synthesizing or totaling elemental time values obtained from previous time studies on other jobs containing similar job elements or from standard data.

ANALYTICAL ESTIMATING:

ANALYTICAL ESTIMATING It is used to determine the time values for jobs having long and non- repetitive operations.

Procedure::

Procedure: Find the job Break the job into elements Select time value from standard data catalogue Estimate time values for remaining elements Add 3 and 4 Add Relaxation allowances

PREDETERMINED MOTION TIME SYSTEM (PMTS):

PREDETERMINED MOTION TIME SYSTEM (PMTS) It is defined as a work measurement technique by which normal or basic times are established for basic human motions and these time values are used to buildup the time for a job at a defined level of performance. Predetermined time standards are standard data for wide variety of basic body motions which are common in many industrial operations.

WORK SAMPLING / ACTIVITY SAMPLING / RATIO-DELAY METHOD:

WORK SAMPLING / ACTIVITY SAMPLING / RATIO-DELAY METHOD Work Sampling randomly samples the work of one or more employees at periodic intervals to determine the proportion of total operations that is accounted for in one particular activity. We precisely record what the worker or machine is doing (i.e., working or idle) at the time of observation.

PowerPoint Presentation:

Let ‘p’ be the proportion of the activity. Then, p = X/N = No. of observations of the activity Total no. of observations Let ‘q’ be the proportion of no activity Then, p + q = 1 Extending the same for several observations (say N) (p+q)^ N = 1 If this is expanded using binomial theorem, the distribution will have a mean value of Np and S.D of √ Npq.

PowerPoint Presentation:

Normal Deviation, Mean = NP/N = p S.D = √ (Npq) / N = √ [p(1-p)/N] N= c^2 p(1-p) / E^2 Where c is the constant corresponding to the confidence level C=1 for 68.3 % CL C=2 for 95% CL C=3 for 99% CL

PowerPoint Presentation:

for c=1; E= 31.7% = 0.32 for c=2; E=5% = 0.05 for c=3; E=1% = 0.01

STATISTICAL QUALITY CONTROL:

STATISTICAL QUALITY CONTROL Quality refers to the sum of the attributes or properties that describe a product. Inputs Acceptance Sampling Outputs Process – Control Charts

CONTROL CHARTS:

CONTROL CHARTS Control charts for variables – X Chart R Chart Control charts for attributes – np chart p chart c chart u chart

TABLE OF CONSTANTS:

TABLE OF CONSTANTS n A 2 D 3 D 4 2 1.880 0 3.268 3 1.023 0 2.574 4 0.729 0 2.282 5 0.577 0 2.114 6 0.483 0 2.004 7 0.419 0.076 1.924 8 1.373 0.136 1.864 9 0.337 0.184 1.816 10 0.308 0.223 1.777

X - CHART:

X - CHART Compute average of averages x. Compute average range R. UCL = x + A 2 R LCL = x - A 2 R

R - CHART:

R - CHART Compute average of averages x. Compute average range R. UCL = D 4 R LCL = D 3 R

C - CHART:

C - CHART C Chart is used where there are a number of defects per unit. Here the sample size should be constant. X- Axis No. of samples Y- Axis No. of defects per each sampled unit UCL = c + 3 √ c LCL = c - 3 √ c Where, c = Total no. of defects in all samples Total no. of samples inspected

P- CHART X- Axis Sample no. Y- Axis % Defective:

P- CHART X- Axis Sample no. Y- Axis % Defective p chart is used where there is data about the number of defectives per sample. It is also called fraction defective chart or percentage defective chart. UCL = p + 3 √ [p(1-p)] LCL = p – 3 √ [p(1-p)] n n Where, P = Total no. of defectives found in the sample Total no. of pieces inspected

Sampling:

Sampling The flow of products is broken into discrete batches called lots. Random samples are removed from these lots and measured against certain standards. A random sample is one in which each unit in the lot has an equal chance of being included in the sample. If a sample is random, it is likely to be representative of the lot.

ACCEPTANCE SAMPLING:

ACCEPTANCE SAMPLING Acceptance Sampling is based on the premise that a sample represents the whole lot from which the former is drawn. It involves extracting a random sample from the lot to determine whether to accept or reject the entire lot based on the quality of the sample.

Acceptance Sampling:

82 Acceptance Sampling Lot received for inspection Sample selected and analyzed Results compared with acceptance criteria Accept the lot Send to production or to customer Reject the lot Decide on disposition

TYPES OF ACCEPTANCE SAMPLING PLANS:

TYPES OF ACCEPTANCE SAMPLING PLANS Single Sampling plan Double Sampling plan Sequential Sampling plan

Single-Sampling Plan:

Single-Sampling Plan Lot of N Items Random Sample of n Items N - n Items Inspect n Items c’ > c c’ < c Replace Defectives n Nondefectives c’ Defectives Found in Sample Reject Lot Accept Lot

Double-Sampling Plan:

Double-Sampling Plan Lot of N Items Random Sample of n 1 Items N – n 1 Items Inspect n 1 Items c 1 ’ > c 2 c 1 ’ < c 1 Replace Defectives n 1 Nondefectives c 1 ’ Defectives Found in Sample Reject Lot Accept Lot Continue c 1 < c 1 ’ < c 2 (to next slide)

Double-Sampling Plan:

(c 1 ’ + c 2 ’) > c 2 Double-Sampling Plan N – n 1 Items Random Sample of n 2 Items N – (n 1 + n 2 ) Items Inspect n 2 Items Replace Defectives n 2 Nondefectives c 2 ’ Defectives Found in Sample Reject Lot Accept Lot Continue (c 1 ’ + c 2 ’) < c 2 (from previous slide)

Sequential-Sampling Plan:

Sequential-Sampling Plan 0 10 20 30 40 50 60 70 80 90 100 110 120 130 3 1 2 Units Sampled (n) 6 Number of Defectives 4 5 7 0 Reject Lot Accept Lot Continue Sampling

DEMING’S CONTRIBUTION TO QUALITY:

DEMING’S CONTRIBUTION TO QUALITY William Edwards Deming was an American Professor widely credited with improving production in US. He taught that by adopting appropriate principles of management, organizations can increase quality and simultaneously reduce costs.

PowerPoint Presentation:

Plan: study current situation Do: implement plan on trial basis Study: determine if trial is working correctly Act: standardize improvements The Deming Cycle

PowerPoint Presentation:

Deming’s 14 Points Point 1: Create a Vision and Demonstrate Commitment Point 2: Learn the Philosophy Point 3: Understand Inspection Point 4: Stop Making Decisions Purely on the Basis of Cost Point 5: Improve Constantly and Forever Point 6: Institute Training Point 7: Institute Leadership

PowerPoint Presentation:

Deming’s 14 Points Point 8: Drive Out Fear Point 9: Optimize the Efforts of Teams Point 10: Eliminate Exhortations Point 11: Eliminate Numerical Quotas Point 12: Remove Barriers to Pride in Work Point 13: Encourage Education and Self-Improvement Point 14: Take Action

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