Work Study PDF

WORK STUDY Introduction ◦ In the 1920’s first efforts started for productivity increase ◦ Frederick Taylor – father of Industrial Engineering 1881 scientific management ◦ Eliminate idle time ◦ Eliminate duplication of effort ◦ Streamline flow of work through plant or firm ◦ Rearrange ta...

WORK STUDY Introduction ◦ In the 1920’s first efforts started for productivity increase ◦ Frederick Taylor – father of Industrial Engineering 1881 scientific management ◦ Eliminate idle time ◦ Eliminate duplication of effort ◦ Streamline flow of work through plant or firm ◦ Rearrange tasks sequences for more efficiency ◦ Reduce jobs to short cycle repetitive ones and eventual replacement of humans with machines ◦ Systematic reduction of skill requirement in each job Work study Work study: systematic examination of the methods of carrying on activities so as to improve the effective use of resources and to set up standards of performance for activities being carried out. Method Study : is the critical examination and systematic recording of the present method in order to develop an improved method Work Measurement: is the application of techniques designed to establish the time for a qualified worker to carry out a task at a defined rate of working. Why is work study valuable ◦ Raises productivity by reorganizing the work, involves little or no capital expenditure on facilities or equipment ◦ Systematic in investigation and in solution development make sure all factors are considered ◦ Most accurate means for setting standards of performance, effective planning and control of production is dependent on standards of performance. ◦ Can contribute to safety and working conditions ◦ Saving from applying work study start immediately and continues as long as improved method is used ◦ Tool can be applied everywhere factory, plant, services and offices ◦ Relatively cheap and easy to apply ◦ One of the most penetrating tools to apply of investigation available to management Pareto Diagram ◦ Simple graphing technique that ranks the contributions of causes in descending order ◦ Horizontal axis – causes e.g. type of defect, downtime ◦ Vertical axis – frequency of the cause / contribution of each cause ◦ Vital few - left Pareto Curve ◦ Pareto Curve is a cumulative frequency line that shows progressively the combined contribution of the causes ◦ The Pareto Diagram and Curve is used to identify areas where attention is required to improve or change ◦ It makes it possible to make the decision of whether or not it is significant enough to focus on ◦ If the Pareto Curve is steep the vital few are significant enough for improvement ◦ If the Pareto Curve is not steep, there are no significant causes Pareto example Procedure Step 1: Define the total effect and the causes that influence it. Decide on a measurement unit Step 2: Collect data – decide how data will be collected and do so over a reasonable period Step 3: Tabulate the causes, frequencies and their cumulative frequencies Step 4: Draw the Pareto diagram. The causes are listed according to importance from left to right on horizontal axis and the frequencies on the vertical axis Step 5: Draw the Pareto Curve. Plot a curve of the cumulative frequencies Step 6: Determine if the Pareto Principle applies Step 7: Use the Pareto diagram and curve to determine a starting/ focus point for improvement EXERCISE The manager of Perrotti’s Pizza collects data concerning customer complaints about pizza delivery. Either the pizza arrives late or the wrong pizza is delivered. Use a Pareto chart to identify the vital few delivery problems. Problem Frequency Topping is stuck to box lid 17 Pizza arrives late 35 Wrong topping or combination 9 Wrong style of crust 6 Wrong size 4 Pizza is partially eaten 3 Pizza never arrives 6 Total 80 Objectives of Method study ◦To increase productivity ◦To lower unit costs ◦Only by intelligently applying these principles can producers increase and at the same time the purchasing potential of all consumers Method Study Approach Select work to be studied Record all relevant fact of current work method Examine facts critically and in sequence Develop the most practical, economic and effective method Evaluate Define the new method, in a clear manner Implement method Maintain the method, periodically check its use Recording Present Method There are different techniques used : Record sequence of activities Record time relationship of activities in jobs Record the path of movement of a part/ a job Most common technique – process flow chart Process Chart ◦ Operation ◦ Indicates that main steps in the process. Usually the part, material or product concerned is modified or changed during the operation. (takes it towards completion) ◦ Inspection ◦ Indicates an inspection for quality purposes and or check for quantity ◦ Transport ◦ Indicates movement of workers, materials or equipment from place to place (if moved from place to place except if movement is part of operation) Process Chart ◦ Temporary Storage or Delay ◦ Delay in the sequence of events, e.g. work waiting between consecutive operations or any object laid aside temporarily until required (stacked on floor till next operation ready for material) ◦ Permanent Storage ◦ Controlled storage where material is received into or issued from a store under some form of authorization or an item retained for reference purposes. Material kept and protected against unauthorized removal ◦ Combined activities ◦ Activities performed at the same time or at the same workstation Outline process chart ◦ Outline process chart gives an overall picture by recording in sequence only the main operations and inspections ◦ Example page 86 (Introduction to work study) Process Chart Process flow chart is a process chart that sets out eh sequence of flow of a product or a procedure by recording all events under review Using the appropriate process chart symbols. Types: Worker type: Records what the operator does Material type: Records how material is handled or treated Equipment type: Records how equipment is used Examine present method Critical Examination technique Purpose: Means: What is achieved? How is it done? Why is it necessary? Why that way? What else could be done? How else could it be done? What should be done? How should it be done? Place: Sequence: Where is it done? When is it done? Why there? Why then? Where else could it be done? When else could it be done? Where should it be done? When should it be done? Person: Who does it? Why that person? Who else could do it? Who should do it? Multiple activity chart A multiple activity chart is a chart on which activities of more than one subject (worker, machine or item of equipment)are each recorded on a common time scale to show their interrelationship Multiple activity charts/ gang process charts ◦ Look at reducing both the idle time of the worker and the machine ◦ May have several workers working on 1 machine ◦ Useful to organize teams of operatives on mass production ◦ Useful for maintenance, where plant can not be idle for any longer than it has to ◦ Operator is responsible for two washing machines. He loads clothes and detergent into the first washing machine (5 min). The machine washes for 25 minutes. After cycle is complete the operator removes the clothes (8min) The operator then loads clothes and detergent into the second washing machine and switches it on (5min). After loading the second washing machine the operator loads the first washing machine again (5min). He waits for the cycles to be completed then unloads machine 2 (8min) and then unloads machine 1. Then he hangs the clothes on a washing line (20 min) ◦Man removes rubber band (3min). Man picks up weight (2min). Deck is placed in hopper (2min). Man replaces weight in deck (2min). Man pushes start button(1 min), Machine runs for 10 min. Man picks up deck from output stacker(3min) Rubber band is placed on the deck (2min.  Flow diagram ◦ Draw a flow diagram of the overall flow of a product through the facility ◦ Method ◦ Obtain a scaled layout of the plant ◦ Plot every step in the manufacturing of the product from raw materials to distribution ◦ Connect activities with a dotted line ◦ Number activities ◦ Write activities next to the symbol  Flow diagram ◦ The Flow diagram illustrates ◦ Cross traffic ◦ Where the flow lines cross ◦ Causes congestion and safety problems ◦ Re-arrange equipment or departments ◦ Backtracking ◦ Where material is moving backward you want to eliminate should move forward ◦ Distance travelled ◦ The smaller the distance the lower the cost Travel chart ◦ A travel chart is a tabular record for presenting quantitative data about the movement of workers, materials or equipment between any number of places over any given period of time ◦String Diagram ◦ Scale plan or model on which a tread is used to trace and measure the path of workers, material or equipment during a specified sequence of events Two handed process chart ◦ The two handed process chart is a process chart in which the activities of a workers hands (or limbs) are recorded in their relationship with one another Operation Is used for activities to grasp, position, use, release etc. of a tool, component or material Transport Is used to represent the movement of the hand (or limb) to or from the work, tool or material Two handed process chart ◦ Delay ◦ Is used to indicate that the hand (or limb) is idle (although other hand may be in use) ◦ Hold ◦ The term storage is not used here. Instead the symbol is renamed as hold. It is used to represent the activity of holding the work, tool or material. Improvement in 5 directions ◦ 1. Layout and design of the factory plant or workplace ◦ Re-arrange machines ◦ Re-locate storage/working areas ◦ Transport facilities ◦ Mechanical handling equipment ◦ Eliminate/combine activities ◦ 2. Working Procedures ◦ Methods & planning ◦ Purchasing ◦ Receiving and storage of materials ◦ Change overs ◦ Batch sizes Method Study 3. Use of Materials, Plant Equipment and Materials Cheaper materials Shift work Mechanisation/automation Balancing operations with skills 4. Working Environment Heating, ventilation, lighting, noise, personal comfort Amenities (useful facility) Adequacy of toilet facilities Times for breaks Safety/ fire extinguisers Washing facilities Method Study 5. Design specifications of the end product Redesign Accessibility Preferred material Standardisation Specifications too high Develop and Install New Method Develop new method Eliminate parts altogether Combine elements Change sequence to improve efficiency Simplify so as to reduce work Install new method and maintain it Project manage the implementation Need to monitor effectiveness of job designs Two handed process chart ◦Move to take a bolt with the LH and at the same time move to get washer with RH. Grasp the bolt with LH and Grasp the washer with the RH (at the same time). Move both hands to the required position. Hold the bolt with the LH while the washer is assembled to the bolt