unit 2 lecture2 lob technique construction mgt.pptx

line of balance technique

1. Unit 2.2

2. Work study Definition: Enhancing the production efficiency (productivity) of firm by elimination of waste and unnecessary operations. Leads to overall cost saving

3. Aim of work study Improve existing and proposed ways of work and establish standard time for work performance To examine human work in all extents Systematically investigate factors affecting efficiency & economy Method study will develop best way to do work Work measurement will check the time required to do work

4. Objectives of Work Study Improve productivity Optimum utilization of resources Set time standards to do work Better working conditions for employees Improve product quality

5. Advantages of work study Reduce cost by eliminating unnecessary operations. Reduction in rejections and maximum utilization of resources. Achieve better working conditions. Better workplace layout. Improves existing process and brings standardization To establish standard time for particular job useful for manpower planning, production planning.

6. Procedure of Work Study Select the job to be studied Examine all facts Develop economic method based on available data Measure amount of work required to be done and calculate standard time required Implement this new method in the company Maintain this new method by using proper control procedures

7. Method Study Definition: Systematic recording of existing method of doing work so as to develop and apply easier and more effective method and reducing the cost. Main purpose is to eliminate unnecessary operations and achieve the best method Also called methods engineering or work design. Method study involves break down of operation into parts and their systematic analysis

8. Objectives of Method study Effective utilization of resources Perform critical examination of facts Find better ways for doing things Increase the efficiency Eliminate unnecessary operations and avoid delays

9. Advantages of method study Improvement in manufacturing processes and procedures Improvement in working conditions Reducing human effort and fatigue Reduce material handling Improvement of plant and equipment design Improvement in the utility of all resources

10. Steps or procedure of Method Study SELECT: work to be studied RECORD: all facts about job EXAMINE: the facts critically & find alternatives DEVELOP: study different improved methods EVALUATE: evaluate different alternatives to study cost effectiveness DEFINE: method, procedure, resources , working conditions, quality INSTALL: plan, arrange and implement new method MAINTAIN: verify at regular intervals

11. Recording Techniques for Method Study Records of all facts about existing method and to assess effectiveness of proposed improved method

12. Advantages of Recording techniques Present information in precise and clear manner for further analysis Easily understandable and clearly visualized In graphical format

13. Charts used in Method study Most popular method of recording the facts. Symbols used to record jobs Measure the movement of operator or work (i.e., in motion study). Charts includes: (a) Adequate description of activities. (b) (c) Date of charting and name of responsible person (d) Time and distance travelled

14. Types of Charts Divided as: Macro motion charts: study done by using ‘stop watch’ Micro motion charts: study not possible by ‘stop watch’. (A) Types of Macro Motion charts: Operation process chart Flow process chart Two handed process chart Multiple activity chart

15. Operation Process Chart (outline process chart) Records only major activities and inspections involved in the process. Does not indicate work place or the worker. Delays, transport and storages also not indicated. Entry points of materials are indicated. Uses only two symbols, i.e., operation and inspection. Helpful to: Visualize complete sequence of operations and inspection (b) for recording maintenance and other indirect work.

16. Operation process chart

17. 2. Flow Process Chart Gives sequence of flow of work of a product. Symbols are placed one below another as per activities and joined by vertical line. Description written on right side of activity symbol and time/ distance on the left Three types: (a) Material type—Process on materials. (b) Man type—Activities performed by the man. (c) Equipment type—How equipment is used. Useful to: (a) reduce the distance travelled by men (or materials). (b) avoid waiting time and unnecessary delays. (c) fix up the sequence of operations.

18. Flow process chart

19. 3. Two Handed Process Chart Detailed flow chart in which activities of worker’s hands are recorded in relation to one another. It gives sequence of manual activities of the worker. Suitable for work carried out at a single workplace. Useful for: Visualize complete sequence of activities in repetitive task. To study work station layout. Guidelines for preparing the chart: 1. Provide all information about the job in the chart. 2.Record one hand at a time. 3. Do not combine the different activities like operations, transport etc

20. Two hand process chart

21. 4. Multiple Activity Chart Activities of more than one subject (worker or equipment) are recorded on a common time scale to show their inter-relationship. Useful for: (a) to study idle time of the man and machines, (b) determine number of machines handled by one operator (c) determine number of operators required to perform the given job.

22. Example: Man-machine chart: Activities recorded on common time scale to show the inter-relationship. Study the worker operating number of machines at same time. Activities of workers/ machines are recorded in vertical columns with a horizontal time scale. Chart shows idle time of worker/ machine during the process. Shows how work load is evenly distributed among the workers/ machines so as to reduce idle time of worker/ machine. High accuracy is not needed.

23. Man-machine chart

24. Diagrams Used in Method Study Flow process chart shows only sequence and nature of movement but does not show the path of movements which may include undesirable features like congestion, back tracking and unnecessary long movements. Diagrams used in method study to record unnecessary features, and representation of the working area. Diagrams are of two types: 1. Flow diagram and 2. String diagram. Uses: 1. Study different layout plans and select most optimal layout. 2. Study traffic and frequency over different routes of plant. 3. Identification of back tracking and obstacles during movements.

25. Flow Diagram Drawn to scale. Position of machineries, gang ways, etc. is drawn first. Then path followed by men or material is marked on the diagram. Different movements can be marked in different colours. Process symbols in diagram shows different activities at different work centers. Uses: 1. To remove unwanted material movement. 2. To remove back tracking. 3. To avoid traffic congestion.

26. Flow diagram

27. 2. String Diagram Procedure to draw string diagram: 1. layout of factory is drawn to scale on soft board. 2. Pins are fixed into boards to mark locations of work stations, pins are also driven at turning points of the routes. 3. A measured length of thread is taken to trace the movements (path). 4. The distance covered by object is obtained by measuring the remaining part of the thread and subtracting it from original length. Advantage: repetitive movements between work stations can be conveniently shown on string diagram.

28. Applications of string diagram 1. Records complex movements of material or men. 2. Back tracking, congestion, bottlenecks easily found out. 3. Used to record irregular movements. 4. Used to find out the most economical route.

29. Symbols Used in Method Study Graphical method of recording developed by Gilberth . For clear presentation of facts without any ambiguity To get information easily, quickly and clearly. Symbols are instead of written description.

30. 1. Operation: (O) Intentional changed in one of its characteristics By operation object goes one stage ahead towards completion. Examples of operation are: Turning, drilling, milling, Welding, brazing, riveting, Lifting, loading, unloading, etc. 2. Inspection: Object is examined and compared with standard for quality and quantity. Examples of inspection are: Visual observations, Counting quantity of incoming material and checking the dimensions. 3. Transportation : (→) Movement of workers, materials or equipment from one place to another. Examples: Movement of materials and Workers travelling to bring tools.

31. 4. Delay: (D) (Temporary Storage) It occurs when immediate performance of next planned thing does not take place. Examples: Work waiting between consecutive operations. Operators waiting for instructions from supervisor. 5. Storage: (∇) Object kept in authorized custody and protected against unauthorized removal. Example: Materials kept in stores

32. (B) MICRO-MOTION STUDY CHART records and measures time for activity. It divides human activities into groups of movements or micro-motions (called Therbligs ) Find the best pattern of movements that consumes less time and requires less effort to accomplish the task. Therbligs was suggested by Frank O. Gilbreth, founder of motion study. Applications: Study activities of two or more persons on a group work Study relationship of activities of operator and machine based on their timings

33. Therbligs Search (SH) – attempt to find an object using eyes or hand Find (F) – mental reaction at end of search Select (ST) – choose among several objects in a group Grasp (G) – grasp an object Hold (H) – hold an object Transport loaded (TL) – move an object with hand and arm Transport empty (TE) – reach for an object Position (P) – position object in defined location Assemble (A) – join two parts

34. Use (U) – manipulate a tool Disassemble (DA) – separate multiple parts that were previously joined Inspect (I) – determine quality of object Pre-position (PP) – position object for next operation Release load (RL) – release control of an object Unavoidable delay (UD) – waiting due to factors beyond worker control Avoidable delay (AD) – worker waiting Plan (PN) – decide on an action Rest (R) – resting to overcome fatigue

35. SIMO Chart Simultaneous motion cycle chart (SIMO chart) is a recording technique for micro-motion study. Simultaneously records on a common time scale the Therbligs (group of movement) performed by different parts of the body of one or more operators. micro-motion form of man type flow process chart. elaborate procedure and use of expensive equipment are required It is used only when saving resulting from study will be very high.

36. SIMO Chart:

37. MOTION STUDY Part of method study where analysis of motion of an operator or work will be done. Frank Gilberth was founder of Motion study The principles of motion study: (a) Use of the human body. (b) Arrangement of workplace. (c) Design of tools and equipment.

38. (A) USES OF HUMAN BODY 1. The two hands should begin and complete work/ movements at the same time. 2. The two hands should not be idle at the same time except during periods of rest. 3. Motions of the arms should be made simultaneously. 4. Continuous curved movements preferred to straight line motions involving sudden and changes in directions. 5. Rhythm is essential for smooth and automatic performance of repetitive type work

39. (B) ARRANGEMENT OF THE WORKPLACE 1. Tools and materials should be pre-positioned to reduce searching 2. Tools, materials and controls should be located within a maximum working area and as near to the worker as possible 3. Provision should be made for adequate lightning 4. The height of the workplace and seat should be comfortable

40. (C) DESIGN OF TOOLS AND EQUIPMENTS 1. The colour of the workplace should contrast with that of work to avoid eye strain. 2. Two or more tools should be combined where possible. 3 . Levers, cross bars and wheel bars should be such that they can be access easily with less effort.

41. WORK MEASUREMENT For planning and control of operations Also called time study Essential for both planning and control of operations Three stages of work measurement: (1) Analysis phase: job divided into small elements (2) measurement phase: find time required by worker to complete the element (3) synthesis phase: all elemental time added together with allowances to construct standard time

42. Objectives of work measurement Assessing the correct manpower requirement planning Planning and control Realistic costing Financial incentive schemes Delivery date of goods Cost reduction and cost control Identifying substandard workers Training new employees

43. Techniques of Work Measurement Various techniques of work measurement are: 1. Time study (stop watch technique) 2. Synthesis 3. Work sampling 4. Predetermined motion and time study 5. Analytical estimating

44. Purpose of work measurement Investigating and eliminating ineffective time Eliminating unnecessary movement of machine Set standard time for carrying out work efficiently

45. Procedure of work measurement

46. TIME STUDY Definition: The application of techniques designed to establish the time for a qualified worker to carry out a specified job at a defined level of performance.

47. Steps in taking the time study are: 1. Select the work to be studied. 2. Record of all information available about the job, operator and working conditions likely to affect the time study work. 3. Breakdown operation into elements. Element smallest part of activity composed of one or more fundamental motions selected for convenience of observation and timing. 4. Measure time taken by operation to perform each element using stop watch. 5. Also assess effective speed of worker related to normal speed. This is called ‘performance rating’. 6. Adjust observed time by rating factor to obtain normal time for each element Normal = (Observed time × Rating)/ 100 7. Add suitable allowance to compensate for fatigue, personal needs, contingencies. etc. to give standard time for each element. 8. Compute allowed time for entire job by adding elemental standard times. 9. Make detailed description of job describing the method for which the standard time is found. 10. Test and review standards wherever necessary.

48. Steps in time study .

49. Standard Time Standard time is the time allowed to an operator to carry out the specified task under specified conditions and defined level of performance. The various allowances are added to the normal time as applicable to get the standard time. It is defined as amount of time required to complete a unit of work under existing working conditions, using the specified method and machinery, by an operator, able to the work in a proper manner, and at a standard pace. Thus basic constituents of standard time are: 1. Elemental (observed time). 2. Performance rating to compensate for difference in pace of working. 3. Relaxation allowance. 4. Interference and contingency allowance. 5. Policy allowance.

50. Allowances Allowances is defined as the extra time which is added to the basic time of an operation to account for personnel desires, delays, fatigue of operators, any special situation and the policies of the firm or organization. Standard time of a job is obtained by adding various allowances to the basic or normal time of the job. Purpose of allowances is to add enough time to the basic time of the production in order to enable the average worker to meet the standard while performing at a normal pace. T Categories of allowances: Relaxation allowance: to recover from fatigue Interference allowance: unexpected work Contingency allowance: Delay allowance

51. Time-motion study Time-motion study is the technique combining time study of Fredick Taylor with motion study of Frank and Lillian Part of Scientific management Time study used to establish standard time while motion study will establish technique to improve working method Two techniques are combined to get new method to improve and upgrade work system Time-motion study will simultaneously record time of doing specific job under specified conditions

52. Building Information Modeling (BIM) Building Information Modelling or Building Information Management. allows architects, engineers, contractors, and other professionals to plan, design, and construct a building within a 3D model. Includes operation and management of buildings using data. Also for renovation and maintenance work

53. BIM levels Level 0 BIM: 2D CAD drawing + zero collaboration Level 1 BIM: 2D construction drawings + some 3D modelling Level 2 BIM: Different teams work on their own 3D models Level 3 BIM: Different teams work on shared 3D model (study clashes) Levels 4 BIM: additional feature of scheduling Levels 5 BIM: additional feature of cost Estimation Levels 6 BIM: additional feature of sustainability (energy consumption)

54. BIM Process 1. Plan: Combine data to create models 2. Design: Prepare conceptual design, analysis, detailing and documentation. 3. Build: Modelling work prepared as per specifications. 4. Operate: operation and maintenance of finished assets

55. BIM Modelling Preparing and analysing 3D models based upon provided data. Different models are developed during entire project life cycle. Modifications are done time to time. 1. Conceptual design model: by Architect team to analyse early planning parameters, building orientation, wind directions, etc. 2. Design development model: for detailed design analysis and find co-ordination issues between different disciplines 3. Construction models: by contractors to stimulate and analyse the schedule, estimate material quantities and costing 4. As-built models: check actual construction with planned one 5. Asset information model: as-built models to manage after handover

56. BIM Management Process of managing & maintaining 3D models during project life cycle All project stakeholders must be involved at early stage 1. Technology: BIM is new tool. It requires specific hardware and software. Also required skilled personnel to handle data 2. Schedule management: BIM facilitates early decision in project. Scheduling done during preconstruction phase 3. Collaboration: Project stakeholders work on same BIM model by collaboration. All stakeholders can modify and share the information within team.

57. How is BIM used in Construction management 3D computer models used to manage the construction project. To plan and design the building. Study design aspects such as structural integrity, fire safety, and energy efficiency. BIM process allows clash detection during the design phase itself. It creates schedule and tracks the progress during the construction phase. To prepare as-built drawings for documentation of completed building.

58. Benefits of BIM Changes monitoring: changes can be made and checked in model itself without any extra cost Clash detection: interference is identified at design stage and corrected instantly, saving time and money Improved scheduling: Removing various setbacks and avoids unnecessary changes and nuances. More time-effective projects: saves time by reducing or removing mistakes, adjustments, reiterations and so on. Lowered risks and expenses: better coordination with contractors, improved accuracy of models, etc.

59. Accurate cost assessment: 5D level BIM makes automated cost evaluation of your projects in real-time. Productivity improvement: overall increase in work productivity by using modular development technology. Better build quality: and more aesthetically pleasing structures by modelling the artificial and natural light emulation. Planning stage with project visualization at planning stage: reduces chances of time-consuming and expensive modification Development sites are more secure: potential disaster identified well in advance, saving time and money

60. Advantages of using BIM Enhanced coordination between different disciplines Improved project quality Reduced rework Increased efficiency and productivity Better understanding of building before construction