Chapter 1 introduction to automation


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Chapter 1 introduction to automation

  2. 2. 2 INTRODUCTION Production system: manufacturing support systems and facilities. Mfg Support System Facilities (Factory Equipments)
  3. 3. 3 • Mfg. Support System - procedures used to manage prod. and to solve logistics & technical prob. Facilities - the equipments in factory and the way the equipment is organized. It includes machines, tooling, material handling equipment, inspection equipment, comp. & plant layout. INTRODUCTION… cont.
  4. 4. 4
  5. 5. 5
  6. 6. 6 INTRODUCTION… cont. • Industrial Automation: • The technology by which a process or procedure is accomplished without human assistance. • A technique that can be used to reduce costs and/or to improve quality. • Can increase manufacturing speed, while reducing cost.
  7. 7. 7 • Can lead to products having consistent quality, perhaps even consistently good quality • It is implemented using a program of instructions combined with a control system that executes the instructions. INTRODUCTION…cont.
  8. 8. 8 • To automate a process, power is required, both to drive the process itself and to operate the program and control system. • Automated processes can be controlled by human operators, by computers, or by a combination of the two. INTRODUCTION…cont.
  9. 9. 9 Definition 1 • Automation is a technique that can be used to reduce costs and/or to improve qual­ity. Automation can increase manufacturing speed, while reducing cost. Automation can lead to products having consistent quality, perhaps even consistently good quality. Definition 2 • Automation is a technology concerned with application of mechanical, electronic and computer-based system to operate and control system. This technology includes;
  10. 10. 10 • Automatic assembly machines • Automation machine tools to process parts • Industrial robots • Automatic materials handling and storage system • Automatic inspection system and quality control • Feedback control and computer process control • Computer system for planning, data collection and decision making to support manufacturing activities
  11. 11. 11 • If a human operator is available to monitor and control a manufacturing process, open loop control may be acceptable. • If a manufacturing process is automated, then it requires closed loop control, also known as feedback control. • example of open loop control and closed loop control. INTRODUCTION…cont.
  12. 12. 12 Example of open loop control system
  13. 13. 13 Example of closed loop control Temperature instruction
  14. 14. 14 Example of closed loop control
  15. 15. 15 Arguments in favor of Automation • Automation is the key to shorter work week – working hours per week reduces and , allowing more leisure hours and a higher quality of life. • Automation brings safer working conditions for workers. • Automated production results in lower prices and better products
  16. 16. 16 Arguments against Automation • It result in the subjugation of human being by a machine – reduces the need for skilled labor • There will be reduction in the labor force – resulting un employment. • Automation will reduce purchasing power- markets will become saturated with products that people cannot afford to purchase.
  17. 17. 17 SOME CONSIDERATIONS • What automation and control technology is available? • Are employees ready and willing to use new technology? • What technology should be used? • Should the current mfg process be improve before automation? • Should the product be improved before spending millions of ringgit acquiring equips.
  18. 18. 18 MANUAL LABOR IN PRODUCTION SYSTEMS • Task is too technologically difficult to automate. • Short product life cycle. • Customized product. • To cope with ups and downs in demand. • To reduce risk of product failure.
  19. 19. 19 BASIC ELEMENT OF AN AUTOMATED SYSTEM • Consists of 3 basic elements: 1) The actuator (which does the work) • Controlled by the controller. • The actuator in a automated process may in fact be several actuators, each of which provides an output that drives another in the series of actuator.
  20. 20. 20 • Some actuators can only be on and off. Other actuators respond proportionally with the signal they receive from a controller • Actuators can be selected for the types of inputs they require, either DC or AC. BASIC ELEMENT OF AN AUTOMATED SYSTEM…cont.
  21. 21. 21 2)The controller (which ‘tells’ the actuator to do work) » A controlled system either may be a simple digital system or an analog system. » Digital and analog controllers are available ‘off the shelf’ so that systems can be constructed inexpensive and with little specialized knowledge required. BASIC ELEMENT OF AN AUTOMATED SYSTEM…cont.
  22. 22. 22 3) The sensor (which provides feedback to the controller so that it knows the actuator is doing work) • Obviously, controlled automation requires devices to sense system output. • Sensors also can be used so that a controller can detect and respond to changing conditions in its working environment. BASIC ELEMENT OF AN AUTOMATED SYSTEM…cont.
  23. 23. 23 • Switches and transducers are another name for sensors. • Switches can detect when a measured condition exceeds a pre- set level. Examples, closes when a work-piece is close enough to work on. • Transducers can describe a measured condition. Examples, output increased voltage as a work- piece approaches the working zone. BASIC ELEMENT OF AN AUTOMATED SYSTEM…cont.
  24. 24. 24 TYPE OF AUTOMATION • Hard Automation – Controllers were built for specific purposes and could not be altered easily. – Early analog process controllers had to be rewired to be reprogrammed.
  25. 25. 25 – This controllers do what they are designed and built to do, quickly and precisely perhaps, but with little adaptability for change (beyond minor adjustments). – Modification of hard automation is time-consuming and expensive, since modifications can only be performed while the equipment sits idle. TYPE OF AUTOMATION…cont.
  26. 26. 26 • Soft Automation – Modern digital computers are reprogrammable. – It is even possible to reprogram them and test the changes while they work. – Even if hardware changes are required to a soft automation system, the lost time during changeover is less than for hard automation TYPE OF AUTOMATION…cont.
  27. 27. 27 • Automated Mfg. System can be classified into three basic types: Fixed Automation – A system which the sequence of processing (or assembly) operations is fixed by the equipment configurations. – Each operations in the sequence is usually simple. AUTOMATED MFG. SYSTEM
  28. 28. 28 – The features of fixed automation; • High initial investment for custom- engineered equipment • High production rates • Relatively inflexible in accommodating product variety. • Examples, machining transfer lines and automated assembly machines. AUTOMATED MFG. SYSTEM… cont.
  29. 29. 29 • Programmable Automation – The production equipment is designed with the capability to change the sequence of operations to accommodate different product configurations. – The operation sequence is controlled by a program, which is a set of instruction coded so that they can be read and interpreted by the system. AUTOMATED MFG. SYSTEM… cont.
  30. 30. 30 – New programs can be prepared and entered into the equipment to produce new products. – The physical setup of the machine must be changed for each new products. – This changeover procedures takes time. – Eg: numerical control (NC) machine tools, industrial robots and PLC. AUTOMATED MFG. SYSTEM… cont.
  31. 31. 31 – The features of programmable automation; • High investment in general purpose equipment. • Lower production rates than fixed automation. • Flexibility to deal with variations and changes in product configuration. • Most suitable for batch production. AUTOMATED MFG. SYSTEM… cont.
  32. 32. 32 • Flexible Automation – An extension of programmable automation. – Capable of producing a variety of parts/products with virtually no time lost for changeovers from one part style to the next. AUTOMATED MFG. SYSTEM… cont.
  33. 33. 33 – The features of flexible automation; • High investment for custom- engineered system. • Continuous production of variable mixtures of products. • Medium production rates. • Flexibility to deal with product design variations. AUTOMATED MFG. SYSTEM… cont.
  34. 34. 34 – Examples, flexible manufacturing systems for performing machining operations. The relative positions of the three types of automation for different production volume and product varieties are shown below. AUTOMATED MFG. SYSTEM… cont.
  35. 35. 35 Relationship between product variety & quantity Low Medium High100 10000 1,000,000
  36. 36. 36 Relationship of fixed, programmable and flexible automation
  37. 37. 37 REASON FOR AUTOMATING • To increase labor productivity • To reduce labor cost • To improve worker safety • To improve product quality • To mitigate the effects of labor shortages • To reduce/eliminate routine manual & clerical tasks.
  38. 38. 38 REASON FOR AUTOMATING… cont. • To reduce mfg lead time • To accomplish processes that cannot be done manually • To avoid the high cost of not automating
  39. 39. 39 MANUAL LABOR IN PROD. SYSTEM There are situations which manual labor is usually preferred over automation: • Task is too technologically difficult to automate. • Short product life cycle • Customized product • To cope with ups and downs in demand • To reduce risk of product failure
  40. 40. 40 American Prod. And Inventory Control Society(APICS) gives three principles: • Understand the existing process • Simplify the process • Automate the process PRINCIPLES AND STRATEGIES
  41. 41. 41 STRATEGIES FOR AUTO./PROD SYSTEM • Specialization of operation • Combined operations • Simultaneous operations • Integration operations • Increased flexibility • Improved material handling and storage • On-line inspection
  42. 42. 42 STRATEGIES FOR AUTO./PROD SYSTEM… cont. • Improved material handling and storage • On-line inspection • Process control and optimization • Plant operations control • Computer-integrated manufacturing
  43. 43. 43 AUTOMATION CONTROL • Usually implies a sequence of mechanical steps. • A camshaft is an automation controller because it mechanically sequences the steps in the operation of an internal combustion engine.
  44. 44. 44 • Manufacturing processes are often sequenced by special digital computers, known as programmable logic controller (PLC). • PLC can detect and can switch electrical signals on and off. AUTOMATION CONTROL… cont.
  45. 45. 45 PROCESS CONTROL • Usually implies that the product is produced in a continuous stream. • Often, it is a liquid that is being processed. • Early process control system consisted of specially-designed analog circuitry that measured a system’s output ( e.g., the temperature of liquid leaving a tank),
  46. 46. 46 and changed that input ( e.g., changing the amount of cool liquid mixed in) to force the output to stay at a preset value. • Now, process control is accomplished using digital computers. PROCESS CONTROL… cont.
  47. 47. 47 MANUFACTURING Manufacturing – the application of physical and chemical processes to alter the geometry, properties and /or appearance of a given starting material to make parts/product - includes the joining of multiple parts to make assembled products
  48. 48. 48 • Economic viewpoint- the transformation of material into items of greater value… • Eg: iron converted into steel, sand transformed into glass, petroleum transforms into plastic etc. MANUFACTURING… cont.
  49. 49. 49 Machinery Tools Power Labor Starting Complete part Material Waste As a technological process MANUFACTURING… cont. Mfg. Process
  50. 50. 50 MANUFACTURING… cont. • • • Value Added • Starting material complete part • Material in Processing Mfg. Process
  51. 51. 51 • Basic activities to convert raw material into finished products: i. Processing and assembly operations ii. Material handling iii. Inspection and test iv. Coordination and control MANUFACTURING… cont.
  52. 52. 52 Processing and assembly operations • Processing operation transform a work material from one state of completion to a more advanced state that is closer to the final desired part/product. materials is fed into the process, energy is apply by the machinery and tooling to transform the material into finished products. • Assembly operations – two or more components combined to form a new entity eg: welding, soldering, screws, rivets etc.
  53. 53. 53 • Moving and storing materials between processing and/or assembly operations. Inspection and test • Both are quality control activities to determine whether products meet the design std. and spec. Material handling & storage
  54. 54. 54 Coordination and control • includes at process and plant levels • Process level – manipulating input and parameters of the process. • Plants level – labor, maintenance, costing, shipping, scheduling etc.
  55. 55. 55 • 4 keys parameters: i. Quality ii. Variety iii. Complexity of assembled products iv. Complexity of individual parts. PRODUCT/PRODUCTION RELATIONSHIPS
  56. 56. 56 Quantity and variety Consider: Q= prod. Quantity, P=prod. Variety : Qj=annual quantity of prod j : Qf= total quantity of all part p Qf = ∑Qj, where P = total no. of diff. j=1 part, j = 1,2,3,…
  57. 57. 57 Product and Part complexity • Complexity refer to the no.of components used to produce a product-the mere parts, the more complex. • Let, np = the no. of part per product no = the no. of operation/pros. Steps The total no. of parts manufactured/year: npf=total no.of part/yr p npf = ∑Qjnpj Qj= annual quantity/yr j=1 npj= no. of parts/prod
  58. 58. 58 Product and Part complexity… cont. • The total no. of processing operations performed in the plant: p npj nof = ∑Qjnpj ∑nojk j=1 k=1 Where; nof= total no. ofoperation cycles nojk= no of processing operation for each part k npj = no.of parts in product
  59. 59. 59 Product and Part complexity… cont. Conceptualize: Consider P = no. of product design Q = quantities So, the total no. of product produced, Qf = PQ the total no. of parts produced, npf = PQnp the total no. of mfg operation performed, nof = PQnpno
  60. 60. 60 Example P=100 different product, each product produced 10,000 unit/yr, each consist of 1000 components, average processing step=10/component, each processing step=1min. Determine: - how many product - how many part - how many prod. operation - how many workers needed
  61. 61. 61 Solution i. Total no. of unit produced, Qf = PQ 100 x 10,000 = 1,000,000 prod./yr ii. Total no of part produced = npf = PQnp 1.000.000 x 1000 = 1,000,000,000 parts/yr iii. Prod. operation = nof =PQnpno iv. Total time = 1,000,000,000 x 1/60=166,666,667 hr v. Workers= 1666,6666,661/2000=83,333 workers
  62. 62. 62 Production rate • Normally expressed as an hourly rate. • Also called operation cycle time, Tc. Tc is defined as the time that one work unit spends being processed/assembled. Tc = To + Th + Tth where Tc = operation cycle time (min/pc) To = time of actual processing/assemb. Th = handling time (min/pc) Tth= tool handling time(min/pc)
  63. 63. 63 Production capacity • Is defined as the max. rate of o.p that the production facilities is able to produce under a given set of assumed operation cond.( num. of shift/day). • Let PC = prod. Capacity, n = num. of m/c Rp = prod. Rate, H = hr/shift, S =num. of shift/week. PC = n SH Rp
  64. 64. 64 Production capacity… cont. • If no = num. of distinct operation through which work units are routed. • To increase/decrease prod. Capacity: i. Short term:  changes of S and H will increase prod. Capacity ii. Long term  to increase capacity, change n, increase Rp and reduce no. PC = n SH Rp / no
  65. 65. 65 MANUFACTURING OPERATION COSTS • Mfg costs – fixed and variable costs. • Fixed costs-remains constant for any level of prod. • Variable costs-varies in proportion to the level of prod. • Let TC = total annual costs (RM/yr), FC = fixed annual costs (RM/yr), VC= variable costs (RM/pc) and Q = annual quantity produced (pc/yr).
  67. 67. 67 MANUFACTURING OPERATION COSTS… cont. • Costs also depend on labor, materials and overhead. • Labor costs- paid to workers • Materials costs- cost of raw materials to produce product. • Overhead costs- factory and corporate o.heat - factory o.h to operate the factory - corporate o.h to run the factory
  70. 70. 70 MANUFACTURING OPERATION COSTS… cont. • J.T Black.
  71. 71. 71 MANUFACTURING OPERATION COSTS… cont. • Overhead rate (burden) to be calculated and to used in the following year to allocate overhead costs. FOHR = FOHC / DLC Where FOHR = factory overhead rate FOHC = annual factory overhead costs DLC = annual direct labor costs
  72. 72. 72 MANUFACTURING OPERATION COSTS… cont. • Corporate overheat rate, COHR = COHC /DLC where COHR = annual corporate overhead rate, COHC = annual corporate overhead costs, DLC = annual direct labor costs DLC = annual direct labor costs
  73. 73. 73 MANUFACTURING OPERATION COSTS… cont. • Eg: determine a) FOHR for each plant b) COHR
  74. 74. 74 MANUFACTURING OPERATION COSTS… cont. Solution: a) FOHR1 = 2,000 / 800,000 = 250% FOHR2 = 1,100,000 / 400,000 = 275% b) COHR = 72,000 / 1,200,000 = 600%