Unit 7_Modern Manufacturing Process.pptx
- 1. Department of Mechanical Engineering Unit no: 7 Unit title: MAIM Subject Name: CAPM Subject Code 07ME0721 ComputerAided Process (CAPM) Management
- 2. Cellular Manufacturing DetailedGroupTechnology Composite part ROC technique (RankOrderClusteringTechnique) Hollier method forGroupTechnology, cell layouts; Flexible Manufacturing- Concept, principles, Lean concept, principles. Modern Approaches in Manufacturing manufacturing
- 3. In manufacturing activity batch manufacturing should be efficient and productive. In addition, there has been a trend to integrate the design and manufacturing functions in a firm. An approach directed at both of these objective is ‘Group Group Technology Technology’. “Group Technology is a manufacturing philosophy in which similar parts are identified and grouped together to take advantage of their similarities in design and production.” Similar parts are arranged into part families, where each part family possesses similar design and/or manufacturing characteristics.
- 4. There are two major tasks that a company must undertake when it implements group technology. Identifying the part families. If the plant makes 10,000 different parts, reviewing all of the part drawings and grouping the parts into families is a substantial task that consumes a significant amount of time. Group Technology Rearranging production machines into cells. It is time consuming and costly to plan and accomplish this rearrangement, and the machines are not producing during the changeover.
- 5. It is reasonable to believe that the processing of each member of a given family is similar, and this should result in manufacturing efficiencies. Group Technology The efficiencies are generally achieved by arranging the production equipment into machine groups, or cells, to facilitate work flow. Organizing the production equipment into machine cells, where each cell specializes in the production of a part family, is called “cellular manufacturing”.
- 6. There are two major tasks that a company must undertake when it implements group technology. Group Technology Rearranging production machines into cells. It is time consuming and costly to plan and accomplish this rearrangement, and the machines are not producing during the changeover. Identifying the part families. If the plant makes 10,000 different parts, reviewing all of the part drawings and grouping the parts into families is a substantial task that consumes a significant amount of time.
- 7. Cellular manufacturing is a manufacturing process that produces families of parts within a single line or cell of machines operated by machinists who work only within the line or cell. A cell is a small scale, clearly-defined production unit within a larger factory. This unit has complete responsibility for producing a family of like parts or a product. All necessary machines and manpower are contained within this cell, thus giving it a degree of operational autonomy. Each worker is expected to have mastered a full range of operating skills required by his or her cell. Therefore, systematic job rotation and training are necessary Cellular Manufacturing conditions for effective cell development. Complete worker training is needed to ensure that flexible worker assignments can be fulfilled.
- 9. + D M M L L M M ~ ~ Cell 2 M L D available for marke ting space Floo CellI - L L A D G L A L L M D Cell 3 Receiving and A G G shipping
- 10. “A part family is a collection of parts that are similar either in geometric shape and size or in the processing steps required in their manufacture.” Part Family Part families are a central feature of group technology. There are always differences among parts in a family, but the similarities are close enough that the parts can be grouped into the same family.
- 11. Two parts that are identical in shape and size but quite different in manufacturing: 1,000,000 units/Yr. tolerance = 0.010 inch, 1015 CR steel, nickel plate; 100/Yr. tolerance = 0.001 inch, 18-8 stainless steel. Part Family
- 12. Ten parts are different in size, shape, similar in terms of manufacturing. All parts are machined from cylindrical parts require drilling and/or milling. and material, but quite stock by turning; some Part Family
- 13. Similar prismatic parts requiring similar milling operations PartFamily Dissimilar parts requiring similar machining operations (hole drilling, surface milling) Identical designed parts requiring completely different manufacturing processes
- 16. Comparison ProcessType Layout GroupTechnology Layout The various machine tools are arranged by function. Machine tools are arranged into cells. To machine a given part, the workpiece must be transported between the departments. Each cell is organized to specialize in the production of a particular part family. This results in much material handling, large in-process inventories, many machine setups, long manufacturing lead times, and high cost. The advantages are, reduced workpiece handling, lower setup times, fewer setups (in some cases, no setup changes are necessary), less in-process inventory and shorter lead times.
- 17. There are three general methods for solving part families grouping. All the three are time consuming and involve the analysis of much of data by properly trained personnel. Grouping Part Families Visual inspection Parts classification and coding Production FlowAnalysis (PFA)
- 18. The visual inspection method is the least sophisticated and least expensive method It involves the classification of parts into families by looking at either the physical parts or their photographs and arranging them into groups having similar features. Visual Inspection Method
- 19. Parts classification and coding Identifying similarities and differences among parts and relating them by means of a coding scheme. Most time consuming and complicated method.
- 20. Production identifying groupings flow part that analysis families (PFA) and is a method for associated machine Production flow analysis (PFA) uses the information contained on process plans rather than on part drawings. Work parts with identical or similar process plans are classified into part families. These families can then be used to form logical machine cells in a group technology layout.
- 21. Parts Classification andCoding Identifying similarities and differences among parts and relating them by means of a coding scheme. Most time consuming and complicated method.
- 22. Reasons for using a classification and coding system Design retrieval. A designer faced with the task of developing a new part can use a design retrieval system to determine if a similar part already exist. A simple change in an existing part would take much less time than designing a whole new part from scratch. Automated process planning. The part code for a new part can be used to search for process plans for existing parts with identical or similar codes. Machine cell design. The part codes can be used to design machine cells capable of producing all members of a particular part family, using the composite part concept. Parts Classification andCoding
- 23. The principal functional areas that utilize a part classification and coding system are design and manufacturing. Features Coding Systems of Accordingly, parts classification systems falls into three categories: one of Systems based on part design attributes Systems based on part manufacturing attributes Systems based on both design and manufacturing attributes.
- 24. Features of Coding Systems PART DESIGNATTRIBUTES PART MANUFACTURING ATTRIBUTES Basic external shape Major processes Basic internal shape Minor operations Rotational or rectangular shape Operation sequence Length-to-diameter ratio Major dimensions Aspect ratio Surface finish Material types Machine tool Part function Production cycle time Major dimensions Batch size Minor dimensions Annual production Tolerances Fixtures required Surface finish Cutting tools used in manufacture
- 25. The three basic coding structures are Coding Structure ChainType Structure Hierarchical Structure Hybrid Structure
- 26. It is also known as a polycode, in which the interpretation of each symbol in the sequence is always the same, it does not depend on the value of the preceding symbols. Chain - type Structure
- 27. It is also known as a monocode, in which the interpretation of each successive symbol depends on the value of the preceding symbols. Hierarchical Structure
- 28. It is a combination of hierarchical and chain-type structures. Hybrid structure
- 29. To distinguish the hierarchical code and chain type structures, consider a two-digit code number for a part, such as 15 or 25. Suppose first digit stands for the general shape of the part, 1 means the part is cylindrical (rotational), and 2 means the geometry is rectangular. In hierarchical structure, the interpretation of the second digit depends on the value of the first digit. If preceded by 1, the 5 might indicate a length to diameter ratio; and if preceded by 2, the 5 might indicate an aspect ratio. In chain type structure, the symbol 5 would have the same meaning whether preceded by 1 or 2. For example, it might indicate the overall length of the part. The advantage of the hierarchical structure is that in general more information can be included in a code of a given number of digits. Coding Structures
- 30. The number of digits in the code can range between 6 to 30. Coding schemes that contain only design data require fewer digit, perhaps 12 or fewer. Most modern classification and coding system include both design and manufacturing data, and this usually requires 20 to 30 digits. Coding Structures
- 31. Opitz classification system – the University of Aachen in Germany, nonproprietary,Chain type. BrischSystem –(Brisch-Birn Inc.) CODE (Manufacturing DataSystem, Inc.) CUTPLAN (MetcutAssociates) DCLASS (BrighamYoungUniversity) MICLASS system PartAnalogSystem (Lovelace, Lawrence &Co., Inc.) Important Systems
- 32. Will it be used for design retrieval or part family manufacturing or both? Scope and application What departments in the company will use the system? What specific requirements do these departments have? What kinds information must be coded? How wide a range of products must be coded? How complex are the parts, shapes, processes, tooling and so forth? Cost and time: The company must consider the costs of installation, training and maintenance of their parts classification and coding system. Factors to Consider
- 33. Adaptability to other systems: Can the classification and coding system be readily adapted to the existing company computer systems and data bases? Can it be readily integrated with other existing company procedures, such as process planning, NC programming, and production scheduling? Factors to Consider Management problems: It is important that all involved management personnel be informed and supportive of the system. Also, will there be any problems with the union? Will cooperation and support for the system be obtained from the various departments involved?
- 34. The basic code consists of nine digits, which can be extended by adding four more digits. First nine are intended to convey both design and manufacturingdata. FormCode First five digits, 12345 are called form code. It describes the primary design attributes of the part, such as external shape, (rotational or non rotational) And machined features (holes, threads, gear teeth and so on. OPITZSystem
- 35. The basic code consists of nine digits, which can be extended by adding four more digits. First nine are intended to convey both design and manufacturing data. FormCode OPITZSystem First five digits, 12345 are called form code. It describes the primary design attributes of the part, such as external shape, (rotational or non rotational) And machined features (holes, threads, gear teeth and so on.
- 36. SupplementaryCode The next four digits, 6789, constitute the supplementary code, which indicates some of the attributes that would be useful in manufacturing (dimensions, work material, starting shape and accuracy SecondaryCode The extra four digits, ABCD, are referred to as the OPITZSystem secondary code and are intended to identify the production operation type and sequence. The secondary code can be designed by the user firm to serve it own particular needs.
- 37. Supplimentary code ,Digit Form code Digit 5 Digit 2 Digit 3 Digit 4 Digit 1 Part class 6 7 8 9 PIane surface machining Machining of plane surfaces al ho1 es Ma ' m shape Rt o f a Ional machining Internal shape element AdditliIon teeth and forming Other holes and teeth LID s 0.5 0 ~ External shape element 1 - 2 0,5 <LID <3 ~ t= ..0 . ... ~ LID~3 ~ ~ ·c ~ Q) With deviation LID$2 With deviation LID>2 Special A/B~3 AJC~4 ~ 0 Machining of plane surfaces Other holes, teeth and forming 3 ~ 8 ~ Rotational machining ~ Main shape .c _: : (/l - a >. -- -, 4 - 5 0 to) .. .. = ' ~ 1-4 ~ 0 8 - 'C (/l c Q) . _ ~ ~ e to) ~ -: <, « to) : E Main shape ~ ~ 0 {/l , 'i 6 ,9 - eo ~ Machining of plane surfaces Main bore and rotational machining Other holes, teeth and forming ' C 0 < a Main shape - .c -: 7 - ·8 AlB >3 i:.. ·· 0 - s ~ / 8 c A/B~3 AJC<4 Special 0 Z Main shape 9
- 38. Digit 4 Digit 5 Digit 3 Digit 2 Digit 1 Plane surface machining Auxiliary holes and gear teeth Internal shape, internal shape elements External shape, external shape elements Part class No surface machining Smooth, no shape elements No hole, no breakthrough No auxiliary hole 0 I--'- L/D ~ 0.5 0 0 0 0 I-- - Surface plane and/or Axial, not on pitch circle diameter No shape elements No shape elements curved direction, in one external 1 1 ."'0 = 1 0.5 < L/D < 3 1 ~ 1 I-- '"0 <l) <l) 0.. = < U f-- I-- 0..'"0 < = l) External plane surface related by graduation around the circle t ~<l) 0 Axial on pitch circle diameter . s ;.... <l) o 2 I-- Thread 2 ... = Thread 2 ... - 3 2 L/D~3 2 ~ I= : .... ..= .. ... .. ...= 0 "'0 c a 0 0 S " "' ..... 0 I-- .=-0 CI) <l) 0.. 0.. g- S CZI ... .. <l) Radial, not on pitch circle diameter Axial and/or radial and/or other direction Axial and/or radial on pen and/or other directions ;... . ... .. <l) External groove ~ Functional groove Functional groove ... .. ~ en I..; 3 3 CI) b.O 3 0 3 I-- and/or slot 0 I-- Z External spline No shape elements No shape elements - g <l) 4 4 ~ 4 4 ~ 4 - 5 ~ (polygon) < = l) ~ .... ... =.. 0 ....c ..:. External plane surface and/or slot, external spline 0 ..0 - 0 ,CJ 5 5 Thread 5 5 I-- Thread .0 .. .. ...- 13 "'!:) <l) 0.. 0.. 0.. E 0.. Internal plane surface and/or slot Functional groove Functional groove .< .. l .) . Spur gear teeth 6 - 7 - 8 - 9 6 6 6 6 en CZ I I-- t "" ' ., Internal spline (polygon) ~ 0.. c a Bevel gear teeth Functional cone 7 Functional cone 7 7 7 - 8 - 9 -5 I= : <l) ..< .l .) . ~ 1-1 <l) b.O -5 ~ ...8 ... Internal and external polygon, groove and/or slot .~ .... 8 = 8 Other gear teeth Operating thread 8 Operating thread 8 s All others All others All others 9 9 All others 9
- 40. Solution Length to Diameter Ratio: L/D = 1.5 Digit 1 = 1 ExternalShape: Both ends stepped with screw thread on one end Digit 2 = 5 InternalShape: Part contains a through hole Digit 3 = 1 Plane surface machining: None Digit 4 = 0 Auxiliary holes, gear teeth etc: None Digit 5 = 0 OpitzExample
- 41. MICLASS stands for Metal Institute Classification System and was developed byTNO, the Netherlands Organization forApplied Scientific Research. The MICLASS system was developed to help automate and standardize a number of design, production and management function. These include: - Standardization of engineering drawings - Retrieval of drawings according to classification number - Standardization of process planning -Automated process planning - Selection of parts for processing on particular groups of machine tools - Machine tool investment analysis MIClass
- 42. The MICLASS classification number can range from 12 to 30 digits. The first 12 digits are a universal code that can be applied to any part. Up to 18 additional digits can be used to code data that are specific to the particular company or industry. For example, lot size, piece time, cost data and operation sequence might be included in the 18 supplementarydigits. MIClass
- 43. MIClass
- 44. The work part attributes coded MICLASS number are as follows in the first 12 digits of the 2 and 3 digits MIClass DIGITS ATTRIBUTES 1st digit Main shape nd rd Shape elements 4th digit Position of shape elements 5th and 6th digits Main dimensions 7th digit Dimension ratio 8th digit Auxiliary dimension 9th and 10th digits Tolerance codes 11th and 12th digits Material codes
- 45. One of the unique features of the MICLASS system is that part can be coded using a computer interactively. To classify a given part design, the user responds to the series of questions asked by the computer. The number of questions depends on the complexity of the part. For a simple part, as few as seven questions are need to classify the part. MIClass For an average part, the number of questions ranges between 10 to 20. On the basis of the responses to its questions, the computer assigns a code number to the part.
- 46. Its universal application is in design engineering for retrieval of part design data, but it also has applications in manufacturing process planning, purchasing, tool design and inventory control. TheCODE number has eight digit. For each digit there are 16 possible values (0 through 9 and A through F) which are used to describe the part’s design and manufacturing characteristics. The initial digit position indicates the basic geometry of the part and is called the Major Division of theCODE system. This digit would be used to specify whether the shape was a cylinder, flat piece, block, or other. The interpretation of the remaining seven digits depends on the value of the first digit, but these remaining digits form a chain type structure. Hence theCODE system possesses a hybrid structure. CODESystem
- 47. The second and third digits provide additional information concerning the basic geometry and principal manufacturing process for the part. Digits 4, 5 and 6 specify secondary manufacturing processes such as threads, grooves, slots, and so forth. Digits 7 and 8 and used to indicate the overall size of the part (diameter and length for a turned part) by classifying it into one of the 16 size ranges for each of two dimensions. CODESystem
- 48. CODESystem
- 49. The part families1 are defined by the fact that their members have similar design and manufacturing attributes. “Composite part is the hypothetical part that represents all of the design and corresponding manufacturing attributes possessed by the various individuals in the family.” To produce one of the members of the part family, operations are Composite PartConcept added and deleted corresponding to the attributes of the particular part design. 1. “A part family is a collection of parts that are similar either in geometric shape and size or in the processing steps required in their manufacture.” “GroupTechnology is a manufacturing philosophy in which similar parts are identified and grouped together to take advantage of their similarities in design and production.”
- 50. Six simple parts consisting of seven Design and Manufacturing attributes
- 51. Composite PartConcept Design Feature CorrespondingOperation ExternalCylinder Turning Face ofCylinder Facing Cylindrical Step Turning (Step) SmoothSurface ExternalCylindrical Grinding Axial Hole Drilling Counterbore Counterboring InternalThreads Tapping
- 52. A machine cell would be designed to provide all seven machining capabilities. The machine, fixtures, and tools would be set up for efficient flow of work parts through the cell. In practice, the number of design and manufacturing attributes would be greater than seven, and allowances would have to be made for variations in overall size and shape of parts in the part family. The composite part concept is useful for visualizing the machine cell design problem. Composite PartConcept
- 53. Production flow analysis (PFA) is a well-established methodology used for transforming traditional functional layout into product- oriented layout. The method uses part routings to find natural clusters of workstations forming production cells able to complete parts and components swiftly with simplified material flow. PFA is traditionally applied to job-shops with functional layouts, and after reorganization within groups lead times reduce, quality improves and motivation among personnel improves. Production FlowAnalysis
- 54. The Rank Order Clustering (ROC) technique is specifically applicable in production flow analysis. It is an efficient and easy to use algorithm for grouping machines into cells. The algorithm, which is based on sorting rows and columns of the machine-part incidence matrix, is given below. 1. Assign row binary weight and using calculate a decimal the weight for each formula RankOrder Clustering i bip 2 Decimal weight for row Where m is the number of row and b is a binary number (0 or 1) 1 m m p p
- 55. 2. Rank the rows from top to bottom in order of decreasing decimal weight values 3. Assign binary weight and calculate column using the formula a decimal weight for each Decimal weight for column Where n is the number of column and b is a binary number (0 or 1) pj RankOrder Clustering 4. Rank the column from left to right in order of decreasing decimal weight values 5.Continue preceding steps until there is no change in the position of each element in each row and column n j b 2n p p1
- 60. ROC Example A B C D E F G H 1 1 1 1 1 1 2 1 1 3 1 1 1 1 1 4 1 1 5 1 1 1 6 1 1 1 1 1
- 61. After part-machine grouping have been identified by rank order clustering, the next problem is to organize the machines into the most logical arrangement. Hollier Method-1 • This method uses the sums of flow “From” and “To” each machine in the cell.The method can be outlined as follows 1. Develop the From-To chart from part routing data. The data contained in the chart indicates numbers of part moves between the machines in the cell. 2. Determine the “From” and “To” sums for each machine. This is accomplished by summing all of the “From” trips and “To” trips for each machine. ➢The “From” sum for a machine is determined by adding the entries in the corresponding row. Arranging Machine Cells – Hollier Method. in ➢The “To” sum is found by adding the entries in the corresponding column.
- 62. 3.Assign machines to the cell based on minimum “From” or “To” sums.The machine having the smallest sum is selected. ➢If the minimum value is a “To” sum, then the machine placed at the beginning of the sequence. ➢If the minimum value is a “From” sum, then the machine placed at the end of the sequence. is Hollier Method-1 is Tie breaker ➢If a tie occurs between minimum “To” sums or minimum “From” sums, then the machine with the minimum “From/To” ratio is selected.
- 63. ➢If both “To” and “From” sums are equal for a selected machine, it is passed over and the machine with the next lowest sum is selected. ➢If a minimum “To” sum is equal to a minimum “From” sum, then both machines are selected and placed at the beginning and end of the sequence, respectively Hollier Method-1 4. Reformat the From-To chart. After each machine has been selected, restructure the From-To chart by eliminating the row and column corresponding to the selected machine and recalculate the “From” and “To” sums. 5. Repeat steps 3 and 4 until all machines have been assigned
- 64. Hollier Method-1 135 SUM 50 45 0 40 SUM 30 45 50 10 To 1 2 3 4 From 1 0 5 0 25 2 30 0 0 15 3 10 40 0 0 4 10 0 0 0
- 65. Hollier Method-1 3 135 SUM 50 45 0 40 SUM 30 45 50 10 To 1 2 3 4 From 1 0 5 0 25 2 30 0 0 15 3 10 40 0 0 4 10 0 0 0
- 66. Hollier Method. 3-2 85 SUM 40 5 40 SUM 30 45 10 To 1 2 4 From 1 0 5 25 2 30 0 15 4 10 0 0
- 67. Hollier Method-1 3-2-1 35 SUM 10 25 SUM 25 10 To 1 4 From 1 0 25 4 10 0
- 69. Develop the From-To chart Determine the From/To ratio for each machine Arrange machines in order of decreasing From/To ratio Machines with high ratios are placed at the beginning of the work flow, and machines with low ratios are placed at the end of the work flow. In case of a tie, the machine with the higher “From” value is placed ahead of the machine with a lower value Hollier Method-2
- 70. Hollier Method-2 3-2-1-4 135 SUM 50 45 0 40 SUM From / To Ratio 30 0.60 45 1 50 ∞ 10 0.25 To 1 2 3 4 From 1 0 5 0 25 2 30 0 0 15 3 10 40 0 0 4 10 0 0 0
- 71. 10 15 Hollier Method Flow Diagram 40 30 25 50 in 3 2 4 1 30 out 5 10 20 out
- 74. Practice Example
- 75. Percentage of in-sequence moves Computed by adding all of the values representing in-sequence moves and dividing by the total number of moves Percentage of backtracking moves Performance Measure Determined by summing all of the values representing backtracking moves and dividing by the total number of moves
- 76. Percentage of in-sequence moves In-sequence moves = 40 + 30 + 25 = 95 Total number of moves = 135 Percentage of in-sequence moves = 95/135 = 70.4% Performance Measure Percentage of backtracking moves Backtracking moves = 5 + 10 = 15 Total number of moves = 135 Percentage of backtracking moves = 15/135 = 11.1%
- 77. - - Flexible manufacturing system (FMS) is a A group of highly automatedGT machine cell, consisting of a group of processing workstations (usually CNC machine tools), interconnected by an automated material handling and storage system, and controlled by a distributed computer system. - Introduction - The reason the FMS is called flexible is that it is capable of processing a variety of different part styles simultaneously at the various workstations, and the mix of part styles and quantities of production can be adjusted in response to changing demand patterns. FMS is most suited for the mid-variety, mid-volume production range.
- 78. FMSSuitability
- 79. A more appropriate term for FMS would be ‘flexible automated manufacturing system.’ The use of the word “automated” would distinguish this type of production technology from other manufacturing systems that are flexible but not automated, such as a mannedGT machine cell. FMSSuitability The word “flexible” would distinguish it from other manufacturing systems that are highly automated but not flexible, such as conventional transfer line.
- 80. The requirement in manufacturing is to get the right materials or parts to the right machines at the right time. Too much or too soon creates backed up excess in-process inventory. Too little or too late causes delayed work schedules and idle machines. The result in many cases is a poor use of capital, in the form of excess in-process inventory and/or underutilization of the equipment. The underutilization of equipment and gross inefficiencies existing in a vast majority of manufacturing industries. Need of FMS Many of these inefficiencies are common day to day disturbances within the overall manufacturing process.
- 81. What is needed in today’s competitive environment, regardless of what products a particular company makes, is the capability to effectively manage and control the day to day disturbances while meeting customer requirements. This implies that: There should be minimum delay between order placement and order delivery. Quality and reliability should be high Operating costs should be predictable and under control Replacement parts should be available and accessible on a quick turnaroundbasis. Need of FMS FMS provides a means to manage and control the uncontrollable disturbances while meeting customer demands and requirements.
- 82. 1.Work Stations 2. Material Handling and Storage System Components of FMS 3.ComputerControl System 4. Human Resources
- 83. In the system designed for machining operations, the principle types of processing station areCNC machine tools. Following workstations are also found in FMS: - Load/Unload stations - Machining stations - other processing stations such as sheet metal fabrication, press working operation, forging process etc. -Assembly operations - Inspection operation stations such as - Co-ordinate Measuring Machine (CMM) and inspection probes and machine vision In addition to above, other operations and functions are often accomplished such as cleaning parts, central coolant delivery systems for entire FMS, and centralized chip removal systems. Work Stations
- 84. The material handling and storage system in a flexible manufacturing system performs the following functions: - Allows random, independent movement of workparts between stations. Enables handling of a variety of workpart configurations such as prismatic and rotational. Provides temporary storage. Provides convenient access for loading and unloading work parts. Creates compatibility with computer control. Material Handling System - - - -
- 85. The FMS includes a distributed computer system that is interfaced to the workstations, material handling system, and other hardware components. A typical FMS computer system consists of a central computer and microcomputers controlling the individual machines and other components. Computer Control System The functions performed by the FMS computer control system can be grouped into the following categories: Workstation control Distribution of control instructions to workstations Production control Traffic control Workpiece monitoring Tool control - - - - - -
- 86. One additional component in the FMS is human labor. Humans system. are needed to manage the operations of the - - - - - - - Functions typically performed by humans include: Loading raw workparts into the system, Unloading finished parts (or assemblies) from the system, Changing and setting tools, Performing equipment maintenance and repair, Performing NC part programming, Programming and operating the computer system, and Managing the system. Human Resources
- 87. 1. Flexibility 2. FMS justification General FMS Considerations 3. Management commitment and planning
- 88. Flexibility to some manufacturers means convertibility – being able to convert from manufacturing one product type, family and/or volume to another within the manufacturer’s predetermined time. Thus, convertibility may be the ‘real’ be flexibility the manufacturer requires, and it may done by more Flexibility upgrading or altering of existing resources rather than the purchase of an FMS. Generally, flexibility refers to: Variety of mix Adaptability to design, production or routing changes Machine changeover by - - -
- 89. - Machine flexibility: the ease with which a machine can process various operations. Material handling flexibility: a measure of the ease with which different part types can be transported and properly positioned at the various machine tools in a system. Types of flexibilities Basic Flexibility - – Operation flexibility: - a measure of the ease with which alternative operation sequences can be used for processing a part type.
- 90. - Volume flexibility a measure of a system’s capability to be operated profitably at different volumes of the existing part types. Expansion flexibility the ability to build a system and expand it incrementally Routing flexibility - - Types of flexibilities System Flexibility: – a measure of the alternative paths that a part can through a system for a given process plan Process flexibility effectively follow - a measure of the volume of the set of part types that a system can produce without incurring any setup Product flexibility the volume of the set of part types that can be manufactured in a system with minor setup. -
- 91. - Program flexibility the ability of a system to run for reasonably long periods without external intervention Production flexibility Types of flexibilities Aggregate Flexibility: - – the volume of the set of part types that a system can produce without major investment in capital equipment Market flexibility - the ability of a system to efficiently adapt to changing market conditions.
- 92. The concept of FMS justification is major obstacle to the success manufacturing innovation and capability. To install a new machining center that works of five people, for instance, meant comparing their salaries plus benefits to the cost of the machine. In this manner, the equipment’s purchase was easily FMS Justification justified. ROI (ReturnOn Investment) is the driving factor. Traditional justification techniques, based on ROI and direct labor cost reduction. Financial people are using formulas and accounting forms that include only traditional or standard line items and benefits to run the numbers.
- 93. FMS projects are more likely to occur in companies that plan from the top down and implement from the bottom up. Planning is a distributed decision making process. It involves, top management for leadership, direction, judgment, major decision making, and removing road blocks; middle management for implementing change, carrying out decisions, and managing results; - Managements’ commitment & planning - - and producers for doing the work and providing information, insight and knowledge.
- 94. Management’s responsibility of the commitment and planning effort, should be: Management must be available to provide guidance and direction. Communication is necessary, not only to members of the project team, but to all employees. Management must surround themselves with strong, competent people. - - Managements’ commitment & planning - - There must be ability in management and function as group. project team to - Acceptance by management to change operational and organizational layout. Bringing outside consultants to assist or advise with FMS . -
- 95. Reduction in the number of uncontrollable variables Improve operational control through: Reducing the dependence on human communication Removing operators from the machining site Objective FMS of Reduce direct labor cost: Eliminating dependence on highly skilled machinists Improve run short Engineering changes, processing changes, cutting tool failure and late material delivery responsiveness consisting of:
- 96. Changing product volumes Improve long-run accommodati ons: New product additions and introductions Eliminating machine set up Objective FMS of Increase machine utilization by: Utilizing automated features to replace manual intervention Reducing lot sizes Reduce inventory by: Improving inventory turnover
- 97. FMS can be distinguished according to the kinds of operations they perform: - Processing vs. assembly operations Two other ways to classify FMS are by 1. Number of machines (Workstations) a) Single machine cell (n = 1) b) Flexible manufacturing cell (FMC)(n = 2 or 3) c) Flexible manufacturing system (FMS) (n Types of FMS = 4 or more) 2. Level of flexibility a) Dedicated FMS b) Random order FMS
- 99. It consist of a fully automated machine capable of unattended operations for a time period longer than one machine cycle. It is capable of processing different part styles, responding to changes in production schedule, and accepting new part Single MachineCell introductions. simultaneous. In this case processing is sequential not
- 100. Single MachineCell photo courtesy ofCincinnati Milacron
- 102. It consists of two or three processing workstation and a part handling system. The part handling system is connected to a load/unload station. It is capable of simultaneous production of different parts. Flexible Manufacturing Cell
- 104. It has four or more processing work stations (typically CNC machining centers or turning centers) handling connected mechanically by a common part system and Flexible Manufacturing System automatically by a distributed computer system. It also includes non-processing work stations that support production but do not directly participate in it. e.g. part / pallet washing stations, co-ordinate measuring machines. These features significantly differentiate it from Flexible manufacturing cell (FMC).
- 106. FMS Summarized
- 107. A) Dedicated FMS A dedicated FMS is designed to produce a limited variety of part styles. The part family is likely to be based on product commonality rather than geometric similarity. Instead of being general purpose, the machines can be designed for the specific processes required to make the limited part family, thus increasing the production rate of the system. Level of Flexibility
- 108. B) Random order FMS A random order FMS is more appropriate when the part family is large, There are substantial variations in the part configuration, new part designs will be introduced into the system Level of Flexibility and engineering changes will occur in the parts produced and production schedule is subject to change from day to day. To accommodate these variations, the random-order FMS must be more flexible than the dedicated FMS. It is equipped with general purpose machines to dead with the variations in product and is capable of processing parts in various sequences (random order).
- 109. Level of Flexibility
- 110. The layout of the FMS is established by the material handling system. Five basic types of FMS layouts 1. In - Line FMS Layout Configuration 2. Loop 3. Ladder 4.Open Field 5. Robot - centred cell
- 111. Machines and handling system are arranged in a straight line. Simplest form. The parts progress from one workstation to the next in well-defined sequence with work always moving in one direction. No back-flow. In-line Layout (without secondary part handlingsystem)
- 112. Line transfer system with secondary part handling each work station to facilitate flow in two direction system at In-line Layout (with secondary part handlingsystem)
- 113. The workstations are organized in a loop that is served by a part handling system. Parts usually flow in one direction around the loop with the capability to stop and be transferred to any station. The load/unload stations are typically located at one end of the loop. Loop Layout
- 114. Rectangular layout allows recirculation of pallets back to the first station in the sequence after unloading at the final station Loop Layout (Rectangular)
- 115. The ladder layout consists of a loop with rungs between the straight which Ladder Layout section of the loop, on workstations are located. Reduction of average travel distance and transport time between the stations.
- 116. Open - Field Layout Consists ladders. Layout of multiple loops and is appropriate for processing large family of parts.
- 117. Uses one or as more the robots material system. Robots handling Robot - CenteredCell Layout equipped with gripper that well the of non make suited them for handling rotational and rotational parts.
- 118. 1. Increased machine utilization, ▪ 24 hour operation likely to justify investment, ▪ Automatic tool changing, ▪ Queues of parts at stations to maximize utilization, ▪ Dynamic scheduling of production to account for changes in demand. 2. Fewer machines required, 3. Reduction in factory floor space required, 4.Greater responsivenessto change, 5. Reduced inventory requirements, 6. Lower manufacturing lead times, 7. Reduced labour requirements 8. Higher productivity 9.Opportunity for unattended production 10. Machines run overnight ("lights out operation") FMS Benefits
- 119. Limited ability to adapt to changes in product or product mix (ex. machines are of limited), capacity and the tooling necessary for products, even of the same family, is not always feasible in a given FMS) Substantial pre-planning activity, Expensive, costing millions of dollars, Technological problems of exact component positioning and precise timing necessary to process a component., Sophisticated manufacturing systems. Disadvantages
- 120. Automated Guided Vehicles (AGVs), as they are commonly referred to “driverless tractors”. An AGV is a battery operated, programmable and automatic guided mobile vehicle without the need of human intervention used for transporting the material from the stores to the shop/assembly line or vice versa. The main parts ofAGV are: Automated Guided Vehicles 1. Structure 2. Drive System 3. Steering Mechanism 4. Power source-battery 5.Onboard computer for control
- 121. 1.Towing 2. PalletTruck Types ofAGVs 3. Unit Load 4. ForkTrucks 5.AssemblyVehicles
- 122. 1.Wired Navigation 2.GuideTape Navigation Types of Navigation in AGVs 3. LaserTarget Navigation
- 123. AGVs Examples
- 124. Towing vehicle pulls one or more trailers to form a train. This type is applicable in moving heavy pay loads over large distance in warehouses or factories with or without intermediate pickup and drop off points along the route. It consists of 5-10 trailers and is an efficient transport system. The towing capacity is up to 60,000 pounds. TowingVehicle
- 125. Pallet trucks are used to move palletized loads along predetermined routes. The capacity of an AGV pallet truck ranges up to several thousand kilograms and some are capable of handling two pallets. It is achieved for vertical movement to reach loads on racks and shelves. PalletTrucks
- 126. These are used to move unit loads from one station to another. It is also used for automatic loading and unloading of pallets rollers. Load capacity ranges up to 250 kg or less. Especially these vehicles are designed to move small loads. by means of Unit Load Carriers
- 127. Fork trucks are equipped with forks which can move in vertical direction to reach palletized loads on racks and stands. This vehicle has an ability to ForkTrucks load and unload the palletized loads both at floor level as well as stands. It can position its forks at any height so that conveyors or load stands of varying height can be assed easily.
- 128. AGV assembly line vehicle is designed to carry subassemblies through a sequence of assembly a finished Assembly Line Vehicle workstations where parts assembly. At assembly workstation, are assembled to build the assembler takes the parts on board and completes his task of assembly.
- 129. Dispatching, tracking and monitoring under real-time computer control Better resource utilization Increased control over material flow and movement Reduced product damage and less material movement noise Routing consistency but flexibility Benefits AGVs of Operational environments reliability in hazardous and special Ability to interface with various peripheral systems, such as machine tools, robots and conveyor systems High location and positioning accuracy
- 130. Limitations of AGVs The system requires high investment AGV system is not suitable for small units
- 131. Automated Guided Vehicles can be used in a wide variety of applications to transport many different types of material including pallets, rolls, racks, carts, and containers. 1. Raw Material Handling:- AGVs are commonly used to transport raw materials paper, steel, rubber, metal, and plastic. such as AGV Applications This includes transporting materials from receiving to the warehouse, and delivering materials directly to production lines. 2.Work-in-Process Movement:- Work-in-Process movement is one of the first applications where automated guided vehicles were used, and includes the repetitive movement of materials throughout the manufacturing process.
- 132. 3. Pallet Handling:- Pallet handling is an extremely popular application for AGVs as repetitive movement of pallets is very common in manufacturing and distribution facilities. AGV Applications 4. Finished Product Handling:- Moving finished goods from manufacturing to storage or shipping is the final movement of materials before they are delivered to customers. These movements often require the gentlest material handling because the products are complete and subject to damage from rough handling.
- 133. “AS/RS refers to a variety of computer-controlled methods for automatically depositing and retrieving loads from defined storage locations”. AS/RS are used widely in both Manufacturing and Distribution operations to hold and buffer the flow of material moving through the process to the ultimate end-user. Automated Storage Retrieval System &
- 134. Problems of conventional storage system: Much time spend for searching lost or damaged products and inaccurate records, Orders spending too much time in the factory, causing customer deliveries to be late, Waste much space, Excess inventory, Workers are exposed dangers. Need ofASRS For the resolution of above problemsASRS is used, because The operation are totally automated, Computer controlled, Fully integrated with factory and warehouse operations.
- 135. 1. Storage structure 2. S/R(Storage/Retrieval) machine Components ofASRS 3. Storage modules e.g. pallets for unit loads 4.One or more pickup-and deposit station 5. External handling system
- 136. 1. Storage structure which is the rack framework made of fabricated steel supports the loads contained in theAS/RS 2. S/R machine Components ofASRS is used to accomplish storage transaction, delivering loads from the input station into storage, and retrieving loads from storage and delivering station. 3.Storage modules are the unit load containers of the stored material. include pallets, steel wire baskets and containers, plastic pans
- 137. 4. Pick-and-deposit station is where loads are transferred into and out of theAS/RS. generally located at the end of the aisles for access the external handling system that brings loads and takes loads away. to the AS/RS Components ofASRS 5. External handling system brings loads to theAS/RS and takes loads away. Example RTV (RoboticTransferVehicle)
- 138. Components ofASRS
- 139. Improved inventory management Reliable and immediate delivery Space efficiency Simplified and faster inventory response Reduced lost or misplaced parts, tools and fixtures Design flexibility to accommodatea wide range of loads Reduced labor costs Reduced scrap and rework Accurate inventory and load location Increased utilization potential Benefits ASRS of
- 140. The initial cost of theASRS is high ASRS requires automatedguided vehicles or conveyors ASRS is feasible only for large manufacturing establishments Limitations ASRS of
- 141. FMS is different from conventional cell by virtue of its central computer control highly developed software complete part tooling and material handling flexibility and control randomness of production scheduling and machining. CellularVs Flexible Manufacturin g Both similarities and difference exists between cellular manufacturing and FMS.
- 142. Similarities Similarities exist from the viewpoint that the level of automation for either cell or system can vary depending upon how much technology and money will be applied. CellularVs Flexible Manufacturing Both cells and systems possess multiple part processing part program storage capability. and Automatic or semiautomatic part loading can be accommodate in either cell or FMS. Magazine, hopper guided vehicle, multi station shuttle and robots can be used both in cell or FMS according to the size, type and complexity of the cell or system.
- 143. Differences Cells lack central computer control with real-time routing, load balancing software and production scheduling logic. While FMS is connected to a high level computer system within the operation. manufacturing Cells are tool capacity constrained. Tools available in the pockets are limited, which limits the part variety produced in the cell. CellularVs Flexible Manufacturing FMS with automated tool delivery and tool management can automatically transfer, exchange and migrate tools through centralized computer control. Cells generally have less flexibility than an FMS and are restricted to a relatively tight family of parts. On the other hand, FMS has greater depth and breadth of flexibility due to range of parts in varying lot size that can be accommodated in system, random machine scheduling and automated material flow and movement.
- 144. Lean is a methodology to reduce waste in a manufacturing system without sacrificing productivity and quality. The general meaning of lean is that it consists of a set of tools that help to identify and eliminate waste. That waste can be created through an overburden and unevenness in workloads.The removal of waste from any system improves quality and production time, while reducing cost. Some lean manufacturing tools include KANBAN (Work Flow Visualisation), 5S, Poka Yoke (Err0r Proof), ROC, Control Charts etc. Lean Manufacturing
- 146. Value. Value is always defined by the customer’s needs for a specific product. Value stream. Once the value (end goal) has been determined, the next step is mapping the “value stream,” or all the steps and processes involved in taking a specific product from raw materials and delivering the final product to the customer . Flow. After the waste has been removed from the value stream, the next step is to be sure the remaining steps flow smoothly with no interruptions, delays, or bottlenecks. Pull. With improved flow, time to market (or time to customer) can be dramatically improved. This makes it much easier to deliver products as needed, as in “just in time” manufacturing or delivery. Perfection. Accomplishing Steps 1-4 is a great start, but the fifth step is perhaps the most important: making lean thinking and process improvement part of your corporate culture. As gains continue to pile up, it is important to remember lean is not a static system and requires constant effort and vigilance to perfect. 5 Principles of Lean Manufacturing