Unit 2 Manufacturing Operations Sections: Manufacturing Industries and Products Manufacturing Operations Production Facilities Product/Production Relationships Lean Production Manufacturing Metrics Manufacturing Lead Time Rate of Production Production Capacity Work in Progress Design Times Utilisation/Availability

Classification of Industries Primary industries – cultivate and exploit natural resources Examples: agriculture, mining Secondary industries – convert output of primary industries into products Examples: manufacturing, power generation, construction Tertiary industries – service sector Examples: banking, education, government, legal services, retail trade, transportation

Manufacturing Industries ISIC Code Food, beverages, tobacco 31 Textiles, apparel, leather and fur products 32 Wood and wood products, cork 33 Paper, printing, publishing, bookbinding 34 Chemicals, coal, petroleum, & their products 35 Ceramics, glass, mineral products 36 Basic metals, e.g., steel, aluminum 37 Fabricated products, e.g., cars, machines, etc. 38 Other products, e.g., jewelry, toys 39

More Industry Classifications Process industries, e.g., chemicals, petroleum, basic metals, foods and beverages, power generation Discrete product (and part) industries, e.g., cars, aircraft, appliances, machinery, and their component parts

Process Industries and Discrete Manufacturing Industries

Manufacturing Industry Transformation Operations Machine Processing Assembly Adding value* Other Operations Material handling Inspection and testing Coordination and control Raw Material Part or Product Transformation Process Scrap or Waste Power Tools Machines Labour

Classification of manufacturing processes

Processing Operations Shaping operations Solidification processes Particulate processing Deformation processes Material removal processes Property-enhancing operations (heat treatments) Surface processing operations Cleaning and surface treatments Coating and thin-film deposition

Assembly Operations Joining processes Welding Brazing and soldering Adhesive bonding Mechanical assembly Threaded fasteners (e.g., bolts and nuts, screws) Rivets Interference fits (e.g., press fitting, shrink fits) Other

Material Handling Material transport Vehicles, e.g., forklift trucks, AGVs, monorails Conveyors Hoists and cranes Storage systems Unitizing equipment Automatic identification and data capture Bar codes RFID Other AIDC

Time Spent in Material Handling

Inspection and Testing Inspection – conformance to design specifications Inspection for variables - measuring Inspection of attributes – gauging Testing – observing the product (or part, material, subassembly) during operation

Coordination and Control Regulation of the individual processing and assembly operations Process control Quality control Management of plant level activities Production planning and control

Production Facilities and Layout Facilities organised in the most efficient way to serve the particular mission of the plant and depends on: Types of products manufactured Production quantity Product variety

Production Quantity (Q) Number of units of a given part or product produced annually by the plant Three quantity ranges: Low production – 1 to 100 units Medium production – 100 to 10,000 units High production – 10,000 to millions of units

Product Variety (P) Number of different product or part designs or types ‘Hard’ product variety – products differ greatly Few common components in an assembly ‘Soft’ product variety – small differences between products Many common components in an assembly

Product Variety (P) vs. Production Quantity (Q)

Low Production Quantity (Qlow) Job shop – makes low quantities of specialized and customized products Products are typically complex (e.g., specialized machinery, prototypes, space capsules) Equipment is general purpose Plant layouts: Fixed position Process layout

Fixed-Position Layout

Process Layout

Medium Production Quantities (Qmed) Batch production – A batch of a given product is produced, and then the facility is changed over to produce another product Changeover takes time – setup time Typical layout – process layout Hard product variety Cellular manufacturing – A mixture of products is made without significant changeover time between products Typical layout – cellular layout Soft product variety

Cellular Layout

High Production (Qhigh) Quantity production – Equipment is dedicated to the manufacture of one product Standard machines tooled for high production (e.g., stamping presses, molding machines) Typical layout – process layout Flow line production – Multiple workstations arranged in sequence Product requires multiple processing or assembly steps Product layout is most common

Product Layout

PQ Relationships P Q

Product Quantity and Variety Let Qj = annual quantity of variety ‘j’ P = variety of products from ‘1’ to ‘j’ Total number of product units = Qf =

Product and Part Complexity Product complexity np = number of components in product Part complexity no = number of processing operations per part

Factory Operations Model Simplified : Total number of product units Qf = PQ Total number of parts produced npf = PQnp Total number of operations nof = PQnpno where P = Product variety Q = Product quantity np = Number of parts in product no = Number of operations in product

Worked Problem 2.2: The ABC Company is planning a new product line and will build a new plant to manufacture the parts for a new product line. The product line will include 50 different models. Annual production of each model is expected to be 1000 units. Each product will be assembled of 400 components. All processing of parts will be accomplished in one factory. There are an average of 6 processing steps required to produce each component, and each processing step takes 1.0 minute (includes an allowance for setup time and part handling). All processing operations are performed at workstations, each of which includes a production machine and a human worker. If each workstation requires a floor space of 250 m2, and the factory operates one shift (2000 hr/yr), determine (a) how many production operations, (b) how much floorspace, and (c) how many workers will be required in the plant.

Solution This problem neglects the effect of assembly time: (a) nof = PQnpno = 50(1000)(400)(6) = 120,000,000 operations in the factory per year. (c) Total operation time = (120 x 106 ops)(1min./(60 min./hr)) = 2,000,000 hr/yr. At 2000 hours/yr per worker, w = = 1000 workers. (b) Number of workstations n = w = 1000. Total floorspace = (1000 stations)(250 m2/station) = 250,000 m2

Manufacturing Capability Technological processing capability - the available set of manufacturing processes Physical size and weight of product Production capacity (plant capacity) - production quantity that can be made in a given time

Lean Production Operating the factory with the minimum possible resources and yet maximizing the amount of work accomplished Utilisation of Resources - workers, equipment, time, space, materials Minimising time Maximising quality (accuracy) Minimising cost Doing more with less, and doing it better

Programs Associated with Lean Production Just-in-time delivery of parts Worker involvement Continuous improvement Reduced setup times Stop the process when something is wrong Error prevention Total productive maintenance

Problem 2.4 The XYZ Company is planning to introduce a new product line and will build a new factory to produce the parts and assembly the final products for the product line. The new product line will include 100 different models. Annual production of each model is expected to be 1000 units. Each product will be assembled of 600 components. All processing of parts and assembly of products will be accomplished in one factory. There are an average of 10 processing steps required to produce each component, and each processing step takes 30 sec. (includes an allowance for setup time and part handling). Each final unit of product takes 3.0 hours to assemble. All processing operations are performed at work cells that each includes a production machine and a human worker. Products are assembled on single workstations consisting of two workers each. If each work cell and each workstation require 200 ft2, and the factory operates one shift (2000 hr/yr), determine: (a) how many production operations, (b) how much floorspace, and (c) how many workers will be required in the plant. If the company were to operate three shifts (6000 hr/yr) instead of one shift, determine the answers to (a), (b), and (c).

Solution Solution: (a) Qf = PQ = 100(1000) = 100,000 products/yr Number of final assembly operations = 100,000 assy.opns/yr Number of processing operations nof = PQnpno = 100(1000)(600)(10) = 600,000,000 proc.opns/yr (c) Total processing operation time = (600 x 106 ops)(0.5 min./(60 min./hr)) = 5,000,000 hr/yr. Total assembly operation time = (100 x 103 asby ops)(3 hr/product) = 300,000 hr/yr Total processing and assembly time = 5,300,000 hr/yr At 2000 hours/yr per worker, w = = 2650 workers. (b) With 1 worker per workstation for processing operations, n = w = 2500 = 2500 workstations. With 2 workers per stations for assembly, n = w/2 = 150/2 = 75 workstations. Total floor space A = (2575 stations)(200 ft2/station) = 515,000 ft2

Solution (a) Same total number of processing and assembly operations but spread over three shifts. Number of final assembly operations = 100,000 assy.opns/yr Number of processing operations nof = PQnpno = 100(1000)(600)(10) = 600,000,000 proc.opns/yr (c) Same total number of workers required but spread over three shifts. Total workers w = 2650 workers. Number of workers/shift = w/3 = 883.33  884 workers/shift. (b) Number of workers for processing operations = 2500/3 = 833 worker per shift (884 on one shift) Number of workers for assembly = 150/3 = 50 workers per shift. Number of workstations n = 833 + 50/2 = 858 (859 on one of the shifts). Using the higher number, Total floor space A = (859 stations)(200 ft2/station) = 171,800 ft2