Unit 2 Manufacturing OperationsSections:Manufacturing Industries and ProductsManufacturing OperationsProduction FacilitiesProduct/Production RelationshipsLean ProductionManufacturing MetricsManufacturing Lead TimeRate of ProductionProduction CapacityWork in ProgressDesign Times Utilisation/Availability

Classification of IndustriesPrimary industries cultivate and exploit natural resourcesExamples: agriculture, mining

Secondary industries convert output of primary industries into productsExamples: manufacturing, power generation, construction

Tertiary industries service sectorExamples: banking, education, government, legal services, retail trade, transportation

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

More Industry ClassificationsProcess 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 IndustryTransformation OperationsMachine ProcessingAssemblyAdding value*Other Operations

Material handlingInspection and testingCoordination and control

Transformation ProcessRawMaterialPart or ProductPowerToolsMachinesLabourScrap or Waste

Classification of manufacturing processes

Processing OperationsShaping operationsSolidification processesParticulate processingDeformation processesMaterial removal processesProperty-enhancing operations (heat treatments)Surface processing operationsCleaning and surface treatmentsCoating and thin-film deposition

Assembly OperationsJoining processesWeldingBrazing and solderingAdhesive bondingMechanical assemblyThreaded fasteners (e.g., bolts and nuts, screws)Rivets Interference fits (e.g., press fitting, shrink fits)Other

Material HandlingMaterial transportVehicles, e.g., forklift trucks, AGVs, monorailsConveyorsHoists and cranesStorage systemsUnitizing equipmentAutomatic identification and data captureBar codesRFIDOther AIDC

Time Spent in Material Handling

Inspection and TestingInspection conformance to design specificationsInspection for variables - measuringInspection of attributes gauging

Testing observing the product (or part, material, subassembly) during operation

Coordination and ControlRegulation of the individual processing and assembly operationsProcess controlQuality controlManagement of plant level activitiesProduction planning and controlQuality control

Production Facilities and LayoutFacilities organised in the most efficient way to serve the particular mission of the plant and depends on:Types of products manufacturedProduction quantityProduct variety

Production Quantity (Q)Number of units of a given part or product produced annually by the plantThree quantity ranges:

Low production 1 to 100 unitsMedium production 100 to 10,000 unitsHigh production 10,000 to millions of units

Product Variety (P)Number of different product or part designs or typesHard product variety products differ greatlyFew common components in an assemblySoft product variety small differences between productsMany common components in an assembly

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

Low Production Quantity (Qlow)Job shop makes low quantities of specialized and customized productsProducts are typically complex (e.g., specialized machinery, prototypes, space capsules)Equipment is general purposePlant layouts:Fixed positionProcess 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 productChangeover takes time setup timeTypical layout process layoutHard product variety

Cellular manufacturing A mixture of products is made without significant changeover time between productsTypical layout cellular layoutSoft product variety

Cellular Layout

High Production (Qhigh)Quantity production Equipment is dedicated to the manufacture of one productStandard machines tooled for high production (e.g., stamping presses, molding machines)Typical layout process layout

Flow line production Multiple workstations arranged in sequenceProduct requires multiple processing or assembly stepsProduct layout is most common

Product Layout

PQ RelationshipsQP

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 productPart complexity no = number of processing operations per part

Factory Operations ModelSimplified :

Total number of product units Qf = PQTotal number of parts produced npf = PQnpTotal number of operations nof = PQnpno

whereP = Product varietyQ = Product quantitynp = Number of parts in productno = Number of operations in product

Worked Problem2.2: 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.

SolutionThis 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 CapabilityTechnological processing capability - the available set of manufacturing processesPhysical size and weight of productProduction capacity (plant capacity) - production quantity that can be made in a given time

Lean ProductionOperating the factory with the minimum possible resources and yet maximizing the amount of work accomplished

Utilisation of Resources - workers, equipment, time, space, materialsMinimising timeMaximising quality (accuracy)Minimising cost

Doing more with less, and doing it better

Programs Associated with Lean ProductionJust-in-time delivery of partsWorker involvementContinuous improvementReduced setup timesStop the process when something is wrongError preventionTotal productive maintenance

Problem 2.4The 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).

SolutionSolution: (a) Qf = PQ = 100(1000) = 100,000 products/yrNumber of final assembly operations = 100,000 assy.opns/yrNumber 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/yrTotal processing and assembly time = 5,300,000 hr/yrAt 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/yrNumber 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