Production Systems

Dr. Umesh Khandey Department of Engg. NIFFT, Hatia, Ranchi Production System Introduction A collection of people, equipment, and procedures organized to accomplish the manufacturing operations of a company. The set of resources and procedures involved in converting raw material into products and delivering them to customers

Production and delivery of products are central to the firm Functions have value only if they enhance the ability to do this profitably Two categories: • Facilities – the factory and equipment in the facility and the way the facility is organized (plant layy)out) • Manufacturing support systems – the set of procedures used by a company to manage production and to solve technical and logistics problems in ordering materials, moving work throug h the ftfactory, and ensuring tha t products meet quality standards The Production System Production System Facilities

Facilities include the factory, production machines and tooling, material handling equipment, inspection equipment, and computer systems that control the manufacturing operations • Plant layout – the way the equipment is physically arranged in the factory • Manufacturing systems – logical groupings of equitipment and workers in the ftfactory – Production line – Stand‐alone workstation and worker Manufacturing Systems Three categories in terms of the human participation in the processes performed by the manufacturing system: 1. Manual work systems ‐ a worker performing one or more tasks without the aid of powered tools, btbut sometimes using hdhand tltools 2. Worker‐machine systems ‐ a worker operating powered equipment 3. Automated systems ‐ aprocessperformedbya machine without direct ppparticipation of a human Manual Work System Worker‐Machine System Automated System Manufacturing Support Systems Involves a cycle of information‐processing activities that consists of four functions: 1. Business functions ‐ sales and marketing, order entry, cost accounting, customer billing 2. Product design ‐ research and development, didesign engiiineering, prototype shop 3. Manufacturing planning ‐ process planning, production planning, MRP, capacity planning 4. Manufacturing control ‐ shop floor control, inventory control, qqyuality control Information Processing Cycle in Manufacturing Support Systems Enterprise

• The task of the enterprise is economic decision‐making and optimization of objectives in all aspects (Durlik I. 1993): 9 marketing, product development, purchase of the necessary elements for the production, 9 processing organization (final product and service), 9 sales and customer service. Company’s operation comprise following areas: • Production and technical area, • Organizational and administrative area, • The financial and economic area, • LlLegal area.

The company is composed of one or more production systems

Implementation can be : • Long‐term • Short‐term • Repetitive • Non repetitive Production systems

• Production sstemsystem – is deliberately designed and organized arrangement of material, energy and information used by humans and aimed to manufacture certain products (goods or services) in order to meet the needs of consumer (Durlik I. 1993). Production system consists of five basic elements: 1. Input vector (data input), 2. Output vector (data output), 3. Processing (input into output), 4. Management syy,stem, 5. Feedback ValueValue--AddedAdded--ProcessProcess

The difference between the cost of inputs and the value or price of outttputs. Value added

Inputs Outputs Land Transformation/ Goods Labor Conversion process SiServices Capital

Feedback

Control Feedback Feedback

R1 R2 R3

M1 M1 M1

M1 M1 The M2

M1 M1 production M3

M1 M1 M5 M4 M6 system may M7

M1 M2 Offices

M1 M1 M3 M4 be very M5 V

M1 M1 complex M6

Operations Machines Resources Raw Materials

18 Production system Production Objectives

High Profitability

Low High Costs Sales

Low Unit Quality High Customer Costs Product Service

High High Low Fast Many Throughput Utilization Inventory Response products

Less Short Low High More Variability Cycle Times Utilization Inventory Variability

Production and Inventory Control‐ Introduction Activity Analysis

Non‐value‐added activity Value‐added activity • Increases time spent on product or service but does • Increases worth of not increase worth product or service to a customer • Unnecessary from customer perspective • Customer is willing to pay for it • Can be reduced, redesigned or eliminated without affecting market value or quality Operation of Production Systems and Production Planning Involve • Planning and execution of the activities that use workers, energy, information, and equipment to convert raw materials into finished products

• Delivering products with the desired fifunctions, aesthihetics, and quality to the customers at right time and with minimum cost

22 Production Activity and Information Flow • Production‐planning decisions typically made in a hierarc hica l manner: 1. Physical material flow from raw material through delivered product 2. Support functions and design activities preceding production 3. Operational decisions for production planning, scheduling, and control

23 Production Activity and Information Flows

Raw Material

Forecasting Administrative Functions Fabrication (Purchasing, Payroll, Plant Finance, Accounting) Strategic Planning Assembly Marketing Plant Aggregate Production Finished Planning Products Product Design Distribution Disaggregation Center Process Planning

Production Scheduling Manufacturing Support Retailer (Facilities Planning, Tool Management, Shop Floor Control Quality Control, Customer Maintenance) a) Product Flow b) Decision Hierarchy c) Support Functions 24 Types of production systems

A production system can be defined as a transformation system in which a saleable product or service is created by working upon a set of inputs. Inputs are usually in the form of men, machine, money, materials etc.

Production systems are usually classified on the basis of the following: • Type of product, • Type of production line, • RtRate of prodtiduction, • Equipments used etc.

They are broadly classified into three categories: • Job shop production • • The types of production system are also grouped under two categories viz.,

Intermittent production system, and

Continuous production system.

Intermittent means something that starts (in itia tes) and stops (halt s ) at ilirregular (unfixed) intervals (time gaps).

Continuous means something that operates constantly without any irregularities or frequent halts. Intermittent Production System In the intermittent production system, goods are produced based on customer's orders. These goods are produced on a small scale. The flow of production is intermittent ((girregular ).Inother words, the flow of production is not continuous. In this system, large varieties of products are produced. These products are of different sizes. The design of these products goes on changing. It keeps changing according to the design and size of the product. Therefore, this system is very flexible. Examples of Intermittent production system Features of an intermittent production system The characteristics of an intermittent production system are listed as follows:

The flow of production is not continuous. It is intermittent.

Wide varieties of products are produced.

The volume of production is small.

General purpose machines are used. These machines can be used to produce different types of products.

The sequence of operation goes on changing as per the design of the product.

The qqy,uantity, size, shapp,e, desigg,n, etc. of the product depends on the customer's orders. System

Continuous means something that operates constantly without any irregularities or frequent halts. CtiContinuous PdtiProduction StSystem

Inthecontinuous prodiduction system, goodsare produced constantly as per demand forecast. Goods are produced on a large scale for stocking and selling. They are not produced on customer's orders. Here, the inputs and outputs are standardized along with the production process and sequence. Examples of Continuous production system

Characteristics of a continuous production system are listed as follows:

The flow of production is continuous. It is not intermittent.

The products are standardized.

The products are produced on predetermined quality standards.

The products are produced in anticipation(An expectation) of demand.

Standardized routing sheets and schedules are prepared Types Continuous Production 1. Mass Production Flows

Here, company produces different types of products on a large-scale and stock them in warehouses until they are demanded in the market.

The goods are produced either with the help of a single operation or uses a series of operations.

E.g. of mass production is the production of toothpastes, soaps, pens, etc.

Characteristics Mass Production Flows

There is a continuous flow of production. However, this depends on the demand in the market.

Here, there is lim ite d work-in-progress.

Supervision is easy because only few itinstruc tions are necessary.

The material handling is done mostly by machines, i.e. conveyors and auttitomatic transfer machines.

The flow of matilterials iscontinuous. There is little or no queuing at any stage of production. 2. Process PdProduct ion Flows

‰ Here, a single product is produced and stocked in warehouses until it is demanded in the market. The flexibility of these plants is almost zero because only one product can be produced.

Examples of these plants include, steel, cement, paper, sugar, etc.

Characteristics Process Production Flows

There is a higgyhly mechanized system for handling materials. Conveyors and automatic transfer machines are used to move the materials from one stage to another. Low-skilled labour and skilled technicians are required. There is very less work-in-progress because material flow is continuous. The production planning and scheduling can be didddecided well inadvance. The full production system is designed to produce only one specific typeofitem. Types Intermittent Production 1. PPjroject PdProduct ion Flows

Here, in project production flows, company accepts a single, complex order or contract. The order must be completed within a given period of time and at an estimated cost.

Examples of ppjroject production flows mainly include, construction of airports, dams, roads, buildings, shipbuilding, etc. Examples Of Project Production Characteristics Project Production

The requirement of resources is not same (it varies). Generally, the resource requirement at the beginning is low. Then in mid of production, the requirement incr eases.Finaay,lly, it ssolow s down when ttehe ppojectroject is near its completion phase. Many agencies are involved in the project. Each agency performs specialized jobs. Here, coordination between agencies is important because all jobs are interrelated. Delays take place in completion of projects due to its complexity and massiveness. As routing and scheduling changes with fresh orders, proper inspection is required at each stage of production. 2. JbJobbing Prodiduction Flow

Here, in jobbing production flows, company accepts a contract to produce either one or few units of a product strictly as per specifications given by the customer. The product is produced within a given period and at a fixed cost. This cost is fixed at the time of signing the contract.

Examples of such jobbing production flows include, services given by repair shops, tailoring shops, manufacturer of special machine tools, etc. Job Production Characteristics Job Production

The production of items takes place in small ltlots. StiSometimes onlyoneprodtduct isproddduced at one time. The items are manufactured strictly as per customer's specifications. Highly skilled labour is required to perform specialized jobs. There is disppproportionate manufacturing cycle time. For e.g. the time needed to design the product may be more than the manufacturing time. 3. BhBatch prodiduction

In batch production flows, the production schedule is decided according to specific orders or are based on the demand forecasts. Here, theprodtiduction of items tktakes place in lots or batches. A product is divided into different jobs. All jobs of one batch of production must be completed before starting the next batch of production. Examples of batch production flows include, manufacturing of drugs and pharmaceuticals, medium and heavy machineries, etc.

Characteristics Batch Production

The products are made and kept in stock until their demand arises in the market. General purpose machines and handling equipments, which can do many different jobs quickly are installed. This is because large varieties of items are to be produced. There is a possibility of large work-in-progress due to many reasons. There is a need for detailed production planning and control. Classification of production systems depending upon working or ftilfunctional bhbehav ior 1. Flexible Manufacturing systems 2. Quick Response Manufacturing 3. Computer Integrated Manufacturing 4. CtConcurrent EEingineer ing 5. Mass Customization 6. Lean Manufacturing, Toyota Production System 7. Canon Production System 8. Electrolux Manufacturing System 9. Kanban System 10. CONVIP System

What Is A Flexible Manufacturing System? Flexible Manufacturing System:

A flexible manufacturing system (FMS) is a highly automated Group Technology (()GT) machine cell, consisting of a ggproup of processing workstations (usually CNC machine tools), interconnected by an automated material handling and storage system, and controlled by a distributed computer system.

An FMS relies on the principles of group technology.

‐ “A system that consists of numerous programmable machine tools connected by an automated material handling system” Group ThTechno logy or GT • Group Technology or GT is a manufacturing philosophy in which the parts having similarities (Geometry, manufacturing process and/or function) are grouped tthtogether toachieve hig her lllevel of itintegra tion btbetween the design and manufacturing functions of a firm. • The group of similar parts is known as part family and the group of machineries used to process an individual part family is known as machine cell. • Group technology emphasizes on part families based on similarities in design attributes and manufacturing, therefore GT contributes to the integration of CAD (Computer Aided Design) and CAM (Computer Aided Manufacturing). FMS is called flexible • 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.

• The FMS is most suited for the mid‐variety, mid‐volume production range.

Three capabilities that a manufacturing system must possess to be flexible: (I) The ability to identify and distinguish among the different part or product styles processed by the system, (()II) Quick changeover of oppgerating instructions, and (III) Quick changeover of physical setup. History of FMS • FMS first proposed in England in 1960’s • The concept is credited to David Williamson.a British engineer employed by Molins during the mid‐l96Os. Molins patented the invention (granted in 1965). • “System 24” operates 24 hours a day • Automation is main purpose in beginning. • First FMS to be installed in the United States was a machining system at Ingersoll‐ Rand Company in Roanoke, Virginia. in the late 1960s by Sundstrand

• The original concept included computer control of the NC machines, avariety of parts being produced and tool magazines holds the variety of tolls for different machining operations To qqyualify as being flexible, a manufacturing system should satisfy several criteria: • 1. Part variety test. Can thesystemprocessdffdifferent part styles in a non‐batch mode? • 2. Schedule change test. Can the system readily accept changesinproductionschedule,andchangesineither part mix or production quantities? • 3. Error recovery test. Can the system recover gracefully from equipment malfunctions and breakdowns, so that production is not completely disrupted? • 4. New part test. Can new part designs be introduced into the existing product mix with relative ease? Automated manufacturing cell with Two machine tools and robot. Is it a flexible cell? Is the Robotic Work Cell Flexible? Types of FMS

FMS is designed for a specific application , that is a specific family of parts and processes. Therefore each FMS is custom engineered, each FMS is unique.

FMS can be distinguished according to the kind of manufacturing operations they perform 1. PiProcessing operations 2. Assembly operations

FMS can also be classified by 1. Number of machines. 2. Level of Flexibility Types of FMS according to number of machines (ki)(workstations): FMS can be distinguished according to the number of machines in the system. The following are the typical categories:

Single machine cell (SMC) consists of one CNC machining center combined with a parts storage system for unattended operation.

Flexible machine cell (FMC) consists of two or three processing workstations (typically CNC machining or turning centers) plus a part handling system. The part handling system is connected to a ld/ldload/unload sttitation.

Flexible manufacturing system (FMS) has four or more processing workttikstation connection mechillhanically by a common part handling systems and electronically by a distributed computer system. • Single‐Machine Manufacturing Cell(n = 1) • A single‐machine CNC machining cell • Flexible Manufacturing Cell (n = 2 or 3) • A two‐machine flexible manufacturing cell for machining (n = 2 or 3) • A five‐machine flexible manufacturing system for machining (n = 4 or more) Features of the Three Categories FMS Types according to Level of Flexibility 1. Dedicated FMS

–Designed to produce a limited variety of part styles

–The complete universe of parts to be made on the system is known in advance

–Part family likely based on product commonality rather than geometric similarity

2. Random‐order FMS

–Appropriate for large part families

–New part designs will be introduced

–Production schedule is subject to daily changes Dedicated vs. Random‐Order FMSs There is a trade-off b/w the flexibility and productivity in the two types of system.

The dedicated FMS is less flexible but more capable of higher production rates.

The random order FMS is more flexible but at the proce of lower production rates. Types of flexibility in Manufacturing

1. Machine Flexibility. It is the capability to adapt a given machine in the system to awiderangeofproduction operations and part styles. The greater the rangeof operations and part styles the greater will be the machine flexibility 2. Production Flexibility. It is the range of part styles that can be produced on the systems. 3. Mix Flexibility. It is defined as the ability to change the product mix while maintaining the same total production quantity that is, producing the same parts only in different proportions. It is also known as process flexibility. 4. Product Flex ibility. It refers toability tochange over toanewset of prodtducts economically and quickly in response to the changing market requirements. 5. Routing Flexibility. It can define as capacity to produce parts on alternative workstation in case of equipment breakdowns, tool failure, and other interruptions at any particular station. 6. Volume Flexibility. It is the ability of the system to vary the production volumes of different products to accommodate changes in demand while remaining profitable. 7. Expansion Flexibility. It is defined as the ease with which the system can be expanded to foster total production volume. Five basic types of FMS layouts 1.In‐line

2.Loop

3.Ladder

4.Open field

5.Robot‐centered cell 1.In‐line • Straight line flow, well-defined processing sequence similar for all work units

• Work flow is from left to riggght through the same workstations

• No secondary handling system

• Linear transfer syyypgstem with secondary parts handling system at each workstation to facilitate flow in two directions Figure: In‐line 2.FMS Loop Layout 3.FMS Ladder Layout

Loop with rungs to allow greater variation in ppgrocessing sequence 4.FMS Open Field Layout

Multiple loops and ladders, suitable for large part families 5.Robot‐Centered Cell

Suited to the handling of rotational parts and turning operations FMS Components can be categorized as:

1.Workstations

2.Material handling and storage system

3.Computer control system

4.Human labor Functions ppyerformed by the FMS com puter control system:

¾ Workstation control ¾ Distribution of control instruction to workstations ¾ Production control ¾ Traffic control ¾ Shuttle control ¾ Work piece monitoring ¾ TlTool control - ()(a) Tool locat ion (b) TlTool lifemoniiitoring ¾ Performance monitoring and reporting ¾ Diagnostics One additional components in the FMS is human labour. Humans are needed to manage the operations of the FMS. Functions typically performed by humans include: ¾ Loading raw work parts into the system. ¾ Unloading finished parts (or assemblies) from the system. ¾ Changing and setting tools. ¾ Equipment maintenance and repair. ¾ NC part programm ing in a machin ing system. ¾ Programming and operating the computer system. ¾ Overall management of the system. Components of Flexible Manufacturing Systems

• NC (Numerical control) • Automated Inspection • CNC (Computer numerical control) • Cells and Centers • DNC ‐(Direct numerical control) • Robotics • AGV‐ (automatic guided vehicles) • ASRS (automated storage and retrieval systems) Flexible Automation

• Ability to adapt to • Ability to accommodate engineering changes in routing changes parts • Ability to rapidly change • Increase in number of production set up similar parts produced on the system Integration of FMS

FMS

Manufacturing CIM Robotics Technology Making FMS Work

– By implementing the components of robotics, manufacturing technology and computer integrated manufacturing in a correct order one can achieve a successful Flexible Manufacturing System Flexible Manufacturing Systems (FMS)

• Using automated Auto Tool machines (DNC) & Chg. materials handling Machine 1 equipment together Robot • Often connected to or AGV centralized computer Computer • Also calle d auttdtomated work cell Auto Tool Chg. Machine 2 S7‐87 PowerPoint presentation to accompany Operations © 2001 by Prentice Hall, Inc., Upper Saddle S7‐88 Management, 6E (Heizer & River, N.J. 07458 Render) General purpose 1000 Work cells CIM Flexible 100 Manufacturing oducts System FdFocused Pr 10 automation Dedicated automation 1 1 10 100 1000 10000 100000 1000000 Volume

S7‐89 FMS ‐ Pros & Cons

• Advantages – FtFaster, l ower-costht changes f rom one part tt to anoth er – Lower direct labor costs – Reduced inventory – Considhbliistent, and perhaps better quality • Disadvantages – Limited abilityypp to adapt to product or p roduct mix chang es – Requires substantial preplanning and capital expenditures – Technological problems of exact component positioning and precise timing – Tooling and fixture requirements

S7‐90 The benefits that can be expected from FMS include • Incceasedreased machine utiliz ati on • Fewer machines required • Reduction in factory floor space required • Greater responsiveness to change • Reduced inventory requirements • Lower manufacturing lead times • Reduced direct labor requirements and higher labor productivity • Opportunity for unattended production