Process Introduction. Types of Processes.

Process Introduction. Types of Processes.
Process Strategy in the industry. Factors affecting Process Design. Tools

Process Introduction Classification of Processes
Process strategies at the Industry Factors that affect (or are affected by) the Process Selection. Tools SPC, SMED… Documents Work Measurement and Standards Job Place Design Line Balancing Measuring Process Performance Queueing Theory

Introduction The information generated during the product design phase specifies how the product must be, but not how to organize the production process to make it (equipment, labor skills required, etc.). Process Design specifies how the activities that Operations must carry out should be developed: Guiding the election and selection of technologies. Clarifying the quantity and type of resources to be acquired, when to be acquire and their availability. Process design and redesign is intimately related to Product Design: Concurrent or Simultaneous Engineering.

Process Selection and System Design
Forecasting Product and Service Design Technological Change Capacity Planning Process Selection Facilities and Equipment Layout Work Design

The process-focused Project Shop
Characteristics “Unique” products with certain complexity (boats, aircrafts, trains, motorways…) The production process is managed like a project Makes a one-of-a-kind product (volume = 1) Uses general purpose equipment Has informal relationships with many vendors Very little vertical integration Flexible layout often with factors of production moving to job

The Job Shop A process structure suited for low volume production of a great variety of non-standard products (highly customized products). Custom or workshop: Low specialized operations carried out by the same worker or group of workers that follow up the whole process for the order. Batch: More specialized operations carried out by different workers or group of workers (need for more specialization and standardization). Characteristics Makes many products in small volume Uses general purpose equipment, grouped by the same function in Work Centres Has informal relationships with vendors Very little vertical integration Departmentalized layout with chaotic flow

The Large Batch (Cell, Flow Shop or Hybrid Shop)
A process structure that produces a variety of standard products at relatively low volumes. This variety of standard products has a similar sequence of operations: The equipment is laid out in line, instead of grouped by the same function. After completing one batch, equipment adjustments for the next one are made and the next batch produced. Characteristics Makes several families of products in moderate volume Uses general purpose equipment often customized Little vertical integration Similar product follows the same path, produced in batches to reduce the impact of setup time. Hybrid layout with flow lines

Assembly Line A process structure designed to make discrete parts. Parts are moved through a set of specially designed workstations at a controlled rate. Characteristics Makes few products in large volume Uses specialized high-volume equipment Has formal relationships with vendors May use vertical integration Product-based layout with linear flow

Continuous Flow An often automated structure that converts raw materials into finished products in one continuous process. Same operations are made in the same equipment to make the same product, reducing waiting time. Objectives: Improvement of material flow and operations. Workers specialization: Increasing speed and added value.

Types of Processes By Projects Job Shop Flow Shop - + Assembly Line
Flexibility and Costs By Projects Job Shop Flow Shop Assembly Line Continuous - + Flexibility Fixed Cost Variable Cost Unit Cost - +

Process Strategy in the industry
Manufacturing Process Life Cycle Processes go through different phases as products do. Interdependency between Product and Process Life Cycles: Process Life Cycle: Affects manufacturing costs, quality and production volumes, which affects sales volumes. Product Life Cycle: Influences the type of manufacturing process that can be economically and financially justified.

These are the major stages of product and process life cycles Product-Process Matrix High Volume, Standard- ization Few Major Products, Higher Volume Low Volume, One of a Kind Multiple Products, Low Volume I. Job Shop Commercial Printer French Restaurant Flexibility (High) Unit Cost (High) II. Batch Heavy Equipment III. Assembly Line Automobile Assembly Burger King IV. Continuous Flow Flexibility (Low) Unit Cost (Low) Sugar Refinery

The Product-Process matrix and the Competitive Advantage The Product-Process matrix helps companies define where their competencies are, concentrating their attention in a limited group of decisions and process alternatives, as well as a limited group of Marketing options. When the company considers at the same time products and processes, it can increase its probability of success. Place in the matrix and Competitive priorities Organization of the Operations and the Product-Process matrix

The Product-Process matrix and the Competitive Advantage Place in the matrix and Competitive priorities Operations Management priorities change as the Product-Process combinations change. I.e.- Flexibility vs. Standardization Each company has to take into account its traditional focus when positioning in the matrix: Market oriented: Flexibility and Quality. Manufacturing oriented: Costs and Process Leadership. Organization of the Operations and the Product-Process matrix

The Product-Process matrix and the Competitive Advantage Place in the matrix and Competitive priorities Organization of the Operations and the Product-Process matrix Paying attention to the process that makes the company more competitive, the company will be able to manage the development of the operations involved per line of products. The knowledge about how the different positions in the matrix affect manufacturing will lead the company to suggest changes in Operations Management. Companies that compete with several products in different markets will probably have their products in different stages of the life cycle: Companies should separate and organize their processes in different areas focalized in the different life cycles.

Process Selection and System Design
Forecasting Product and Service Design Technological Change Capacity Planning Process Selection Facilities and Equipment Layout Work Design

Factors affecting Process Design
Capital Investment Flexibility Vertical Integration / Outsourcing Nature of Demand Quality of the product or service Customer participation The Learning effect Financial Planning and Evaluation

Capital Investment Combination of equipment and human resources at the manufacturing process. The new manufacturing technologies provide a wide variety of available options: As the mechanical and/or automated operations increase, more capital is required. Most of the available options require a high capital investment, which create a high risk in case our sales volumes (and therefore our production volumes) are lower than the expected.

Flexibility A production process is more flexible when their equipment and human resources are able to manage a wider variety of products, outputs, responsibilities and functions, at a reasonable cost and time frame. Capital vs. Flexibility Flexibility New technologies Traditional technologies Capital

Flexibility Flexibility affects the type of human resources required and their job stability: More training is required. Job stability is more variable for companies working by projects or job shop type of process. Flexibility is one of the best ways to get a reliable customer service and reduces bottle necks.

Vertical Integration/Outsourcing The degree of vertical integration is related to the number of processes at the supply chain that are carried out by the own company. The vertical integration can generate savings when the company has the necessary skills to carry out some processes at a lower cost and better quality. If the resources acquired are basic, the company may loose competitiveness with non-vertical integration. Outsourcing is interesting when a resource consumption is low, and its efficient management has a certain economy of scale. Outsourcing is used as well when the technology to be used is so complex that being competitive requires a big effort not balanced with the benefits obtained.

Nature of the demand Manufacturing processes have to have the necessary capacity to support the demand of products and services that the company is going to offer. Seasonality, tendency and other characteristics of the demand are going to affect the capacity required over the time. Some processes are able to expand and contract more easily than others. The final selection of processes will be affected by the estimated demand. Price: If it’s high, consumers will tend to buy less and vice versa. To fix the price, the company has to take into account factors like advertising costs, sales force, financial conditions, services provided to the customer, specific designs, inventory and delivery policy, quality, etc., at the same time than the costs related to manufacturing. It should be coordination between product price and process selection, due to the competitive advantages provided by the different types of processes

Quality of the product or service Quality is a competitive advantage in the current business environment. The level of quality to be offered will affect directly the selection of the production process. The level required is directly related to the level of automation of the process, since the automatic equipment manufactures products with a high and consistent uniformity. Customer participation Services that require higher contact with the customer generally need less capital investment and have more flexibility. Customer presence normally affects the process efficiency in a negative way, which increases cost.

The Learning effect The working hours required per unit of product represent a decreasing function of the number of cumulative production units. This reduction of working hours (and therefore cost) are based on the gain of experience in design of products and services, automation and capital investment, as well as changes in methods and experience of the working force. Companies competing in price try to have high manufacturing volumes to take advantage of the learning effect, and therefore have a lower cost. Production volume Working hours per unit

Financial Planning and Evaluation Operation managers are continuously looking for new and different ways of producing that: Increase productivity. Follow the Operations Strategy. Provide sufficient profit to justify the capital investment required. Each type of process has different capital requirements, thus limiting the company’s possibilities of process selection in case of limited financial resources.

Tools and Concepts Simplify/Mechanize/Automate/Integrate SMED CAD/CAM
Statistical Process Control Bottlenecks

How much is the profit? A company manufactures 2 products P & Q. Sale price of P is 90 € and Q price is 100 €/unit. Weekly Demand is 100 units for P and 50 units for Q. Both products require the same PC component, the raw material of which worths 20 €/unit. To transform PC 15 minutes of a given resource B are required and 5 minutes of a given resource C. Product P also requires Component 1 (C1) that should be transformed from a raw material that cost 20 €/unit, and it requires 15 minutes of a given resource A and 10 minutes of C. To assembly PC with C1 a new component C3 is required with a cost of 5 €/unit and 5 minutes of the D resource. Product Q follows a very similar process. To manufacture C2 raw material with a cost of 20 €/unit is needed, and it is processed using 20 minutes of A and 15 minutes of B. Then resource D assembles PC with C2 during 5 minutes. Each week has 5 days of 4 hours. Total cost are 3600 €/week.

Work Measurement and Standards
The Purpose of Work Measurement is to set time standards for a job. Such standards are necessary for 4 reasons: To schedule work and allocate capacity. To provide an objective basis for motivating the workforce. To bid for new contracts and to evaluate performance on existing ones. To provide benchmarks for improvement. Methods Time Study (stop watch) Work Sampling (observing a sample) Predetermined times Elementary standard data Reference points. Reference Book (B.W. Niebel, Motion and Time Study) How long would it take? How much does it cost? How many people do you need?

Time Study A time study is generally made with a stopwatch, either on the spot or by analyzing a videotape for the job. The job or task to be studied is separated into measurable parts and then timed individually. Some general rules Define each work element to be short in duration but long enough to be timed and the time can be written Separate activities related with machine from the rest. Define any delays or acyclic activities. After a number of repetitions, collection times are averaged. Normal Time = Observed Performance Time x Performance Rating Standard Time = NT x (1 + Allowances)

Work Sampling Three primary applications Five Steps
Determine the activity-time percentage for personnel or equipment. Performance measurement to develop a performance index for workers. Evaluate time standards to obtain the standard time for a task. Five Steps Identify the specific activities that are the main purpose for the study. Estimate the proportion of time of activity of interest of the total time. State the desired accuracy in the study results. Determine the specific times when each observation is to be made. At two or three intervals during the study period recompute the required sample size by using the data collected thus far.

Predetermined Motion Times (MTM, MODAPTS, )
Get Put N X F GE 8 13 16 GD 17 20 25 Move with Weight (5 UMT) Coger funda GDF 25 Coger "tinta" GDF 25 Poner "tinta en funda" PDN 19 Coger y Poner GEN+PEN 5+8 Aplicar Presión 14 Coger caperuzón GDF 25 Reajustar tras coger 6 Poner caperuzón PDN 19 Dejar bolígrafo PEF 14 Grasp (6 UMT) Apply Presure (14 UMT) Eye Movement (7 UMT) Step (18 UMT) Bend Down (29 UMT) Stand up (32 UMT) 6.3 seconds

Documents Flowchart.A flowchart is a graphical representation of a process, depicting inputs, outputs and units of activity. It represents the entire process at a high or detailed (depending on your use) level of observation, allowing analysis and optimization of workflow.It can serve as an instruction manual. Assembly Drawing: An exploded drawing containing a set of number parts combined to make a complet product. Value Stream Map: Value stream mapping is a paper and pencil tool that helps you to see and understand the flow of material and information as a product or service makes its way through the value stream.

Process Documentation using Flowcharts
Shampoo directions Lather Rinse Repeat Example: Any problems with the following set of directions? Basic flowchart symbols Begin or end Shampoo? Begin shampoo Rinse hair with warm water Lather shampoo into hair Select bottle Wet hair with Information on bottle No Yes Hair clean? End shampoo Information input Operation Information output Question yes/no?

Process Flow Diagram (PFD)
A process flow diagram is a mapping of the specific processes that raw materials, parts, and subassemblies follow as they move through a plant. Builds on the concept of flowcharting. A more constrained version of the operation symbol used in flowcharting Requires a resource Resource has a capacity constrain Adds value Activity Flow Arrow indicates the flow of jobs Multiple flow units (types of jobs) possible Buffer Buffer or inventory location Normally does not have a capacity Multiple units possible Trees RM Debark Stems WIP Scan Saw Acceptable Lumber FG Grind Chips

Flow Diagrams Three types of flow diagram
1. Single object, follow single object or person 2. Assembly 3. Action decision

Single Object Process Chart

Assembly Process Chart
Assembly charts Disassembly charts

Action Decision Flow Diagram

Multi Activity Charts If columns represent people -> gang chart
people and machines ->human-machine chart left/right hand chart

Job Design (I) Job design is the function of specifying the work activities of an indidividual or a group in an organizational setting. The objective is to develop job structures that meet the requirements of the organization and its technology and that satisfy the job holder’s personal and individual requirements. Trends of Job Design Decisions Quality control as part of the workers job Cross training workers to perform multiskilled jobs Employee involvement and team approaches to designing and organizing work “Informating” ordinary workers through internet, … Extensive use of temporary workers Automation of heavy manual work Organizational commitment to providing meaningful and rewarding jobs for all employees.

Job Design (II) The improvement of the job methods leads to a higher level of specialization. A workplace with a high level of specialization covers a narrow set of tasks, high repetitive levels, and, hopefully, high efficiency and quality. Specialization produce benefits as quicker training and faster working rates. This way of working has also some disadvantages as worker demoralization, reduces flexibility and increases the work of upper levels of management. To avoid those disadvantages: Wider jobs Job enlargement (horizontally expanded) Job enrichment (vertically expanded) Job Rotation Socio-Technical Systems Task variety Skill variety Feedback Task identity Task autonomy

Line Balancing Introduction Line Balancing
Mathematical Programming Model Heuristic Methods Yamazumi Duration of the Tasks Longer than Cycle Time Other Considerations. Mixed Model Assembly Line

Introduction The design of the line, constraints the alternatives when scheduling the activity of the line. A decision on the productive system (in the long term): Defines the allocation of facilities. Constrains the sequence (lines with mixed models). Constrains the production volumes (lines multi-model).

Final product inventory
Assembly line Manufacturing Made and bought inventory of components and subassemblies Final product inventory Conveyor moving at constant speed Work Work Work Station 1 Station 2 Station m

Production Organization
1 2 3 4 N In Out single model line 1 2 3 4 N In Out batch model line 1 2 3 4 N In Out mixed model line

Use of the Assembly line
Advantages Performance increase due to the learning effect. Reduces the difficulty of the task. Increases the team work, avoiding isolations. Constant rate of work. Ongoing quality control. Disadvantages Alienation. Less flexibility. El uso de la Línea de Montaje Ventajas Incremento de efectividad debido al efecto aprendizaje. Reduce la dificultad de la tarea. Fomenta el trabajo en equipo, evitando las islas. Ritmo de trabajo constante y definido. Control autónomo de defectos. Inconvenientes Alienación del trabajador. Pérdida de flexibilidad.

Line Balancing. Definition.
Line Balancing consists of assigning operations to the workstations of such form that the sum of their durations in each station is as similar as possible. With this procedure bottlenecks should be avoided, unproductive time will be reduced and the productivity of the line will increase. This implies that: Each operation will be assigned to an one only and only one workstation. Relations and bounds between operations will be respected. Times of the stations will not exceed their cycle time.

Objectives. Capacity Cost Organizational-social
Minimization of total idle time (maximization of the use of the line). Minimization of product flow-time. Balance the levels of capacity used at the workstations. Cost Minimization of the machinery costs, tools or idle equipment. Minimization of the costs of materials or reworks. Minimization of the costs by adjustment and change. Organizational-social Job Enrichment Modifications at the Line balancing

General definitions.(I)
Operation: Smaller unit of work than cannot be divided without creating an unnecessary interference. Workstation: Segment of the line where a set of operations is executed. Characterized by its surface, machinery or type of assigned work. Line Balancing: Process to assign operations to workstations. It intends to assign personal or equipment of efficient way to obtain the performance maximum. Cycle time: Amount of time between two consecutive products. Balance Efficiency: It indeed represents the percentage of invested total time in making products. Station Pitch: The distance of a product and the one that follows to him in the conveyor belt. Stations Nº x Cycle Time Operations Total Time Efficiency =

General Definitions. (II)
Bounds between operations. Precedence Relations. Imposed generally by technological constraints. “Operation 'í' cannot be made if before the 'h' has not taken place” In the case of linear configurations, this implicates that 'h' will have to be in the same station that 'i' or in a previous one, but never in a following one.

General Definitions. (III)
Positive Zoning. It is compulsory to locate an operation in the same station that another one. Operations that need the same tool Operations that need the same ability on the part of the worker Operations that need the same physical training conditions Negative Zoning or incompatibility. It is demanded that an operation is not in the same station that another one. Position of the unit in the line (Operations to be made at the right side are not compatible with those to be made at the left) Exigency of a high specialized workers Processes of painted sandpapering and of surfaces Allocation of varied activities to avoid monotony. Limit Zone. It is demanded that certain operations are assigned to stations previous or next to one given Fixed zone of material arrival. Zone of preparation or control.

General Definitions. (IV)
Line Speed Productivity Operation Time in a station Minimum number of workstations V=L/C 1 minute TO C

General Definitions. (IV)
Idle time of a station Total idle time of a station or delay Station saturation Efficiency Delay ... 0.9 minutes 1 minute

Mathematical Programming Model Heuristic Methods Duration of the Tasks Longer than Cycle Time Other Considerations. Mixed Model Assembly Line

Resolution Procedures for problem SALBP 1.
Exact methods Mathematical Programming Models Exact algorithms of directed exploration and dynamic programming. Heuristic methods Constructive. Based on rules and strategies Heuristic of a single one happened. Simple Composed Heuristic with backward movement Approaches from exact algorithms Others

Model of PLM of problem SALBP1.
Variables of allocation xij: Binary variables that they indicate if operation i is assigned to station j. Variables of existence yj: Binary variables that they indicate if station j exists. This existence comes imposed when not being able to assign but operations to anyone of the stations already defined.

Heuristic procedures Although nonexact, some heuristic procedures provide solutions that can be considered acceptable. The known procedures of constructive type more are the bound ones to the duration of the task or the number of consequent. One of them chooses to assign to the open station the task with greater duration than still it fits in the station. The alternative procedure chooses to assign to the open station the task with greater number of consequent. Procedimientos Heurísticos Aunque no exactos, algunos procedimientos heurísticos proporcionan soluciones que se pueden considerar aceptables. Los procedimientos de tipo constructivo más conocidos son los ligados a BBBBB. Uno de ellos elige para asignar a la estación abierta la tarea con mayor duración que aún quepa en la estación. El procedimiento alternativo elige para asignar a la estación abierta la tarea con mayor número de consecuentes.

Yamazumi C Y L E T I M e 5 9 6 3 4 10 12 8 2 11 7 1

Objectives. Capacity Cost Organizational-social
Minimization of total the idle time (maximization of the use of the line). Minimization of products flow-time in the line. Balance the levels of capacity use at the workstations. Cost Minimization of the machinery costs, tools or idle equipment. Minimization of the costs of materials or reworks. Minimization of the costs by adjustment and change. Organizational-social Job Enrichment Modifications in the Line balancing

Mathematical Programming Model Heuristic Methods Yamazumi Duration of the Tasks Longer than Cycle Time Other Considerations. Mixed Model Assembly Line

A real Example Operation Time Preceding Task 1 0,175 - 16 0,200 2
0,139 17 0,084 3 0,078 18 0,116 13;15 4 0,349 19 0,199 5 0,007 20 0,079 6 0,050 21 0,103 7 0,211 22 0,098 9 8 0,158 23 0,230 24 0,210 10 0,080 25 0,140 11 0,075 26 12 0,395 27 0,177 13 0,219 28 0,234 14 0,188 29 0,090 15 0,122

Yamazumi Graphics Example
1 2 3 4 5 6 7 8 17 18 19 20 21 22 23 24 25 26 27 28 29 16 14 9 12 13 15 10 11

Measuring Process Performance
Productivity: Ratio of Output to Input Effiency: Ratio of Actual output to some standard. Utilization: Ratio of the time that a resource is actually activated relative to the time that it is available for use. Cycle time (takt time): Average time between the completion of succesive units. Run Time: time required to produce a batch of parts Setup Time: is the time required to prepare a machine to make a particular item. Operation Time: sum of setup and run time. Throughput time: time that unit spents actually being transformed or waiting. Throughput rate: output rate that the process is expected to produce over a period of time. Process velocity: Total throughput divided by Value Added Time Value Added Time: Time that useful work is actually done

Queueing Theory L=  W Lq =  Wq
Little’s Law: The size of a queue is proportional to the input rate and the average throughput time. L=  W Lq =  Wq

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