Table of Contents:-
- Meaning of Process Selection
- Process Selection Decision
- Factors in Process Selection
- Process Selection Method
- General Guidelines for Process Selection
- Process Selection Life Cycles Matrix
Meaning of Process Selection
Process selection refers to how an organization opts to produce its goods or deliver its services. Together with capacity planning, it helps an organization develop different approaches to meet the irregular demand patterns of customers.
It takes into account the selection of technology, capacity planning, layout of facilities, and design of work systems. Process selection is a natural extension after the selection of new product and services.
Process selection plays an important part in the overall design of production and operations management systems. It allows an organization to offer a safe and reliable product and service through pragmatic designs and effective capacity planning.
With the help of process selection, one can understand the different types of processing including manual, rigid, and flexible as well as various automated approaches to processing. Process selection allows an operations manager to better understand the need for the management of technology. Together with capacity planning, it helps an organization develop different approaches to meet the irregular demand patterns of customers.
An organization process strategy would include:
1) Process Flexibility: The extent to which the system can adapt to changes in processing requirements resulting from factors such as product or service design alterations, fluctuations in processed volume, and technological advancements.
2) Make-or-Buy Decisions: The extent to which an organization will produce or provide goods in-house instead of relying on an outside organization to create or deliver them.
3) Capital Intensity: The mix of equipment and labour will be used by the government.
Process Selection Decision
There are many ways to categorize processes. One can order them based on their orientation, such as market orientation or manufacturing processes. Additionally, they can be categorized based on the production methodology or consumer involvement.
Given below are the various categorizations of processes commonly used:
1) Processes by Market Orientation
Processes can also be categorized based on four market orientations:
i) Make-to-order (MTO): Make-to-order products are made from previously engineered designs but are made only after an order has been received. ‘Make to order’ products are utilized when a standard product is too costly to stock, exhibits uncertain demand, or will deteriorate if stored on a shelf. Examples of goods made using the ‘Make to order’ products market orientations are: commercial aeroplanes, prescription glasses, etc.
ii) Engineer to Order (ETO): This market orientation is used to make unique products that have not been previously engineered. Extensive customization to suit the customer’s need is possible, but only if the customer is willing to wait for this additional stage in the value creation process. For example, it includes specialized industrial equipment, hand-built furniture, etc.
iii) Make to Stock (MTS): The goods usually are standard, mature products with few product customization options. As a general rule, ‘make-to-stock’ products compete primarily based on cost and availability. For example, such products include most retail goods such as breakfast cereals, milk, shirts, jeans, and office desks.
iv) Assemble to Order (ATO): ‘Assemble to order products are standard items that are assembled from in-stock sub-assemblies. This allows customers to select a wide range of options. For example, many camera dealers can ‘assemble’ any configuration of a single-lens reflex camera from a bare body. The customer specifies the exact type of lens desired, the viewing system, etc.
2) Processes as Production Systems
A production system refers to how an organization organises materials flow using different process technologies. Five major types of production systems have been generally identified:
- Project
- Job Shop
- Batch Production
- Assembly Line
- Continuous Flow
3) Processes and Customer Involvement
Many processes are designed keeping in mind the value provided by involving the customer in the delivery of the final product. The level of involvement may vary, ranging from self-service by the customer to deciding the time and place where the service is to be provided.
i) Partnerships: Organizations actively engage in dialogue with customers using emerging technologies. Customers are increasingly becoming partners in creating value, as they can now determine the time and location to deliver services or products. Billing and pricing systems are modified for customer convenience.
ii) Self-Service: This can be explained with the help of examples. Morning stores in Delhi started a new trend in buying groceries by introducing self-service. This marked a departure from the traditional system where the customer provided a list to the grocer, who then supplied the items. Morning Store found that not only did they save money by not employing people, but they also increased sales due to high impulse buying. While traditionally, self-service was intended to save money and offer more excellent value to the customer, it soon found applications for other strategic considerations.
iii) Product Selection: Business organizations are increasingly attempting to involve their customers in product design by providing them with different options for customization. For example, Maruti Udyog Limited, the premier automobile manufacturer in India, aims to maintain its leading position in the market by offering customization for its basic car model, the Maruti 800, even before consumers have requested it. The customer has been offered a choice of colour combinations, materials and functionality add-ons. The facility is not only available for new purchases but also available for in-use cars so that the company retains the goodwill of its existing customers. This option has implications for both product and process design decisions.
Factors in Process Selection
There are several factors involved in process selection:
1) The number of components to be made.
2) The component size.
3) The component weight.
4) The precision required.
5) The surface finish and appearance required.
All of these aspects have already been considered during the material evaluation stage. However, when it comes to material evaluation for process planning, the focus will be on ‘manufacturability or processability,’ as it is also known.
Thus, process selection will immensely impact the quality of the part, and the chosen process must be appropriate for the material.
Finally, in addition to all the aforementioned technical factors, economic considerations must also be considered. The associated costs will influence many decisions in the design and manufacture of a product. Consequently, the total cost of the product must be regarded as early as possible. Other economic considerations will be determined by the quantity required in production volume, production rate, and economic batch size.
Process Selection Method
Selecting a process is complex; therefore, one needs a method to make the approach more systematic. Researchers developed the process selection method to help undergraduates understand the complexity of process selection while providing them with a systematic approach to follow.
Two fundamental assumptions are made when using this method. These are:
1) The material has been selected first, as opposed to manufacturing processes and specified at the design stage.
2) All the information contained within the design documents, i.e., drawings, parts lists, etc., is comprehensive and all information required for manufacturing can be derived during the drawing interpretation.
There are four stages to this process selection method given as follows:
Stage 1: Drawing Interpretation
This interpretation is the foundation for process selection, involving three distinct analyses and outputs. The first is the geometry analysis, where the complexity of the required shape is assessed using the geometry classification matrix, identifying various candidate processes. Consideration is also given to the size of the part. The second analysis and output pertain to manufacturing information in the design documents, encompassing details like process parameters, surface finish, dimensional and geometric tolerances, limits and fits, unique treatments, gauge references, and tooling references. The third and final analysis and output involve the material evaluation stage, which assesses the material based on desired geometry, material properties, and manufacturing considerations. Using the PRIMA matrix, additional candidate processes can be identified.
Stage 2: Critical Processing Factors
The first stage’s combined output must be correlated to identify the critical processing factors. Specifically, connecting the candidate processes from the geometry analysis and the material evaluation may allow the list of candidate processes to be shortened based on these factors. This is because they establish quantitative limits within which the candidate process must operate.
Stage 3: Consult Process Tables
Utilizing the correlated data from the previous stage, the candidate processes are compared using the appropriate process selection table. This approach usually facilitates a clear-cut decision based on all the gathered information. However, in scenarios where more than one process meets all the requirements, economic data, such as labour, equipment and tooling costs, batch size, and production rate, may offer further clarification. Sometimes, a detailed cost comparison between processes may be necessary to assist decision making. Finally, in some cases, the decision may revolve around making or buying a part/product when the in-house process expertise is unavailable. Costing methods should be incorporated into the design and manufacturing process as early as possible.
Stage 4: Identifying a Process
Utilizing the data from the second stage and conducting a detailed economic analysis, a suitable process should be chosen if necessary. If one method is sufficient to manufacture the part, then the process selection is complete. However, except in the case of the use of some primary processes, secondary processing is usually necessary. Therefore, in cases where further processing is required, the critical processing factors should be reconsidered, and stage 3 is repeated. The process selection is complete once all the necessary processes have been identified.
General Guidelines for Process Selection
Various criteria can be used in the selection of manufacturing processes. These could include material form, component size and weight, economic considerations, dimensional and geometric accuracy, surface finish specification, batch size, and production rate, as already mentioned. In many instances, the technology used to manufacture a product may be so well-established that the choice is obvious. Regardless of the factors, some general guidelines can be applied to the selection of manufacturing processes:
1) Select a process capable of providing the specified dimensional and geometric accuracy, as well as surface finish.
2) Specify the most comprehensive possible tolerances and surface finish variations for products to allow the broadest possible choice of manufacturing processes.
3) Use prototypes as much as possible, considering the variation in performance of methods used to manufacture a one-off compared to volume manufacturing.
4) Carry out a detailed comparison of candidate processes early in the design process, paying particular attention to the variation in assembly costs among different methods.
The geometry classification matrix and the PRIMA selection matrix are valuable tools for identifying candidate processes. Once candidate processes have been identified, they can be narrowed down using the process selection tables.
Product and Process Life Cycles Matrix
The product and process life cycle matrix suggests that as the product progresses through its life cycle from introduction to maturity and decline, the process that best suits the needs of the firm also goes through similar stages.
The so-called ‘job shop’ process is appropriate during a product’s introductory stage when production volumes are low and the product is often customized. As the product progresses through the growth and maturity stages it becomes more standardized and the production volumes increase. The job shop is then replaced by intermittent and repetitive batch production.
Continuous flow processes take over as the product becomes a commodity, and the competitive focus shifts to price. Thus the diagonal of the production/process life cycle matrix, sometimes called the product possibility frontier represents the best set of product/process combinations.
Two types of organization are shown on the diagonal to illustrate the two extremes. The first, shown in the top left-hand corner, is a customized equipment manufacturer (such as a specialized machine tool company) for which every product is unique and can be representative of the introductory stage of the product life cycle. In this type of organization, an early life cycle ‘job shop’ process would be commonly used where the priorities both for the product and process would be flexibility and quality.
The second example, shown in the bottom right-hand corner, is a public utility producer, such as an electric power company, for which the product has progressed beyond the maturity stage and become a commodity. In this type of organization a late life cycle ‘continuous flow’ process would be commonly used where priorities both for the product and process would be dependability and cost.