Published on International Journal of Engineering & Industry
Publication Date: May, 2020
Okolie Chukwulozie Paul, Sylvester Emeka Abonyi, Oluwadare Benjamin Segun & Okolie Uchenna Onyebuchi
Mechanical Engineering Department, Nnamdi Azikiwe University, Awka, Anambra State
Mechanical Engineering Department, Ekiti State University, Ado Ekiti, Ekiti State
Electronics Development Institute (ELDI) Ukwuru, Awka Capital Territory, Anambra State
Journal Full Text PDF: Manufacturing Processes and Methods.
This term paper seeks to analyse the various processes and methods of manufacturing used in the production of parts of systems or of products such as petroleum products for efficient and quality products and the minimisation of cost and waste. The advent of technology has made these processes easier compared to the period before the industrial revolution since there are a lot more machines to make production of parts of large volume products such as aircrafts and automobiles easier and neater as well as the production of products such as refined petroleum products possible. Based on the production processes and methods used in the manufacture of automobiles at Innoson vehicle manufacturing co. LTD, the batch production type was analysed as this is the major type of production executed at Innoson vehicle manufacturing Co. LTD, IVM. This paper discusses the various methods of manufacturing, types of production, classification of manufacturing processes and the measuring of process performance for a better understanding of the topic of discussion manufacturing processes and methods.
Keywords: processes, methods of manufacturing & industrial revolution.
Manufacturing is the production of products for use or sale using manual labour machines, tools, chemicals and biological processing, or formulation and is the essence secondary industry. Manufacturing involves making products from raw materials by various processes or operations. It can also be said that manufacturing is the process of converting raw materials, components or parts into finished goods that meet a customer’s expectations or specifications. In a large-scale production, a man- machine setup with division of labour is employed.
From the information and data obtained at IVM, which engages in the manufacture of automobiles of different sizes on a large scale, the afore mentioned company only engages in producing less complex parts of vehicles like the body of the vehicle, tyres, etc. and not parts like the engine. Generally, engines are not produced in Nigeria due to factors like unavailability of technical knowhow and the inability to meet up with the standard of SON (Standard Organisation of Nigeria). The batch system of production is used in the manufacture of automobiles at IVM as individual parts are being transferred from one work station to the next till the assembly is complete.
2. MANUFACTURING METHODS
Manufacturing methods are the various ways of producing finished goods, depending on the intensity of market demand and customer requirement. The objective of a manufacturer is to satisfy the needs and desires of customer and to make profit for his own upkeep. He uses raw materials to make products that will be needed by consumers. Hence, he uses all available economical methods to minimize cost but conscious of quality of the products produced. Manufacturing involves people with different disciplines and skills and a wide variety of machinery, equipment, and tooling with various levels of automation, including computers, robots, and material-handling equipment. To meet the demands of customers, manufacturing activities must take into cognizance the following:
• A manufactured product will have to follow specifications outlined in the design of a product.
• The product must be within the reach of most customers.
• The manufacturer must ensure quality must of the product at each stage, from design to assembly.
• In a highly competitive environment, production methods must be sufficiently flexible so as to respond to changing market demands, types of products, production rates, production quantities, and on-time delivery to the customer.
• Manufacturers must be ready to adapt to new technologies and developments in materials, production methods, and computer integration and managerial activities in a manufacturing organization. These activities must be constantly be evaluated with a view to their timely and economic implementation.
• Manufactures must view manufacturing activities as a large system that can be integrated to achieve a better result. Such systems can be modelled in order to study the effect of factors such as changes in market demands, product design, material and various other costs, and production methods on product quality and cost.
• Manufactures must constantly strive for higher productivity, ensure that they make good use of their raw materials, machines, energy, capital, labour and technology. Output per employee per hour in all phases must be maximized (Dakumar, 2004).
Manufacturing methods can be classified into the following categories;
• Mass Production, this can be further classified into,
(a) Discrete manufacturing
(i) Continuous production process
(ii) Batch production process
(b) Process manufacturing
(i) Continuous production
(c) Repetitive manufacturing
(i) Batch production
(ii) Continuous production
• Assemble to order Manufacturing
• One Off Production
3. DISCRETE MANUFACTURING
Distinct manufacturing entails the production distinct items. Example, washing machines, turbines, cement mixers, automobiles, furniture, toys, mobiles and aircraft manufacturing. Factory works to fill specific orders for highly differentiated products that differ from competitive products in easily identifiable ways. The output products are easily identifiable and differ greatly from process manufacturing where the products are undifferentiated, for example, oil, natural gas and salt because discrete products have serial numbers, a different one for each product that roles off the assemble line. This kind of manufacturing is often characterised by separate unit production. Units can be produced in low volume with very high complexity or high volumes of low complexity.
Low Volume/ High Complexity
This results from demand for high quality product with high specifications, hence the system can improve quality and time-to-market speed.
High Volume/ Low Complexity
This puts high premiums on inventory control, lead times and reducing or limiting material cost and waste. The process deployed in discrete manufacturing are not continuous in nature. Each process can be individually started or stopped and can be run at varying rates. The final product may be produced out of single or multiple inputs.
4. PROCESS MANUFACTURING
Process manufacturing is characterised by formulas and recipes for mixing, separating, refining or performing chemical reactions between various ingredients, usually to produce a largely commoditised products, say paints, gasoline or soda pop. It can be contrasted with discrete manufacturing which is concerned with bills of material and routing. In process manufacturing the end product is obtained by a continuous process or a set of continuous processes. A simpler definition of process manufacturing is, once an output is produced by this process, it cannot be distilled back to its basic components. For instance, a can of soda cannot be returned back to its basic component such as carbonated water, citric acid, aspartame and other ingredients, whereas, a car or computer on the other hand, can be disassembled and its components to a large extent can be returned to stock.
5. REPETITIVE MANUFACTURING
Repetitive manufacturing is commonly used when a production process meets the following criteria:
i. The same or similar product are produced a lengthy period of time.
ii. The products produced are not manufactured in individually defined lots. Instead, a total quantity is produced over a certain period at a certain rate per part-period.
iii. The products produced always follow the same sequence throughout the machine and work centre in production.
iv. Routings tends to be simple and not vary much.
The benefit includes simplified handling process with full cost control.
Back flushing in repetitive manufacturing is used to record the work progress on the production line in the system. For this purpose, a final back flush is usually carried out at the end of the production line.
6. ASSEMBLE TO ORDER
Assemble to order manufacturing is a strategy for which parts, components or subassemblies are required or manufactured according to forecasts, while schedule for remaining components, subassemblies and final assembly are not execute until detailed product specifications have been derived from booked customer order. It is one of the oldest styles of manufacturing and is the most appropriate approach used for highly customised, low volume products. This method is used for highly configured products, for example, automobiles, aircrafts, or for products where building inventories is very expensive, example, ship building, and is a demand driven production approach where a product is scheduled & built in response to a confirmed order received for it from a final customer.
7. TYPES OF PRODUCTION
The types of production are; Continuous production, Batch production, Job or One off production.
8. CONTINUOUS PRODUCTION
This type of production organized so that different operations can be carried out, one after another in a continuous sequence. Continuous production is method used to manufacture, produce, or process materials without interruption. It is also called continuous process or continuous flow process because the materials, either dry bulk or fluids that are being processed are continuously in motion, undergoing chemical reactions or subject to mechanical or heat treatment.
The main features of continuous production are:
i. The production of larger quantities;
ii. A simplified or standardized product;
iii. A semi-skilled workforce, specialising in one operation only;
iv. Large amount of machinery;
v. Large sock of raw materials and components.
Continuous usually means operating 24 hours per day, seven days per week with infrequent maintenance shutdowns such as semi-annual or annual. Some chemical plants can operate far more than one or two years without a shutdown. Blast furnaces can run eight to ten years without stopping. Some common processes are the following: oil refining, power stations, metal smelting, synthetic fibres, fertilizers, etc.
9. BATCH PRODUCTION
Batch production is a technique used in manufacturing in which the object in question is created stage by stage over a series of work stations (Mahmoud, 2014). Batch production may be used for firm’s product or service is regular rather than a “one off” production is divided into a number of operations. A particular operation is carried out on all products in a batch. Batch production is most common in bakeries and in the manufacture of sport shoe, inks, paints and adhesives. It can reduce initial capital outlay (the cost of setting up the machines) because a single production line can be used to produce several products. Batch production can be useful for small businesses who cannot afford to run continuous production lines. It is also useful for a factory that makes seasonal items, products for which it is difficult to forecast demand or products that have a high profit margin.
Batch production is used in the production of vehicles at Innoson vehicle manufacturing Company. LTD. The vehicles parts are produced in different stage through various work stations. Then the body of the car is joined up to the point where the electrical system of the vehicle is installed.
The advantages of batch production include;
i. Even though large quantities are produced than in job, production, there is flexibility as each batch can be changed to meet customers’ need.
ii. employee concentrating on one operation rather than on the whole task,
iii. less variety of machinery would be needed than in job
iv. it often results in stock of partly finished goods which can be stored. This means that firms can respond more quickly to urgent order, by processing a batch quickly through the final stages of production.
10. JOB PRODUCTION or ONE – OFF PRODUCTION
Job production, also known as jobbing or one-off production, involves producing customised work, such as a one-off product for a specific customer or a small batch of work in quantities usually less than those of mass- market products. Jobbing is most often associated with specialized production, small firms (making railings for a specific house, making flower arrangements for a specific wedding, etc.). Large firms use job production too, for example, construction of bridges, building a new factory, installing machinery in a factory, etc. The advantage job production includes; ability to provide emergency parts in the shortest possible time, high quality production and customisation is very possible.
11. CLASSIFICATION OF
Manufacturing process can be classified as, forming processes, moulding processes, machining processes, drilling, turning, Assembly Processes and finishing processes
Forming operation that may take place in metal industry are rolling of basic shapes in steel, aluminium. Shapes that can be obtained from the process are bars, sheets, billets and I-beams. These shapes can be used in other manufacturing processes which can include, stamping, extrusion or punching.
10. MOULDING PROCESS
A lot of products require moulding. Examples includes, sand casting, diecasting to get achieve certain shapes that may or may not additional processing. Any process selected will depend size of job, required quantity, accuracy, complexity and cost.
Machining of metals is achieved using basic machine tools. This can lead to generation of different shapes or surfaces either flat, cylindrical of complex surfaces. The determinant of the tool o be used depends on size or shape to be machined, the output quality, and the rate of production required. Machining processes are turning, shaping, drilling boring and grinding.
In all these operations metals are removed in small chips with the aid cutting tools. The cutting is achieved by rotating or reciprocating action machine of the relating to the part
12. ASSEMBY PROCESS
This is the process of assembling different parts together using methods, which includes riveting, welding, brazing, mechanical fasting, adhesive joining or soldering.
13. FINISHING PROCESS
The finishing processes is aimed at achieving surface finishing, and accuracy. This process which comprises od cleaning, polishing, blasting, honing, lapping, painting etc, increase the life span of the product. Hence very important in manufacturing process.
14. MEASURING PROCESS PERFORMANCE
Rate, Cost, Quality, and Flexibility
The production of finished products requires different processes. To actualize these processes each process that contributed to the production has to be examined and its effect on the overall processes noted. A lot of factors contribute to successful production of products. These includes, Rate, Cost, Quality, and Flexibility.
This measures how fast a product can be produced. Products undergoes a lot machine operation to get the final output, so the various unit of operation that the products pass through to achieve the finished product determine the rate of operation. Some processes are repeated severally in which case the cycle time can be a factor to determined rate of production.
It is important to note that the rate of production depends on the design pattern and the technology involved. Hence it takes different time to produce different products and materials. To achieve a very highly production rate a specialized tools, devices special purpose machines tool are utilized to produce a product or component that have different efficiency.
If the production process line is not very balance, the working of the system depends will on output of the slowest machine. This will result in extreme idle time for other machine in the production chain.
The determinant of what a manufactured product will be sold is the cost of production. The manufacturing process encompasses different units of production which incur cost per unit. Hence the cost of each unit affects design and the manufacturing the product. These cost can be categorized into fixed and variable cost. The fixed cost can be regarded as the cost of equipment, tools and installation cost. The variable cost is the labor, raw material and routine cost like power and dues paid to government.
The total cost of manufacturing a product can be obtained from the fixed and variable cast as follows; if fixed cost is = U and variable cost is =V. then total cost =Y for a number N of parts produced.
Hence as production increases, the unit cost of each part decreases leading to much profit to the manufacturer. Therefore, to enhance the reduction of manufacturing cost there is need to reduce the cost of machine set-up time and material handling. Also simplifying the planning process functions will reduce cost.
For example the development of microelectronics have increased the computational ability of most factories to achieve a very low cost of production. It becomes imperious that low cost availability of both fixed and variable cost is very important to manufacturers.
The objective of a manufacturer is to process engineering materials and achieve a useful component with desired shape, size and finishes that will attract consumers. The manufacturing operation undergoes specified process plan using drawings for clarity. The quality of any manufactured product depends on the ability to control manufacturing functions which might cause some disparity due chance and cause.
With increased demand for quality products many manufacturers have invested more on research to improve the quality of their product – live span and its attractive nature. Hence in this our era, most industries pay adequate attention to maintain quality and improve upon the same from time to time, since it aids their surviving a longer time and to maintain their reputation among users.
Since quality target is not always met because of factors such as; disparity in raw materials, temperature different and timing error.
Hence it is imperative that manufacturers understand and compute the process variation to enable him monitor the quality of the output product and check when the acceptable boundary is exceeded.
A manufacturing system that is flexible is one can react to changes either predicted or unpredicted. We have two categories of flexibility: – i. machine flexibility which is the ability of the system to produce new products different from what it used to produce before and the ability to change the order of operation executed.
ii. Routing flexibility, this has to do with using different machines to achieve the same operation and the system’s ability to engage large scale changes such as change in volume or its capability
As an example of a system that has a flexible manufacturing can consist of robots, computer controlled machine and computer numerical control (CNC), sensors and other stand-alone machines. These machines can perform different operation depending on its adaptation. There is flexibility in additive manufacturing because unique designs and good number of similar parts can be produced without significant change in machine setup.
It was realized in unit manufacturing process that the measuring process performance are interwoven. According to Rebouila et al 2016 increasing the accuracy of a process often results in decrease in rate or increase in cost. The same is true for a flexible process like machining can have a higher cost than computer numerical control machine.
In analysing the various methods of manufacturing, types of production, classification of manufacturing process, and measuring of process performance, we can develop a robust and efficient ways of manufacturing various products in order to get the best of the product and in order to determine which process would be best for the product to maximise quality and minimise cost. From this work, it can be seen that due considerations like market demand, capital, and manual handling required have to be considered before venturing into the manufacturing of any product in order to maximise profit, minimise cost and reduce waste. Optimum efficiency can be achieved through the measuring of process performance to know when to increase production, how to fix cost, the level of quality required and how flexible the entire process should be to accommodate changing market demands or requirements.
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