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Home , Assembly line, Mass Production, Production line

Topic 4.5 systems

Guiding Questions & Tasks

1. Outline the effect and mechanisation has had on the craft industry. 2. List the advantages and disadvantages of craft production 3. List some examples of products manufacture by craft production 4. Explain why craft production is still commonplace in developing countries 5. Define mechanisation 6. Compare mechanisation to 7. Outline how in an automated system the roles of people change 8. List the advantages and disadvantages of assembly lines 9. Outline the role of standardized parts in manufacture 10. Describe mass production 11. List the advantages and disadvantages of automation 12. List the advantages and disadvantages of mass production 13. List examples of design contexts where mass production would be appropriate 14. Outline how ‘design for materials’ can lead to better designed products 15. Outline why ‘design for process’ is an important consideration 16. Outline why ‘design for assembly’ is an important consideration 17. Outline why Design for disassembly can improve the recyclability of a product and the recovery of materials used 18. List the main considerations when designing for

Topic 4.5: Production systems

The design of a production system requires a complete understanding of a product, its function and the quality of finish. Each system can be unique and specific to the product it is creating, often requiring the designers to adapt their design to be manufactured using certain methods.

Essential idea:

The development of increasingly sophisticated production systems is transforming the way products are made.

Nature of design:

As a business grows in size and produces more units of output, then it will aim to experience falling average costs of production—. The business is becoming more efficient in its use of inputs to produce a given level of output. Designers should incorporate internal and external economies of scale when considering different production methods and systems for manufacture.

Concepts and principles:

• Craft production • Mechanized production • Automated production • Assembly line production • Mass production • Mass customization • Computer (CNC) • Production system selection criteria • Design for manufacture (DfM): design for materials, design for process, design for assembly, design for disassembly • Adapting designs for DfM

Guidance:

• Advantages and disadvantages of different production systems • Impact of different production systems on the workforce and environment • Production system selection criteria include time, labour, skills and training, health and safety, cost, type of product, maintenance, impact on the environment and quality management • Design contexts where different production systems are used

Production systems

You are expected to have a deep enough understanding of production systems to be able to make sound decisions when determining which ones are appropriate for a specific job. This includes being able to explain advantages and disadvantages of different production systems, the impact they have on the workforce and environment, and the selection criteria.

How do firms choose their method of production?

Firms choose their method of production based on a number of different factors, such as: ● The amounts they are likely to sell. ● The product they are making. ● The costs of production. ● The variety of goods expected by customers.

[https://en.wikibooks.org/wiki/GCSE_Business_Studies/Methods_of_Production] ​ ​

Craft production

Craft production is a small­scale production process centred on manual skills.

Advantages and disadvantages of craft production. Consider economies of scale, value of the product, labour, market forces and flexibility of manufacture.

Advantages A lot more care is put into making the product as good/nice as possible, therefore the quality tends to be seen as considerably higher than something that was mass­produced. The product can also be customised to fit personal needs, and there is a good deal of flexibility for the designer, customer and craftsman. Much skill is often required for the craftsman; therefore they are able to charge more for the manufacturing of the product.

Disadvantages Although the manufacturing process does not require for the producer, it takes a great amount of time and effort; therefore it becomes much more expensive for the buyer. Also, with craft production it is not possible to produce on a larger scale. This could mean a loss of profit for the manufacturer, however the higher prices of craft produced products can sometimes make up for this. Another disadvantage may be that the product is not designed for disassembly, so if something goes wrong during the making of it, there are no . Every piece also becomes more valuable so any defects will be more important. Design Contexts include: one­off products such as custom made furniture, pottery, art and crafts

Mechanized production Mechanized production is a volume production process involving machines controlled by . Originally, very small numbers of products were made by craftsmen in home workshops. But, the increasing demand for consumer goods following the , meant that larger numbers of products needed to be manufactured in a more efficient way. [http://www.ruthtrumpold.id.au/destech/?page_id=334] ​ ​

The image below shows the of Rice Production. When thinking about the advantages of mechanisation think about the efficiency, accuracy, cost, but also the reduction in the need for manual labour ­ which means less jobs for people.

Advantages ● The creation of economies of scale … the product is cheaper than craft production ● The quality of the product is improved as fewer errors will occur, the finish of the product will also be improved. ● Increased wages due to training and becoming skilled. ● Efficiency of production: less time is taken to produce goods

Disadvantages ● Redundancy – machinery for labour substitution ● Health and safety. Work conditions are usually poor in the , lack of safety standards can be an issue in some cases. Repetitive strain injury. ● Cost of energy, training and capital machinery. Increased wages due to highly skilled operators needed. ● Environmental pollution. ● Boredom for the workers ● Low job satisfaction for workers [http://www.ruthtrumpold.id.au/destech/?page_id=334] ​ ​

Automated production

Automated production is a volume production process involving machines controlled by computers. An automated is comprised of a series of workstations linked by a transfer system and an electrical control system. Each station performs a specific operation and the product is processed step by step as it moves along the line in a pre­defined production sequence. A fully automated production line does not need people directly involved in the operation, and all or part of the process of the production is completed by mechanical equipment and automated systems. Therefore, in an automated environment, the tasks of human are more likely to change to system design, adjustment, supervision and monitoring the operation of the system rather than controlling it directly.

[http://www.rnaautomation.com/blog/benefits­automated­production­lines/] ​ ​

Watch this video for an overview https://www.youtube.com/watch?v=sjAZGUcjrP8 ​

Advantages and disadvantages The main advantages of automation are: ● Increased . ● Improved quality or increased predictability of quality. ● Increased consistency of output. ● Reduced direct human labor costs and expenses. ● high degree of accuracy ● Replacing human operators in tasks that involve hard physical or monotonous work ● Replacing humans in tasks done in dangerous environments (i.e. fire, space, volcanoes, nuclear facilities, underwater, etc.) ● Performing tasks that are beyond human capabilities of size, weight, speed, endurance, etc. ● Economic improvement: when a state or country increases its income due to automation like Germany or Japan in the . ● Frees up workers to take on other roles. ● Provides higher level jobs in the development, deployment, maintenance and running of the automated processes. The main disadvantages of automation are: ● Security Threats/Vulnerability: An automated system may have a limited level of intelligence, and is therefore more susceptible to committing errors outside of its immediate scope of knowledge (e.g., it is typically unable to apply the rules of simple logic to general propositions). ● Unpredictable/excessive development costs: The research and development cost of automating a process may exceed the cost saved by the automation itself. ● High initial cost: The automation of a new product or plant typically requires a very large initial investment in comparison with the unit cost of the product, although the cost of automation may be spread among many products and over time. [https://en.wikipedia.org/wiki/Automation#Advantages_and_disadvantages] ​ ​

Assembly line production

Assembly line production is a volume production process where products and components are moved continuously along a conveyor. As the product goes from one workstation to another, components are added until the final product is assembled.

Advantages For manufacturers, the benefits of assembly line production are enormous. An inherent part of the idea of assembly lines is that each item produced is as close to identical as possible. This allows quick and easy assembly throughout the process, and it also means that maintenance and replacement of worn or broken parts is a much simpler task down the road. Prior to assembly line production, items were often made one at a time by hand by a single crafter. This meant that there were often great variations between one crafter’s work and the work of another crafter, and even among the products of a single crafter. If one part of a musket or were to break, it was no simple task to replace that part. Repairs and replacements had to be custom made to fit the specific item at hand. With standardized, interchangeable parts being a key part of the assembly line process, the next generation of manufacturing did not suffer as much from those issues of difficult repairs. If part of a product breaks, it can easily be replaced with an identical part matching the item. Generally speaking, assembly line production requires each person involved to only perform a small number of simple and specific operations, meaning training requirements are not very demanding, and nearly anybody can fill a spot on the production line in many cases. This allows companies to keep expenses low and easily replace employees who leave.

Disadvantages The disadvantages of the assembly line style of production are the same qualities described above but looked at from another angle. While several workers using interchangeable, standardized parts makes for easy repairs and replacements, it also means each item loses that individualistic flare of unique craftsmanship. For some products, especially decorative or luxurious items, it can be very desirable to know that the piece was uniquely crafted by a single skilled and experienced artisan, who put a lot of heart and soul into the creation—not just a bunch of disinterested people on a production line slapping parts together with no personal investment in the quality of the finished product. Other disadvantages of assembly line production are based on the worker’s point of view. Because little training is generally required, wages may not be very competitive. The work itself can also be extremely repetitive and monotonous, offering little in the way of mental stimulation and creative critical thinking. [https://workhorsesofindustry.wordpress.com/2012/12/28/advantages­and­disadvantages­of­assembly­line­manufacturing/] ​ ​

Mass production

Mass production is the production of large amounts of standardized products on production lines, permitting very high rates of production per worker.

Originally, very small numbers of products were made by craftsmen in home workshops. But, the increasing demand for consumer goods following the industrial revolution, meant that larger numbers of products needed to be manufactured in a more efficient way. To facilitate the mass production process, organisation of the following factors is necessary. ● A , where the manufacturing process is broken down into small specialised tasks that each worker carries out over and over again. ● The standardisation of parts across a number of products so that large numbers can be made cheaply and efficiently. ● The development of machinery to perform standardised tasks and produce components. ● The production process needs to be designed to efficiently integrate the processes and human tasks. The best known example of a mass production process was the assembly line developed by to manufacture the Model T Ford in 1913.

Mass production has many advantages and disadvantages.

Advantages include: ● efficiency of production: less time is taken to produce goods ● ‘economies of scale’: cheaper to make products in large quantities ● workers only need to be trained in one or two tasks. Disadvantages include: ● boredom for the workers ● occupational overuse syndrome (repetitive strain injury) ● low job satisfaction for workers ● large stockpiles of finished goods waiting to be sold ● difficult to change the product’s design quickly to respond to changing styles and consumer demand.

These disadvantages have led to a change in direction for manufacturers to try and be more responsive to changes in the marketplace. The development of ‘just in time’ (JIT) manufacturing has evolved as an appropriate production technique to address the problems of excess stock and lack of responsiveness by manufacturers, to trends in the marketplace. JIT is covered in more depth in T10 Commercial Production [http://www.hsc.csu.edu.au/ind_tech/ind_study/industry_study/MASS_PRODUCTION.html] ​ ​

Mass customization

Mass customization is a sophisticated CIM system that manufactures products to individual customer orders. The benefits of economy of scale are gained whether the order is for a single item or thousands. This is covered in greater depth in T4.3 Scales of Production

Computer numerical control (CNC)

Computer numerical control (CNC) refers to the computer control of machines for the purpose of manufacturing complex parts in metals and other materials. Machines are controlled by a programme commonly called a “G code”. Each code is assigned to a particular operation or process. The codes control X, Y and Z movement and feed speeds.

G­code which has many variants, is the common name for the most widely used numerical control (NC) programming language. It is used mainly in computer­aided manufacturing to control automated machine .

Design for manufacture (DfM)

Design for manufacture (DfM) means designers design specifically for optimum use of existing manufacturing capability. There are four aspects of DfM. ○ Design for materials: designing in relation to materials during processing ○ Design for process: designing to enable the product to be manufactured using a specific manufacturing process, for example, ○ Design for assembly: designing taking account of assembly at various levels, for example, component to component, components into sub­assemblies and sub­assemblies into complete products ○ Design for disassembly: designing a product so that when it becomes obsolete it can easily and economically be taken apart, the components reused or repaired, and the materials repurposed or recycled

Design for Manufacturing (DFM) and design for assembly (DFA) are the integration of product design and process planning into one common activity. The goal is to design a product that is easily and economically manufactured. The importance of designing for manufacturing is underlined by the fact that about 70% of manufacturing costs of a product (cost of materials, processing, and assembly) are determined by design decisions, with production decisions (such as process planning or selection) responsible for only 20%.

The heart of any design for manufacturing system is a group of design principles or guidelines that are structured to help the designer reduce the cost and difficulty of manufacturing an item. The following is a listing of these rules.

1. Reduce the total number of parts. The reduction of the number of parts in a product is probably the best opportunity for reducing manufacturing costs. Less parts implies less purchases, inventory, handling, processing time, development time, equipment, engineering time, assembly difficulty, service inspection, testing, etc.

2. Develop a modular design. The use of modules in product design simplifies manufacturing activities such as inspection, testing, assembly, purchasing, redesign, maintenance, service, and so on. One reason is that modules add versatility to product update in the redesign process, help run tests before the final assembly is put together, and allow the use of standard components to minimize product variations.

3. Use of standard components. Standard components are less expensive than custom­made items. The high availability of these components reduces product lead times.

4. Design parts to be multi­functional. Multi­functional parts reduce the total number of parts in a design, thus, obtaining the benefits given in rule 1. Some examples are a part to act as both an electric conductor and as a structural member, or as a heat dissipating element and as a structural member.

5. Design parts for multi­use. In a manufacturing firm, different products can share parts that have been designed for multi­use. These parts can have the same or different functions when used in different products [http://www.unm.edu/~bgreen/ME101/dfm.pdf] ​ ​