Final Production / 4.5 /
Production Systems
Final Production / 4.5 /
Production Systems
The development of increasingly sophisticated production systems is transforming the way products are made. As a business grows in size and produces more units of output, then it will aim to experience falling average costs of production—economies of scale. 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 manufacturing.
Internal economy of scale: Falling average cost of production as a producer becomes more efficient due to larger number of units of output. E.g. through mechanization, automation, buying raw materials or parts in bulk etc.
External economy of scale: Falling average cost of production as a producer to becomes more efficient due to growth of industry in a region. E.g. through better infrastructure (roads, ports, housing etc.), through having easier access to more suppliers of part and raw materials, through innovation forced by competition, through lobbying in larger industry collaborations, etc.
This type of production generally makes a single, unique product from start to finish. Craft production tends to be labour-intensive, and often highly skilled or specialised.
Prior to the Industrial Revolution, most products were manufactured by craft techniques. The processes, techniques and materials that were used were restricted by the technology and energy sources that were available at the time. The development of skills was slow; sources of materials and energy were few and would depend on what was available locally. Sales and distribution happened on local markets. The craftsman was the designer, and the client was the user.
Advantages
Flexible production system enabling a large variety of products to be made.
Quality tends to be seen as considerably higher than mass-produced products.
Products can be customised to fit personal needs.
Value of the product will be high due to people willing to pay the higher costs of a one-off product. High status is linked to craft products.
Disadvantages
Production costs are high, particularly labour costs due to the need for skilled craftsmen.
Unit cost is usually high.
Can take a long time to produce individual items due to the fact this is the first time it is being made.
Craft production cannot be used for large-scale production.
Materials costs can be high, due to the craftsman not being able to buy in bulk.
Mechanised production is a volume production process in which human-operated machinery is used to carry out some or all of the repetitive tasks.
Mechanisation might include the following elements:
Using machines optimized to perform specific tasks fast, safely and accurately.
Using jigs and templates to ensure quality control.
Using conveyor belts to control the rate of production and keep components flowing from one process to another.
Advantages
The creation of economies of scale - A product is cheaper due to the decreased cost per unit.
Less time is taken to complete individual steps in a production process.
Often repetitive or hazardous tasks can be carried out by machines.
Material costs are low due to high volume, bulk buying options.
Quality control - little variance in products (consistency), so quality controls or checks are easy to enforce.
The standardisation of products and components is possible due to the reduction of human error.
Disadvantages:
Cost of energy, training, initial set up costs.
Redundancy - machines replacing humans.
Low job satisfaction of workers due to repetitive nature of the job.
Health and safety - factories can be dangerous places with large, noisy machines.
Repetitive strain - from performing the same task continually over long periods of time.
Increased wages due to highly skilled operators of specialist machinery or processes.
Consumer choice is minimal as products are identical. Lack of customisation.
The term ‘automation’ refers to a wide variety of systems or processes that operate with little or no human intervention. In most modern automated systems, control is exercised by the system itself, through control devices that sense changes in conditions.
The development of computer and information technology led to the introduction of automation via computer-controlled, electrically powered assembly lines. Automation has made a major contribution towards an increase in both free time and real wages enjoyed by most workers in industrialised nations.
The difference between automated and mechanised production is that automation is more focused on technology and electronic data processing that replaces human labour with machines, while mechanization is based on machinery and equipment that ensures accuracy and speed of operation.
Advantages
Eliminates human error.
Built-in quality control.
Minimises waste.
Consistency of output.
Reduced labour costs.
Improved health and safety - less humans, less accidents.
Machines can run 24/7.
Adaptable.
Consumer choice; a wider variety of products can be produced cost-effectively, giving them more options to choose from.
Disadvantages
High start-up costs. Capital investment.
Training costs of staff.
Social implications - reduced workforce.
Maintenance costs - expensive. Can stop production.
Re-tooling - expensive and time-consuming.
Assembly line production is the mass-production of a product via a flow line based on the interchangeability of parts, pre-processing of materials and work division.
Put more simply, it means:
Each manufacturing task is divided up into basic stages.
Each stage is carried out using specialist labour and equipment - work division.
A flow line (conveyor belt) moves each part from one stage to the next. This controls the rate of production - how fast it is made. This can, and often is, sped up or slowed down depending on demand.
This makes each individual task repetitive and therefore gives the manufacturer a great deal of quality control. However, these repetitive tasks are increasingly being carried out using control technology - robots.
The benefits of assembly line manufacture to both the consumer and producer are cheaper products - cheaper to make, cheaper to buy.
Mass customisation is a production process that combines elements of mass production with those of bespoke tailoring. Product features are adapted to meet individual customers' needs.
Mass customisation uses some of the techniques of mass production; for example, its output is based on a small number of platforms, the core elements of the design or components that make the basis of the product. In the case of a watch, the internal mechanism is the platform to which can be added a wide variety of personalised options at later stages of the production process.
Therefore the purchaser of the Swatch watch has thousands of different options in terms of colour, straps, watch faces etc, yet all of them are based on just a few timekeeping mechanisms. Mass customisation is being introduced by many companies. Even a traditional mass production manufacturer like BMW is introducing personalisation of their cars. Nike By You (formally NIke ID) allows customers to customise their clothing and footwear before buying - Have a go: Nike By You.
Parameters
Mass production
Mass customisation
Goal
Deliver standardised goods/services at a low price.
Deliver varied goods/services to fulfil specific consumer groups with different wants/needs. Try to offer a lower unit cost.
Economics
Economies of scale.
Economies of scope with customer integration.
Focus
Efficiency through large volume production, stability and control.
Variety through personalisation, flexibility and responsiveness.
Key features
Stable demand, low cost, consistent quality.
Fragmented demand, mid-high cost, specific quality.
Customer involvement
Passive.
Active.
Computer Numeric Control (CNC) refers specifically to the computer control of machines for the purpose of manufacturing complex parts in a variety of materials. The machines are commonly controlled by a standardized programming language called ‘G code’ (Geometry code). Each code is assigned to a particular operation or process. The codes also control X, Y, and Z axis movements as well as feed rate (speed).
When CAD systems are linked to manufacturing equipment which is also controlled by computers, they form an integrated CAD/CAM system. Computer Aided Manufacture (CAM) equipment relies on a series of numeric codes, stored as computer files, to control manufacturing processes. This is then passed onto the CNC where the codes are translated into component shape geometry. The CNC then uses these to cut the required parts.
CAM offers significant advantages over traditional manufacturing approaches. CAM is usually associated with the elimination of human error, reduction in costs, and precision manufacturing. Although the initial set-up costs of a CAD/CAM system can be significant, these can be offset by increased production time, and manageable and predictable tool wear, replacement and maintenance.
Designer design specifically for optimum use of existing manufacturing capability. Design for Manufacture (DfM) is the process of designing products to improve the ease of manufacture; i.e. manufacturability. Simply put, it’s an approach to designing products with ease of manufacture in mind. By making things easier to assemble, one also makes the assembly process faster and more cost-efficient. This results in higher profits for the manufacturer, and can also add value to the customer, while benefiting the environment.
Before DfM the motto was ‘I design it, you build it!!’. Design engineers worked alone or only in the company of other design engineers in “The Engineering Department”. This separation of ‘departments’ went further up the manufacturing and marketing process and often lead to changes in design, concept or manufacturability when each department had its segregated input. This often leads to delayed product launches or issues with manufacturing sufficient quantities. The new approach to manufacturing is the integration of development teams. The team work together to not only design for functionality, but also optimise cost, delivery, quality control, reliability, ease of assembly, testability, ease of service, shipping, human factors, styling, safety, customisation, expandability, and various regulatory and environmental compliance.
There should also be consideration of how a product can be easily disassembled to be recycled more efficiently and effectively. Repair of the product is also considered to extend the product's life cycle and reduce its environmental impact.
Design for manufacture (DfM): design for materials, design for process, design for assembly, design for disassembly.
Design for materials: is related to the consideration and use of materials in the manufacturing process. For example; a green designer would consider the use of recycled materials during the design of the product. This would be the initial part of the design process and not just an ‘afterthought’ to make the product more environmentally friendly. They would also consider the local availability of materials to reduce costs. This also has an added environmental benefit.
Design for process: this relates to the design of a product to be made using a specific manufacturing technique; for example, injection moulding. Design for process allows the process to be mass produced, by developing the design of the product to specifically meet the available characteristics and the availability of certain processes. You would be surprised at how many products have been designed without the thought of ‘how’ it would actually be made being taken into consideration. If a product has a specific manufacturing process in mind at the time of conception, then it can be specifically tailored to take advantage of the advantages of this process and negate its disadvantages. For example, if a designer worked for a company that had compression moulding equipment, they would specifically have this process in mind when designing new products.
Design for Assembly: is designing and taking into consideration how a product is put together, and how different parts interact with each other. For example, component to component, components to sub-assemblies, and sub-assemblies into complete products. The ultimate aim of design for assembly (DfMA) is to reduce the cost of a component, parts or product without reducing its performance. Eliminating unnecessary components or parts not only reduces material costs, but also reduces the production, processing, and assembly time - therefore further reducing costs to the manufacturer.
Design for disassembly: designing a product so that when it becomes obsolete, damaged or out of date, it or its components can be easily and economically taken apart. These parts, or components can then be reused or repaired, and the materials repurposed or recycled. When the design for disassembly (DfD) is taken into consideration at the early stages of the design cycle, the design team would consider some of these questions:
Will the product need to be repaired?
Does it make economic sense to repair?
Which parts will need to be replaced?
Who will repair it?
How can the experience be simple and intuitive?
Can the product be reclaimed, refurbished or resold?
If it is discarded, how can we facilitate disassembly into recyclable parts?
What components are likely to wear out first?