Unit 2 Flashcards
The role of the client
The client identifies the need for a product through market research and uses this to provide a design brief for the designer. They set production deadlines and the price of the product. The client is usually a manufacturer or retailer.
The role of the user
The user or consumer demands a product that meets their requirements: high quality, value for money and safe product.
The role of the designer
The designer works to the design brief and researches market trends, fabrics and processes, taking unit account any relevant societal, cultural, moral, environmental or safety issues. They produce a design specification, product costings and help plan manufacturing.
Mock up
A model of a product built for study, testing and display. It is usually quick, rough in finish and often simply to test the concept for further development.
Prototype
A life sized working/functioning model of a design used for testing, development and evaluation.
Model making can be a very quick and cheap method of producing a prototype. Suitable materials include paper, card, foam board, styrofoam, wire and 3mm MDF.
Computer CAD modeling
CAD can be used when modeling and offers the following advantages.
Designs can be modeled on screen and can be viewed from any angle
Reaction to outside forces such as wild flow and pressure can be modeled.
Product analysis
Fit for purpose.
Analyzing a product to see if it is suitable for the intended use. To analyze whether a product is fit for purpose or not you should ask some questions such as.
Has the design been met?
Are the needs of the intended users being met?
Find out if the product user is satisfied with the final product. Does the product suit the environment it is used in?
Is the product fit for purpose it was designed and manufactured for? Does it do what it was intended for?
Computer aided design CAD
Cad stands for computer aided design. It is particularly good for producing working drawings and 3d models
Advantages of CAD
They produce high quality and consistent drawings
Information can be sorted easily and electronically and transmitted, for example e-mail
Complex assembly drawings can be produced quicker once the user gets used to the package.
Standard parts can be accessed from a library, reducing the time to draw each one.
Changes to drawings can be easily made and instantly seen on screen.
Components and dimensioned automatically with most CAD packages
Solid modeling allows the product to be viewed from various angles and a 3d image gives a more realistic view than a 2d image.
Images can be scanned into the system or photos imported, which is beneficial to project work.
Drawings can be emailed.
Disadvantages of CAD
They are not substitutes for free hand sketching, which is quick and essential at the initial design and development stages of a design project.
The initial set up cost can be expensive, as a computer is essential, so,e software is expensive and operators need to be trained to use it.
Aesthetics
The term aesthetics concerns our senses and our responses to an object. If something is aesthetically pleasing to you, it is pleasurable and you like it. If it is aesthetically displeasing to you, it is displeasurable and you don’t like it. Aesthetics involves all of your senses - vision, hearing, touch, taste and smell and all of your emotions.
Line, shape and form.
Line is the path of a moving point through space. Although lines can vary in appearance (they can have different lengths, widths, textures,directions and degree of curve), they are considered one dimensional and are measured by length. A line is also used by a designer to control the viewers eye movement. Shape looks at 2d layout of a product and form is used to describe the 3d looks of the product.
Texture
Texture refers to how things feel, or look as if they might feel if touched. Texture is perceived by touch and sight. Objects can have rough or smooth textures and matte or shiny surfaces.
Proportion and balance
This has a lot to do with how the product feels alongside its visual balance. We often say things can look out of proportion or unevenly balanced due to poor aesthetics. Proportion is used to describe the relationship between one product part and another. Balance looks at the designers use of symmetry and asymmetry to create visual appeal and impact.
Ergonomics
The role of the product designer no longer solely focuses on aesthetics. They now also need to integrate the science of ergonomics into the products they design to meet the changes of the consumers.
Ergonomics is the study of the people in their environments. It means making the product fit the user.
Consumers demand a product that functions; they expect it to be usable and are looking for a product that gives them other feelings or emotions. It will be the aesthetics of the product - the way it looks, the feel of the material, the tactile response evoked by controls on a product or more abstract feelings - that will give pleasure. Remember this when designing and that the best design occurs when aesthetics, ergonomics and technology are considered together from the start of the design process.
As a product designer you must understand the relationship between people and products so they need awareness of ergonomics and anthropometrics.
The factors of ergonomics
Sight, touch, taste, smell and sound are psychological factors concerned with how the brain works. Designers need to understand how people think and react to these senses when producing designs.
Sight: is a major consideration for designers as how people see and react to visual information such as signs, symbols and displays are very important. Designers use of color to make a product attractive, as using different colors and shapes creates feelings within people, can alert us or suggest issues such as gender or cleanliness.
Touch: is a key feature in products as it can be designed to give the user texture, warmth or coolness, or controlled by touch such as a computer mouse or games console.
Smell: is an important consideration in the development of products like cosmetics and household fragrances. Our sense of taste is influenced by smell.
Taste: is another valuable consideration in the design of products intended to appeal to this sense, such as toothpaste and lip products.
Sound: is used by designers in warning products such as security alarms and fire alarms, alarm clocks and car horns, as humans reacts to noise.
Anthropometrics
Anthropometrics is the study of the human body and the movement of each part. As a product designer you must consider the person or people who are your intended users. There is a wide variation of sizes amongst people so Anthropometric data is collected and collated.
Form and function
Form follows function!
Is functionality the primary driver in the design solution? Is the function of a product more important than the appearance?
Function follows form:
Are the aesthetics the primary driver in the designer solution? Is the appearance of the product more important than the function?
One off/jobbing production
One off/jobbing production is making a single product. The specific and individual requirements of the customer have to be met, so every item will be made differently. It requires a highly skilled workforce and is very labour intensive.
Advantages - made to exact personal spec. High quality materials used, high quality crafts.
Person ensures a high quality product at the end
Disadvantages - final product is expensive. Labour intensive and a slow process.
Batch production
Batch production is when a specific quantity of a product is made, between two and one hundred. A production line is set up where each worker completed one task then passes it along the production line to the next worker. The workers are either semi skilled or unskilled but must be able to switch from one part of the production line to another. This is known as a flexible workforce. The production line needs to be easily and quickly changed so that different products are made.
Advantages - making in batches reduces unit costs.
Can still address specific customer needs.
Use of specialist machinery and skills can increase output productivity.
Disadvantages - time lost when switching between batches - machinery may need to be reset.
Need to keep stock of raw materials
Cash also investment in work in progress
Potentially demotivating for staff.
Mass production
Mass production is the high volume production of products, usually in their hundreds. Mass production uses a high proportion of machinery and energy in relation to workers and is highly automated. The initial setup cost is high for machinery and energy, but when this cost is is spread across a very large number of products, the cost per unit is reduced greatly. With the high set up costs, there needs to be some assurance that the product produced with make a profit.
Advantages - labour costs are usually lower.
Materials can be purchased in large quantities, so they are often cheaper.
Large number of goods are produced.
Disadvantages - machinery is very expensive to buy, so production lines are very expensive to set up.
Workers are not very motivated, since their work is very repetitive.
Not very flexible, as the production line is difficult to adapt.
If one part of the line breaks, the whole production line has to stop until it is repaired
Continuous production
Continuous production is uninterrupted, non stop, 24/7 mass production of tens of thousands of identical products. A semi automated production line is set up using computer control and a combination of skilled and unskilled workers. The workers are less flexible than those working in batch production, as the product seldom changes. However they also require little training as the product and equipment changes slowly, and training is only needed when new equipment is introduced or new staff begin. Quality control occurs at every stage of production and sampling takes place at various stages. A high level of investment in machinery and equipment is needed for continuous production.
Advantages:
Reduced processing time of work pieces.
Saving costs on temporary storage.
Control of the entire course of production.
Disadvantages:
Much capital is required to install production lines.
Low flexibility in changing products.
High receptiveness to malfunctions since a single fault can stop the entire course of production
In line assembly
In-line assembly is used for mass production, as most of the production line is automated. Unskilled labour is used mainly for assembly, whilst some semi skilled workers make sure that there is continuous flow along the production line.
Advantages:
As tasks are mainly carried out by machinery, human error and validation is reduced.
A company can produce a larger quantity of one product at a lower cost than using traditional non linear methods because labour costs are reduced and production rates increase.
Disadvantages:
The system is inflexible as it is difficult to alter a design or production process after the production line has been implemented.
The system can lead to a lack of variety, as products are all produced on one production line so they are identical or very similar, making it very difficult to cater for individual needs or wants.
Flexible manufacturing systems.
Flexible manufacturing systems use semi skilled workers who are able to do a variety of jobs. The approach is based on the idea that a flexible workforce and flexible machinery is the key to successful manufacturing.
Advantages:
FMS is useful for batch production where change and flexibility are essential.
Manufacturing time is reduced per unit.
Cost per unit is reduced.
Disadvantages:
FMS requires a great deal of pre-planing and organization prior to production starting.
Just in time manufacture
Just in time manufacture requires a high level of forward planning, as materials and components are only bought as and when they are needed. Modern manufacturing plants will use sophisticated production scheduling software and plan production, which includes ordering the correct stock. Supplies are delivered directly to the production line as they are needed. JIT is implemented successfully it can improve a manufactures profits, quality and efficiency by continuous improvement, as it is a very responsive method of production.
Advantages:
Resources are not stockpiled which saves warehouse space and money.
It reduces the likelihood of stock perishing, becoming obsolete or going out of date.
It avoids the build up of unsold finished products as demands change.
Disadvantages:
There is little room for mistakes as minimal stocks is kept for re-working faulty products.
Production is very reliant on suppliers and if stock is not delivered on time the whole production schedule can be delayed.
Standardized components, assemblies and bought in components
Standardized components, assemblies and bought in components are the building blocks of much more complex products. Components include nuts, bolts, screws and rivets, all made to the same specification, with standard size and weights and the same material and quality. This allows manufacturers to order the components required for their products with the confidence that they have been manufactured to a very high specification.
Advantages:
It speeds up manufacturing and reduces manufacturing and maintenance costs, as the same unit can be purchased and used all around the world.
It means manufacturers do not have to create everything from scratch themselves. Pre-manufactured parts can be bought in by a manufacturer for use in their products. For example a car manufacturer may buy in the headlights from another supplier rather than make them themselves.
Disadvantages:
The manufacturer is depending on the other manufacturers to supply them, which has the potential to be a less reliable system if deceivers dates are not adhered to. Production may slow or cease if a manufacturer is waiting for a delivery of standardized components, assemblies or bought in components.
Sub contracting
Sub contracting is when part of a job or manufacturing process is contracted out to another source or company to complete. It can happen if a manufacturer has too much work. This happens when machines and operators are working to full capacity and production is at full efficiency but orders are still being placed. The manufacturers ability to produce products is thus exceeded by the time available, if quality is to remain the same. On time delivery to customers becomes unachievable if there is a back log in the manufacturing process which can affect the customer service. To avoid this happening but without having to refuse orders, the manufacturer will sub contract.
Advantages:
It provides relief to the manufacturer and prevents the manufacturing plant from being overwhelmed.
It can improve efficiency by ensuring manufacture of the product is optimized.
It helps manufacturers meet delivery dates without compromising on quality.
Disadvantages:
It can be time consuming waiting for the sun-contractors to get the work completed and returned.
It can be difficult to ensure quality when different manufacturers are responsible for different parts.
Tracking parts can be an issue.
Quality assurance
Quality assurance is about setting standards and meeting them. When QA is completed well in a company, they are awarded an international standard of quality. To achieve this, a company will monitor products through all stages of production, from design and development through to performance and customer satisfaction. Constant checks are made of equipment, materials and staff training. The two main principles of QA are “fit for purpose” meaning product should be right for its intended users and “right first time” meaning mistakes should be eliminated.
Quality control
Quality control is how you check those standards. Quality control ensures that a product:
Does the job it was designed to do.
Conforms to the design specification.
Meets the relevant criteria of standards institution such as BSI and CE.
Gives customer satisfaction.
It achieves the above by testing a sample of a part at every stage of production. It ensures specific tolerances are worked to.
Sample testing
Costly waste can be reduced or prevented when testing is carried out as faults with machining and tool settings can be found and corrected. Types of testing include:
Measuring
Non-destructive testing
Destructive testing
Non-destructive testing
Non-destructive testing does not damage the sample, as the testing is visual and could include using x-rays or penetrative dyes to find defects. The dye method is used to test for surface defects such as hairline cracks in casting, forgings and welds.
Destructive testing
Destructive testing is physical and destroys the product being tested to discover how the product would collapse or how fractures develop. It is only economical to carry out destructive testing on mass produced goods, where the costs to destroy a small number of goods is insignificant.
Tolerance
Tolerance is testing a sample is the amount of error allowed. It is expressed as an upper and lower deviation. Tolerance can be defined as the variation allowed on a dimension or a surface. It is equal to the difference between the minimum and maximum limit is a specific dimension.
Injection mounding
Injection molding moulds plastic or metal by forcing the molten material into a casing mould. There are heaters that melt the material within the machine.
Advantages:
High production rates are achievable as the process is automated and continuous. The cycle for a 3mm thick part could be completed in 40 seconds.
Products can be produced with a good surface finish and consistent quality.
Disadvantages:
Initial setups is very expensive as the tools, such as the dies or moulds are produced to a high degree of accuracy or surface finish.
Die casting
Die casting is a proceed used to mould thermoplastics and metals. The material is melted and poured into a mould that is the required shape of the product
Advantages:
Die casting production is fast. A small component can be less than one second whilst a larger component weighing 2kg may take 2-3 minutes.
Die casting produces parts that are durable and have high dimensional accuracy, while maintaining close tolerances.
Die casting provides the widest range of possible shapes available from any manufacturing technique.
Thinner walls are achievable with higher quality mould.
The assembly of die cast parts can be simplified by casting parts with external threads or holes.
The parts have a good surface finish, as they can be finished smooth, textured or can be easily plated with little preparation.
Disadvantages:
The initial costs of moulds to achieve a good surface finish and machine set up are high.
A large production volume is required to make the process cost efficient.
Some empty spaces occur in die casting material.
Only non ferrous metals with high fluidity such as as zinc, aluminum, magnesium, copper, lead and tin can be die casted.
Castings can be smaller than 600mm and the thickest wall section should be kept below 13mm
Blow mounding
Blow mounding uses air to blow plastic into a solid mould. A tube of hot plastic is extended down the center mould and when the mould closes around the plastic, compressed air is blown into the center. This forces the plastic out to the side walls of the mound, where it swells out, filling up the whole mould forming the part. PVC, polythene and polypropylene are common blow moulding materials.
Advantages:
Blow moulding is a less expensive process to run than injection moulding.
Production is fast, with high outputs achievable.
The need for using adhesives is reduced, as one piece construction is achieved by the process.
New blow moulding machines have been developed that allow 3D products to be produced, such as plastic pipes for the automotive industry.
Disadvantages:
The process can only be used to manufacture hollow products.
Laminating
Laminating is the process of constructing a material with two or more layers together. Thin strips of wood can be glued together into a sandwich, which is kept in a good shape using a jig until the glue dries. Plywood is a good choice of material for laminating with, sometimes when the process of laminating is used in industry, the wood veneers would be softened with steam first in a steam chamber. Next they would be clamped into shape until dry and glued together.
Press moulding
Press moulding is used to force sheet metal into 3D shapes. The metal sheet is placed between two moulds, which are forced together until the sheet metal takes shape of the moulds. Press moulding is often used to shape thermosetting plastics by placing powder form plastic into female mould and pressing a male former onto it. This pushes the plastic into the mould. High temperatures and pressure liquefies the powder and it sets into a permanent shape.
Circular saw
Power saws such as circular and band saws have fast moving blades that cut the material it is in contact with. They are used for cutting plastic and timber. Pupils in schools are not permitted to use circular or band saws, as operators must have a health and safety certificate to certify training. These saws are instead used by teachers and technicians in the T&D departments to cut materials for pupil use.
Circular saws - rotates and the material is moved across the blade.
Bandsaw - rotates a continuous strip of saw blade that is a long flexible loop. It can only make straight cuts.
Jigsaws
A jigsaw is a power tool with a thin blade that reciprocates and moves front and back at various speeds. It is used to cutting arbitrary curves and custom shapes into wood and other materials. They are ideal for cutting thin man made boards such as MDF and plywood. Different blades are available for different types of cutting. The metal plate at the bottom is an adjustable foot, which will pivot between 0 degrees and 45 degrees. This will allow you to make angle cuts in the wood, as you cut your line with a jigsaw, the wood particles tend to build up in front of the blade, obscure the cutting line. There is a little roller on the back of the blade that helps support it while using the tool. It helps reduce flex in the blade, which provides straighter cuts and an increased blade life. Most models also have a tool free blade changing system, which will hold the arm no matter how much pressure you put on the tool when using it. This means that changing the blade can be done without the use of tools such as Allen keys. A jigsaw is an extremely versatile tool, as it can be used as a portable scroll saw and band saw. Always keep the guard in place when cutting.
Electric sander
An electric sander is used to sand or smooth wood. The sand paper sheets are clipped in place to the base, which vibrates and smooths the material beneath it. If the surface is rough, start sanding with the course paper. Most models have a dust extraction system to collect the saw dust like a bag.
Bandfacers
Bandfacers have a revolving belt of adhesive material powered by an electric motor. Material is removed evenly and quickly because all parts of the belt are moving at the same speed. The dust is drawn away by an extraction system. For safe operation:
Keep the workpiece flat on the work table
Keep your fingers behind the workpiece
Never try to shape materials with a Bandfacers
Never try to shape small pieces of material
Planer
A power planer is for rough shaping or reducing material to a required size, by removing shavings of wood just like a bench plane is used for. It is not as accurate as a bench plane but it is faster and requires less effort.
Extrusion
Extrusion is used for thermoplastics and some metals. The material is forced through a nozzle under high pressure into a mould. The process produces long continuous strips of the moulding into the shape of the nozzle it leaves. Thermoplastics such as polythene, PVC and nylon: and metals such as aluminum, copper, lead, tin, magnesium, steel and titanium are materials commonly used for extrusion.
Advantages:
Products with high detailed cross sections can be processed.
High production rates are achievable as the process is automated and continuous, so cost per unit is very low.
Products are manufactured with very good surface finish.
Many types of raw materials can be extruded.
Disadvantages:
Complex parts cannot be processed.
Only shapes with uniform cross sections can be produced.
CNC Router
On a CNC machine it is possible to make hundreds or even thousands of the same item in a day. First a design is drawn using solid works, then it is processed by the computer and manufacture using the CNC machine.
Center lathe
An engineers lathe or a centre lathe, as it more common known as, it is used working metal but wood lathes are also available to turn wood. The material is held and rotated, whilst a cutting bit is pressed onto the material to cut it. They are used to produce round objects from metal and plastics. A manual lathe is controlled by an operator turning the handles of the top and cross slides to make the product. A chuck or headstock can be controlled by turning the gear levers on the top of the headstock, which contains all of the gears controlling the lathe.
Milling machine
Milling machines are used to machine solid material such as aluminum and mild steel, as well as plastics such as Perspex and nylon. The material rotates as it is pushed against the cutting tool. The machine is available in a vertical or horizontal model. The material and cutting tool are both controlled very precisely by slides and lead screws. The machine should be set to cut away only small pieces each time to prevent the tools from being damaged, as they are very expensive. A milling machine can also be operated manually, mechanically or computer controlled and is available in a range of sizes, from bench top products up to full room sizes. It can produce a wide range of operations from simple slot cutting to complex contouring, using different shapes of cutting tools that are made from high speed steel. The cutting tools are threaded at one end so they can be screwed onto the chuck. Cutting fluid can be used to cool and lubricate the tool amd wash away debris or waste known as swarf, from the cutting operation.
Laser cutting
Laser cutters are capable of very accurate work as lasers are used to etch or cut material precisely. They can be used in the cutting/ shaping of a precise parts of prototype models and etching in a range of materials such as acrylic, rigid polystyrene, some woods,felt and leather. In school the design will typically be developed on solid works then the DXF file is transferred to a laser cutter.
The laser cutter can offer more materials and is faster than a CNC machine however the CNC machine is capable of cutting thicker sections.
Like the CNC a laser cutter has a bed size.
3D printer
A 3D printer takes material, usually ABS plastic wrapped in a spool, heats the material and then fuses the material layer by layer to build a three dimensional object. The material is extruded, or pushed out and deposited.
Precision is critical for 3D printers. The print head pulleys, and extruded hardware must be aligned as well as software dimensions translated into the correct real world dimensions used by the printer hardware .
Quality assurance
Quality assurance is about setting standards and meeting them. When QA is completed well by a company they are awarded an international standard of quality known as 1509000. To achieve a 150, a company will monitor products for quality throughout all stages of production, from design and development through to performance and customer satisfaction. Constant checks are made of equipment, materials and staff training. The two main principles of QA are ‘fit for purpose’, meaning the product should be right for its intended users and ‘right first time’ meaning mistakes should be eliminated.
