Commercial Manufacture Flashcards
What is injection moulding?
Injection moulding is the process of melting plastic pellets (thermosetting/ thermoplastic polymers) that once malleable enough, are injected at pressure into a mould cavity, which fills and solidifies to produce the final product.
Describe the process of injection moudling
Plastic granules are heated until they become fluid.
They are then forced into a mould the shape of the product being produced.
They are then quickly cooled and released from the mould.
Why is injection moulding used?
- The products produced are extremely accurate
- A large number of products can be produced quickly
- All products made using the same mould will be identical
What are the disadvantages of injection moulding
- The tools and equipment are usually expensive to buy.
- A high volume of products needs to be produced to make this cost effective.
What are common uses of injection moulding?
- Bottle caps
- Golf tees
- Toys
Lego bricks
What are the identifying features of injection moulding?
- Shrinkage mark
- Mould split lines
- Ejection pin marks
- Accurate, complex shapes
- High quality finish
Sprue marks
Describe the process of Vacuum forming
- A mould of the shape required is placed in a vacuum forming machine then a thin sheet of plastic is clamped above it.
- The sheet is then heated and the mould is forced into the heated sheet.
- The air is vacuumed out of the space between the plastic and the mould, allowing the plastic to take the shape of the mould.
Once cooled, a small burst of air is pumped into the space to help release the mould from the plastic.
Why is vacuum forming used?
Products can be produced relatively quickly.
Flexibility of the design possibilities.
Tooling costs are less compared to other plastic processes.
What are the disadvantages of vacuum forming?
Only one product can be made in the machine at a time.
Plastic can warp during the heating process.
What are common uses of vacuum forming?
- Trays
- Dishes
- Containers
- Lighting panels
What are the identifying features of vacuum forming?
- Thin sheet plastic
- Surface pips
- Pronounced tapers (draft angles)
- Patterns or textures imprinted
Thinning at corners.
Describe the process of rotational moulding
Plastic beads are placed into a mould where they are then heated.
While the plastic is being heated, the mould rotates both horizontally and vertically to coat the mould evenly.
The mould is then cooled slowly and the product removed.
Why is rotational moulding used?
It provides a uniform wall thickness around the entire product, except on corners where it is thicker.
Smaller numbers of products can be produced as the tooling cost is lower than other processes.
Products are a single part that can then be fitted to other parts if required.
What are the disadvantages of rotational moulding?
it can be quite a slow process as the mould needs to be coated and dried evenly.
Some shapes and detailed features are difficult to incorporate.
What are common uses of rotational moulding
- Balls
- Hollow plastic toys
Road markers
- Hollow plastic toys
What are the identifying features of rotational moulding?
- Split lines
- Draft angles
- Hollow objects
Uniform wall thickness
Describe the process of sand casting
A mould is put into a box (drag) and then the box is filled with sand.
The mould is removed and another box (cope) is placed on top.
The cope has channels in it to pour the molten metal into, which fills the mould cavity.
It is left to cool and then excess metal is removed.
Why is sand casting used?
It is suitable for batch production
Large parts can be created
Equipment for sand casting is cheap compared to other methods
What are the disadvantages of sand casting?
It takes a skilled person a lot of time to create one product using this method
The sand leaves a bad surface finish
What are some common uses of sand casting?
- Engine blocks
- Gear blanks
- Crankshafts
Brake drums
What are the identifying features of sand casting
- Rough surface texture
- Tapered angles
- Large parts without intricate detail
- Rounded corners
Runner and riser marks
describe the process of die casting
Molten metal is forced into a mould (die) to cool and then set.
Why is die casting used?
It is extremely accurate.
It leave a very good surface finish.
Parts can be produced quickly and are all identical.
What are the disadvantages of die casting
- High initial cost to set up equipment and machinery.
A large number of products have to be being produced to make this process affordable.
What are some common uses of die casting
- Hooks
- Door handles
- Sharpeners
- Golf clubs
What are the identifying features of die casting?
- Complex designs
- Ejector marks
- High quality surface finish
Mould split lines
Describe the process of laser cutting
A laser, which is controlled by a computer, is fired at the chosen material to create the pattern designed on the computer program
What are some common uses of laser cutting?
Craft projects
Etching on glass
Cutting precise patterns on various materials
Wooden puzzles
Paper crafts
What are the benefits of laser cutting?
- Can be used on a wide range of
materials- Designs can be very intricate and
detailed - Every product is an exact replica of
each other
- Designs can be very intricate and
What are the drawbacks of laser cutting?
The time taken to produce a product
varies depending on the level of detail in the design
Laser cutters can have a high energy consumption
Describe the process of 3D printing
A 3D object is created from a computer based design by ‘printing’ successive layers of material.
What are some common uses of 3D printing
- Architecture
- Art
- Engineering
- Fashion
- Jewellery
- Prosthetic limbs
What are the benefits of 3D printing?
- Designs can be highly customised and
almost any shape can be printed.- Products can be printed when
needed, reducing waste. - Each printed item is identical.
- Products can be printed when
- No moulds or formers are needed
What are the drawbacks of 3D printing?
- The number of materials that can be
used is still limited.- The run time is quite slow so takes a
long time to create just one product. - Equipment is expensive, as is
maintenance. - Training is needed
- The run time is quite slow so takes a
Describe Computer aided manufacture (CAM)
Computer aided manufacture is when a machine is controlled by a computer to create an exact replica of the digitally designed product. Examples include 3D printing, laser cutting and using a CNC router.
What are the benefits of CAM
Unit cost for mass production is very low.
Quality assurance – all will be made the same, no room for human error.
Digital distribution – because they are digital, plans and production drawings can be sent via the internet all over the world.
Clean manufacturing – no waste, clean energy sources used to manufacture.
What are the drawbacks of CAM
Breakdown – if something breaks down, all production stops.
Set up costs – machines, computing equipment and software can be expensive.
What are standard components?
- These are individual parts or
components made in very large
quantities.- They are identical to one another and
are readily available. - Examples include screws, nails, pins
and bolts.
- They are identical to one another and
What are the benefits of standard components?
- produced in standard sizes so easy to
incorporate into designs- reduces the need for a skilled
workforce - cheaper than producing yourself
- can be used on different products
- quality assured by producer
- easy to repair/maintain
- available in large quantities/easy to
source - will fit common tools
- can transfer across different products
- don’t have to manufacture them
yourself - fewer stages in production
- reduces the need for a skilled
accurate/exactly the same.
What is One - off production?
- This method is used to produce single items to a customer’s specification, but at a high unit cost.
- This is time consuming, very expensive and labour intensive.
- However, it offers total flexibility and the opportunity to custom-make products.
Examples include boats, bridges, bespoke furniture and made to measure clothes.
What is Mass production?
Mass production is a method of manufacturing thousands of your final solution/product, in a factory.
* This is where identical products are manufactured in large quantities. * Automated machinery and assembly lines are often used in the production of mass manufactured products.
Examples include cookers, washing machines, televisions, mobile phones and flat pack furniture.
What are the benefits of mass production?
- Increased productivity: Mass production makes it possible to manufacture large volumes in less time.
Uniformity: Mass production helps ensure each product is the same. As a result, manufacturers have greater control over quality, and consumers know what to expect.
- Lower cost: Mass production enables companies to produce larger quantities with fewer workers.
- Faster production: When companies use machinery and mass production techniques, they can develop and produce products much faster.
- Increased worker safety: Manufacturers who mass produce goods often employ automation technology to complete strenuous or dangerous tasks.
What are the drawbacks of mass production?
- Initial costs: It takes a lot of capital and time to build a factory equipped with specialized machinery.
- Energy consumption: Factories that mass produce goods use powerful machinery which requires substantial amounts of energy.
- Pollution: Factories cause pollution. During the Industrial Revolution, for example, factories polluted the water and air by burning coal and producing metals and chemicals.
Loss of jobs: Mass production fosters innovation and has led to the development of advanced machinery.
