Manufacturing

Brian Russell

Exam expectations

Issues associated with Manufacturing are regularly tested in the written paper. Questions deal with both commercial manufacturing as well as your own manufacturing. You should be able to identify the different types of manufacturing and describe the processes related to your chosen material area.

Manufacturing

Manufacturing involves efficiently turning raw materials into goods which we need or want and are able to sell to others.

ManufacturingManufacturing requires:• Special buildings or places of work• Organisation of people• Organisation of tools & equipment• Communication systems• Efficient working methods• Health and safety considerations

Manufacturing Terms

There are two different types of manufacturing associated with the production of commercial products:

• Primary processing

• Secondary processing

Primary processing

• This involves turning raw materials into standard stock sizes and forms. Manufacturing industries rely on consistency in terms of material types, sizes, colour etc.

There are sometimes questions on standard stock forms. Make sure you know what the available shapes and sizes are of the materials you are working with.

Primary processing

• Cotton fibres into fabric• Milk into cheese• Trees into plywood sheets• Copper and zinc ores into brass rod• Oil into polystyrene sheet• Silica sand and sodium carbonate into soda-lime glass

Examples of primary processing would include turning :

Origins of materials

Materials come from:

Out of the ground

Animals

Trees & plants

Oil

Few materials are ready for us to use without primary processing

Primary processing

You are expected to be able to briefly explain how at least one material which you have used is processed from the raw materials. It is also a good idea to understand how paper/card is manufactured from wood pulp.

Making Paper

Trees cut & shredded

Water added

Boiled up to make wood pulp

Chemicals and dyes added

Pulp poured over fine mesh and squeezed between rollers

Secondary processing

This involves taking those standard materials and processing them into products or separate components

Manufacturing in school is generally done using secondary processing only, as the materials have already been processed into regular forms such as sheets, rods, rolls etc.

Secondary Processingcan be broken down into six basic groups:• Casting & moulding (pouring or forcing liquid material into a hollow shaped

mould)• Forming (pressing materials into new forms)• Wastage (cutting or separating materials)• Conditioning (changing the properties of materials through heat, chemical or

mechanical action)• Assembling (joining parts together)• Finishing (usually coating materials to improve their appearance or to prevent

deterioration)

Manufacturing groups

Products are usually manufactured using a combination of two or more of these processes and in many products you will be able to identify all six methods.

Casting and moulding• This is a particularly useful way of processing

materials as a complete product or component can often be made in a single process and is one of the most common methods used by manufacturing industries

Casting and moulding

• The accurate production of moulds is essential if the products are to be identical. Moulds can be made from a wide range of materials from sand used for casting iron to silicon rubber used for a variety of food moulding.

• Moulds can be flexible or rigid depending on the materials being cast.

Open moulds

• Open moulds are often used when moulding food. The liquid material simply allowed to settle into the mould by gravity and harden.

Closed moulds• Closed moulds are used for moulding plastics

and metals. Often, the material needs to be forced into the mould under pressure. Injection moulding thermoplastics and die casting metal alloys are both done this way.

Forming materials

• Many materials can be shaped cold although these processes often require heat to allow the material to be manipulated

Forming materials

• This involves stretching or bending materials under pressure to form new shapes.

• Many materials can be processed in this way and one of the most common examples is the sheet steel which is pressed to form body panels on cars.

Forming materials

• Forging is one of the oldest manufacturing methods as far as working metals is concerned and gives us our most common name – Smith

Formers• Materials are often pushed into a single

surface mould to ensure the shapes are identical. These are usually called formers and can be made from a variety of materials including timber, metals and plaster of Paris.

Vacuum forming is a very common forming process used with thermoplastic sheet

Forming materials• Pastry can be formed into pie dishes, felt formed over

hat blocks, clay pushed into plaster moulds.

Forming materials

• In addition many materials can be extruded by forcing softened material through a die to produce continual shapes

Wastage• As the name suggests materials can be cut in a wide

variety of ways and this always creates some form of waste. It is the earliest form of manufacturing known as products were shaped from a single piece of material such as wood or stone.

Wastage• A wide variety of hand and machine processes

fit into this category from cutting fabric with scissors to machining metals on a centre lathe.

Wastage

• Materials can be abraded (or worn away) using a harder material. A simple example of this is using abrasive paper to smooth timber.

• A slicing action is probably the most common wastage process using a sharp blade and pressure to cut through the material.

Cutting by machine

• Using Computer Numerical Control allows materials to be cut in very sophisticated ways and to also minimise waste. Many industries use these methods as they are fast, reliable and very accurate.

Precision cutting

• Laser cutting and water-jet cutting are just two of the methods used to cut sheet materials into very detailed shapes. One of the advantages of these methods is that they can be used to cut different materials and shapes at the press of a few computer controls.

Stamping• Using a shaped cutter to stamp out materials is

also a common industrial method for cutting lots of identical parts. Punch tools, press-knives and die-cutting formes are all examples of this. The disadvantage of this method is that the cutting tools are made for one specific task.

Conditioning materials

• The properties of materials often need to be changed during manufacturing. Really simple examples of this would be to cook bread dough to create the foamed material we would refer to as a loaf or to bake clay in a kiln to turn it into hard, brittle pottery.

Conditioning materials

• Food is often heated to kill off bacteria or cooled to preserve the products.

• Conditioning through cooking also alters the taste and texture of foods

Conditioning materials

• Metals are often heat treated at high temperatures to make them harder or softer. Temperature is also used to expand or contract metals to allow parts to be joined together.

Conditioning natural materials• Natural timber is very moist and the water

content needs to be carefully controlled. That process is known as seasoning and most industrial methods dry out the timber in large kilns over many days then add a controlled amount of moisture. Traditionally, wood left outside but under shelter takes several years to season.

Conditioning natural materials

• Wool conditioning, for example, involves cleaning the wool with chemicals to stabilise the material. One aim is to make the material less inclined to shrinkage.

Assembling

• This involves joining materials or components together to make a complete product or a sub-assembly. One example of a sub-assembly would be a circuit board complete with soldered components.

Assembling

• Joining might be permanent or non-permanent (temporary) depending on whether there is likely to be any maintenance issues later.

Assembling

• Examples of permanent assembly methods would include gluing, welding, soldering, riveting, sewing, heat sealing, binding ingredients using cheese or egg etc.

Assembling

• Examples of non-permanent assembly would include screws, nuts and bolts, Knock-Down fittings, Velcro, using cream to hold layers of a cake together etc.

Assembling• One of the main advantages of assembling is

that the different properties of materials can be fully used to make a single product.

Finishing• As the name suggests finishing is often

something which is applied at a late stage of manufacturing a product to improve the way a material or product looks.

Finishing

• It can improve the natural look of the material or it can completely change its colour and texture.

• Applying a finish will sometimes protect a material from deterioration or corrosion.

Finishing

• Moulded products are usually self finished • It is the mould which is polished not the

product.

Finishing

• When considering paper and card materials the finish, in terms of print, varnishing, foil blocking etc. is the first process in the manufacturing stages and comes before cutting, folding and assembling the product.

Choosing the right processes

In industry• When choosing which processes to use one

of the major considerations will be how many products are required.

• Investment in new equipment, labour (including upgrading skills, energy and transportation costs will all impact upon the final decisions.

Manufacturing Costs

Finance

Labour Costs

(or Automation)Transportation

EnergyPlant

Raw Materials

Choosing the right processes

In school ask: • What facilities are available to me? • What materials are available to me?• What skills do I already have or do I need to

learn new ones?

In the end, the questions you ask will be very similar to the ones the production manager will be considering.