Topic 11: Advanced Manufacturing Techniques 10 hours

11.1 Joining (2 hours)

	Assessment statement	Obj	Notes	References
11.1.1	Describe friction welding.	2	Friction welding is a completely mechanical solid-phase process in which heat generated by friction is used to create the ideal conditions for a high-integrity welded joint between similar or dissimilar metals.	For Topic 11: www.technologystudent.com
11.1.2	Explain how two metal parts are welded using friction.	3	Diagrams should include two parts, one revolving, and the other fixed.
11.1.3	Describe plastic welding.	2	Consider hot air and friction welding techniques.
11.1.4	Explain how two plastic parts are welded together.	3	Only thermoplastics that do not burn or decompose when heated to their softening temperature can be welded.
11.1.5	Define permanent joining techniques.	1
11.1.6	List a range of permanent joining techniques.	1	Consider pop-rivets, brazing, welding and adhesives.
11.1.7	Discuss how permanent joining techniques lead to planned obsolescence and environmental issues.	3	Permanent joins do not allow for the disassembly and easy maintenance of products.
11.1.8	Define adhesive.	1
11.1.9	Identify a range of adhesives suitable for joining metals, woods and plastics.	2	PVA (polyvinyl acetate), epoxy resin, contact adhesive, cascamite, tensol cement and superglue (cyanoacrylate).
11.1.10	Discuss the advantages and disadvantages of using adhesive bonding in products.	3	Consider preparation of surfaces, clamping, bonding time, type of material, and health and safety.
11.2 Moulding (3 hours)
11.2.1	Define sprue, flash, parison, die, draft angle and injection moulding.	1
11.2.2	Explain how an injection-moulded product is made.	3	Diagrams must include the hopper, hydraulics, heaters, screw, sprue and mould.
11.2.3	Outline the advantages of injection moulding.	2	Consider initial capital investment, tooling, accuracy, quality control and quantity of product.
11.2.4	Discuss how standardized bottle caps have constrained bottle design, but have cut costs for manufacturers.	3	Bottle caps can be classed as standardized parts. Bottle tops are injection moulded, while bottles are normally made by blow moulding. It is financially beneficial for a blow moulding company to use off-the-shelf bottle tops instead of purchasing an injection moulding machine and new tooling.
11.2.5	Describe how a blow-moulded product is made.	2	Diagrams must include the extruder, parison, the mould and air inlet.
11.2.6	Explain how a rotational-moulded product is made.	3	Diagrams must include the mould, filling the mould, heater chamber, rotation and cooling chamber.
11.2.7	Explain how a compression-moulded product is made.	3	Diagrams must include the mould, pre-form, hydraulic press, finished part and flash material.
11.2.8	Discuss why some products have to be made using compression moulding.	3	Consider the heat the product must withstand, quantity and type of product to be made. Refer to thermosets.
11.2.9	Describe how a vacuum-formed product is made.	2	Diagrams must include the vacuum chamber, former, platen, heater, air in and out.
11.2.10	Identify manufacturing methods suitable for thermoplastics and thermosets.	2	Thermoplastics: vacuum forming, blow moulding, injection moulding and rotational moulding. Thermosetting plastic: compression moulding.
11.3 Casting (3 hours)
11.3.1	Describe lost wax casting.	2
11.3.2	Describe how lost wax cast products are made.	2	Consider preparation of the master pattern; injection of wax to create copy; creation of a wax tree to make a wide range of small parts from the same metal; covering wax with ceramic or plaster of Paris; removal of wax; and the addition of the final chosen material.
11.3.3	Explain how a range of products are made using lost wax casting.	3	Jewellery, dental implants, hip replacements and wind instrument keys.
11.3.4	Describe high-pressure die casting.	2	Die casting is mainly used for low-melting alloys. Molten metal is forced into a mould under high pressure.
11.3.5	Describe how high-pressure die cast products are made.	2	Draw a diagram to include holding furnace, injector, gooseneck and die.
11.3.6	Explain how a range of products are made using high-pressure die casting.	3	Consider hip replacements, disk drive chassis and carburettors.
11.3.7	Outline two advantages and two disadvantages of high-pressure die casting.	2	Advantages: high accuracy, good surface finish, thin walls, and high rate of production. Disadvantages: high plant costs, high tooling costs, cannot be used for a wide range of alloys, and limitations on maximum size that can be cast.
11.4 Forming (2 hours)
11.4.1	Describe the process of spray-up.	2	Spray-up is carried out on an open mould, where both the resin and reinforcements are sprayed directly onto the mould. The resin and glass may be applied separately or simultaneously “chopped” in a combined stream from a chopper gun. Workers roll out the spray-up to compact the laminate. Wood, foam or other core material may then be added, and a secondary spray-up layer embeds the core between the laminates (sandwich construction). The part is then cured, cooled and removed from the reusable mould.
11.4.2	Identify products that could be made using spray-up processes.	2	For example, pleasure boats and swimming pools.
11.4.3	Describe the process of hand lay-up.	2	In hand lay-up processing, fibreglass continuous strand mat and/or other fabrics such as woven roping are manually placed in the mould. Each ply is sprayed with catalysed resin and the resin is worked into the fibre with brushes and rollers to wet-out and compact the laminate.
11.4.4	Identify products that could be made using hand lay-up processes.	2	Products of varying sizes that do not need a high accuracy finish, for example, prototypes.
11.4.5	Describe the process of filament winding.	2	This process is primarily used for hollow, generally circular or oval-sectioned, components, such as pipes and tanks. Fibre tows are passed through a resin bath before being wound on to a mandrel in a variety of orientations, controlled by the fibre feeding mechanism, and rate of rotation of the mandrel. Filament winding machine design varies with part geometry.
11.4.6	Identify products that could be made using filament winding processes.	2	For example, fishing rods and rowing oars.
11.4.7	Describe the process of vacuum bagging.	2	This process is basically an extension of the wet lay-up process where pressure is applied to the laminate once laid-up in order to improve its consolidation. This is achieved by sealing a plastic film over the wet laid-up laminate and onto the tool. The air under the bag is extracted by a vacuum pump, and thus up to one atmosphere of pressure can be applied to the laminate to consolidate it.
11.4.8	Outline the benefits of using vacuum bagging when using composite lay-up techniques.	2	Large products are possible; top-quality products through the use of pre-pregs; clean production method; and low moulding costs.
11.4.9	Identify products that can be made using vacuum bagging processes.	2	For example, laminated curved furniture.