Engineering Materials, Processes and Production

R109- Learning Objective 1 Properties of Materials

Malleability The ability of a material to permanently deform in all directions without cracking.

Ductility The ability of a material to deform, usually by stretching along its length.

Conductivity/Resistivity The ability of a material to conduct heat or electrical energy. Opposite for resistivity

Hardness Resistance of a material to deformation, indentation, or penetration by means such as abrasion, drilling, impact, scratching

Machinability Machinability is a characteristic of a material, such as a metal, that makes it easy to drill, shape, cut, grind

Corrosion Resistance How well a substance (especially a metal) can withstand damage caused by oxidization or other chemical reactions

Elasticity/Plasticity The ability of a material to permanently change in shape.

Types of Materials

Metals

Ferrous Metals

Ferrous metals which contain iron. They may have small amounts of other metals or other elements added, to give the required properties. They will corrode if unprotected

Iron, carbon steels, high speed steels

Non Ferrous metals

Non Ferrous metals which do not contain iron. Pure metals (have no other metal or element)

Copper, brass, bronze, aluminium, zinc, tin, lead, titanium

Alloys Alloying metals involves mixing two or moremetals and other elements to improve their properties.

Brass, Aluminium and Titanium Alloys.

Polymers

Thermoplastics

Thermo Plastics -a polymer, which becomes soft when heated and hard when cooled. Thermoplastics can be cooled and heated several times without any change in their chemistry or mechanical properties.

ABS, Polyethylene, HIPS, PVS, polycarbonate, polypropylene, Nylon, Acrylic.

Thermoset plastics

Polymer that irreversibly becomes rigid when heated. Cannot be reheated and reshaped,making them harder to recycle.

Polyester resin, urea –formaldehyde, epoxy resin, phenol- formaldehyde.

Other Materials

Ceramics A ceramic is an inorganic non-metallic solid made up of either metal or non-metal compounds that have been shaped and then hardened by heating to high temperatures.

Tungsten carbide, Glass, ceramic bearing material

Composites A composite material is a material made from two or more materials with significantly different physical or chemical properties that, when combined, produce a material with characteristics different from the original components

Glass reinforced plastic, Carbon fibre, Concrete

Smart Materials

Smart materials, are designed materials that have one or more properties that can be significantly changed in a controlled fashion by external stress, moisture, electric or magnetic fields, light, temperature, pH, or chemical compounds

Shape memory alloys, thermochromic materials,Shape memory plastics, Quantum Tunnelling Composite.

New & Emerging Materials

Nano Technology

Developing and engineering materials at an atomic level. (Tiny) Allowing for Nano particles to be added to fabric, or glass.

Self cleaning glass, stain proof fabrics.

Metal Foams

Think AERO – chocolate but in metals, common in Aluminum alloys, allowing for strength but reducing the weight.

Metal Foams

Materials Testing Processes

Destructive testing

Is undertaken in order to understand a specimen’s performance or material behavior, these procedures are carried out to the test specimen’s failure.

Tensile Testing, Hardness testing

Non Destructive Testing

Is a testing and analysis technique used by industry to evaluate the properties of a material, component, structure or system for characteristic differences or welding defects and discontinuities without causing damage to the original part

Conductivitytesting, Crack testing, Ultra Sonic Testing

Materials and Uses

Ferrous and non ferrous metals and alloys

Used for cast iron machine bases, bronze for boat propellers, Copper used in wiring and circuit boards.

Thermoplastics ABS for appliance casing

Thermoset Plastics Phenol-formaldehyde for heat resistant saucepan handles.

Ceramics Tungsten carbide for cutting tool tips)

Composites Carbon fibre for bicycle frames

Smart materials Shape memory alloy in alarm systems

Characteristics of Engineering Materials (Reasons for selection alongside properties)

Relative Cost Ease of Use Forms of Supply

Availability Safety in Use Sustainability

Material Removal : Hand

SawingHacksaw and Junior Hack Saw to cut metal by hand.

FilingFiling is a material removal process in manufacturing.

Threading

Threading is the process of creating a screw thread, on the Lathe or by hand with a Tap and Die.

Understand Engineering Processes and their Application

Unit R109- Learning Objective 2

Forming

Forging

Forging is a manufacturing process involving the shaping of a metal through hammering, pressing, or rolling. These compressive forces are delivered with a hammer or die.

Die & Investment

Casting

Liquid metal is poured into a mold that contains a hollow shape. The metal and mold are then cooled, and the metal part (the casting) is extracted. GravityDie Casting Shown.

Press Forming

The shaping and cutting of sheet metal into 3D Forms. Think / lookup how car body panels are made.

Extrusion

Using a DIE to shape metal into tube shapes under pressure and heat. (You extrude toothpaste from a tube, think of that, the die would give different shapes.)

Shell Moulding

Casting using a thin layer of sand held together with a resin binder.

Joining Methods

WeldingWelding is a joining process whereby two or more parts are united by means of heat or pressure or both.

Riveting

When installed the rivet is either drilled, placed or punched into a hole, afterwards the tail is then deformed, holding the rivet in place.

The rivet is deformed by of the tail, which makes the material flatter and usually causes the tail to be expanded by about one and a half times the size of the stem's original diameter.

Soldering

Soldering is a process in which two or more items are joined together by melting and putting a filler metal into the joint,

Brazing

Brazing is a metal-joining process in which two or more metal items are joined together by melting and flowing a filler metal into the joint,

Threaded Fasteners

A threaded fastener is a discrete piece of hardware that has internal or external screw threads. They are usually used for the assembly of multiple parts and facilitate disassembly. The most common types are the screw, nut and bolt.

Self Tapping Screws

A self-tapping screw is a screw that can tap its own hole as it is driven into the material.

AdhesivesA glue, these will be carefully selected dependant on the materials being joined. Permanent fixing not good for recycling.

Heat Treatment

Hardening and Tempering

Hardening is the process of increasing the hardness of the material by heating and then quickly cooling, quenching.Tempering is the heating process to a set temperature which reduces the hardness.

Case HardeningCase-hardening or surface hardening is the process of hardening the surface of a metal object while allowing the metal deeper underneath to remain soft.

NormalisingNormalising is the process of heating a material to a temperature above a critical limit and then cooling in open air.

AnnealingIs the process of returning a metal to its original hardness and working properties. Taking out any hardening or tempering. Heated to a set temperature and allowed to cool very slowly.

Nitriding

Nitriding is a heat treating process that diffuses nitrogen into the surface of a metal to create a case-hardened surface. These processes are most commonly used on low-carbon, low-alloy steels.

Moulding

VacuumForming

Where a sheet of plastic is heated to a forming temperature, stretched onto a single-surface mold, and forced against the mold by a vacuum. This process can be used to form plastic into permanent objects

Injection Moulding

Plastic injection Moulding is the process of melting plastic pellets (thermosetting/ thermoplastic polymers) that once malleable enough, are injected at pressure into a mold cavity, which fills and solidifies to produce the final product.

Blow Moulding

Blow Moulding is the process of forming a molten tube of thermoplastic material and placed within a mold cavity and inflating the tube with compressed air, to take the shape of the cavity and cool the part before removing from the mold.

Rotational Moulding

Rotational Moulding involves a heated hollow mold which is filled with a charge or shot weight of material. It is then slowly rotated, causing the softened material to disperse and stick to the walls of the mold.

Compression moulding

Compression Moulding is the process of Mouldingin which a preheated polymer is placed into an open, heated mold cavity. The mold is then closed with a top plug and compressed in order to have the material contact all areas of the mold.

Material Removal : Machining

DrillingThe use of Drill Bits in a drilling machine to make holes in materials.

TurningUse of a Lathe to turn components. This is generally cylindrical work.

Milling Use of a milling machine to change the shape of flat work.

Grinding

Surface grinding is the use of an abrasive wheel to machine very accurate surfaces.

Surface Finish

Linishing Plastic & Powder Coating Electroplating

Polishing Painting Galvanising

Developments in Engineering ProcessesR109- Learning Outcome 3

Application of Computer Numeric Control (Use of CNC)

CNC Lathe

Lathe turning operations run from G&M code, with lathe axis movements controlled by the computer program. These machine can also change tooling within the program, allowing for various levels of automation.

CNC Mill

Milling operations run from G&M code, with mill axis movements controlled by the computer program. These machine will can also change tooling within the program, allowing for various levels of automation.

CNC Router

Three axis machines used to cut and engrave sheet material, most widely used for engraving. The same axis set up would be used for most CNC cutting process, Water Jet, Laser & Plasma cutting. Work holding and bed designs would change but the 3 axis movement stays the same.

Multi Axis Milling Center 5 Axis)

With both the work rotating and swinging and the milling tool able to rotate and change its angle of approach these machines can machine very complicated shapes that traditional mills could not do and a manual mill would be unable to move this number of axis simultaneously. With 5 Axis machines some turning operations can also be carried out.

CNC Water Jet

Very high pressure water sometimes mixed with abrasive materials is used to cut a range of materials. Advantages of water jet, is the surface finish of the cut, little need to clean or de burr cuts, also no distortion from heat when cutting metals.

CNC Laser & Plasma Cutter Welding

Same CNC 3 axis set up as a router and water jet. Both plasma and laser will burn through the materials. This means cleaning up after cutting. With the axis of movement staying the same the cutting tool is different, obviously a welder would weld not cut.

CNC Punching Machine

Metal punches are used to cut and put 3D shaping into sheet metal parts. CNC punches will move the sheet metal and change cutting PUNCH and DIE to allow for multiple cuts and shaping to be done to single parts or multiple cut outs of a single sheet.

Press Break Machines

Press breaks will cut and bend metal parts. (You used a press break the bend you Tool Caddy) CNC Press Breaks will allow the machine stops to be moved for positioning work along with being able to change the bending die and punch. Not a CNC machine that lends its self to full automation. Operator loads the material and cycles the machine once positioned.

Additive Manufacturing & Rapid Prototyping

Selective Laser Sintering (SLS)

Selective laser sintering is an additive manufacturing technique that uses a laser as the power source to sinter (Melt together) powdered material, aiming the laser automatically at points in space defined by a 3D model, binding the material together to create a solid structure.

Stereo Lithography (SLA)

Stereolithography is a form of 3D printing technology used for creating models, prototypes, patterns, and production parts in a layer by layer fashion. Lasers or light exposure can be used to fuse the modelling materials into solid parts.

Direct Metal Laser Sintering (DMLS)

Direct Metal Laser Sintering is a form of rapid prototyping process that makes parts and molds from metal powder that is melted by a laser to form solid metal parts.

Fused Deposition Modelling (FDM)

Fused filament fabrication, also known under the trademarked term fused deposition modelling, sometimes also called filament freeform fabrication, is a 3D printing process that uses a continuous filament of a thermoplastic material. Very similar in practice to DMLS & SLS.

Digital Communications in:

Research & Development

The development of the internet has played a crucial role in the effectiveness of R&D (research and development) activities. Organisations can now quickly access primary and secondary research. Competitors’ products can be analysed thoroughly to avoid any copyright issues and to exploit potential gaps in the market. The use of the internet also allows individuals working in R&D to communicate instantly and share resources electronically and remotely. The impact of this is products are released faster to market, costs are reduced, and products are more likely to meet the demands of the end user.

Materials Supply & Control

Stock and the management of inventory (any type of resource to do with an organisation) is now primarily done electronically.

An engineering organisation, especially large global companies, need to be in control of thousands perhaps even millions of units of stock and inventory. When figures this high are being dealt with, error and confusion is a real possibility, hence the use of electronic means to track and communicate this data.

JUST-IN-TIME (JIT) is a system of organisation used by some manufacturers. JIT is a system that relies on purchasing just enough materials to manufacture a batch of products, once an order from a customer has been placed. Over-ordering or storing materials is not permitted. JIT aims to eliminate waste and to speed up the supply of products to the customer. JIT relies on the manufacturing company having a very good business relationship with suppliers and distributers. Delays must not happen, or production will stop.

Computers and digital communication systems play a vital role in the successful application of JIT. Orders for stock will be digitally sent to suppliers (immediate and fast), the monitoring of stock within the company will be done electronically; once stock falls too low it will be automatically re-ordered with next to no human input.

Global Manufacturing

Global Manufacturing

In the 21st century the complete manufacture of a product is rarely fully home-grown.

Large companies can set up a GLOBAL SUPPLY CHAIN, where factories may be set up to produce components in multiple locations, then the components are shipped else- where for assembly.

An example of this is JCB; a large portion of steel and other raw materials come from Brazil. This, combined with the economic boom from the 2014 World Cup, lead to JCB building a factory in Brazil. This factory was able to take advantage of close proximity to steel resources, as well as being close to a growing economy.

This does not have to apply only to large global companies, however. Our ability to communicate across the world can narrow the gap between available skill bases. If a company needs to communicate with an expert on a different continent this is more than possible.

Likewise, if an exotic raw material is needed, the ability to contact, extract and receive this material can all be achieved very quickly due to transportation and communication methods available to businesses now.

Automation in:

Industrial automation is the use of control systems, such as computers or robots, andinformation technology for handling different processes and machineries in an industry to replace a human being. It is the second step beyond mechanisation in the scope of industrialisation.

Output

The output of a factory making use of industrial automation can be greatly increased.Machinery is capable of producing finished items at a far greater rate than human workers. Machines can also work 24 hours a day, 7 days a week, where human workers need breaks. Faster production means products can get to market quicker, and high consumer demand can be met.

Quality

The quality of finished goods can also be higher when automation is used. A machine can reproduce the same step precisely and consistently over and over again, usually with greater accuracy than human machinists. This also reduces waste from defects — machines don’t make mistakes unless they malfunction.

Workforce

Automation has a significant impact on the workforce. A factory running a fully-automated assembly line needs fewer workers to produce goods. Fewer employees will be needed for lower-skilled, repetitive tasks, and those who remain may have to be re- trained to operate or maintain the production machinery. However, with repetitive, unpleasant or dangerous tasks taken over by machinery, this presents better workingconditions for employees.

Costs

All these factors affect the cost of manufacturing. By increasing the rate of output and quality, by reducing waste, and by reducing the size of the workforce, the overall cost of production for each finished item is reduced. However, industrial automation has a very high initial outlay —machinery is expensive to buy, and may have to be designed and built especially for some processes, which represents a significant investment for the manufacturer. However, this initial outlay will be repaid over time through the reduced cost of production.

Digital Communications

Digital communication has wide-reaching impacts on every stage of production, from design to completion. We now have access to phones, computers, the internet, email, online cloud drives, video conferencing, portable storage devices and other communication technology. The way that engineering organisations are able to interact usingthis equipment is vast, and expands beyond the obvious phone calls and video conferencing.

Computer technology also brought about Computer-Aided Design (CAD). Products can be designed, modelled and tested entirely within the computer, which speeds up the design process and allows changes and revisions to be made quickly. Designers can collaborate remotely using CAD software and digital communication, allowing them to share their expertise and produce designs for manufacturers without even having tolive in the same country.