FINAL PRODUCT
IB DESIGN TECHNOLOGY
4
RAW MATERIAL TO FINAL PRODUCT
Edited by Jolan Martinez
RAW MATERIAL TO
4.1
Properties of Materials
Featured Designers
Properties of Materials
“The rapid pace of scientific discovery and new technologies has had a major impact on material science, giving designers many more materials from which to choose for their products. These new materials have given scope for “smart” new products or enhanced classic designs. Choosing the right material is a complex and difficult task with physical, aesthetic, mechanical and appropriate properties to consider. Environmental, moral and ethical issues surrounding choice of materials for use in any product, service or system also need to be considered.”.
4.1
Raw Material to Final Product
In this section, we will get to know a variety of material types and their properties. Before we look at individual materials in depth, lets get familiar with key terms that will apply to many of them.
Physical properties... describes the state of materials, for example, mass, weight, volume and density.
Mechanical properties involve the relationship between stress and strain or a reaction to an applied force.
DENSITY
ELECTRICAL RESISTIVITY
THERMAL CONDUCTIVITY
THERMAL EXPANSION
HARDNESS
How compacted a substance is
How easily the material conducts/resists a current
How easily the material conducts/resists heat
How a material will change its shape, area, volume, and density in response to a change in temperature
How resistant a material is to abrasion and cutting.
TENSILE STRENGTH
STIFFNESS
TOUGHNESS
COMPRESSIVE STRENGTH
Maximum load that a material can support without fracture when being stretched
How a material bends under force, while still returning to its original shape once the force is removed
How resistant a material is to cracks.
Degree a material reduces in size under pressure
ELASTICITY
The ability of a material to return to its original form after being distorted.
DUCTILITY
How easy it is to pull a material into a string like form (eg making wire from metal).
MASS + WEIGHT
Mass is the amount of matter contained in an object. Higher mass = higher weight.
4.1
Properties of Materials
Raw Material to Final Product
Aesthetic characteristics
Include: taste, smell, appearance and texture. Some aesthetic characteristics are only relevant to food, while others can be applied to more than one material group. Although these properties activate people’s senses, responses to them vary from one individual to another, and they are difficult to quantify scientifically, unlike the other properties..
Smart materials
…have properties that can be changed by external stimuli (like heat or light) in a controlled way. Below are five examples of smart materials:
When a piezoelectric material is deformed, it gives off a small electrical discharge. These materials are widely used as sensors in different environments. For example, Piezoelectric materials can be used to measure the force of an impact, for example, in the airbag sensor on a car. The material senses the force of an impact on the car and sends an electric charge to activate the airbag.
Photochromicity
Photochromicity refers to a material that can described as having a reversible change of colour when exposed to light. One of the most popular applications is for colour-changing sunglass lenses, which can darken as the sun brightens. A chemical either on the surface of the lens or embedded within the glass reacts to ultraviolet light, which causes it to change form and therefore its light absorption spectra.
Q: Think of an interesting use?
Q: Which three areas in school would generate the most power from piezoelectric flooring?
4.1
Properties of Materials
Raw Material to Final Product
Shape memory alloys (SMA)
Shape memory alloys (SMA) are metals that exhibit pseudo-elasticity. This means its shape can be deformed when cold, but it returns to its original shape when heated.
Applications for pseudo-elasticity include eyeglasses frames, and teeth braces (when they are warm they try to return to original shape, putting force on the teeth).
One application of shape memory effect is for robotic limbs (hands, arms and legs). By passing an electrical current through the fingers, the movement of an artificial joint like a finger can be controlled.
Electro-rheostatic (ER) and magneto-rheostatic (MR)
Electro-rheostatic (ER) and magneto-rheostatic (MR) materials are fluids that can undergo dramatic changes in their viscosity. They can change from a thick fluid to a solid in a fraction of a second when exposed to a magnetic (for MR materials) or electric (for ER materials) field, and the effect is reversed when the field is removed.
MR fluids are being developed for use in car shock absorbers, and damping washing machine vibrations. This is as they can help can vary the resistance
Watch this to see how it is used.
Q: How could these fluids be used to give an airplane a smooth landing?
Q: Think of a smart use of SMA?
4.1
Properties of Materials
Raw Material to Final Product
Thermoelectricity
Thermoelectricity is, at its simplest, electricity produced directly from heat. It involves the joining of two dissimilar conductors that, when heated, produce a direct current. Thermoelectric circuits have been used in remote areas and space probes to power radio transmitters and receivers.
Stress Strain Graphs and Material Selection Charts
Designers have to be able to to identify appropriate materials depending on the context. Stress strain graphs allow us to know how a material responds when a force is applied to it. Whats stress and strain?
Stress - The force applied to a material.
Strain - The response of a material due to stress
Material Selection Charts can also be used to help do this.
These charts allow you to compare properties to select a material that suits a particular purpose.
Q: Lets do a chart test!!!
This yellow section represents the materials ability to be elastic and return to its original shape. Elasticity is measured using something called Young's Modulus.
The yield point is where the material experiences plastic deformation (can't return to its original shape). Its no longer elastic, its now plastic.
The graph ends with the point the material breaks.
4.2
Types of Materials
Featured Designers
4.2a
Metals and Metallic Alloys
Typically hard and shiny with good electrical and thermal conductivity, metals are a very useful resource for the manufacturing industry. Most pure metals are either too soft, brittle or chemically reactive for practical use and so understanding how to manipulate these materials is vital to the success of any application.
Extracting metal from ore
Some metals exist as elements, already fully metalish in the ground, such as gold. Most however, are found in ores. Ores are rocks that contain a metal, albeit as a compound with other materials. To extract that metal from the ore, Electrolysis can be used if the metal is reactive enough (such as aluminium). For less reactive metals like iron, heating with carbon (found in coke) and limestone is required to extract them by melting.
Modifying physical properties by alloying, work hardening and tempering
ALLOYING
A mixture that contains at least one metal. This can be a mixture of metals or a mixture of metals and non-metals.
WORK HARDENING
Also known as strain hardening or cold working, this is the process of increasing the hardness of a metal through plastic deformation.
TEMPERING (Heat treatment)
A hot ferrous metal is quenched in water, increasing hardness but making it brittle.
Then it is reheated, increasing the toughness by reducing hardness. It is now less brittle and will crack less.
Raw Material to Final Product
Grain size
Under a microscope, we can see that metal is made up of multiple crystals. The size of the boundaries between them is how we determine the grain. The quicker the metal cools, the smaller the grain size. The smaller the grains, the more brittle but harder the metal. The larger the grains, the more ductile the metal
4.2a
Metals and Metallic Alloys
Q: Search Man at Arms on youtube, and see if you can spot these ideas in use.
Raw Material to Final Product
Types of metal
Design criteria for super alloys
Superalloys, also known as high-performance alloys, have a very high tolerance for oxidisation (where a material changes because of exposure to oxygen) and also extreme high temperatures. They are formed using either nickel, cobalt, or iron. Super alloys help avoid the following issues:
Creep - If metal is put under extreme stress for extended periods of time, its shape can start to slowly deform. This is especially the case if the metal is held near to melting point for extended periods of time.
Oxidation resistance - Oxidation can be devastating for a metal structure or part. One of the main effects is corrosion, where the surface of the metal begins to wear away due to the chemical reaction. If you have ever had a rusty bike chain, this is why. Look after your bike chains people!
Recovery and disposal of metals and metallic alloys
The good thing about metal is that it can be recycled without losing quality. For this reason scrap metal has a real financial value. True story. Once Mr Martinez took his fridge outside into his garden while he painted the kitchen. A few hours later it was gone. Scrap thieves! Recycling goes like this. The metal is sorted, often with magnets and sensors. Then it is shredded. This helps it to melt quicker and with the use of less energy. Then it is melted down. Electrolysis is used to purify the metal, and then it is cast ingot bars to be used again.
MILD STEEL
An alloy of iron and carbon
High tensile strength.
High impact strength.
Good ductility
CAST IRON
Iron, silicone and manganese
Compressive strength
Hardness
Melting point above 1100c
ALUMINIUM
Pure metal
Non magnetic
Lightweight
Heat/electrical conductor
TITANIUM
Pure/alloy
Low density
High strength
Corrosion Resistance
FERROUS
Include Iron- No Iron no ferrous!
NON-FERROUS
Metals that contain no iron
Types of timber - Natural and Human Made
The first thing we need to know is that wood can be natural, as in straight from the tree, or it can be human made, aka engineered wood or composite wood, these are made by fixing strands, fibres, or veneers together to create composite materials. Typical examples include MDF, plywood and chipboard.
Timber
Timber is a major building material that is renewable and uses the Sun’s energy to renew itself in a continuous cycle. While timber manufacture uses less energy and results in less air and water pollution than steel or concrete, consideration needs to be given to deforestation and the potential negative environmental impact the use of timber can have on communities and wildlife.
SOFTWOOD
The wood from a coniferous tree. Aka “Evergreen” - keep leaves all year.
eg. Pine
HARDWOOD
The wood from a deciduous tree. Aka “Leaf losers” as leaves fall in in autumn.
eg. Oak
PARTICLE BOARD
Made from wood chips and joined with glue.
eg. MDF
LAMINATE
Sheets of material made from layers of veneers
eg. Plywood
NATURAL
HUMAN MADE
CHARACTERISTICS
Grows quick. After 30 years can be used for timber
Spaced out grain because of quick growing
Usually lighter in colour
Cheaper
Lower fire resistance
CHARACTERISTICS
Grows slow. After 100 years can be used for timber
Close grain because of slow growing
Usually darker in colour
Expensive
Higher fire resistance
CHARACTERISTICS
Usually smoother surface
Bend/ Warp resistant
Can bloat with moisture
Cheaper due to use of scraps.
CHARACTERISTICS
Strong because layers are fixed at 90 degrees on the grain
Waterproof glue can make them usable outside.
Resistant to warping
Raw Material to Final Product
4.2b
Wood related problems
It's not all fun and games in the world of wood. Like any material, it has issues. Here are some common problems.
4.2b
Timber
Q: Get out there and find examples...
WARPING
A distortion in wood caused by uneven drying, which results in the material bending or twisting.
KNOTS
Imperfections in timber, caused by the growth of branches in the tree that reduces its strength.
BOWING
A warp along the length of the face of the wood.
DRY ROT
When timber is subject to decay and attack by fungus.
CUPPING
A warp across the width of the face of wood, in which the edges are higher or lower than the centre.
Treating and finishing timbers
Treatment of wood can involve using solutions, which make the wood poisonous to insects, fungus, and marine borers as well as protecting it from the weather. One example is…
Creosote. This is a material that penetrates the timber fibres protecting the integrity of the wood from insects such as woodlice. Don’t let it get on your clothes.
Wood and Moisture
Moisture in wood can be broken down into two categories.
Absorbed moisture contained in the cells walls.
Free moisture contained within cell cavities and intercellular spaces.
You might have noticed a freshly cut tree has lots of moisture. This needs to be dried out before use.
Seasoning is the commercial drying of timber which reduces the moisture content of wood. It can be done by Air, or by Kiln. Which is better? Let's find out...
Recovery and disposal of timbers
Reforestation is the process of restoring tree cover to areas where woodlands or forest once existed. If this area never returns to its original state of vegetative cover the destructive process is called deforestation.
Raw Material to Final Product
Characteristics of glass
Glass is formed from a molten mix of soda, ash, limestone and sand. Here are some common types
Recovery and disposal of glass
Glass in 100 percent recyclable, and doesn't lose quality no how matter how many times it is recovered. To recycle glass, it is first crushed, and has contaminants removed. It is then melted in a furnace, and reformed.
Transparency - High
Colour- Various
Strength - Low
Most common glass
Transparency - High
Colour- Various
Strength - High
Heat treated for strength
Transparency - High
Colour- Various
Strength - HIGH
Holds together on shatter
Transparency - low
Colour- Various
Strength - Low
Great UV Protection
CHARACTERISTICS
CHARACTERISTICS
CHARACTERISTICS
CHARACTERISTICS
4.2c
Glass
Q: Search up toughened glass, and find an example of someone really testing those material properties.
The rapid pace of technological discoveries is very evident in the manufacture and use of glass in electronic devices. Different properties have been presented in glass for aesthetic or safety considerations for many years but the future of glass seems to be interactivity alongside electronic systems. The structure of glass is not well understood, but as more is learned, its use is becoming increasingly prominent in building materials and structural applications.
Raw Material to Final Product
The regular glass found in most windows.
Also known as tempered glass, or safety glass. Is heat treated to make it much tougher than regular glass.
Laminated glass is made from at least two layers of glass, with a layer of film in the middle. If it breaks, the film keeps the broken glass in place, so it doesn't go everywhere.
Have a metal oxide added that limits the amount of light that can pass through.
Most plastics are produced from petrochemicals. Motivated by the finiteness of oil reserves and threat of global warming, bio-plastics are being developed. These plastics degrade upon exposure to sunlight, water or dampness, bacteria, enzymes, wind erosion and in some cases pest or insect attack, but in most cases this does not lead to full breakdown of the plastic. When selecting materials, designers must consider the moral, ethical and environmental implications of their decisions.
4.2d
Plastics
Raw materials for plastics
The source for plastics is wide. Many are formed from crude oil (not processed petrol), but other sources include coal, salt, and the cellulose of plants (bioplastic). The two main categories that can be made are…
THERMOPLASTICS - have weak bonds/can be reheated and reformed and shaped/can be recycled/cannot withstand high temperatures. To recycle they are sorted, shredded, and reshaped into pellets to be sold.
THERMOSETTING PLASTICS -have strong bonds/can be shaped only once/cannot be recycled/can withstand high temperatures;
Thermoplastics
PP - Polypropylene
Elasticity /semi rigid
Toughness
Lightweight
PE - Polyethylene
Cheap
Lightweight
Fatigue resistant
HIPS - High Impact polystyrene
Cheap
Impact resistant
Food safe
CHARACTERISTICS
CHARACTERISTICS
CHARACTERISTICS
ABS - Acrylonitrile Butadiene Styrene
Toughness
Strain resistant
Dimensional stability
PET - Polyethylene terephthalate
High toughness
Clear as glass
Does not absorb water
PVC - Polyvinyl chloride
Hardness
Lightweight
Hydrophobic
CHARACTERISTICS
CHARACTERISTICS
CHARACTERISTICS
Raw Material to Final Product
Thermosetting plastics
How plastics are shaped
Plastic deposition.
Layer by layer as in FDM 3D printing.
Plastic fusion.
Such as welding two parts together
Plastic moulding.
Shaping in a mould, under compression (eg injection)
Plastic casting.
shaping in a mould, under no pressure, just that of the gravity
Recovery and disposal of plastics
One way to find out if your plastic can be recycled is to look to see if there is a number printed on it (The Resin Identification Code), contained within a triangle. This indicates the plastic type, and helps in sorting for recycling. If it can't be recycled, it's usually off to landfill, unless it can be repurposed somehow. Time for a review!
4.2d
Plastics
Q: What plastics can we find in this room?
POLYURETHANE
Mold Resistant
Oil/water resistant
Cut/tear resistant (Hardness)
UREA-FORMALDEHYDE
Tensile strength
Resists heat distortion
High compressive strength
MELAMINE RESIN
Heat Resistant
Flame retardant
Scratch Resistant
EPOXY RESIN
High Strength
High adhesion
Often used in fibreglass
CHARACTERISTICS
CHARACTERISTICS
CHARACTERISTICS
CHARACTERISTICS
GRIDWASTE.COM
Raw Material to Final Product
Raw materials for textiles
Textiles break down into two main categories, Natural and Synthetic. Natural fibres such as cotton or wool are sourced from plants (cotton), animals (wool), and minerals (rock wool). Synthetic fibres are created from fossil fuels, such as Polyester or Acrylic.
Properties of natural fibres - sourced from plants, animals, minerals
Natural fibres usually have high absorbency, burn with a flame, but does not melt. Often dry slowly
Properties of synthetic fibres - sourced from fossil fuels such as oil
Synthetic fibres usually wick moisture, dry quickly, and melt with a flame.
4.2e
Textiles
The continuing evolution of the textiles industry provides a wide spread of applications from high performance technical textiles to the more traditional clothing market. More recent developments in this industry require designers to combine traditional textile science and new technologies leading to exciting applications in smart textiles, sportswear, aerospace and other potential areas.
WOOL
Very absorbent
Elastic and Durable
Hypoallergenic
Keeps you warm…and also cool!
COTTON
Absorbent but slow to dry
Cool to wear on the skin
Can be machine washed and ironed
Creases easily
SILK
Absorbent
Stronger than cotton
Elastic and resilient
NYLON
Very resilient/abrasion resistant
Can melt at high temperatures
Dries quickly
Moisture wicking (good for sport).
POLYESTER
Very resilient/abrasion resistant
Can melt at high temperatures
Dries quickly
Moisture wicking (good for sport).
Very elastic - think cyclists
Stronger than rubber
Hardly absorbs water/Dries quickly
Raw Material to Final Product
Conversion of fibres to yarns
You have collected lumps of fluffy cotton and want to make that into a shirt. Right now that cotton is in ball form. This is called a FIBRE. It isn't quite ready yet. It needs to be SPUN into a YARN (a long thread). The spinning process will take that raw material and create long threads that can be used in sewing, knitting etc. Here is how it is done.
Individual yarns are weak, but when weaved together, eg. in a rope, they have a much higher tensile strength..
Conversion of yarns into fabrics: weaving, knitting, lacemaking, and felting
Once we have that yarn, there a a range of processes to convert them into a fabric. (cloth or material produced by weaving, knitting etc). Each is a different method of interlacing.
Recovery and disposal of textiles
Textile waste can be recovered both pre consumer, such as the the waste from cut patterns or failed manufacture in the factory. It can also be post consumer, such as the clothes we throw away.
As we know, a huge amount of clothing ends up in landfill. Some is sent to other countries, and some is used industrially for cleaning. It can often be recycled however. To do this...
1 Material and colour sorting. Fabrics that don't need to redyed are separated to save energy.
2 Materials are then shredded or respun into new fibres.
3 Fibres are then CARDED, which means being disentangled and cleaned ready for reuse.
4.2e
Textiles
Q: What materials are used in what you are wearing today?
WEAVING
KNITTING
LACEMAKING/EMBROIDERY
FELTING
Raw Material to Final Product
Two sets of threads interlace at 90 degrees
Multiple loops of yarn called stitches create items of clothing
Multiple threads are interlaced…or…stitched to a fabric base. Known for being decorative
Repeated pushing causes the wool to hook and clump together
Composites are an important material in an intensely competitive global market. New materials and technologies are being produced frequently for the design and rapid manufacture of high-quality composite products. Composites are replacing more traditional materials as they can be created with properties specifically designed for the intended application. Carbon fibre has played an important part in weight reduction for vehicles and aircraft.
4.2f
Composite
Composites
A composite is created when two or more materials with different properties are combined (but not chemically). This method allows designers to create bespoke materials that have the qualities they need for their products. A good example is a bike frame that needs to be strong, but also lightweight. Examples include
-Laminated wood It is strong because of the glue used, and the fact that multiple sheets can have different properties. This also helps avoid problem for defects.
-Concrete is an aggregate (a mix of loose compact fragment ) of cement, air, water, sand, and gravel.
Carbon fiber is light and strong due to its use of fibers and resin.
The difference between a composite and something like an alloy, is that the different materials are not mixed, but fixed together, therefore keeping their original properties. Think of it this way, an alloy is like pouring two pots of paint into a bowl of water. They will mix and become one. A composite is more like pouring bricks and metal nails into a bowl of glue. The bricks and nails keep their original state.
Matrix
We need something to bond these different materials together. This is called the matrix. This bond has many forms. It can be resins, thermoplastics, thermosetting plastics, ceramics, metals. The matrix itself can take the following forms
FIBRES eg CARBON FIBRE
SHEET eg KEVLAR
PARTICLE eg MDF
MATRIX
MATERIAL
MATRIX
MATERIAL
MATRIX
MATERIAL
Raw Material to Final Product
Process: weaving, moulding, pultrusion and lamination
So how are these materials and matrixes combined to form a composite. Here are a few methods.
Composition and structure of composites:
There are many advantages and disadvantages of composite materials. The obvious advantage is that they allow custom properties for materials. Downside would be sometimes cost, and difficulty in manufacturer. Each composite material is very different however, and so has its own advantages and disadvantages. Let's look at some common composites
4.2f
Composite
Q: What are they comprised of, used for, and what are the advantages and disadvantages?
WEAVING
The act of forming a sheet like material by interlacing long threads passing in one direction with others at a right angle to them
MOULDING
Injecting resin into a mould so it completely fills the spaces between fibres.
PULTRUSION
A continuous manufacturing process used to create composite materials with a constant cross-section. Reinforcing fibres are saturated with a liquid polymer resin,then pulled through a heated die to form a tube.
LAMINATE
Covering the surface of a material with a thin sheet of another material typically for protection, preservation or aesthetic reasons.
Carbon reinforced plastic
Other…
Fibreglass
Kevlar®
laminated veneer lumber (LVL)
Particleboard
Concrete
Carbon Fibre
Raw Material to Final Product
4.3
Scales of Production
Featured Designer
CONTINUOUS FLOW
Scales of Production
“Decisions on scale of production are influenced by the volume or quantities required, types of materials used to make the products and the type of product being manufactured. There are also considerations of staffing, resources and finance”.
4.3
Q: Find a clothing manufacturer making bespoke clothing to your tastes. What is the process, and How much does it cost?
Scales of production
When manufacturing products, the number made and processes used can scale. In order of scale…
Let’s look at these, and learn a little about when they are suitable, and their pros and cons.
ONE
OFF
BATCH
MASS CUSTOMISATION
One-off production
The smallest scale required when manufacturing products is...one. These are often bespoke products, which are products made for a particular user according to their specifications and requests. Think bespoke suits, prosthetic limbs, or custom made furniture. One off production is often handmade, and often made by individuals or small teams. One off can also be used in the creation of a prototype to present to users or clients at the end of the design phase..
Pros: Products can be unique
Products can be made to the users exact specifications.
Cons: Takes longer for a product to be manufactured.
More expensive than mass produced products.
Raw Material to Final Product
4.3
Scales of Production
Batch production
Batch production is the smallest example of mass production. Large numbers of identical products are produced to a set number (a batch). An example might be a sneaker company making 50,000 pairs of a particular design, before moving on to producing a different line. As the number of products made rises, it becomes more cost effective to invest in machinery and production lines.
Pros; Increased quantity in terms of products made.
Cons: Cost of machinery.
Continuous flow
In batch production, the product being made has a set number. It might be a thousand, or a million, but eventually production on this product will stop. Continuous flow doesn't have a cap. It is used when there is a need for product to manufactured without interruption or end. Think of a product like Coke, that shops are constantly needing to replenish. Each stage of the process is constantly feeding in products, and feeding them out at a steady rate.
Pros: Higher volume of production. Never stops.
Cons: Higher cost equipment. Requires complex control systems.
Mass Customisation
Mass customisation is a new combination of one-off products and mass production. While still using machinery and production lines, users are able to select a series of options such as colour, pattern, and fit. A good example of this is Nike’s “Nike by you” service. Users pay for designs to be made according to custom specs.
Pros: Users can personalise their product.
Cons: Slower than regular batch production. Slower lead time.
Q: Lets knock up some custom Air Force 1’s on the Nike By You service.
4.3
Scales of Production
LINKS
TBA
Q: Lets look at the things around us. What do you think the scale of production was?
Selecting an appropriate scale of production
When deciding on the scale of production, we need to consider...
Size of market- This one is obvious! How big is your user base?
Desired manufacturing processes- The users for some products might demand that products are handmade, as this brings with it a certain status.
Product characteristics - Some products lend themselves to being handmade or mass produced. Could there be a handmade LP?
Material characteristics - Some materials are easily to manipulate in a mass produced context.
Nature of market- What price would people accept for this kind of product? Would people want bespoke paper clips?
4.4
Manufacturing Processes
Featured Designer
Manufacturing Processes
“Designers sometimes engineer products in such a way that they are easy to manufacture. Design for manufacture (DfM) exists in almost all engineering disciplines, but differs greatly depending on the manufacturing technologies used. This practice not only focuses on the design of a product’s components, but also on quality control and assurance”.
4.4
Manufacturing Processes
We have the raw materials, now it is time to do something with them! Let’s look at some of the manufacturing techniques that can be used to create a product. The key is knowing which is right for which purpose. We will cover:
Additive techniques Wasting/subtractive techniques Shaping techniques Joining techniques
Additive: Manufacturing techniques that add material in order to create a product
Paper-based rapid prototyping
Laminated object manufacture (LOM)
3D Print eg. Stereolithography
Raw Material to Final Product
This uses regular paper. It works by glueing together layers and layers of paper to form 3d shapes. If done by machine, colour can be printed to each layer. It can be done by hand or by machine.
Advantages
Cheap, and quicker than other additive methods such as 3D printing.
Disadvantages
The forms possible less complex than 3D printing.
A CAD model is converted into slices, each which is cut from a roll of material. These are then attached together using an adhesive.
Similar to paper prototyping, but perhaps on a larger scale.
Advantages
A range of materials - Thin plastics, papers, metals.
Disadvantages
The forms possible less complex than 3D printing.
3D printers that cure a photosensitive resin. Light is targeted onto the surface of the resin, causing it to hard. This is repeated in layers to form a model.
Advantages
High detail and complex forms possible.
Disadvantages
Resin is expensive.
4.4
Manufacturing Processes
Wasting/subtractive: Manufacturing techniques that cut away material in order to create a component.
Shaping techniques: Manufacturing methods for modifying the shape of a material.
Cutting
Machining
Abrading
Injection Molding
Thermoforming
Laminating
Raw Material to Final Product
A material such as plastic, glass or metal is heated, and then injected under pressure into a mold where it is left to cool and harden.
Advantages
Quick meaning high volumes possible
Can be seamless, unlike fusion.
Disadvantages
Molds are very expensive, as are the injection machines.
Also research Blow, Rotational and Compression
A plastic sheet is heated until it is able to be reshaped, and then is pulled over a mold or form to create a model.
Advantages
Quick
Disadvantages
Complex forms with internal cavities are not possible.
Multiple thin, flexible veneer sheets of wood, plastic, or metal are layered together in the desired form using a glue to bond them together.
Advantages
Strong when layers dry
Can be cheaper than using bigger, thicker pieces of wood.
Disadvantages
Complex jigs needed
Cutting can be done manually with hand tools, or by CNC machines such as laser cutters. A wide range of materials can be used.
Advantages
Speed for CNC such as laser.
Disadvantages
Waste material produced
A tool that moves across the surface (often metal), removing parts of it to create a form.
Advantages
High accuracy.
Safe because no direct human contact.
Disadvantages
Expensive machinery.
Waste created
Abrading - Removal of various materials by abrasives (eg. sandpaper, turning, drilling).
Turning - Removal of various materials as they spin.
Advantages
Speed.
Disadvantages
Waste material.
Dangerous if not CNC. Waste created.
4.4
Manufacturing Processes
Raw Material to Final Product
Casting
Knitting
Extrusion
Metal is heated into a melted state, and then poured into a mold and left to cool.
Materials - Metals, Alloys
Advantages
Alloys can be created
Disadvantages
N/A
Long needles are used to weave wool or other thick yarns into a fabric. By hand or machine.
Advantages
Quick if CNC
Disadvantages
N/A
Pushing a material through a DIE to create a long pipe form.
Advantages
Uniform shape
Can have a hollow cross section.
Disadvantages
N/A
Fastening
Adhering
Fusing
Joining techniques: Methods that are used to join two similar or dissimilar materials together.
Shaping techniques: Manufacturing methods for modifying the shape of a material.
Use of permanent fasteners such as nails or rivets, or temporary fasteners such as bolts.
Advantages
Can be disassembled
Disadvantages
Can become loose
Use of adhesives such as glues to fasten parts of a product together.
Materials - Various
Advantages
Can be discreet and hard to see.
Reduced number of required components.
Disadvantages
Hard to disassemble after use
The heating of two surfaces, which are then placed together and allowed to cool, joining them.
Materials - Metals, Plastics
Advantages
Very strong joins
Disadvantages
Can have visible seam.
Choosing a production method
When choosing your manufacturing method, consider the following:
Material Characteristics (for example melting point)
Cost
Desired properties of the product
Scale of Production
4.4
Manufacturing Processes
LINKS
TBA
Q: Lets look around and find examples here...
Raw Material to Final Product
4.5
Production Systems
Production Systems
“As a business grows in size and produces more units of output, then it will aim to experience falling average costs of production—economies of scale. The business is becoming more efficient in its use of inputs to produce a given level of output. Designers should incorporate internal and external economies of scale when considering different production methods and systems for manufacture. ”.
4.5
Q: Let’s go shopping on Etsy...
Production can roughly be divided into these three categories.
1.Craft production (suits one off)
Craft production is a small-scale production process centred on manual skills
ADVANTAGES- Products can be made to order. Can be unique.
DISADVANTAGES- Slow rate of production. Higher cost per product.
IMPACT- Once the main method of production, pre industrial revolution,
2.Mechanized production (suits batch and M.C.)
Mechanized production is a volume production process involving machines controlled by humans. This method allows for Mass production - the production of large amounts of standardized products on production lines, permitting very high rates of production per worker. One particular method is Assembly line production. This is a volume production process where products and components are moved continuously along a conveyor. As the product goes from one workstation to another, components are added until the final product is assembled.
ADVANTAGES- Quicker than craft. Enables products to be sold cheaper.
DISADVANTAGES- Expensive machines. Human error. Humans need breaks.
IMPACT- Greatly impacted the way workers lived and worked.
Raw Material to Final Product
4.5
Production Systems
3. Automated production (suits continuous flow)
Automated production is a volume production process involving machines controlled by computers. Humans are mostly moved out of the process.
ADVANTAGES- Human error minimised. Faster than humans. 24 hour run.
DISADVANTAGES- Complex and expensive machinery. Complex control.
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Computer numerical control (CNC)
It was once the case that parts would be manually created by workers, but in many cases this has been replaced by CNC. Computer numerical control refers to the computer control of machines for the purpose of manufacturing complex parts in metals and other materials. Machines are controlled by a programme commonly called a “G code”. The codes control X, Y and Z movement and feed speeds.
ADVANTAGES- More accurate than human tooled.
DISADVANTAGES- Expensive machinery.
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We touched on this in the previous section. Mass customization is a sophisticated CIM (computer integrated manufacture) system that manufactures products to individual customer orders. The benefits of economy of scale are gained whether the order is for a single item or thousands
.
ADVANTAGES- Fast, cheap production, still allowing for unique products
DISADVANTAGES- A little slower than if products were identical.
Q: Choose your favourite food. Is it being automated?
Raw Material to Final Product
4.5
Production Systems
LINKS
TBA
Q: Using the criteria above, what method of production would suit the making of plastic BB’s
Design for manufacture (DfM)
Design for manufacture (DfM) means designers design specifically for optimum use of existing manufacturing capability. There are four aspects of DfM.
Design for materials: designing in a way that suits the materials. For example, if you know that using a certain type of material is quicker to process, you might work that into the design.
Design for process: designing to enable the product to be manufactured using a specific manufacturing process, for example, injection moulding
Design for assembly: designing taking account of assembly at various levels, for example, component to component, components into sub-assemblies and sub-assemblies into complete products
Design for disassembly: designing a product so that when it becomes obsolete it can easily and economically be taken apart, the components reused or repaired, and the materials repurposed or recycled
Production system selection criteria
Production system selection criteria include time, labour, skills and training, health and safety, cost, type of product, maintenance, impact on the environment and quality management.
Raw Material to Final Product
4.6
Robots in Automated Production
Featured Designer
Robots in Automated Production
“Designers should consider the benefits of increased efficiency and consistency when using robots in production and be able to explore the latest advances in technology to ensure the optimum manufacturing process is used. However, a good designer will also understand their responsibility to consider the moral and ethical issues surrounding increased use of automation, and the historical impact of lost jobs.”.
4.6
Q:How could m2m be used in a factory making sneakers?
Did you know that robot means “Serf labor” in Czech. Time to look at how robots are used in the overthrowing of their meatbag masters creation of products. Before we get into the details, let's look at some key terms.
Single and Multi-Task robots.
Single task- Purpose built with a single job in mind, such as screwing in bolts. Less versatile, but less can go wrong and they do one job well.
Multi-task- You guessed it! These robots are designed to be able to handle a wide range of tasks. More versatile, and more complex + expensive.
Work Envelope
This refers to the 3D space a robot can operate within, considering clearance and reach. When they turn on us, remember to stay out of the work envelope.
Load Capacity
This refers to the maximum weight a robot can manipulate. A robot designed to fit car doors will need a higher work capacity than one designed to carry humans to be processed fit phone screens.
Machine to machine refers to wired and wireless communication between similar devices. Eg. a central processing robot, linking up and communicating with multiple vision sensors scanning things on the line.
Raw Material to Final Product
4.6
Robots in Automated Production
Robot Generations
Robots are quickly evolving. What follows is a rough breakdown of the generations that robot development has taken so far.
First-generation robots
The Granddaddies- First-generation robots are
Second-generation robots
The Daddies - Second-generation robots are
The young whippersnappers. Third-generation robots are:
Q: Go on youtube robot safari. Try and find an example for each.
Raw Material to Final Product
4.6
Robots in Automated Production
LINKS
TBA
Q: ---
Advantages and disadvantages of using robots in automated production
Let's look at the pros and cons of using robots in production.
Raw Material to Final Product
ADVANTAGES | DISADVANTAGES |
Reduction of human error. Potential quicker production. Removes people from more dangerous tasks. Improved quality Create less waste due to less error | Potential for job losses, especially low skilled. Massive upfront cost in buying the machinery and installing |
4
GLOSSARY
TOPIC 4 GLOSSARY
TERM | DEFINITION |
Absorbed moisture | The moisture within timber that is contained in the cells walls. |
Additive techniques | Manufacturing techniques that add material in order to create it. |
Aesthetic appeal | Favourable in terms of appearance. |
Aesthetic characteristics | Aspects of a product that relate to taste, texture, smell and appearance. |
Air-drying | Air- drying places the stacks of sawn timber in the open or in large sheds hence there is little control over the drying process. |
Alloy | A mixture that contains at least one metal. This can be a mixture of metals or a mixture of metals and non-metals. |
Assembly line production | A volume production process where products and components are moved continuously along a conveyor. As the product goes from one work station to another, components are added until the final product is assembled. |
Automated production | A volume production process involving machines controlled by computers |
Batch production | Limited volume production (a set number of items to be produced). |
Bio-compatibility | The product ensures the continued health of a biological environment. |
Bowing | A warp along the length of the face of the wood. |
Brittle | Breaks into numerous sharp shards. |
Chemically inert | Lack of reactivity with other materials. |
Composite | A material comprised of two or more constituent materials that have different properties. |
Compressive strength | The ability of a material to withstand being pushed or squashed. |
Computer numerical control (CNC) | Refers specifically to the computer control of machines for the purpose of manufacturing complex parts in metals and other materials. Machines are controlled by a program commonly called a “G code”. Each code is assigned to a particular operation or process. The codes control X, Y, Z movements and feed speeds. |
TOPIC 4 GLOSSARY
TERM | DEFINITION |
Continuous flow | A production method used to manufacture, produce or process materials without interruption. |
Craft production | A small-scale production process centred on manual skills. |
Creep | The slow, permanent deformation of a solid material under the influence of a mechanical stress. |
Creosote | A material that penetrates the timber fibres protecting the integrity of the wood from attack from borer, wood lice and fungal attack. |
Cupping | A warp across the width of the face of wood, in which the edges are higher or lower than the centre. |
Density | The mass per unit volume of a material. Its importance is in portability in terms of a product’s weight and size. Design contexts include, pre-packaged food (instant noodles) is sold by weight and volume, packaging foams. |
Design for assembly | Designing taking account of assembly at various levels, for example, component to component, components into sub-assemblies and subassemblies into complete products. |
Design for disassembly | Designing a product so that when it becomes obsolete it can easily and economically be taken apart, the components reused or repaired, and the materials recycled |
Design for manufacture | Designers design specifically for optimum use of existing manufacturing capability. |
Design for materials | Designing in relation to materials during processing. |
Design for process | Designing to enable the product to be manufactured using a specific manufacturing process, for example, injection moulding. |
Dry rot | When timber is subject to decay and attack by fungus. |
Ductility | The ability of a material to be drawn or extruded into a wire or other extended shape. |
Elasticity | The extent to which a material will return to its original shape after being deformed. |
Electrical insulator | Reduces transmission of electric charge. |
Electrical resistivity | The measure of a material's ability to conduct electricity. A material with low resistivity will conduct electricity well. |
Electro-rheostatic | This smart property relates to a fluid that can undergo a dramatic change in its viscosity when exposed to an electric field. |
TOPIC 4 GLOSSARY
TERM | DEFINITION |
Equilibrium Moisture Content (EMC) | EMC is at which the moisture content of wood achieves an equilibrium with the environment which can be affected by humidity and temperature. |
Felting | A method for converting yarn into fabric by matting the fibres together. |
First generation robots | A simple mechanical arm that has the ability to make precise motions at high speed. They need constant supervision by a human operator. |
Free moisture | The moisture within timber that is contained within the cell cavities and intercellular spaces. |
Glass | A hard, brittle and typically transparent amorphous solid made by rapidly cooling a fusion of sand, soda and lime. |
Grain size (metals) | Metals are crystalline structures comprised of individual grains. The grain size can vary and be determined by heat treatment, particularly how quickly a metal is cooled. Quick cooling results in small grains, slow cooling results in large grains. Grain size in metals can affect the density, tensile strength and flexibility. |
Hardness | The resistance a material offers to penetration or scratching. |
Hardwood | The wood from a deciduous (broadleaved) tree. |
Joining techniques | Methods that are used to join two similar or dissimilar materials together. |
Kiln drying | Kiln-drying places the stacks of sawn timber in a kiln, to reduce the moisture content in wood, where the heat, air circulation, and humidity is closely controlled. |
Kiln seasoning | Thermally insulated chamber, a type of oven, which produces temperatures sufficient to complete some process, such as hardening, drying, or chemical changes. |
Knitting | A method for converting a yarn into fabric by creating consecutive rows of interlocking loops of yarn. |
Knots | Imperfections in timber, caused by the growth of branches in the tree that reduces its strength. |
Lacemaking | A method for creating a decorative fabric that is woven into symmetrical patterns and figures. |
Laminated boards | Sheets of material made from layers of veneers (e.g. plywood). |
Laminated object manufacture (LOM) | A rapid prototyping systems that creates a 3D product by converting it into slices, cutting the slices out and joining the slices together. |
Lamination | Covering the surface of a material with a thin sheet of another material typically for protection, preservation or aesthetic reasons. |
TOPIC 4 GLOSSARY
TERM | DEFINITION |
Load capacity (Robots) | The weight a robot can manipulate. |
Machine to machine (M2M) | Wired and wireless communication between similar devices. |
Magneto-rheostatic | This smart property relates to a fluid that can undergo a dramatic change in its viscosity when exposed to a magnetic field. |
Man-made timber | Also known as engineered wood or composite wood, these are wood products that are made by binding or fixing strands, particles of fibres, veneers of boards of wood together with adhesives or other fixing methods to create composite materials. Typical examples include MDF, plywood and chipboard. |
Mass | Relates to the amount of matter that is contained with a specific material. It is often confused with weight understandably as we use Kg to measure it. Mass is a constant whereas weight may vary depending upon where it is being measured. |
Mass customization | A sophisticated CIM system that manufactures products to individual customer orders. The benefits of economy of scale are gained whether the order is for a single item or for thousands. |
Mass production | The production of large amounts of standardized products on production lines, permitting very high rates of production per worker. |
Material selection charts | A chart used to identify appropriate materials based on the desired properties. |
Mechanical properties | Properties of a material that involve the relationship between stress and strain or a reaction to an applied force. |
Mechanized production | A volume production process involving machines controlled by humans. |
Multi task robots | A type of robot that can perform more than one task in a manufacturing environment. |
Natural fibres | Materials produced by plants or animals that can be spun into a thread, rope or filament. |
Non-toxic | Absence of toxic breakdown products/lack of reactivity. |
One-off production | An individual (often craft-produced) article or a prototype for larger-scale production. |
Oxidization resistance | A property of a metal that means that it does not readily react with oxygen and degrade. |
Paper-based rapid prototyping | Often the first step in a rapid prototyping process, paper prototyping is widely used in UCD for designing and testing interfaces. |
Particle boards | A material made from different sizes of wood chips and joined with glue. |
TOPIC 4 GLOSSARY
TERM | DEFINITION |
Photochromicity | A property of a smart material. A photochromic material changes colour in response to an increase in light. When the light source is removed, it returns to its original colour. |
Physical properties | Any property that is measurable that describes a state of materials, for example, mass, weight, volume and density. These properties tend to be the characteristic of materials that can be identified through non-destructive testing (although some deformation is required to test hardness). |
Piezoelectricity | A property of a smart material. A piezoelectric material gives off a small electrical discharge when deformed. |
Plasticity | The ability of a material to be changed in shape permanently. |
Pultrusion | A continuous manufacturing process used to create composite materials that have a constant cross-section. Reinforcing fibres are saturated with a liquid polymer resin and then pulled through a heated die to form a part. |
Reforestation | Reforestation is the process of restoring tree cover to areas where woodlands or forest once existed. If this area never returns to its original state of vegetative cover the destructive process is called deforestation. |
Seasoning | Seasoning is the commercial drying of timber which reduces the moisture content of wood. |
Second generation robots | Robots that are equipped with sensors that can provide information about their surroundings. They can synchronize with each other and do not require constant supervision by a human; however, they are controlled by an external control unit. |
Shape memory alloys | Shape memory alloys are metals that when deformed, can spring back into its original shape once released. |
Shaping techniques | Manufacturing methods for modifying the shape of a material. |
Single task robots | Robots that can perform one task only. |
Smart material | Materials that have been designed to have one or more properties that can be modified when subject to an external stimuli in a way that the output can be controlled. |
Softwood | The wood from a coniferous (evergreen) tree. |
Stiffness | The resistance of an elastic body to deflection by an applied force. |
Strain | The response of a material due to stress, defined as the change in length divided by the original length. |
Stress | A force on a material divided by the cross-sectional area of that material. |
Super alloys | An alloy that exhibits excellent mechanical strength, resistance to thermal creep deformation, good surface stability and resistance to corrosion. |
TOPIC 4 GLOSSARY
TERM | DEFINITION |
Synthetic fibres | Fibres made from a man-made material that are spun into a thread; the joining of monomers into polymers by the process of polymerisation. Examples include polyester, acrylic, nylon, rayon, acetate, spandex, and Kevlar. |
Tempering | A heat treating process designed to increase the toughness of an iron-based metal by heating it and allowing it to cool in air. Tempering decreases the hardness of the material, which usually increases the ductility and decreases the brittleness. |
Tensile strength | The ability of a material to withstand pulling forces. |
Thermal conductivity | The measure of how fast heat is conducted through a slab of material with a given temperature difference across the slab. |
Thermal expansion | A measure of the degree of increase in dimensions when an object is heated. This can be measured by an increase in length, area or volume. The expansivity can be measured as the fractional increase in dimension per kelvin increase in temperature. |
Thermo-electricity | This refers to a smart material that when heated can produce an electric current. A thermoelectric material is comprised of two dissimilar conductors. |
Thermoplastic | A type of plastic that can be heated and formed into a new shape repeatedly. |
Thermosetting plastic | A type of plastic that once formed into a shape, cannot be reformed into a different shape. |
Third generation robots | Autonomous robots that can operate largely without supervision from a human. They have their own central control unit. Swarms of smaller autonomous robots also fit in this category. |
Toughness | The ability of a material to resist the propagation of cracks. |
Transparency | Ability to allow light to be transmitted with minimal scattering allowing a clear view through material. |
Twisting | A distortion in which the two ends of a material do not lie on the same plane. |
Volume | The quantity of three-dimensional space enclosed by a boundary, for example, the space that a substance solid, liquid, gas, or shape occupies or contains. |
Warping | A distortion in wood caused by uneven drying, which results in the material bending or twisting. |
Wasting/subtractive techniques | Manufacturing techniques that cut away material in order to create a component. |
Weaving | The act of forming a sheet like material by interlacing long threads passing in one direction with others at a right angle to them. |
Weight | Relies on mass and gravitational forces to provide measurable value. Weight is technically measure as a force, which is the Newton, i.e. a mass of 1 Kg is equivalent to 9.8 Newton [on earth]. |
TOPIC 4 GLOSSARY
TERM | DEFINITION |
Wood recycling | Wood recycling is the process of turning waste timber into usable products. Recycling timber is a practice that was popularized in the early 1990s as issues such as deforestation and climate change prompted both timber suppliers and consumers to turn to a more sustainable timber source. |
Wood treatment | Treatment of wood can involve using solutions, which make the wood poisonous to insects, fungus, and marine borers as well as protecting it from the weather. |
Work envelope | A fixed 3D space where work activities take place, considering clearance and reach. |
Work hardening | Also known as strain hardening or cold working, this is the process of toughening a metal through plastic deformation. |
Yarn | A long continuous length of interlocked synthetic or natural fibres. |
Young's Modulus | A measure of the stiffness of an elastic material and defined by stress/strain. |