MYP Design Classifying Materials Notes

Six Families Cover Almost Everything in the Workshop

1. Materials in MYP design are sorted into six families: woods, metals, polymers, textiles, ceramics and composites.
2. Woods come from trees and keep a grain, a direction the fibres run in, which makes a stick of pine far stronger along its length than across it.
3. Metals are dug out of the ground as ore, conduct heat and electricity well, and can usually be bent into a new shape without snapping.
4. Polymers are long repeating chains of molecules, mostly made from crude oil, and tend to be light, waterproof and cheap to mould in large numbers.
5. Textiles start as thin fibres that are spun into yarn and then turned into a flexible sheet, so they drape over a shape rather than holding one.
6. Ceramics are clays and glasses fired at high temperature, giving a surface hard enough to scratch steel but a body that shatters if you drop it on tiles.
7. Composites lock two materials together so the pair does something neither manages alone, like glass fibre held in cured resin.

Natural or Manufactured: The Second Question in Every Family

1. Inside each family you split again by origin: natural materials are shaped from something that grew or was mined, manufactured ones are built up in a factory.
2. Oak planks are natural wood; MDF is manufactured, made from wood dust and resin pressed into a board.
3. Cotton and wool are natural fibres; polyester and nylon are manufactured from oil in a chemical plant.
4. The line is about how much a person controlled the structure, not about whether the material is good or bad for the planet.
5. Manufactured versions are usually more consistent: every sheet of 6 mm MDF behaves the same, while two oak planks from the same tree can warp differently.
   1. That consistency is why a school laser cutter has saved settings for MDF and acrylic but nothing for a random piece of driftwood.

Classification Predicts Behaviour Before You Cut Anything

1. Knowing the family gives you a first guess at how a material will behave, and a first guess is enough to reject most of the wrong options.
2. If a part must carry electricity, the metals family is the only place to look, because woods, polymers, textiles and ceramics are all insulators.
3. If a part will be dropped on a hard floor every day, you can rule out ceramics straight away, since hard but brittle is a bad combination for a phone case.
4. If a part must soften in a strip heater so you can bend it, you have narrowed the search to thermoplastics before opening a single price list.
5. Testing is still the check, but classification is how you get from two thousand candidates down to the three worth testing.

Family Gives You Rules of Thumb, Not Exact Answers

1. Each family carries a set of typical behaviours that hold for most members most of the time.
2. The rules break often enough to matter: balsa is a wood you can dent with a fingernail, and lead is a metal soft enough to mark with a coin.
3. Treat the family as a starting position you then check against real figures for the exact material you plan to buy.

Where the Families Blur, Designers Gain Options

1. Plywood is wood by origin and a composite by structure, because thin veneers are glued with their grain turned at right angles to each other.
2. Carbon fibre cloth is a textile until resin sets around it, at which point the part behaves like a stiff shell.
3. Reinforced concrete is a ceramic-like mix carrying steel bars inside it, so a bridge deck gets hardness from one part and pulling strength from the other.
4. An overlap is a design opportunity, because you borrow a property from a second family without giving up the first.

Classification Is Evidence, So Put It in the Folder

1. For Inquiring and analysing, research that names families and gives one reason each reads as far stronger than a list of copied product photos.
2. For Developing ideas, your specification should name a material precisely enough that a classmate could order it without asking you a question.
3. The family you pick also decides which workshop processes are open to you, since casting suits metals and vacuum forming suits thermoplastic sheet.
4. Sustainability sits in the same table, because family and origin between them tell you whether a material gets recycled, composted or buried.

Writing a Material Name a Supplier Could Actually Order

1. A usable name has three parts: the family member, the thickness or size, and the form it comes in.
2. Clear plastic becomes 3 mm clear cast acrylic sheet, and metal becomes 20 mm by 20 mm mild steel square tube with a 1.5 mm wall.
3. Adding the finish or grade where it matters, such as 18 mm birch plywood, removes the last guess from someone else building your design.