Classifying Making Processes

Four ways to make a shape

Every making process does one of four things to a material. It cuts some away, it joins more on, it bends a solid piece into a new shape, or it melts the material and sets it again. Examiners love to name a process and ask which of these four families it belongs to. This module teaches the four families and how to sort any process into the right one.

The four families

Every making process fits one of these four families, and each one does something different to the material. Learn what each word means before you try to sort any process, because the exam question almost always names a process and asks you which family it belongs to.

Deforming against reforming

These two families are the ones learners mix up most, because both change the shape of the material without cutting any away. The difference is the state of the material while it is being shaped, so read the next two columns carefully and remember which one melts.

How to classify any process

Ask four questions in order. Is material being cut away? Then it is one family. Is material being joined or built up? Then it is another. If nothing is added or removed, ask one more thing. Does the material stay solid while it is bent or pressed, or is it melted to a liquid first and then set? Solid means one family, melted means the last. Work through the questions and any named process lands in the right place.

Match the family to what it does

Which family is injection moulding?

Plastic granules are melted to a liquid, pushed into a mould and left to set. Which family is this?

• Reforming, because the material is melted then set.
• Deforming, because the shape changes.
• Wastage, because plastic is used up.
• Addition, because plastic is added to the mould.

Pick the wastage processes

Select the TWO processes that remove material by cutting it away.

• Drilling a hole
• Sawing a board to length
• Welding two plates together
• Bending a metal bar

How much is left after cutting

A bar starts 50 mm long. A wastage process cuts 12 mm away. Subtract to find the finished length in mm. What is the answer?

Order the classifying questions

Put the four questions in the order you should ask them to classify a process.

• Is material being cut away?
• Is material being joined or built up?
• If not, does the material stay solid as it is shaped?
• Or is it melted to a liquid then set?

Complete the rules

A process that cuts material away belongs to the _____ family. Welding and gluing join material, so they are _____. Bending a solid bar into a curve is _____ because nothing is added or removed. Casting melts the material and sets it in a mould, so it is _____.

Match the named process

Spot the addition processes

Tap the TWO processes that join or build up material.

• welding
• gluing
• sawing
• bending

Classify the process

Read each process and choose its family.

• A worker heats a plastic sheet until it is soft, then pulls it down over a mould so it takes the shape. The plastic never becomes a liquid. Which family is this?
• A part is made by melting metal to a liquid and pouring it into a mould to set. Which family is this?
• A frame is made by cutting slots into a sheet with a milling machine. Which family is this?

Explain the four families

Explain the four families of making process and how you would sort a named process into the right one.

• Name the four families and say what each one does
• Give one named process for each family
• Explain how you tell deforming apart from reforming