TOOLS AND TECHNIQUES - CUTTING PLASTICS Flashcards
Most sheet plastic can be ‘cut’ by scoring and breaking but in schools this method is only really suitable for which materials?
Thin polystyrene and ABS materials up to 2mm thick.
Name the 2 methods of cutting plastics
- Scoring and breaking
2. Sawing with a machine
What must you wear when using the scoring and breaking method to cut plastic?
ALWAYS wear googles
Explain the method for scoring and breaking plastics - there are 4 points
- Mark out using a pencil or pen
- Score over the mark with a scoring tool with a hooked cutting edge - (old hacksaw blades can be ground to make this kind of tool)
- The groove cut out by the tool becomes a line of weakness along the material
- When the sheet is bent over the edge of a bench, the grove opens up into a crack
What do should you do if your cut is a long or curved one?
The sheet should first be bent at one end and this bending action moved along the score line so the crack follows it
How do you protect your work when using a metalworking vice rather than a bench hook?
Use two piece of wood or thick card to protect it from the vice jaws
How do you cut curved shapes on plastic?
Curved shapes can be cut using a coping saw which uses replaceable blades held in a frame.
How do you tighten a coping saw?
A coping saw can be tightened or tensioned by turning the handle of the saw and can be set at different angles. The teeth on a coping saw point backwards.
What is abrafile saw?
Similar to a coping saw but it’s thin blade has teeth all around its surface and so will cut in any direction the saw is directed.
Work to be cut using an abrafile or coping saw should be held how?
Upright in a woodworking vice and the saw cut must be close to the vice jaws.
When using an abrafile or coping saw why must you cut as close to the vice jaws as possible?
To avoid vibration and prevent the brittle plastic from breaking.
What is a vibrosaw?
A machine where the blade is moved up and down by the machine about 50 times per second.
It doesn’t move very far and will tend to get blunt in one place.
How is the blade different in a vibrosaw when compared with the blade of a coping saw?
They are both replaceable blades but the vibrosaw blade is much finer.
What should you remember when using a vibrosaw? (7 points)
- Do NOT put your fingers near the moving blade
- Wear goggles
- Do NOT push your work too hard against the blade
- DO press your work firmly on to the table at all times otherwise it will simply stick on to the blade and vibrate up and down with it
- Do NOT turn your work too quickly around curves
- Do NOT cut too fast, otherwise the cut will weld together behind the blade
- NEVER USE A MACHINE WITHOUT PERMISSION OR SUPERVISION
