Engineering - Exam Mistakes Flashcards
What is a screw tap?
A tool used to cut an internal thread into a hole
What is a vernier?
A tool that can measure distances to high accuracy and sometimes have an electronic display
What are the 3 hazards of using a centre lathe and how are these controlled?
Chuck key flying from chuck (take the chuck key out of the chuck before you turn on the machine)
Loose clothing / hair (tie back long hair, remove dangerous clothing)
Debris flying out away from the work piece (wear safety goggles to protect eyes and put lathe safety guard in place before activating machine)
How do you draw straight line and diameter dimensions?
For straight dimension, lines coming down from the edges of the dimension, solid arrow heads and actual number between arrow and part
For diameter, diagonal line and solid arrow pointing to circle, the line becomes horizontal and the measurement is written at the end with a circle with a line through it in front of it (diameter symbol)
Describe how you make a pattern
You need the coping and tenon saws, marking and measuring equipment and glass paper
You mark out the correct shape out of a prototype material, cut it to size and finish it to leave smooth edges
What equipment do you need to cast?
Cope / drag, split pattern, runner / riser, sprue and crucible
How do you machine a casted part to the correct size and tolerances?
You need the vertical milling machine, cutting tool and vice
You place the part into the vice ensuring the correct level and remove excess material
What equipment do you need to make holes in a part?
You need to centre punch, pillar drill, the correct sized drill bit and the vice
What are the 3 reasons that steel is hardened?
Increases wear resistance
Greater durability
Increases usefulness for more more applications that need harder materials
What are the 3 disadvantages of hardening steel?
Material becomes more brittle
Labour intensive
Harder to shape or form
Describe the process of case hardening low carbon steel
Material is heated using a gas torch
Material becomes red in colour
Material is introduced to carbon rich environment
Material is reheated
Above steps are done until material is as hard as it needs to be
Material is rapidly cooled
How do you answer a 6 mark question in engineering?
3 points explained
Good English
What 5 things does a designer always need to know about a product that they are going to make?
Does it need to be particularly light or strong
Dimensions
Target user
Price range
Scenarios that it will be used in
Describe de-burring
Uses a grinder
Area to be made smooth is pressed against the grinder
Angle grinders can be used for getting rid of sharp or rough edges
Describe de-scaling
A file, emery cloth and polishing wheel is used to take off the layer of oxide formed by hearing and to give the surface a shiny finish
Describe tempering
Uses a controllable heat source to heat the object to a specific temperature for a while before quenching it
This allows some excess hardness to be removed so the material becomes more tough and less brittle
What are the 3 main techniques of applying artwork to a surface?
Stencils and spray paint
Laser engraving
Air brush spray painting
In what 4 ways has modern technology helped the development of electronic equipment?
Size of electronic equipment reduced because of microchips containing info and tiny circuit components
Use of ICT to test electronic circuits (don’t need to make prototype circuits)
Use of CAD to design circuits reduces the amount of prototypes that need to be made saving time and money
Cost reduction because more companies make circuit things and we have cheaper ways of making them
Describe how you would finish a metal surface
Take off the top layer of a surface using the vertical milling machine
You need a milling machine, vice, cutting tool
Hold part in the vice with the surface to be finished held completely horizontal in all directions
Lower the cutting tool so that it is just below the surface and then slowly move it across the surface until the whole surface is finished
How do write specification points for 2 marks?
Actually state what is needed
E.g. for the number of bikes to be held by the bike rack the specification point would be:
“The bike rack needs to be adjustable so that it can hold between 1 and 3 bikes at a time”
Describe how you do a sectional view
The line (A - A) represents where you cut the object in half
Draw lines across / down to make sure the sectional view is to scale
Imagine you have the cut the object in half and are looking at the cut face of one of the halves. The parts that the “knife” has touched when cutting it are drawn on the sectional view as cross-hatched and for the parts the knife has not touched, only the outline is drawn
A ruler is used to make sure all measurements are correct
YOU HAVE TO WRITE SECTION A-A UNDERNEATH YOUR SECTIONAL VIEW
What are the 4 advantages of CAD?
More accurate
Less human error
Save files to edit
Sent electronically
What are the 3 disadvantages of CAD?
High initial costs
Needs training
Needs a computer
What are the 4 advantages of CNC?
Used 24 hours a day
Accurate
Same component can be created over and over
Faster than making be hand
What are the 3 disadvantages of CNC?
Initial costs high
Less workers so job losses
Not learnt within schools as much
What are the 4 main smart materials?
Thermochromic ink that changes colour when exposed to hear
Heat shrinking materials that contract around wires when they are heated
Polymorph is a hard material that can be re shaped when placed in hot water
Smart wire that goes back to original shape when heated
In what type of production is injection moulding used in and why?
Mass production
High set up costs
How do motors work?
Current travels through copper wire
Positive and negative magnets pointing at wire cause a magnetic field
The current and magnetic field cause the wire to spin half a turn
Now the commutator reverses the current in the wire so that the wire can complete its rotation
The output is a rotary motion used to power a wheel or gears
What are gears used for?
Increasing speed and decreasing torque or vice versa
Or changing direction of spin
What is torque?
A measure of how much force acting on an object causes that object to rotate around an axis
3 benefits of using plastic gears
Always corrosion resistant
Cheaper and easier to manufacture
Lighter than metals
