Quality Control

Question 1

Quality control checks the quality of manufacturing

Answer 1

Quality control checks that all products are made to a high enough standard, and are made at every stage of manufacturing.
This involves testing materials, components and products to check if they fit the specifications eg cut accuracey
It would take too much time to check all the products, so a sample of them are tested

Question 2

Tolerance is the requires accuracy of a measurment

Answer 2

Its important dimensions are correctso the product can be assembled
Tolerance is the margin of acceptable error
Tolerance is given as an + upper or - lower value, similar to bounds in maths
Shown on engineering drawings
Products must pass these tests in order to fulfil quality control

Question 3

Go/No go tests

Answer 3

Limit gauges check to see whether a component fits its tolerance
has 2 ends one for upper limits, one for lower
These checks are quicker than measuring every product individually.
Often used in timber

Question 3

Go/No go tests

Answer 3

Limit guages check to see whether a component fits its tolerance
has 2 ends one for upper limits, one for lower
These checks are quicker than measuring every product individually.
Often used in timber

Question 4

Registration marks

Answer 4

Colour registration marks are used to check the quality of printing onto paper or board
Used to make sure the printing plates are in the right places

Question 5

Prints are checked against the original

Answer 5

Can be done well by eye, these checks are to make sure that dyes are printed correctly on fabrics.
Quicker than measuring the size and shape of stripes or chequers

Question 6

Depth Stops

Answer 6

Depth stops are rods that make the drill cut exact depth holes, the rod comes into contact with the material preventing the drill going in any furthur.
This also allows you to control the width and the other dimensions of the holes

Question 7

Laser cutters

Answer 7

They need to be programmed in order to function correctly.
Power settings need to be inputted carefully in order to make sure the material is cut, not burned
If done well, it can have a low tolerance, and high precision.
Samples need to be checked to make sure the machine is working properly

Question 8

PCBs need to be made with the same exposure times

Answer 8

Printed circuit boards are made by photo etching.
Leave the board in solution for too long and risk removing the copper tracks, but too little time and you leave excess copper on the board.
Once chosen, the exposure time should be kept the same.