1. BTEC First Engineering
Learning aim A Know about engineering processes used to produce modern engineered products

2. Aerospace
Automotive
Communications
Electrical/Electronic
Mechanical
Biomedical
Chemical

3. Learning objectives: -
Bigger picture: -
Know about engineering processes used to produce modern engineered products
Learning objectives: -
Be able to explain what is meant by the term fabrication
Describe a range of different fabrication processes used within engineering
Be able to explain the manufacture of PCB and surface mount technology
Success criteria: -
Provide a description of different fabrication techniques
Correctly identify different fabrication techniques
Correctly describe the manufacturing process of PCB
Literacy key words: PCB etching, surface mount technology

4. Engineering processes
BTEC First Engineering
Processes can be divided into groups, which are linked by the features of the processes.
Machining
Forming
Fabrication
Electrical/ electronic
Teacher notes (PS 3):
Items such as car lock nuts could be turned, while milling is used to get a smooth finish to a casting.
Casting is used for things such as making car engine blocks; forging is used for products such as spanners and crankshafts.
Welding is used to join sheet steel, such as in a structure, or for making products such as skips.
PCB manufacturing and surface mounting can be associated with almost all electronic products.
Casting
Forging
PCB manufacture
Surface mount
Turning
Milling
Drilling
Welding
Shearing
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5. Divide the various joining techniques into permanent and non permanent
Rivets
Adhesive
Solder
Bolt
Screws
Threads
Welding
Nails
Pressed joints
Permanent
Non permanent

6. Divide the various joining techniques into permanent and non permanent
Rivets
Threads
Bolt
Solder
Adhesive
Nails
Screws
Welding
Pressed joints

7. Fabrication processes:
Engineered products/parts need to be joined up in some way. Sometimes the solution is as simple as a nut, bolt and washer, but on other occasions a more permanent method is required.
Assembling is done by welding, binding with adhesives, riveting and threaded fasteners

8. Welding . . .
One of the most efficient methods of permanently joining two pieces of metal together.
It can be done in many different ways but most methods use intense heat to fuse the metal together.
A number of energy sources – a gas or electric, laser or ultra sound – can be used.

9. Homework – due 4th February 2014
Welding process
Description
Advantages
MIG welding
 common industrial welding process. It uses electricity to generate the heat required to weld materials.
MIG stands for metal inert gas.
 Suitable for large scale production
 Varying thickness of materials can be joined
 Reduced cost due to no further cleaning required
Oxy-acetylene
 A gas welding process where a flame is produced using a mixture of oxygen and acetylene.
No pressure on the product is required – the heat is there to control the welding of parts.
 Ease of controlling the low and high temperatures needed for welding, brazing and soldering
 Relatively inexpensive in comparison with other welding processes and commonly found in school workshops  
Spot welding
 A type of electrical resistance welding generally used to join sheet material together. The basic principle uses a transformer with a primary winding and a secondary winding connected to copper electrodes..
When the two electrodes trap the sheet material they generate enough heat to fuse the two together.
 The process is free from fumes or spatter
 Requires little or no maintenance
 Cost effective

10. Surface mount
Surface-mount technology (SMT) is a method for producing electronic circuits in which the components are mounted or placed directly onto the surface of printed circuit boards (PCBs). An electronic device so made is called a surface-mount device (SMD).
In the industry it has largely replaced the through-hole technology construction method of fitting components with wire leads into holes in the circuit board. Both technologies can be used on the same board for components not suited to surface mounting such as large transformers and heat-sinked power semiconductors.

11. Printed circuit board
Electronic circuits in schools and industry are normally manufactured through the use of PCBs (Printed Circuit Boards). The boards are made from glass reinforced plastic with copper tracks in the place of wires
Components are fixed in position by drilling holes through the board, locating the components and then soldering them in place. The copper tracks link the components together forming a circuit.

12. Process of manufacturing a PCB and SMT
Printed circuit board (PCB) manufacture
The Surface Mount Technology (SMT) process 1. 1. 2. 2. 3. 3. 4. 4. 5. 5. 6.

13. Process of manufacturing a PCB and SMT
Printed circuit board (PCB) manufacture
The Surface Mount Technology (SMT) process
Components are soldered to the surface of the board
Producing the artwork
The finished board is then inspected for imperfections
Designing the layout
Conveyor belts are used to transport the boards to the reflow soldering oven
PCB etching
Populating the board and soldering
The board is heated to a temperature that melts the solder plate
Drilling the board
Place components using pick and place robot
Apply solder paste to copper pads