Transcript pn4035-presentation

Design 1
Properties of Aluminium/Brass
◦ Soft ductile material.
◦ Corrosion resistant.
◦ High electrical conductivity.
◦ High strengths.
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High strength,
Good machinability,
Ductile material,
High wear-resistance/ hardness
Corrosion resistance.
The Production of Aluminium
The Production of Brass
Health and Safety
Classroom rules provided.
Demonstrations with in the classroom.
Work Matrix.
Group work.
Posters.
Mechanisms
• A Mechanism is an assembly of
moving parts performing a
complete functional motion.
Types of Motion (Mechanisms)
Common Mechansims
• Bevel Gears: Speed up
rotation depending on the
number of teeth.
• Worm and Wormwheel: Huge
reductions in speed.
Cam and
Follower
Rack and Pinion
(Linear)
Belts and
Pulleys
Economic Costings of Project
• Boundaries in place for them amount of cost put into a project. (Design Brief)
 The brief will indicate what materials can be used.
 These materials should be readily available in the workshop.
 The brief will also indicate the size of the project which will in turn limit the amount of
material used.
 This will also limit waste material.
• Students will finalise designs of project.
 This way material can be ordered without over ordering etc.
 Recycled motors and gears can be used over and over again.
ELECTRONICS.
This is where the power source for the mechanism will
come from.
• Transfer of Energy
Transfer of electric energy to mechanical energy.
As the mechanism needs to function in both forwards
and backwards motion, it must have a double pole,
double throw switch (DPDT).
Simple circuit soldered together. Possible components:
- Battery
- Motor
- Variable resistor
- Switch
- Fly Wires
All components of the circuit will be available to
students within the classrooms.
• Double Pole, Double Throw
Switch
Mechanical Design
Requirements:
Design Considerations:
Project must be able to transfer a given load
to a certain distance and back to its starting
point within the time constraints.
- Strength
Project should not exceed maximum
dimensions and should work efficiently and
correctly.
- Friction
- Reliability
- Wear
- Cost
- Safety
- Weight
- Size
- Control
Mechanical Design
Possible Motions:
Worm wheel
Bevel Gear
Turning at a right
angle.
Rack and Pinon
Gear Train
Turning rotary
motion into
Linear Motion
Design Ideas
• Object/ Load does not have to move in a
linear distance.
A B
A
B
Manufacturing Processes
BENCHWORK
 Marking
out using, vee blocks, scribing block
and height gauge.
Selection of suitable speeds, feeds and
coolants.
Fitting and assembly of parts using pins,
dowels, rivets, screws, bolts, nuts and
adhesives.
PLASTICS PROCESSING
Application of practical safety methods in the
working of plastics.
Cutting, bending, edge finishing and bonding of
acrylic sheet.
Sintering and casting of polyethylene; resin casting;
simple mould making.
The machining of plastics drilling, turning, milling (or
shaping).
FABRICATION AND FINISHING OF METALS
Application of practical safety methods in the use of materials and equipment.
Joining of materials by means of solder and adhesives. Construction, use and care
of gas welding equipment: cylinders, regulators, gauges and blowpipes.
Basic techniques involved in the brazing and welding of mild steel. Construction,
use and care of transformer type arc welding set; selection of electrode and
welding current.
Downhand butt welding of mild steel. Gravity die casting and sand casting of
aluminium.
Making of simple dies and sand moulds.
MACHINING
 Application of practical safety methods in the operation of machine tools and
accessories.
 Use of the centre lathe and the shaping machine and/or the milling machine.
Selection, care and use of cutting tools. Correct methods of holding the tools and
of gripping the work.
Selection of speeds, feeds and coolants.
Use of automatic feeds, machine dials and precision measuring equipment.
Parallel turning, knurling and drilling in the lathe. Taper turning including use of
topslide and off-set tailstock.
Parameters of Project, Physical size,
Time Allocation, Within Skill Set of
Students
Physical Size
Influenced by the distance (y) which is the distance the load has to be transported.
The artefact should be as compact as possible whilst achieving the brief.
Rough estimate for size is 300mmx150mm.
Time Allocation
Practical project is worth 25% of the total leaving cert marks.
As a result we ill allocate 25%min of senior cycle time to the project.
http://www.rte.ie/exams/Others/engineering.pdf
Skill Set of Students
For this particular brief we are to assume that all pupils are all of equal competent skill set.