11 adv revision_notes_term_3
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3D printing uses additive manufacturing by laying down material in layers to build an object. It allows objects to be created without molds or dies. There are different types of 3D printing including stereolithography, selective laser sintering, and fused deposition modeling which use different materials and processes. 3D printing involves modeling the object digitally, setting up the print, and then printing it layer by layer. Common materials used are PLA and ABS plastics. Basic electronic and circuitry concepts are also introduced such as voltage, current, resistance, batteries, resistors, diodes, LEDs, and motors.
11 adv revision_notes_term_3
- 1. CDI 11 ADVANCED Term 3 Revision Notes
- 2. 3D Printing Technology • 3D printing technology uses this method. • A process that adds material layer by layer to create an object. • Benefit - Objects can be created without the use of moulds or dies. • Traditional manufacturing techniques. • This process involves starting with a raw material such as stone or wood and removing the unnecessary material until you are left with the product you wanted to manufacture. SUBTRACTIVE MANUFACTURING ADDITIVE MANUFACTURING CNC: COMPUTER NUMERICAL CONTROL • A computer converts the design produced by Computer Aided Design software (CAD) like 123D Design, into numbers (like coordinates of a graph). • Numbers - control the movement of the cutter ; Computer - controls the cutter speed, and direction to cut and shape of the material. • CNC can create fine and detailed pieces.
- 3. 3D Printing Types STEREO-LITHOGRAPHY (SLA) SELECTIVE LASER SINTERING (SLS) FUSED DEPOSITION MODELLING (FDM) • Stereo-solid + Lithography-printing • 1986 – Charles Hull – created first SLA device. • Resin-a light sensitive glue-like liquid substance-becomes solid when a specific frequency of light shines on it. • Lasers-controlled by computer; draw the outline of the 3D model, slice by slice until the layer is completely hardened. • 1987 – Carl Deckard– created first SLS device • Advantage – powders from plastic, ceramic, glass or metal to create objects with extreme detail and complexity. • After each layer is bonded the model is repositioned so that a roller can apply a new coat of powder. The lasers then bond that layer and so the process is repeated until the model is complete. • Expensive process. • The printer generally uses plastic filament (a roll of plastic much like a roll of string) and adds many layers to build solid objects. • Cost effective process.
- 4. PARTS OF 3D FDM PRINTER Filament : Used to produce printed object Extruder : It is a mechanical system that forces filament into the heated nozzle at a controlled rate. Heated nozzle: Tools that melts the filament at high temp.(180-220 0 Celsius) Print bed/ build platform: A surface on which final object is printed.
- 5. 3D PRINTING PROCESS Modelling : Process of designing and creating digital representation of an object using 3D modelling application (123D design ) Printing setup : Setting up the 3D model so that it can be printed using the printer by setting the parameters. You have used - FlashPrint to make your project – 3d car. 3D Printing Formats .stl .gx
- 6. Filament And Material Types PLA • Thermoplastic. • Most commonly used. • Biodegradable and eco-friendly . • Used in items such as water bottles, plastic cups and mugs, food containers and small electronic product casings. ABS • Thermoplastic • Higher temperature for melting so not all 3D printers have a heated nozzle and extruder than can support ABS • Not biodegradable or eco-friendly • Commonly used in manufacturing plastic industrial pipes, Lego blocks, car parts and in kitchen appliances. • Strong, durable and less flexible than PLA • Quite heat resistant.
- 7. • Electricity : A form of energy used to drive televisions, washing machine, mobile telephones. • Electronics : Control electric circuits. • Current : Rate of flow of charges • Embedded systems : It is a specialized computer system with a specific function within a larger mechanical or electrical system. Examples - • Air conditioner in car. • Seatbelt warning in car. • Garden watering system. • Motion sensitive security system. An “embedded system” is known as an input, which is a device that contains a computer unit or a microcontroller that reads the changes in an environment. It then controls an output system to change the environment.
- 8. Electric Circuit : Group of electric components connected by conductors for current flow Voltage Source Conductive Path Load It causes the current to flow through circuit. Consumes electric power. Through which current flows. Types of Voltage Source Alternating Current : Wall Socket Direct Current : Battery
- 9. ELECTRICAL SCHEMATIC Ohm’s Law • Voltage is the difference in charge between two points. • Measured in Volts(V). • Resistance is a material’s tendency to resist the flow of charge (current). • Measured in Ohms(Ω). • Current is the rate at which charge is flowing. • Measured in Amperes(A).
- 10. Batteries : Change chemical to electrical energy, consists of many cells. Resistor : Electrical component for electrical resistance. Breadboard : It is a solder less board that can be used to make temporary circuits. 4-band Resistor 5-band Resistor How to calculate resistor value:
- 12. Diode : Two Terminal electronic component Current flows from anode to cathode. DIODE vs LED • LED : A diode emits light when current flows. Uses advanced semiconductor materials. • Advantages of LED over traditional light bulbs: more robust; consume less power; last longer. Testing of an LED using Multimeter Set the multimeter to diode test option. To anodeTo cathode • Notice the dim light of the LED due to the electric current flowing through the LED (the diode). • Here you can read the voltage across the LED.
- 13. EXAMPLE:LED Flash Task SCHEMATIC DIAGRAM: 1. Students will be required to design or complete a circuit diagram related to a product or process suggested. (Sample as shown aside.) 2. There will also be a written element in relation to the circuit diagram. e.g. How many LEDs are connected? To which pin LED is connected to? CODING: A code will be provided and students will be asked to redesign or adjust the program code by adding appropriate component parts. (a) Int ledPin = 10; (wrong) int ledPin = 10; (correct) (b) void loop() (wrong) void loop() { (correct) (c) Make the LED off for 5 secs. delay(5000); Int ledPin = 10; // the setup function runs once when you press reset or power the board void setup() { pinMode(ledPin, OUTPUT); } // the loop function runs over and over again forever void loop() digitalWrite(ledPin, HIGH);// turn the LED on (HIGH is the voltage level) delay(2000); // wait for 2 seconds digitalWrite(ledPin, LOW); // turn the LED off by making the voltage LOW delay(2000); // wait for 2 seconds }
- 14. MOTORS 1. Have two leads – red(positive) and black(negative). 2. It runs at high RPM(revolutions per minute). 3. Controlling DC motor directly from Arduino board will damage it. 1. Have three leads – orange(control), red(power) and brown(ground). 2. It takes angle commands from a series of pulses(sent every 20 milliseconds) sent from Arduino. 3. Controlling servo motor is done from a special library called - ‘Servo’. DC Motors Servo Motors Applications Fan, Hair dryers, car, lifts, cranes Robots, Camera auto focus, Automatic Door openers PWM Signal • Pulse Width Modulation (PWM), is a technique for generating an analog signal using digital means. Toff T = Time Period (secs) = Ton + Toff ; Frequency (Hertz) Duty Cycle Ton