Flashcards
Engineering- Manufacturing processes/surface finishing/describing systems 7
Cards in this deck (29)
- 1ENGINEERING MANUFACTORING PROCESSESA
- 2What is CAM, and what does it mean?• Computer Aided Manufacture
• This is when a computer is used to program and control a manufacturing machine - 3What does CNC stand for, and what does it mean?• Computer Numerically Controlled
• CNC machines are controlled by a number system known as machine code
• All machines that are controlled by computers use CNC - 4How is CAM achieved?• First, a design must be drawn using a CAD software package such as 2D Design, Solidworks, or Circuit Wizard PCB Design.
• This CAD drawing is then converted into CNC code by the computer
• A CAM software package is then used to convert the CAD drawing into CNC code, and then to control the machine to manufacture the part. - 5Define 2D CAM, and give details of examples• With 2D CAM, the cutting tools can only move in 2 directions (along the x axis and the y axis),
• Examples include:
o Laser cutter – CNC used to control a laser that engraves and cuts materials
o Vinyl cutter – a cutting blade is placed in a CNC tool-holder, allowing self-adhesive vinyl to be cut
o CAM PCB manufacture – pcb artwork is printed on clear aetate to allow copper patterning for etching
o CNC lathe – CAM can control both the speed of the chuck and the speed and path of the machine tool using CNC - 6Define 3D CAM, and give examples• With 3D CAM, the cutting and forming tools move in 3 axes (x, y, and z), allowing 3D shapes to be produced
• 3D CAD software is needed, e.g. Solidworks
• Processes include:
o Rapid prototyping – a 3D printer uses an additive manufacturing technique called fused filament fabrication (extruded molten plastic is deposited and built up in layers to form a 3D component)
o 3D milling/routing – machines use CNC to perform multi axis machining to produce complex shapes - 7Surface Finishinga
- 8List 3 reasons why surface is useful?• Improves the material’s resistance to corrosion
• Increases the material’s ability to resist scratches and damage
• Improves the material’s appearance - 9What are the advantages of painting?• Increases corrosion resistance of material
• Improves appearance of material
• Quick to carry out
• Low cost - 10What methods of painting are there?• Manually – when only a few parts need painting
• Using robot arms – to spray paint larger quantities
• Applied by dipping - 11What does paint consist of?• Pigments – for colour
• Vehicle – makes paint adhere (stick) to the surface and forms a film as the paint dries
• Solvent – controls how easy the paint is to apply (thinner) – evaporates as paint dries - 12Describe dip coating• Dip coating is used to apply polymer coatings (e.g. PVC, nylon, polyethylene) to metal parts
- 13What are the advantages of dip coating?• It provides a thick, wear resistant finish, helping to prevent corrosion
- 14What are the steps of dip coating?• Clean metal part
• Heat part in an oven (250 – 400 0C)
• Dip metal part in a fluidised container of powdered polymer particles
• Particles stick to the hot metal surface, and melt
• Keep part in the fluidised container until the required thickness is achieved
• Reheat the coated metal part to ensure the polymer powder has melted - 15What is electroplating?• Electroplating is a process where a part to be coated is placed in a chemical bath and a current is passed through it to build up a coating
• The most common coatings are nickel, zinc, copper, or tin - 16What is galvanising?• Galvanising is the application of a coating to steel by dipping it in molten zinc
• For example, metal dustbins, buckets, external trunking - 17Define polishing.• Polishing is the process of smoothing the surface of a part by removing or wearing away a small amount of material
• It is used for metals and some polymers
• The resulting surface is made both smooth and shiny - 18Describing systemsA
- 19Identify 3 ways to communicate and describe a system.• System block diagrams
• Circuit schematics
• Flowcharts - 20What do the blocks in a system diagram represent?• They represent the functions or sub-systems
• They can be simplified visual representations of electronic circuits or mechanical systems - 21What do the arrows in a system diagram represent?• They represent the signals that are received and sent out from each block
- 22State, with examples, what is meant by the input to a system diagram?• The input block turns a real world signal into a signal that the process sub-system can understand
• For example, an input block can convert the light level of its surroundings into a proportionate voltage
• Another example, an input block can convert the heat level of its surroundings into a proportionate voltage - 23State, with examples, what is meant by the output of a system diagram• The output block turns an electronic signal back into a real world signal
• For example, the output block can turn an electronic voltage into light (LED or bulb), motion (motor), heat (heater), sound (loudspeaker or buzzer), a switch (using a relay to turn on a separate high voltage circuit) - 24State, with examples, what is meant by a process block• A process block changes or manipulates electronic signals in some way
• For example, process blocks can: convert analogue signals into digital signals (comparator); create on-off pulses (astables); create time delays (monostables); check whether one or more inputs are on or off (logic gates); count events (counters); or a combination of all these and more (microcontrollers) - 25Explain why schematics are used• A schematic is a circuit diagram that shows the individual components required and how they are connected together
• They are also used to help engineers design appropriate PCBs - 26Define what is meant by a flowchart• A flowchart is a diagram that shows the order and flow of operations in a system
- 27What is a terminator block, and describe its purpose in a flowchartThis is used to indicate the beginning and the end of a series of events shown in a flowchart
It is in a oval square shape. - 28What is a process block, and describe its purpose in a flowchart• This is used to show when an action or instruction is to be carried out, e.g. wait, increment, expression,
It is a square box. - 29What is a decision block, and describe its purpose in a flowchart• This is used to show where a choice must be made or a question answered. This must be in the form of a yes/no response.
It is a square diamond
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- Flashcards on Engineering- Manufacturing processes/surface finishing/describing systems, created by AsimAli Rehman on 02/11/2019.
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