TG - 3D/2D CAD Commands Flashcards
(32 cards)
1
Q
What is a library of parts?
A
- Collection of standard parts commonly used for assemblies
- Nuts, screws, bolts, etc
2
Q
What are 3 benefits of a library of parts?
A
- Saves time as CAD designer doesn’t need to model standard parts
- Ensures standard parts are consistent with international standards
- Allows manufacturers to understand what standard components are required
3
Q
What are 5 advantages to 2D CAD over manual drawing?
A
- Quicker and more accurate production
- Easier to edit/change
- Repetitive elements can easily be imported via library
- New designs can be built off existing designs
- Drawings can easily be scaled
4
Q
What are 5 disadvantages of CAD compared to manual drawing?
A
- Start-up and maintenance costs
- Continual need to upgrade systems to remain competitive
- Risks of viruses/crashes preventing work
- Power-cuts preventing work
- Staff training costs
5
Q
What are 5 advantages of 3D CAD over physical modelling?
A
- Cheaper to model and test than physical model
- Easy to edit and change with changing design
- No need to source materials/resources
- Animation allows designer to see how parts interact
- More quick to create and more accurate
6
Q
Lists 2 different arrays
A
- Radial array
- Rectangular array
7
Q
What are 2 common files used when importing/exporting CAD models?
A
- STL
- IGES
8
Q
Name 6 different CAD constraints and their purpose
A
- Concentric: aligns two circles
- Parallel: puts two lines in parallel
- Tangent: makes a line touch a circle
- Coincidental: fixes a line to a particular point
- Collinear: causes lines/ellipses to fall on a certain line
- Perpendicular: puts a line at 90 degrees to another
9
Q
What is surface modelling?
A
- Directly changes the surface of a wire model
- Adds curves, contours or other elements to a flat surface
- Works in squares or polygons
- Does not provide solid properties, such as weight or centre of mass
10
Q
What is an extrusion along a path?
A
- A path is defined and then a profile is defined on a plane perpendicular to the path
- The profile is then extruded along the defined path
11
Q
What is morphing?
A
- Pulling or distorting a model using ‘handles’ to form a new shape
- Similar to surface modelling but with 3D CAD
- Typically used for more natural shapes
12
Q
What are irregular fillets/chamfers?
A
- Where the chamfer/fillet changes in depth/radius throughout the edge
- Fillets create curves, chamfers create flat faces
13
Q
What is a loft?
A
- Links two or more sketches together to create a 3D shape
- Can be edited and pulled to create various shapes
- Typically used for irregular geometry which can’t be achieved with extrusions/revolves
14
Q
What is blending?
A
- Similar to a chamfer/fillet
- Connects two 2D/3D sketches/objects smoothly or with a consistent curve
- Effectively ‘blends’ two shapes together
- Either a tangent or a curve blend (3rd or 5th degree spline)
15
Q
Where is the plan in third angle projection?
A
Above the elevation
16
Q
Where is the plan in first angle projection?
A
Below the elevation
17
Q
Is the trapezium to the left or right of the circle in first angle projection?
A
Left
18
Q
What does CFD stand for?
A
Computational fluid dynamics
19
Q
What does FEA stand for?
A
Finite element analysis
20
Q
What is CFD used for?
A
- Analysing how air, water, or other fluids interact with a project
- Highlights points of pressure on design
- Shows if vortexes are forming and where within the product
21
Q
What is FEA used for?
A
- Analyses how a product reacts to forces and pressures within a virtual environment
- Shows high points of stress and can estimate the breaking point for various materials/joints
22
Q
What are 3 benefits of CFD?
A
- Instantaneously yields data that is useful for improving the design
- Cost effective
- Effectively locates where vents, heaters and other air-flow machines can be placed
23
Q
What are 3 benefits of FEA?
A
- Much less expensive than testing and potentially breaking real-life models/components
- Can easily be altered and re-tested in a short amount of time
- Colours give a clear and precise idea of how the product reacts to forces
24
Q
What is mechanical animation?
A
- Create a simulation of 3D CAD models moving to represent assemblies, components or products and how they interact with each other
- Helps to show efficiency of product
- Helps to make clients understand how the product is going to look
25
List 5 different CAM machines
- 3D printer
- Lathe
- Router
- Laser cutter
- Milling machine
26
What are 5 different elements that FEA tests?
- Mechanical stress and vibration
- Fatigue
- Motion
- Heat transfer
- Fluid low
27
What is a roughing process used for in CAM?
- Roughly cuts out the model
- Gets rid of excess materials
- Typically large cuts taken in a zig-zag manner
28
What is a semi-finishing process used for in CAM?
- Works from a roughed product and takes it to a nicer finish
- Middle stages are usually required for difficult materials to process
- Uses raster passes and pencil millings
29
What is a finishing process used for in CAM?
- Final cuts to make a smooth and high-quality finish
| - Much more slow than semi-finishing or roughing due to time taken for quality
30
What is contour milling?
- Milling which achieves a much higher quality finish
| - Not only moves the tool on 4-axis but can also rotate, hence using a 5-axis tool
31
How can we calculate the mass/centre of mass/volume of a model for CAM?
- Using CAD software packages
| - Input material used and rough weight of 1 cm^3 of said material and the software will run a calculation for you
32
Why is COM/mass/volume important in CAM processes?
- Manufacturing engineers need to check whether the mass of a product is within a CAM machines' limits
