1.7 Digital Design and Manufacture Flashcards
What does CAD stand for?
Computer aided design
What does CAM stand for?
Computer aided manufacture
What are the advantages of using CAD?
CAD speeds up the product design and development process. The ability to edit and develop existing drawings that are stored on a computer makes it faster than having to redraw items by hand.
Using CAD makes it easier for teams of designers to work collaboratively. Such teams may be located in different offices and even different countries. The use of CAD and web conferencing makes working possible and reduced the need for people to travel.
Completed CAD drawings can be downloaded to CAM equipment such as laser cutters,routers, lathes and milling machines. Alternatively, they can be sent to 3D printers to make models or prototypes.
What are the disadvantages of using CAD?
The initial setup cost can be quite expensive, especially when staff have to be trained in the use of software.
Software has to be updated on a regular basis, which can be expensive.
CAD software is not very easy to use for quick sketches.
What does 3D CAD software allow designers to do ?
To produce high quality ‘artist impressions’ of their designs This can include full colour rendering with light , tone and texture to give a real impression of what a product would look like when made.
What ways is CAD used to develop products ?
Original artwork can be scanned and copied into CAD software, so that the drawing can be digitally developed. Editing tools allow designers to change drawings quickly.
Libraries of standard component drawings can be used to complete designs. This is particularly useful for design engineers who might need to do circuit designs in electronics, pneumatics or hydraulics.
Designers can use ‘layers’ to draw on.
Why is simulation used in CAD and CAM software?
Can highlight any potential problems and any potential clashes with clamps, vices or the tool moving beyond the X, Y or Z limits.
What is simulation used in 3D printers?
To show what the model will look like and how long it will take to machine. It is also used to indicate where the support material is required, so that the model will not collapse under its own weight when being printed.
What does CAM involve?
Downloading completed CAD drawings to machines that will cut and shape materials. Most CAM equipment uses software to convert CAD drawings into a machining programme and only requires the operator to select the appropriate paper and power settings for the material they are machining.
How does laser cutting work?
Uses a high-energy laser beam to cut or vaporise materials and compressed gas or air to blow the waste material away, leaving a clean edge. 2D CAD drawings are downloaded to laser cutters, which convert the drawing into a computer numerically controlled (CNC) program. This program controls the movement of the laser in the X and Y axes, and the power and speed can be adjusted to cut or engrave different materials.
How does routing work?
Both 2D and 3D CAD drawings can be downloaded to CNC routers. They are usually used to cut sheet materials that are too thick for laser cutting, such as 9mm MDF or thicker materials such as blocks of timber and Styrofoam, or high density modelling foam to make moulds or 3D models.
How does milling work?
Milling machines can be fitted with tools to drill holes, cut slots or shake the surface and edges of a range of materials. Some milling machines can also angle the cutting head and the machine bed. These are called 5-axis machines and they are ideal for complex engineering components.
What is different about modern CNC milling machines?
They have the ability to automatically change tools to suit different machining jobs and different materials.
Why are CNC milling machines usually totally closed?
They improve safety in the work area. They will be fitted with automatic coolant which floods the tooling and workpiece with a lubricant, resulting in improved tool life and surface finish. The machines are fulling enclosed so workers are protected from potentially health and safety problems from flying debris and exposure to the coolant.
How does turning work?
It involves the use of lathes, usually to machine metals in bar forms or plastic rods. This could be to reduce the diameter and length of a bar, or for complex operations such as thread cutting and boring.
Industrial CNC lathes form part of what type of manufacturing system?
They form part of a flexible manufacturing systems together with milling machines, laser cutters or punches, all served by robot arms loading material and transferring parts between machines.
What is plotter cutting?
Plotter cutters convert 2D CAD drawings into a CNC program that will use X and Y coordinates to cut out what has been drawn, usually on to thin sheet materials such as self-adhesive vinyl for graphic applications.
How do plotter cutters work?
Most plotter cutters pull the sheet material in and out of the machine (Y axis), while the cutter moves from side to side in the X axis.
What is virtual modelling?
Can be used to test products before they are manufactured. By creating 3D CAD drawings, the product or a component can be put into a virtual model of where it may be used.
What can virtual modelling be used for?
Can be used to simulate a manufacturing process.
In industry, it might also be used to plan a whole production line before investment is made in purchasing new equipment. The equipment needed is highly specialised and costs millions of pounds to purchase and install.
What does CFD stand for?
Computational fluid dynamics
What are computational fluid dynamics and what are they used for?
A tool available in some 3D CAD packages, and is used to simulate the flow of fluids or gases in or around a product.
What are some advantages of CFD?
Designers can save time and money which would be needed to produce physical models and prototypes, and the expense of using other expensive equipment.
What does FEA stand for?
Finite element analysis
What does FEA use?
Uses computer modelling to carry out component stress analysis. A designer or engineer can use FEA software to simulate things such as vibration or shock loads of products or components that they have drawn.
What are the advantages of FEA?
Can highlight any potential weak points in a product which might need further development, before the design is actually manufactured.
Using such software can save a lot of time and expense that be required to make prototypes for physical testing.
