1.21/1.7 Digital Design and Manufacturer Flashcards
Advantages and disadvantages of CAD
The main disadvantages of using CAD include:
The main advantages of using CAD include:
• 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 i different offices and even different countries. The use of CAD and web conferencing makes collaborative working possible, and reduces 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.
• The initial setup cost can be quite expensive, especially when staff have to be trained)n 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.
(Need to edit) describe in detail the following CAM and CNC processes:
CAM, LASER-CUTTING, ROUTER AND MILLING
CAM usually involves 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 speed and power settings for the material they are machining. (Usually a slower speed and higher power is selected for denser material, and with increased thickness.) This ease of use has made it possible to use CAM processes for one-off production.
Laser cutting ( CNCler) CNC= campuler neverta
Laser cutting uses a high-energy laser beam to cut or vaporise materials and compressed gasor air to blow the waste material away, leaving a clean edge.
Two-dimensional 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. Laser cutters in school or college are usually powerful enough to cut materials such as woods and plastics, but in industry, more powerful lasers are commonly used to cut sheet metals.
avc condole rovevat
Routing - HDMF
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 9 mm MDF or thicker materials such as blocks of timber and Styrofoam, or high density modelling foam to make moulds or 3D models.
Milling
Milling machines work in a similar way to routers, and can be fitted with tools to drill holes, cut slots or shape the surface and edges of a range of materials (see Figure 1.7.4). Milling machines can move the ‘bed’ of the machine in the X and Y axes, but the cutter can also be moved in the Z axis to vary the depth of cutting. 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. Modern CNC milling machines often have the ability to automatically change tools to suit different machining jobs and different materials.
CNC milling machines are usually totally enclosed, which improves safety in the work area. They will be fitted with automatic coolant which floods the tooling and workpiece witha lubricant. Jesulting in improved tool lite and surface finish. The machines are fully enclosed, so workers are protected from potential health and safety problems from flying debris and exposure to the coolant.
CNC milling machines can obviously operate much more quickly and accurately than human operators, and they can continue to machine for long hours with the exception of stoppage for maintenance.
What is CNC turning?
Involves using lathes to machine metals in bar form or plastic rods
They could reduce the diameter, the length of the bar and thread cutting and boring for more complex shapes.
They are also industrially able to change lathes too automatically
They can be part of a FMs with other machines e.g. CNC Router with robots to transfer material
What is plotter cutting?
Uses a 2D CAD drawing, using X and Y coordinates to cut through material
Used for applications such as self-adhesive vinyl for graphics’s e.g. on a car
What does virtual modelling do in CAM processes?what can it also do for manufacturing processes?
Using 3D CAD drawings to produce a virtual model and put in places where it may be used e.g. a virtual engine connected to other bits around it
It can also be sued to check wether a product will be manufactured correctly and can plan a whole production line before purchasing the right or needed equipment to
Using simulation programmes can help designers and engineers produce a layout of cells needed for production - this includes the positioning of robots and workstations as well as people too and were the components for production will be delivered at
What is computational fluid dynamics? Give me one advantage of using it
A tool used in 3D CAD software which can be used to stimulate the flow of liquids and gases through components that have been designed on CAD programmes.
E.g. the flow of air as a car is moving through it - the developers can use the highlighted red/green areas to see where its most affected and improve on it
One advantage of using this tool is that the designer can save money and time instead of producing physical models to test for the same results (which may be less accurate) using special wind tunnels
What is finite element analysis?
Uses computer modelling to process forces and weights onto components (stress)
- they can be sued to stimulate stress, shocks and vibrations e.g.
This would then highlight any potential weak points in a product which might need further development
Pa = stress!
One advantage is that we can save money and time rather than making physical models and testing the stresses out themselves
What is rapid prototyping? Give me one disadvantage of rapid prototyping before 3D printing.
Using 3D CAD files to machine the software into a 3D object in a range of materials making the designs in the fastest way possible - prior to this it would have been done by hand with highly skilled professionals which was time consuming and increased the costs to produce products
A machine used: stereolithography
What is a Fused Deposition Modelling?
A common type of 3D printer which uses fused depositions to print 3D models in slices’’’ using an extruder in paths to build the product from the bottom up layer by layer - suing materials such as thermoplastic filament
They may also use scaffolding in order to to use the model - which is less dense and can be broken once competed
What are the advantages of using FDM? What is another recent improvement made which benefits manufactures in terms of metals?
They can be produced quickly, accurately and cheaply and can then be used to obtain feedback from
They can be used to make medical products e.g. skeleton joints or prosthetics
There are now able to use some machines which can use metals - using this process there is no need to fabricate (join the parts together) which can cause weakness in the parts - they normally use titanium and aluminium for this also SSteel
It uses either EBM electron beam welding or Selective laser melting SLM - fusing metal powder layer by layer
What can normal 3D printer be used to make?
Used for one-off production of bespoke items e.g. cast jewellery - where the printing would be used to create the moulds for casting
What is EPOS?
Electronic point of sales which captures data when consumers purchase goods labelled with barcodes - used to control stock levels so that a replacement stock can be made
E.g. when items are scanned via their barcode the sale is recorded under EPOS
Other than controlling stock the system also is used to monitor items being sold, which can be used to help with targeting arresting products to help improve sales or determine when a new/improved item should be made
What is MPS? Master production scheme?
A plan that determines how many products will be made in a given time using other parts of the business to network and plan this out. It will also determine the required amount of labour and availability of labour and will also network with suppliers to order materials and control stock inventory
electronically via EPOS, and this is transmitted automatically to the manufacturer. The customer’s order is then placed in the MPS software.
This software will determine the appropriate timing for production of the customer’s order, and trigger the ordering of materials and components from the supplier.
In the automotive industry, customers can specify particular requirements for their car, for example colour, two- or four-door, engine size, manual or automatic, diesel, petrol or hybrid. These details are transmitted 10 the manufacturer and their suppliers, so that the required materials and components are ordered in time for JiT production.
JiT production requires suppliers of materials and components to deliver stock only when it is needed for production (usually just a few hours before it is actually used). This has several advantages, such as less warehousing needed to store stock, and companies are not left with unused materials and components.
Many of the modern manufacturing systems that we use today were originally developed by the Japanese car manufacturer Toyota (known as the Toyota Production System). For this reason, much of the terminology is derived from Japanese words and phrases.
In manufacturing, the flow of materials and components through a factory is often controlled using a Kanban’ system. Small consumable items such as fasteners (nuts, bolts and screws) are kept in reusable plastic bins, and a barcode is used on these bins. As each bin is drawn from stores, the barcode is scanned and an order is placed to reorder them from suppliers, Kanban is Japanese for ‘signal card’ and originally, as materials or components were used on a production line, a card would be put into a holder by the relevant workstation. These were collected at several points in the shift and the items reordered. These have now been replaced with barcodes and scanners or radio frequency identification (RFID) tags, and orders are sent automatically using computer networks. The Kanban system is also used to ensure materials and parts arrive at the correct point in an production or assembly line at the correct time. In the car industry, this is typically achieved using overhead gantries and conveyors that deliver parts to work cells at the precise time they are needed. As a car under assembly moves down the line, it will be tracked using barcodes or a telemetry device such as RFID. This feeds back to the MPS computer so that the progress of the assembly can be monitored.
int carMeDs alsodo?
MPS software can also be used
I to control manufacturing equipment.
For example, in the production of cars, robots and other equipment can be automatically recontigured to produce different models of cars or even completely different vehicles on the same production line. Jaguar Land Rover is an example where the production line can switch between making Jaguar cars and Land Rover Discovery models in order to respond Lo customer demand. This is an example of QRM: the use of flexible manufacturing equipment is an essential part of such manufacture.
On a smaller scale, FMS typically consisting of computer controlled lathes, milling machines, laser cutters and punches can make a wide range of different engineering components. The part programs that contain the
- machining code will be downloaded from the MPS network. The flow of materials coming into the flexible manufacturing cell can be automated by using robots and automatic guided vehicles (AGVs) - also scheduled by Kanban and MPS software. Because some processes take longer than others, there will be ‘buffer zones’ where items will be temporarily held in order to allow time for the slower processes to be completed. Finished items can be transported to the warehouse using AGVs and the warehouse itself can often be computer controlled and networked to the MPS system.
