1.7 Digital Design and Manufacture Flashcards
CAD (definition)
Computer Aided Design
- the use of computer to software to draw, design and model on screen
CAM (definition)
Computer Aided Manufacture
- the use of computer-controlled equipment to machine materials
CNC (definition)
Computer Numerically Controlled
- a program, converted from CAD files, which uses special codes to control CAM equipment
advantages of CAD (8)
- designs easily altered
- designs easily saved & recalled
- designs can be emailed
- photorealistic renderings possible
- stress testing can be done before manufacture
- faster to draw complex shapes
- parts of designs can easily be reused
- designs can be simulated to judge ease of manufacture
disadvantages of CAD (7)
- software can be expensive
- security risk of hacking
- computer memory etc needs updating as as software improves
- can be complex to learn
- not all software is compatible
- requires regular updates
- data can be lost (eg power cuts)
advantages of CAM (5)
- faster than traditional machine tools
- products can be repeated accurately
- can produce work directly from CAD file
- more accurate than traditional manufacture
- machinery can operate 24/7
disadvantages of CAM (5)
- manufacture technicians need training
- less employment
- data can be lost (eg power cuts)
- machinery is expensive
- specialist engineers required for maintenance & repair
CNC router
- 2D & 3D drawings can be uploaded
- used to cut sheet materials that are too thick for a laser cutter
CNC miller
- similar to router
- can be fitted with different tools to drill holes/cut slots/shape surfaces
- bed can move on X & Y axis
- cutter can also be moved on Z axis (vary depth of cutting
- 5 axis machines can also angle the cutting head & bed
- can often change tools automatically
- used for: metals (eg aluminium), polymers (eg ABS, nylon), foam, timbers, composites
CNC lathe
- usually used to machine metal rods, polymers & timbre
- can be used to reduce diameter or more complex precess (eg threading, boring)
- can change tools automatically
laser cutter
- high energy laser beam cuts/vapourises material
- compressed gas/air blows away waste material
- 2D CAD drawings downloaded to the laser cutter and converted into a CNC file
- laser moves on X & Y axis
- used for: wood, plastic (<9mm sheet material)
plotter cutter
- converts 2D CAD file to CNC file and uses X & Y coordinates to cut out file
- usually pulls sheet material in & out of machine (Y axis) while cutter moves on X axis
- used for: thin sheet materials (eg vinyl)
advantages of CNC (5)
- more accurate (no human error)
- faster (less time to set up machinery, tools change automatically)
- increased safety (machines supervised not operated- more guards)
- more cost effective (less training, less workers, more products)
- more complex products can be produced (increased accuracy)
disadvantages of CNC (5)
- workers lose jobs
- very high initial cost
- high maintenance cost (specialist needed)
- if one machine breaks it can hold up the whole production line
- skills to operate machines lost
key differences of laser cutting vs other CNC machines
- uses laser not blades
- more precise & faster
- does not come into contact w/ material- tool not worn down/blunted
- BUT cannot cut thick material
- requires more power
- more expensive
- release dangerous fumes
advantages of rapid prototyping (3)
- very fast (can produce realistic models directly from CAD file)
- cheap (low running cost)
- little waste (addition process not wasting process)
main type of 3D printing
- stereolithography (.stl)
advantages of EPoS (electronic point of sale) (7)
- quicker to use (prices not entered manually)
- keep track of stock automatically
- employee work rate tracked & daily evaluated
- more accurate
- itemised bill = less mistakes
- does calculations automatically (quicker, less errors)
- can read credit cards
implications/disadvantages of EPoS (5)
- expensive to invest in/set up
- software needs regular maintenance/updating
- employees need additional training
- initial set up can be time consuming (input every product)
- software needs updating for improved features (and for provider to maintain competitive edge)
virtual modelling
- test products before manufacture
- model can be put into a simulated environment of how it will be used
- eg engine components can be connected to other components & tested
- simulate manufacture
- plan production line
FEA
- finite element analysis
- carry out components stress analysis
- simulate vibration, shock loads etc
- highlights potential weaknesses before manufacture
- saves time & money on physical prototypes & testing
CFD
- computational fluid dynamics
- simulate flow of fluids & gases in/around a product
- saves time & money on prototypes & testing eg specialist wind tunnels/wave tanks
- eg test aerodynamics of a car
JiT (definition)
- Just in Time
- production method that relies on materials & components being delivered to the point of manufacture just in time for production
disadvantages of keeping large amounts of stock (2)
- takes up lots of space (costly)
- may over stock leading to waste of materials & money
2 key factors needed for JiT to work?
- components MUST arrive on time
- components MUST be ordered when needed
master production schedule (MPS) (definition)
plan used to determine how many products will be made in a given time period
kanban (definition)
system used to control the movement of materials & components from suppliers & through the factory
RFID (radio frequency identification) tags (definition)
small electronic devices that can be scanned & used to track items as they move through the factory & to dispatch
AGVs (automatic guided vehicles) (definition)
robots, similar to forklifts, used to transport items around the factory
disadvantages of JiT (3)
- if components are delayed whole production line held up, time frame of production reliant on speed of suppliers
- if stock is not kept track of properly risk of running out
- requires more planning
kanban (explain)
- controls flow & movement of materials & components through factory
- small consumable items kept in bins marked with a barcode, each time a bin is used the barcode is scanned and more parts are ordered
