Machining Operations, CNC, CAM software, Lastest development Flashcards
For turning what is the equation for rotational speed, feed rate and volumetric material removal rate?
N=v/(ππ·0)
fr=Nf
MRR=vfd
For drilling what is the equation for rotation speed, feed rate and volumetric material removal rate?
N=v/πD0
fr=N*f
MRR= (ππ·^2)*fr/4
For milling what is the equation for rotation speed, feed rate and volumetric material removal rate?
N=v/ΟD
fr=NZf or f=fr/NZ
MRR=frdw
What is part programming?
- Using a computer program containing a number of lines, instructions or statements called NC BLOCKS
What are the 6 parts of a part programming?
1) Sequence number
2) Preparatory function
3) Interpolation function
4) Miscellaneous function
5) Spindle speed function
6) tool function
Spastics Poo In My Special Toilets
What does the first block do in a typical NC program?
Block sequence number
What does the Second block do in a typical NC program?
G- preparatory functions
What does the Third block do in a typical NC program?
X, Y, Z, coordinates for motions
What does the Fourth block do in a typical NC program?
Miscellaneous function
What does the 5th block do in a typical NC program?
Spindle Speed
What does 6th first block do in a typical NC program?
Tool number
What is linear interpolation?
Uses G01 where the velocities of two axes are controlled to keep the tool on a straight path in a plane of motion
What is Circular interpolation?
G02 is clockwise
G03 is anticlockwise
The next two types are radius arc: N010 G90 G03 X30 Y65 R45
centre arcβs: N010 G90 G03 X30 Y65 I-45 J0
What is used instead of NC?
CAM! Can do all the long bits you cant be arsed for!
What are the four-man strategies for 2D machining?
In order
Facing
Drilling and hole making
2D Contouring
Pocketing
What are the high-speed, very high speed and ultrahigh speeds for cutting speed?
High speed: 600-1800 m/min
very high: 1,800-18,000 m/min
Ultrahigh speed >180,000 m/min
What are some characteristics for spindles with high speeds?
High stiffness
High accuracy
Hydrostatic/aerostatic are desirable
What are some requirements for building precision machine tools?
- Highly damping capacity
- Thermally stable
- Dimensionally stable in liquids
Candidates: cast iron, polymer concrete, natural granite
What are some considerations for precision and ultra-precision machining?
- Tool design/construction/assembly (e.g stiffness, damping, accuracy)
- Spindle and slide-way technology such as hydrostatic
- Thermal growth of the machine tool, compensation for thermal growth control of the machine-tool environment
- Cutting-tool selection and application- ceramic and diamond tools are commonly used
- Motion control and sensor system forr both linear and rotational components
What are some of the application for micro-machining?
- Create 3D components or features
- Smart phone, medical devices, automotive
- Product miniaturisation demands innovative micro-machining technologies
- Competing with and complementing other micro manufacturing approaches
What are some ADVANTAGES of micro-machining?
- Broad range of workpiece materials
- True 3-dimensional accuracy and surface finish
- High dimensional accuracy and surface finish
- Easy setup, low cost and suitable for small/medium batch direct manufacture or making moulds for mass production
What are some DISADVANTAGES of micro-machining?
- Need to have much higher spindle speeds
- Harder to achieve good surface quality
- Edge quality
Low tool life
Name some commonly used micro milling tools:
Tungsten carbide Coated tools CBN tools PCD (polycrystalline diamond) tools CVD (chemical vapour deposition) diamond Natural diamond tools
D=50(*10^-6) - 1mm
What are the three main aspects in green machining?
Resources
Lower costs
Maintaining health environments
What are some examples of green machining?
Traditional flood coolant
Dry machining
Minimum quantity lubricant
Cryogenic machining
