Chapter 2 Machining Operations Flashcards
What are the 2 classification of machined parts and how are they machined?
- Rotational > done by turning
- Non-Rotational > done by milling or drilling
What are the different shape generations?
- Straight, Taper and Contour Turning
- Plain and Profile Milling
What are the key ways to hold the work materials in an engine lathe taught in chapter 2?
- Chuck - to centre pieces about rotational axis
- Lathe Dog & Centre - used for long, thin, cylindrical parts
- Collet - squeeze workpiece
- Face Plate - for customized workpiece
What are the different shape formations?
- Form Turning
- Drilling
- Broaching
What are the other turning machines?
- Turret Lathe - key to mass production
- Chucking Machine - ideal for threading
- Bar Machine
- Automatic Screw Machine - makes fasteners
- Multiple Splindle bar Machine - 1 tool per spindle
Whats the difference between using “Chuck & Key” and “Lathe Dog & Centre”?
Chuck & key - to hold cylindrical parts (3 jaw) & non-cylindrical (4 jaw)
Lathe Dog & Centre - for high aspect ratios (long parts) to help stabilise (reduce vibration)
How does the Collet work?
It is mainly used for high aspect ratio parts, where it allows squeezing of the workpiece as the tool is cutting.
What is the purpose of boring?
To increase depth and diameter of a hole.
Note: Chips will be stuck during boring, so to fix it, after a certain depth the cutter will be moved out and remove the chips. And continue after.
When do you use vertical & horizontal boring?
Vertical is used when the part is too heavy for horizontal, e.g. turbine
How does the drill’s point angle affect the cutting of different materials?
Usually, greater angles are used to cut harder materials and vice versa for softer materials.
What are the different drill operations? (6) And what are they used for?
- Reaming - increase diameter of a drilled hole
- Tapping - create screw threads
- Counterboring - creation of final geometry (flat surface)
- Countersinking - creation of final geometry (tapered hole)
- Centre drilling - done prior to drilling
- Spot facing - to ensure a fastener is flushed with the surface
What are the different work holding for drill presses (3) and its purposes?
- Jigs - for positioning of cutting tool
- Vise - clamping of workpiece
- Fixtures - holds workpiece at predetermined positions
What are the 2 types of milling and their differences?
- Peripheral milling - axis of rotation is parallel to face
- Face milling - axis of rotation is perpendicular to face
Whats the difference between up and down milling? (5)
Up Milling:
1. Work piece fed in the opposite direction of the cutter
2. progressively thicker chips
3. Strong clamping required
4. Poor surface finish
5. Used for hard materials + Quick removal
Down Milling:
1. Fed in same direction as cutter
2. Progressively thinner chips
3. Allows weak clamping
4. Good surface finishing
5. For softer materials + Finishing operations
What are the principal types of Milling Cutters?
Plain milling cutter
Form milling cutter
Face milling cutter
End milling cutter