Fundamentals of Chip-Type Machining Processes
Why machine parts?
Create prototypes, models, molds, tool and dies, one-offs, . Repair parts Create unique features
Produce a part(s) dimensionally more accurate than castings Whe
Infeed: The depth of cut is obtained by feeding the grinding wheel into the part or vice versa. The finished surface is obtained by traversing the wheel across the part or vice versa. Plunge Cut: The whee
Cutting tool Most critical part of machining system Tool Temperature: 1000 C High Local Stresses Severe Friction
High Hardness Resistant to abrasion, wear, chipping Hi
Turning Boring Facing Parting Knurling Drilling, tapping, reaming Threading
Majority of lathe work Feed is from right to left Rough cut: large DOC, slow feed Finish cut: 1 or more cuts, less than 0.015" DOC
Early Milling Machine
Used primarily to produce flat surfaces Multi-tooth cutter High Material Removal Rates Surface finish 60 to 150 in Used in mass production Tolerances Machining: +/- 0.0005" Slott
Tomahawk Cruise Missile Intake Air Cover
Started as blank, pre-curved part Holes machined, outside beveled edge machined.
12 minutes machining time (included 5 minutes to bolt part once holes machined)
Slotted holes are for explosive bolts Pa
Safety Risk Management
Note: No homework for this topic!
Codes & Standards
ASME Pressure Vessel Code
Cutting, welding, modifications void code rating of a pressure vessel
National Electrical Code National Plumbing Code
100 BC Archimedes Screw 1841 Whitworth thread 1908 British Standard Fine 1918 SAE, National Course and National Fine standard threads 1949 American Standard for Unified Threads
Turning, Boring and Related Operations
Wheel set from Narrow Gauge Steam Engine Chama, NM 30" Diameter December 2005
The lathe is the most common machine tool.
John Wilkinson, Boring machine fo
Broaching, Sawing and
Originally developed for producing
Multi-tooth cutter, single pass
Used in production to finish holes,
splines, and flat surfaces.
Rapid operation, low cycle ti
Material removal process involving abrasive grits with a work piece at high speeds and shallow penetration depths.
Each cutting edge is very small and