Drilling

**Group 1: Drilling Techniques**

– Drilling process creates sharp edges and burrs, with helical feed marks inside holes.
– Impact on mechanical properties includes low residual stresses.
– Surface finish ranges from 32 to 500 microinches.
– Spot drilling guides the beginning of the final drilling process.
– Centre drilling involves a 60° countersink for center holes.
– Deep hole drilling is for holes deeper than ten times their diameter.
– Gun drilling is used for deep small diameter holes.
– Vibration drilling involves axial vibrations for deep holes.

**Group 2: Specialized Drilling Methods**

– Gun drilling depth-to-diameter ratio can exceed 300:1.
– Gun drilling bits are self-centering for accuracy.
– Vibration drilling technologies include self-maintained and forced systems.
– Circle interpolating uses machine cutters to create holes with dynamic offset.
– Laser drilling is a specialized drilling method.

**Group 3: Drilling Materials**

– Metal drilling involves swarf removal, cutting fluid for cooling, and peck drilling for deep holes.
– Magnetic drilling machines allow drilling in various positions.
– Oil-hole drills with lubricant are used for heavy feeds.
– Wood drilling does not require cutting fluids, uses sharp bits, and specialized drill bits.
– Backing wood minimizes chipping in wood drilling.

**Group 4: Drilling Equipment and Tools**

– Drill bits are used for drilling, with various sizes and shank types available.
– Drilling rigs and die heads are equipment used in drilling processes.
– CAD, CAM, G-code, and numerical control are related to drilling and machining.
– Stewart platform is used in drilling and computing.

**Group 5: Additional Information**

– Materials may expand when heated, affecting hole size.
– Undesirable chipping at hole entry and exit points.
– Specialized drill bits like spade bits and self-feeding auger bits exist.
– Methods to start holes easily in wood.
– References and resources related to drilling and manufacturing processes.