Drilling is often performed late in the manufacturing process, after previous operations have increased the value of the initial part. Drilling applications may seem simple, but they are actually 

complex processes in which tools that malfunction or exceed their capabilities can have serious consequences.

Initial considerations for drilling

The 3 basic elements of drilling are:

Aperture

Hole depth

Hole quality

Hole shape and accuracy requirements influence tool selection. Drilling can be affected by irregular or angled entry/exit surfaces and cross holes.

Component

After analyzing the required holes, look at the workpiece material, part shape and quantity.

Workpiece material

Does the material have good chip breaking properties? Long-chip or short-chip material?

Machinability?

Material hardness?

alloy element?

Part shape

Does the part rotate symmetrically relative to the hole (or can the hole be machined with a fixed drill)?

Are the parts stable? Or are there thin-walled sections that could cause vibration?

Can the parts be securely fastened? What stability issues need to be considered?

Need to extend the tool? Do I need to use long tool overhangs?

quantity

Batch size affects which drill bit is used.

Large production batches - using optimized drill bits, custom drill bits

Small production batches - using drills optimized for versatility

3. Machine tools

It is important to know how to perform safe and productive drilling operations in machine tools. The machine tool affects the following choices:

Process type

Type of holder and/or collet to be used

Be sure to consider the following:

Overall stability of the machine tool, especially the spindle

Is the spindle speed (rpm) sufficient for small diameter hole machining?

Coolant supply. Is coolant flow sufficient for large diameter drill bits?

Is the coolant pressure sufficient for small diameter drills?

Workpiece clamping conditions. Is it stable enough?

Horizontal or vertical spindle? Horizontal spindle enables better chip evacuation

Power and torque. Is the power sufficient for large diameter drilling? If not, can a nesting drill be used? Or can it be used as an alternative to using a milling cutter for helical interpolation 

milling?

Is the space in the tool magazine limited? In this case, a step and chamfer drill may be a suitable solution.