Drilling process (2)

Drill Bit

 

Overview

The drill bit needs to sequentially machine holes in the stacked board, so it is composed of high-strength materials, mainly tungsten and cobalt.

 

Drill Bit Ring

The collar ring that supports the bit to be aligned with the appropriate length in the Drilling M/C and Spindle Chuck is referred to as the drill bit ring.

 

This ring is color-coded for different diameters to allow easy visual identification of the bit's diameter (phi).

 

Color coding is managed according to the degree of bit sharpening.

 

Types of Drill Bits

ST (Straight Drill): A general-purpose bit with a common shape.

UC (Undercut Drill): Minimizes friction with the inner wall of the hole.

RD (Reverse Drill): Primarily used for larger diameter holes.

SD (Slot Drill): Intended for deep holes where conventional bits are not suitable. Emphasizes chip evacuation while maintaining strong cutting edges.

 

Drill Accessories

 

Entry Board

The entry board suppresses the generation of burrs on the upper surface of the panel during drilling operations. It uses materials from the aluminum family that have good thermal conductivity to disperse the heat generated during drilling, preventing thermal degradation that could lead to bit breakage and reduced stiffness.

 

Primarily, the LE Sheet series, which consists of an aluminum foil with a layer of soluble lubricant, is used. This reduces the load on the drill bit and enhances the condition of the hole's inner wall and the accuracy of drilling position.

 

Back-up Board

The back-up board is used to prevent the occurrence of burrs on the sufficient penetration and drilling penetration surface (lower part) of the substrate.

 

Melamine material is commonly used for the back-up board, and materials coated with soluble lubricants are used to enhance the wear and tear of the drill bit and the quality of the hole's inner wall.

 

The down limit value, at which the bit passes through the lower part, is adjusted to allow dual-sided use.