Commonly Used Drill Bits for Micro-Part Machining | Complete Guide

Common Types of Drill Bits for Micro-Part Machining

In precision micro-part machining, selecting the right drill bits is critical to ensure machining accuracy, workpiece quality and tool service life. The commonly used drill bits for micro-part machining include center drills, standard twist drills, reaming drills, deep hole drills and countersink drills. Below is a detailed introduction to each type of micro machining drill bit:

1. Center Drill for Micro-Part Machining

Center drill is the most basic positioning tool in micro-part machining, mainly used for accurate hole positioning before formal drilling. Considering the ultra-small diameter of its cutting portion, center drills must be used with a relatively high rotational speed to ensure cutting efficiency and positioning accuracy.

2. Standard Twist Drill for Micro-Part Machining

The cutting part of a standard twist drill consists of two main cutting edges, two minor cutting edges, one chisel edge and two spiral flutes. When drilling on a machining center without a fixture-guided drill jig, asymmetric cutting forces from the two cutting edges easily cause drilling deviation.

For precision micro-part machining, two solutions are recommended: ensure high grinding accuracy of the two cutting edges (equal length, symmetrical point angle around the drill bit centerline), or use a center drill to pilot a center hole first, then perform drilling with a standard twist drill.

3. Standard Reamer (Reaming Drill) for Micro-Part Machining

A standard reamer generally has 3 to 4 main cutting edges, made of high-speed steel or cemented carbide. It is available in straight shank, taper shank and sleeve type structures. In small-batch micro-part production, twist drills are often modified into standard reaming drills to improve hole finish and dimensional accuracy.

4. Deep Hole Drill for Micro-Part Machining

Deep hole drill is specially designed for deep hole machining in micro-part processing. The core challenges of deep hole machining include poor heat dissipation, difficult chip evacuation, and low rigidity of the drill pipe, which may cause workpiece damage and hole axis deflection, reducing machining accuracy and productivity. Professional deep hole drills can effectively solve these problems.

5. Countersink Drill for Micro-Part Machining

Countersink drills are mainly used to machine tapered or flat-bottomed counterbore holes in micro-parts. The common issue in countersinking is chatter marks on the countersunk surface or cone surface. To avoid this, strict selection of tool parameters and cutting parameters is required during spot facing and counterboring.

Key Tips for Micro-Part Machining Drill Bit Application

For high-precision micro-part machining, matching the correct drill bit with the processing requirements is essential to prevent workpiece damage. To guarantee stable machining quality and efficient production, regularly inspect the service life of worn drill bits and replace them in a timely manner.