Why Carbide Drill Bits are Important for CNC Machining

Since the beginning of the First Industrial Revolution, drilling holes in various materials and metal objects has been done using drill bits. Over the years, with advancements in industrial and materials science, machine drill bits have evolved to use harder, more suitable materials. This brief tutorial will explain why carbide drill bits are so important for CNC machining.

First, let’s distinguish between high-speed steel drill bits and carbide drill bits.

For many years, machining plants and metal manufacturers have relied on high-speed steel (HSS) drill bits, which are designed with straight shanks or hexagonal shanks. 

While these drill bits can withstand moderate cutting temperatures and support manual sharpening, they fail to meet the precision requirements when faced with increasingly hard materials. 

Additionally, they require frequent sharpening, which wastes a significant amount of time. As a result, manufacturers have shifted their focus to carbide drill bits.

Carbide drill bits are primarily made of tungsten carbide, which features high hardness, high wear resistance, and thermal stability. 

For factories aiming to maximize the production efficiency of their machining centers, solid carbide drill bits have become the obvious choice.

Comparison Overview

Characteristics	High-Speed Steel (HSS) Drill Bits	Solid Carbide Drill Bits
Material Composition	HSS (High-Speed Steel)	Tungsten carbide
Typical shank types	Straight shank, hex shank	Straight shank
Rigidity/brittleness	Lower rigidity, more ductile	Higher rigidity, more brittle
Heat resistance	Lower	Higher
Cutting speed	Moderate	High
Tool life	Shorter	Longer
Impact resistance	Higher (more forgiving)	Lower (more prone to chipping/fracturing)
Initial cost	Lower	Higher
Main applications	General-purpose, softer materials, handheld operations	Precision, hard materials, high-volume CNC machining

Selecting the appropriate drill bit geometry

Carbide drill bits feature different tip angles, flute types, and helix angles, each optimized for specific applications.

Tip angles: 118°, 135°, 140°

118°: A universal angle suitable for most materials and machining scenarios.

135°: Features self-centering functionality, suitable for harder materials.

140°: Used for deep hole machining or high-speed CNC applications.

Flute design:

Straight flute: Suitable for shallow holes in hard metals.

Helical flute: Aids chip evacuation in deep or blind holes.

Helix angle design:

15-20° low helix angle is suitable for machining hard materials.

30-40° high helix angle suitable for soft materials like aluminum.

Internal cooling design suitable for machining deep blind holes, beneficial for chip removal and cooling.

Understanding coatings and their advantages

Coatings enhance wear resistance, lubricity, and heat dissipation. The following are common coatings used on carbide drill bits:

Manufacturer’s Note: When using carbide drill bits for machining, please note the following:

Clamping Stability: Carbide tools are brittle, so it is essential to strictly control runout during clamping. Failure to do so may cause the drill bit to break during machining, resulting in product damage.

Spindle speed: This must be adapted to the material being machined. Excessively high speeds can generate excessive heat, leading to premature tool wear.

Feed rate: A stable and consistent feed pressure must be applied to ensure the drill bit is continuously cutting rather than dry grinding the material, which can cause rapid tool wear.

Cutting depth: This must be considered during the design phase. For deeper holes, internal cooling of the drill bit should be considered to improve chip removal and temperature control.

If you find these concepts too abstract, that’s okay. Simply inform us of your machining requirements, and ZLY’s engineering design team and service team will handle everything for you, including providing technical guidance.

Conclusion

The advent of carbide drill bits has revolutionized the entire hole-making process. 

They offer higher machining speeds, extended tool life, superior surface finish, and effective machining of difficult-to-cut materials. 

In today’s increasingly demanding precision requirements, these characteristics have solidified carbide drill bits’ unshakable position in machining shops and metal manufacturing companies.

Need custom carbide drill bits?

It’s easy, you can view our custom carbide drill bits page to custom you tools.

Or contact our customer support team at email: info@zlycuttingtools.com and our sales staff: liam@zlycuttingtools.com or click here to the WhatsApp, both of which will help you get in touch with our sales and support teams to resolve your issue.

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