Internal Cooling Drills vs. Non-Internal Cooling Drills: Which One Should You Choose?

In modern manufacturing, CNC drilling is a basic and important machining Process. The choice of drill bit directly affects machining efficiency, tool life, part quality, and overall production costs. Wrong drill bit selection may result in reduced machining quality or premature tool wear, and may even cause damage to the equipment.

Introduction

Based on the difference coolant methods, drill bits are mainly divided into two categories: internal cooling drills and non-internal cooling drills.

Internal cooling drills deliver coolant directly to the cutting end through channels inside the drill bit, while traditional drill bits rely on external coolant or dry machining.

This article provides a detailed introduction to internal cooling drills and non-internal cooling drills to help you make a better choice.

Internal cooling drill

The internal cooling drill bit is designed with through holes, either spiral or straight. High-pressure coolant can be sprayed directly onto the cutting area along the channel during the machining process.

This cooling method offers multiple advantages:

Efficient heat dissipation: Coolant rapidly removes heat, effectively controls the temperature of the machining area and providing a stable machining environment.

Effective chip removal: High-pressure coolant continuously flushes away chips, ensuring the machining area remains clean and free from chip interference.

Improved machining accuracy: By controlling heat, thermal expansion effects on the workpiece and tool are reduced, thereby enhancing machining accuracy.

Applications and materials

Deep hole drilling: For holes deeper than three times the tool diameter, external coolant cannot reach the depths, so internal cooling drills are required.

Difficult-to-machine materials: It is an ideal choice for machining high-hardness materials such as stainless steel, titanium alloys, nickel alloys, and hardened steel.

Non-internal cooling drill

Working principle: External cooling or no cooling

A non-internal cooling drill is a traditional drill bit. The cooling method is typically external cooling (coolant spray or high-pressure gas) or no cooling dry machining. This machining method primarily relies on the drill bit material itself and its geometric shape.

Additionally, traditional drill bits have advantages that internal cooling drill bits do not:

Lower cost: The procurement cost of non-internal cooling drill bits is lower than that of internal cooling drill bits.

Low machine tool requirements: It can be used with simple equipment or equipment with low-pressure spraying, offering broad applicability.

Easy to use: You can even use it on a desktop mini lathe. It is ideal for DIY projects.

Applications and materials

Suitable for most applications: Non-internal cooling drills are suitable for most machining scenarios and have extremely strong adaptability.

Suitable for most materials: Tungsten carbide drills can process a variety of materials, including high-hardness materials.

Although non-internal cooling drills are suitable for most machining scenarios, there are still some differences between the two in specific machining applications.

Performance Comparison

Summary

Non-internal cooling drill bits are suitable for most machining scenarios and are widely chosen due to their low price. Internal cooling drill bits are more expensive and, due to their superior cooling properties, are typically used for difficult-to-machine materials and machining applications with high product requirements.

Need custom internal cooling drill bits?

It’s easy, you can view our Custom Carbide Drill 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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