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Advanced Metal Drilling Techniques: Effective Strategies and Best Practices

Advanced Metal Drilling Techniques: Effective Strategies and Best Practices

Drilling in metal is the process of mechanically removing material using a cutting tool called a metal drill. In this guide we will discuss the process of drilling metal, choosing the right drill bit, techniques for drilling in different types of metal and practical tips.

Metal drilling basics

Drilling in metal involves creating holes of a certain diameter and depth in different types of material. Depending on the type of metal, the process may vary in terms of techniques and tools.

Material classification: differences between hard and soft metals

The categorisation of materials into hard and soft metals has important implications for the drilling process. Hard metals, such as steel or titanium, have greater endurance and hardness, which can make drilling more difficult. Soft metals, on the other hand, such as aluminium or copper, are easier to drill, but require care not to damage the material. The differences between these types of metals affect the choice of the right drill bit and the drilling method.

Basic rules for using a metal drill

The use of a metal drill includes, but is not limited to:

  • Setting the correct drill speed: When drilling in hard metals, it is recommended to use lower speeds to avoid overheating the drill. For soft metals, higher speeds can be used, but care must be taken not to damage the material.
  • Using correct techniques: Before you begin drilling, mark the area where the hole is to be created, for example with a centroid. Then, apply the drill bit to the metal at a right angle and start drilling, gradually increasing the pressure on the drill.
  • Using a coolant for drilling: A cooling oil or emulsion reduces friction between the drill and the metal, and prolongs the drill bits’ lifespan.

By following these rules, you can drill effectively and safely in a variety of metal types, both hard and soft.

How to choose a metal drill

Choosing the right metal drill bit is of considerable importance for effective and safe drilling.

When choosing a drill bit, the following steps should be considered:

  1. Metal identification: Depending on whether a metal is hard or soft, you may need a different type of drill bit.
  2. Selection of drill bit material: Drills for hard metals should be made of carbide, while drills for soft metals can be made of high-speed steel.
  3. Selection of the right drill diameter: The diameter should be in accordance with the project requirements.
  4. Appropriate drill selection: Check whether, for example, a magnetic drill or a drill-milling machine is needed for a project.

Types of drill bits: from helical to conical

Among the types of metal drill bits we can distinguish:

  • Spiral: The most common metal drill bits, characterised by a spiral shape that helps remove chips during drilling.
  • Conical: Used for drilling holes of different diameters, thanks to their conical shape.
  • Special: Include milling, CNC, diamond and other drills for specific applications.

Special drills

Special drills are designed for specific applications and materials:

  • Milling drills: Used for drilling and milling in one process, saving time.
  • CNC drills: Used in numerically controlled machine tools, they are characterised by high precision and durability.
  • Diamond drills: Coated with a diamond layer, which increases their durability and allows them to drill into very hard materials such as stainless steel or ceramics.

By choosing the right drill bit and equipment for metal drilling, you can achieve high quality work and minimise the risk of damage to tools and materials.

Selecting drilling equipment

Depending on the type of metal and project’s requirements, a suitable drilling machine should be selected:

  • Magnetic drilling machines: Ideal for drilling in heavy gauge metals, thanks to a powerful magnet that holds the drill in place during work.
  • Drill-milling machines: Combine the functions of a drill and a milling machine, allowing you to drill and machine a metal’s surface in one device.
  • Cad drilling machines: Provide accurate drilling thanks to their stable construction and height-adjustability.
  • Radial drilling machines: Ideal for drilling large workpieces, thanks to a movable arm that allows the drill to be positioned precisely at different points without having to move the workpiece. They are characterised by a large working range and the ability to drill at different angles.
  • Series drilling machines: Designed for serial drilling multiple holes at equal distances. Thanks to the possibility of aligning multiple spindles, they allow several holes to be drilled at the same time, making the production process much faster and more efficient.

Techniques for drilling in various types of metal

Depending on the type of metal or alloy (hard, soft, stainless steel and thin sheet), different techniques and tools apply.

Hard metals

When drilling hard steel and other hard metal alloys, it is important to use the right techniques and tools:

  • using carbide drills,
  • using low drilling speeds,
  • using coolants,
  • making small incisions before drilling.

Soft metals

The following methods must be used when drilling in soft metals such as aluminium or brass:

  • using drill bits made of high-speed steel,
  • using a higher drilling speed,
  • being careful not to overpressure the drill bit,
  • using shims or other support material.

Stainless steels

Drilling in stainless steel can be extremely difficult due to its hardness and corrosion resistance, so it is important to:

  • use carbide or titanium coated drills,
  • use low drilling speed and high contact pressure,
  • use coolant,
  • make small incisions before drilling.

Thin metal sheets

Drilling in thin sheets requires particular precision and care, so care must be taken to:

  • use a drill with a sharp tip angle,
  • use a low drilling speed,
  • use shims or other supporting materials,
  • consider using conical drills or step drills when drilling holes with large diameters.

Practical tips and drilling techniques

When working with metals, it is very wise to consider different drilling techniques and drill bit maintenance methods. Hole drilling and speed adjustment techniques can prove to be particularly useful.

How to make a hole in metal

You can create a hole in metal by adhering to the following tips:

  • using a centring tool, mark the place where you want to make a hole,
  • choose the right drill bit for the metal type,
  • set the drill to the right drilling speed,
  • hold the drill perpendicular to the metal surface and start drilling, gradually increasing the pressure,
  • use coolant to ensure adequate lubrication and cooling of the drill bit,
  • clean the hole of chunks and possible burrs after drilling.

Drilling large holes

When drilling larger holes, it is good to use the following techniques and tips:

  • use conical or step drills that gradually increase a hole’s diameter,
  • use a coolant,
  • for very hard metals, consider drilling a smaller initial holes and then widening them with a larger drill,
  • be careful not to over-pressure the drill to avoid damage.

How to adapt the drilling speed to metal's hardness

In order to correctly adjust the drilling speed to a metal’s hardness, a table of drilling rotational speeds should be used and the following rules should be taken into account:

  • the harder the metal, the lower the drilling speed should be used to avoid overheating the drill bit and damaging the material,
  • for softer metals, a higher drilling speed can be used to reduce work time and increase efficiency,
  • the drilling speed can be adjusted on the drill usually with a knob or switch.

Extending drill's lifespan

To optimise the lifespan of your drill bit and extend its usefulness, consider the following advice:

  • regularly check the drill bit’s condition, looking for signs of wear such as dulling or cracking,
  • use acorrect coolant,
  • store drill bits in suitable containers to avoid mechanical damage,
  • when a drill bit is worn, consider sharpening it or replacing it with a new one.

The most common errors and problems occurring during drilling

Among the most common drilling mistakes we can list:

  • wrong drill bit selection for the type of metal,
  • excessive drilling speed,
  • incorrect use of coolant,
  • overstressing pressure on the drill bit.

To avoid mistakes when drilling, it is advisable to apply the following tips:

  • carefully select a drill bit for the type of metal,
  • adjust the drilling speed according to the hardness of the metal,
  • use the correct coolant,
  • avoid excessive pressure on the drill bit in order not to damage the tool or the material.

Causes of drill bit damage

Damage to the drill bit can be caused by various reasons, such as:

  • blunting of the drill bit,
  • overheating of the drill bit,
  • mechanical damage.

Summary

In this article, we have covered both the basics and advanced techniques for drilling in metals. We have shown the differences between hard and soft metals, how to choose the right drill bit for metal and which equipment is best for drilling. We also discussed techniques for drilling in different types of metal, practical tips, and also mistakes and problems that can occur when drilling in metal.

By following these rules, you will achieve better working results and longer tool lifespan. If you need professional help with metal drilling, you can utilise the services offered by CPP PREMA. Our team of experts has the modern equipment and experience to handle even the most demanding projects.