Cutting Parameters
Selecting suitable cutting parameters is crucial to optimizing the drilling process, especially when using hard alloy drills. These drills are made from extremely resistant materials, such as carbides, which allow them to cut harder materials with greater precision. The table we mentioned earlier provides a detailed guide to adjusting the cutting parameters depending on the material to be drilled, thus ensuring greater efficiency and tool life.
Understanding Cutting Parameters
- Cutting Speed (V) : This is the rate at which the drill passes through the material. It is measured in meters per minute (m/min) and varies significantly depending on the hardness and machinability of the material. For example, aluminum alloys with high machinability can be drilled at much higher speeds than high hardness steels.
- Drill Diameter (d) : The drill diameter influences the material removal rate and stability of the drilling process. Smaller bits are generally used for fine details and softer materials, while larger bits are suitable for deeper drilling and hard materials.
- Drill Helix Angle : This angle helps determine how effectively chips are evacuated from the drill hole. A larger angle makes chip removal easier, reducing resistance and heat, especially on soft materials like aluminum.
- Drill Tip Angle : This is crucial for initiating the cut and affects the load required to pierce the material. Larger tip angles are typical for harder materials to reduce the force required and increase stability.
- Feed Rate (f) : Indicates how quickly the drill advances through the material, usually measured in millimeters per revolution (mm/rev). A faster feed rate can increase efficiency, but it also requires a more robust drill and machine to prevent breakage.
Practical Applications
- Aluminum and its alloys : Ideal for aeronautical and automotive applications due to its lightness and resistance to corrosion. The cutting speed can be quite high to maximize efficiency.
- Carbon and alloy steels : Commonly used in construction and tool making. Careful selection of cutting parameters is essential to avoid excessive wear or damage to the bits.
- Cast iron : Used in industrial applications and automotive components, where robustness and durability are crucial. Requires cutting parameters that minimize abrasion and maintain structural integrity.
- Plastics and hard rubber : These materials require specific parameters to prevent melting or deformation during drilling.
| Part Material | Hardness (Brinell HBS / Rockwell HRB) | Cutting Speed V (m/min) | Drill Diameter d (mm) | Drill Helix Angle (°) | Drilling Tip Angle (°) | Feed Rate f (mm/rev) |
|---|---|---|---|---|---|---|
| Aluminum and aluminum alloy (high machinability) | 45-105 / ~62 | 105 | <3 - >25 | 32-42 | 90-118 | 0.08 - 0.48 |
| Aluminum and aluminum alloy (low machinability) | ~124 / 118 | 10-70 | <3 - >25 | 20 | 118 | 0.08 - 0.48 |
| Magnesium and magnesium alloy | 50-90 / ~52 | 45-120 | <3 - >25 | 25-35 | 118 | 0.08 - 0.48 |
| Zinc Alloy | 80-100 / 41-62 | 75 | <3 - >25 | 32-42 | 118 | 0.08 - 0.48 |
| Carbon steel (~0.25°C, ~0.50°C, ~0.90°C) | 125-225 / 71-98 | 24-20-17 | <3 - >25 | 25-35 | 118 | 0.08 - 0.32 |
| Alloy steel (0.12~0.65°C) | 175-225 / 88-98 | 21-15-18 | <3 - >25 | 25-35 | 118 | 0.05 - 0.48 |
| Tool steel | 196 / 94 | 18 | <3 - >25 | 25-35 | 118 | 0.08 - 0.32 |
| Cast iron (soft, medium-hard, ductile) | 112-225 / ~71-98 | 43-18 | <3 - >25 | 14-30 | 90-118 | 0.08 - 0.48 |
| Plastic and hard rubber | – / – | 30-90 | <3 - >25 | 10-25 | 90-118 | 0.05 - 0.32 |
Concluding
Careful selection of cutting parameters for different materials not only increases drilling efficiency and accuracy, but also extends the life of drill bits and reduces maintenance and replacement costs. We invite you to leave your comments and experiences with hard alloy drills, sharing best practices that can benefit our entire machining community.
