The feed per tooth is a critical parameter in the machining process, especially when using a square milling cutter. As a supplier of square milling cutters, I have witnessed firsthand how the feed per tooth can significantly impact the performance of these tools. In this blog, I will delve into the effects of feed per tooth on the performance of a square milling cutter, exploring both the positive and negative aspects.
Understanding Feed per Tooth
Before we discuss its effects, it's essential to understand what feed per tooth means. Feed per tooth (fz) is the distance that the cutter advances into the workpiece for each tooth revolution. It is measured in millimeters per tooth (mm/tooth) or inches per tooth (in/tooth). This parameter is closely related to the feed rate (Vf), which is the speed at which the cutter moves along the workpiece, and the number of teeth (z) on the cutter. The relationship between them can be expressed by the formula: Vf = fz × z × n, where n is the spindle speed in revolutions per minute (RPM).
Positive Effects of Appropriate Feed per Tooth
1. Increased Material Removal Rate
One of the most significant advantages of setting the right feed per tooth is an increased material removal rate (MRR). When the feed per tooth is optimized, the cutter can remove more material in a shorter period. This is particularly beneficial in roughing operations, where the goal is to quickly remove large amounts of material from the workpiece. For example, in a heavy - duty machining process where a large block of metal needs to be shaped into a specific form, a higher feed per tooth within the recommended range can significantly reduce the machining time. This not only improves productivity but also reduces the overall cost of production.
2. Improved Surface Finish
Contrary to what one might think, an appropriate feed per tooth can also lead to an improved surface finish. When the feed per tooth is too low, the cutter may rub against the workpiece rather than cutting it cleanly. This can cause built - up edge (BUE) formation, which degrades the surface quality. On the other hand, when the feed per tooth is set correctly, the cutter cuts through the material smoothly, resulting in a better surface finish. This is crucial in finishing operations, where a high - quality surface is required. Our 2 Flutes Flat End Mill can achieve excellent surface finishes when the feed per tooth is properly adjusted.
3. Reduced Tool Wear
When the feed per tooth is within the optimal range, the cutting forces acting on the cutter are more evenly distributed. This helps to reduce the stress on individual teeth, which in turn reduces tool wear. A well - adjusted feed per tooth ensures that each tooth of the square milling cutter is engaged in the cutting process effectively, preventing excessive wear on a single tooth. This extends the tool life, reducing the frequency of tool changes and the associated costs.
Negative Effects of Inappropriate Feed per Tooth
1. Excessive Cutting Forces
If the feed per tooth is set too high, the cutting forces acting on the cutter will increase significantly. These high cutting forces can cause the cutter to deflect, leading to inaccurate machining results. In extreme cases, the excessive forces can even cause the cutter to break. This is a serious problem as it not only damages the tool but also poses a safety risk to the operator. For example, in a high - precision machining operation, a large deviation in the cutting forces due to an improper feed per tooth can result in parts that do not meet the required dimensional tolerances.
2. Poor Surface Finish
As mentioned earlier, a feed per tooth that is either too low or too high can lead to a poor surface finish. When the feed per tooth is too high, the cutter may tear the material rather than cutting it cleanly. This results in a rough surface with visible tool marks. In some cases, the high feed per tooth can also cause chatter, which further deteriorates the surface quality. This is a major concern in industries where a smooth surface finish is essential, such as the aerospace and automotive industries.
3. Accelerated Tool Wear
An inappropriate feed per tooth can accelerate tool wear. If the feed per tooth is too high, the cutting edges of the cutter will experience excessive stress, leading to rapid wear and chipping. On the other hand, if the feed per tooth is too low, the cutter may rub against the workpiece, causing abrasion and built - up edge formation, which also shortens the tool life. This means that the operator will have to replace the cutter more frequently, increasing the production cost.
Factors to Consider When Selecting Feed per Tooth
When selecting the feed per tooth for a square milling cutter, several factors need to be considered:
1. Workpiece Material
Different workpiece materials have different machinability characteristics. For example, soft materials like aluminum can generally tolerate a higher feed per tooth compared to hard materials like stainless steel or titanium. When machining aluminum, a feed per tooth of 0.1 - 0.3 mm/tooth may be appropriate, while for stainless steel, a lower feed per tooth of 0.05 - 0.15 mm/tooth is usually recommended.
2. Cutter Geometry
The geometry of the square milling cutter, such as the number of teeth, helix angle, and rake angle, also affects the feed per tooth selection. A cutter with more teeth can generally handle a lower feed per tooth but a higher feed rate. The helix angle can influence the cutting forces and chip evacuation, which in turn affects the optimal feed per tooth.
3. Machining Operation
The type of machining operation, whether it is roughing or finishing, also plays a role in determining the feed per tooth. As mentioned earlier, roughing operations typically require a higher feed per tooth to maximize the material removal rate, while finishing operations require a lower feed per tooth to achieve a better surface finish.
Conclusion
In conclusion, the feed per tooth has a profound effect on the performance of a square milling cutter. An appropriate feed per tooth can lead to increased material removal rates, improved surface finishes, and reduced tool wear. On the other hand, an inappropriate feed per tooth can cause excessive cutting forces, poor surface finishes, and accelerated tool wear. As a square milling cutter supplier, we understand the importance of providing our customers with the right advice on feed per tooth selection. We offer a wide range of square milling cutters, including the Recoveralbe Bead Glass Door Bit Set and Other Handrail Bit, which are designed to perform optimally under different feed per tooth conditions.
If you are looking for high - quality square milling cutters and need expert advice on feed per tooth selection, please don't hesitate to contact us. Our team of experienced professionals is ready to assist you in choosing the right cutter and setting the optimal feed per tooth for your specific machining needs.
References
- Trent, E. M., & Wright, P. K. (2000). Metal Cutting. Butterworth - Heinemann.
- Kalpakjian, S., & Schmid, S. R. (2009). Manufacturing Engineering and Technology. Pearson Prentice Hall.
- Stephenson, D. A., & Agapiou, J. S. (2006). Metal Machining: Theory and Applications. CRC Press.
