CNC machining center is one of the most productive and widely used CNC machine tools in the world. We generally want to machine efficiently with the shortest possible time, using stable and long-life tools and achieving high precision. For the high-efficiency metal cutting of machining centers, the amount of feed, cutting speed, and depth of cut are the three major elements. These factors determine machining time, tool life and machining quality. Reasonable cutting conditions are a necessary condition for economical and efficient machining. And how to choose these three elements correctly is a course that must be mastered in metal cutting.
Cutting speed has a very large impact on tool life. Typically, a 20% increase in cutting speed reduces tool durability by half. And tool life would be 20% of the original life if cutting speed is increased by 50%.
In addition, low-speed cutting is prone to vibration, which shortens carbide milling cutters tool life also.
The cutting speed depends on the revolutions per minute of the spindle, and it is necessary to know the value of the cutting linear speed first. However, the choice of cutting line speed depends on the carbide inserts material, workpieces and processing conditions, etc.
Feed rate refers to the amount of movement of the tool per revolution of the workpiece.
The feed rate is a key factor in determining the quality of the surface being machined, and it also affects the life of the tool. Small feed rate leads to large clearance face wear, reducing tool life. While for too large feed rates, the cutting temperature will increase, and the clearance face abrasion will also be large, but its impact on the tool life is smaller than that of the cutting speed. Therefore, suitable feed rate setting is important. When finishing, the surface requirements are high, and the feed rate should be small. When roughing, it is better to be larger.
The cutting depth should be determined according to the machining allowance, shape of the workpiece, machine power, rigidity of machine and the tool.
At the same time, we should pay attention to the selection of carbide insert. When roughing, we should choose tools with high strength and good durability, so as to meet the requirements of large cutting tool and large feed. When finishing, a high precision and good durability tool can meet the requirements of machining accuracy.
Let us make an example of fast feed milling insert SOMT140520, you can follow up with below cutting parameters. But it is just for a reference, the exact data needs to adjust per your workpiece material , hardness, shape and properties of machine.
As for normal steel, Linear speed VC=100-200m/min, Single tooth feed rate fn=0.5-1.5mm/rotation, and depth of cut ap=0.5-2mm.
And for stainless steel, you can refer to this: VC=80-150m/min, fn=0.5-1mm/rotation, ap=0.5-1.5mm.
For cast iron processing, it can refer to such cutting parameters: VC=100-180m/min, fn=0.5-1.5mm/rotation, ap=0.5-2mm.
And if you need to work aluminum, you can set VC=100-250m/min, fn=0.5-1.5mm/rotation, ap=0.5-2mm.
In addition, if you need to process super alloy materials, making them as VC=60-120m/min, fn=0.5-1mm/rotation, ap=0.5-1mm.
Last, when processing hard materials, follow VC=100-150m/min, fn=0.5-1mm/rotation, ap=0.5-1mm.
Okay, that’s all, hope you have a fruitful experience about the three cutting parameters. And your machining will surely high improved.