Cutting grooves is an important processing method. To successfully complete this processing, you must master the following ten key points:
Understand groove types
There are three main types of grooves: cylindrical groove, inner hole groove and end face groove. The cylindrical groove is convenient for chip removal and processing quality inspection, and it is relatively easy to process. When the tool tip of the grooving tool is kept slightly below the center line, the cutting effect is the best. Inner hole grooving is more challenging in the application of coolant and chip removal. The best performance can be obtained when the tool tip is slightly higher than the centerline. When machining the end groove, the tool must be able to move along the axial direction, and the radius of the back face of the tool must match the radius to be machined. The machining effect is the best when the tool tip position is slightly higher than the centerline.
Machine tools and Applications
Turning and grooving requires the machine tool to have enough power, rigidity, accuracy and coolant pressure and flow. In addition, in order to process the correct groove shape and size, it is also crucial to properly debug and calibrate the machine tool.
Understand the material characteristics of the workpiece
It is necessary to understand the tensile strength, work hardening characteristics and toughness of the workpiece material. For different workpiece materials, different cutting speeds, feed rates and tool characteristics should be adopted, including the specific geometry and coating of the tool, which is necessary for chip removal and prolonging the service life of the tool.
Select the correct tool
Turning and grooving can be completed by cutting in at one time or by cutting in multiple times and step by step. The tools selected by the two methods are different. Choosing the right cutting tools according to the processing needs and processing methods determines the cost-effectiveness of processing.
Forming tool
The forming tool can cut in all or most of the groove shapes at one time, so it can vacate the tool position and shorten the processing cycle time, which is suitable for mass processing. In addition, when selecting, we should also consider the chip generated by the control tool and the machine power required for forming cutting.
Select single point multifunctional tool
The use of multi-functional tools can generate tool paths in the axial and radial directions, so it can not only process grooves, but also turn out diameters, interpolate radii, and process angles. In addition, the multi-function tool can also carry out multi-directional turning. In this way, the time of tool change or empty stroke movement can be reduced and the machining efficiency can be improved.
Adopt correct processing sequence
The correct processing sequence needs to consider many factors. For example, after the groove is processed first, the strength of the workpiece will be reduced, affecting the parameter setting of the next process; After the internal and external diameter turning is completed, the machining shall be started from the farthest point from the tool chuck to avoid the burr being pushed into the machined groove in the next process.
Effect of feed rate and cutting speed
The wrong setting of feed rate and cutting speed will cause chatter and reduce the service life and machining efficiency of the tool. When setting the feed rate and cutting speed, the effects of workpiece material, tool geometry, type and concentration of coolant, blade coating and machine tool performance should be fully considered. For various cutting tools, the manufacturer will generally provide the latest and most practical processing parameter information as a reference.
Select blade coating
The coating can play a lubricating role between the tool and the chip, so it can improve the service life of the cemented carbide blade, improve the machining efficiency and improve the surface finish of the workpiece. At present, commonly used coatings include TiAlN, tin, TiCN, etc. in order to obtain the best performance, the coating must match with the processed material.
Cutting fluid
Cutting fluid has the dual functions of cooling and chip removal, so it is necessary to provide sufficient cutting fluid at the cutting point of the grooving blade and the workpiece. When machining the inner diameter groove of blind hole, increasing the cutting fluid pressure at the cutting point is very effective for improving chip removal. High pressure cooling has obvious advantages for grooving of difficult to machine materials. Generally speaking, the typical concentration of water-soluble coolant is between 3% and 5%. Sometimes, in order to improve the lubricity, the concentration can also be increased to no more than 30%.
