Four Steps to Select the Optimal Cutting Tool: “Cut – off” machining is a common processing method in small – scale lathe machining. In this article, we will introduce the key points of tool selection by dividing them into four steps. Understand each characteristic and choose a cutting tool suitable for the machining scenario.
1.Tool Holder Size
Check the size of the tool shank and the diameter of the workpiece to be cut. Examine the “tool shank size”. The tool shank to be connected varies depending on the machine tool. Please check the interface specifications of the machine tool.
Confirmation of tool shank size
Confirm the “diameter of the material to be processed” and the “diameter of the workpiece during the cut – off process”. This is an important point to prevent interference between the tool and the workpiece.
After confirming the material diameter and the workpiece diameter, select the corresponding cutting tool from the sample.
Select the appropriate cutting tool
2.Tool holder selection
Select the right – hand or left – hand tool holder. Decide between the R (right – hand) and L (left – hand) tool holders.
Cutting tools come in “left – hand” and “right – hand” designs. Basically, the “right – hand design” is used, but the “left – hand design” is employed in some machining scenarios.
Scenarios where the left – hand design is used include the following:
① When the total length of the workpiece is short and cannot be clamped by the tool shank of the sub – spindle.
② When using a Swiss – type lathe, the spindle of the Swiss – type lathe rotates in the opposite direction, so the left – right direction will be changed.
What is a long – neck collet tool holder? A long – neck collet tool holder can prevent interference between the main collet and the tool holder, and allows machining to be carried out closer to the guide bushing. This type of tool holder is highly suitable for cut – off machining of workpieces with weak rigidity.
3.Insert shape
Insert Shape After choosing the tool holder, select the insert. There are two types of insert shapes: those with a “rake angle” on the cutting edge and those “without a rake angle”. Basically, “inserts with a rake angle” are used, but “inserts without a rake angle” are also used depending on the cut – off scenario.
Advantages of Using Inserts without a Rake Angle
① Compared with inserts with a rake angle, the cutting edge has higher strength, enabling stable machining.
② Chips are discharged in a straight line, minimizing damage to the end face of the workpiece. The wear of the cutting edge tends to be more uniform, thus extending the tool life.
