In the process of gold powder processing is often encountered vibration tool problems, resulting in workpiece surface chatter, high rework rate and scrap rate problems.
Today, I’ve compiled 12 ways to reduce the cutting vibration of CNC milling machines in the hope that it will help you all!
Use sharp inserts to reduce the cutting force of CNC milling machines.
Clamp inserts are divided into coated and uncoated inserts, and uncoated inserts are usually sharper than coated inserts because if the inserts are to be coated, they must be passivated (ER-treated) at the edge.
This is because a sharp edge will affect the strength of the coating’s bond at the edge site.
When cutting to a certain depth, the use of a small tip radius can undoubtedly reduce cutting forces, especially radial ones.
The radial cutting force is the main factor that causes vibration in slender rod tools or workpieces.
Whether it is bumping or milling, at the same cutting depth, the larger the radius of the tip arc, the greater the tendency of the slender shank to vibrate.
When the depth of cut is selectable, it should be avoided that the depth of cut is equal to the arc radius of the tool tip.
For the key cutting of the slender shank of the sharp knife, or the external turning of the slender shaft, the use of a tool with a 90 ° main declination is beneficial for vibration reduction.
Whether it is an external turning tool turning a slender shaft or a keyhole in the keystone of a slender tool holder, it is always 90° and the tool with the main offset angle produces the least radial cutting force.
At the same time the blade edge produces the greatest axial force.
For milling cutters with slender rods, the round insert cutters are most beneficial for vibration damping.
The milling cutter is opposite to the agitating cutter.
The closer the main declination angle is to 90 °, the greater the radial cutting force and the greater the vibration of the arbor.
When CNC milling machines use slender rod end mills to mill deep cavities, plunge milling is often used. Insertion milling is the axial feeding of a tool like a drill when milling deep cavities.
The overhang of a long bar is usually greater than 3 times the diameter of the bar, and we recommend the use of axial feed insertion milling.
However, the end mill insert has a radial cutting edge of a certain width.
The tool supplier has the technical data to prove the maximum width of the tool when inserting and milling.
In the milling of thin-walled workpieces, the cause of the vibration is entirely from the workpiece, which is called a box or bowl part.
Since the vibration comes from the workpiece itself, the main focus when dealing with the milling of such parts is to improve the clamping of the workpiece.
When boring in the inner hole, the smaller the blade edge angle, the better.
As a result, the submajor deflection is very large and the chattering contact area between the subcutter and the surface to be worked is small, making it difficult for the chatter to turn into vibration.
The chances of a secondary cutting edge squeezing a chip are also small.
If the face milling cutter uses a sparse-tooth unequal pitch milling cutter, the milling vibration can be reduced.
The word “tooth” here refers to the blade.
Face mills of the same diameter (say 100mm) must produce 50% less milling force with a 5-blade cutter than with a 10-blade cutter if they cut all three elements equally.
Use front and large rear corners of the blade with a light-hearted chip breaker slot.
Such inserts have the smallest cutting wedge angle in filing or milling, and the cutting is certainly light and fast.
Adjust the cutting parameters, which may only be effective if the cutting vibration is not severe.
The general adjustment method is as follows: reduce the tool or workpiece rotation speed, reduce the depth of cut and increase the amount of tool per revolution or milling tool abusive tooth travel.
If vibration occurs during the turning of an internal thread, the feed step to complete the thread turning can be reduced by 1 or 2 cuts.
Rationalize the process path of the blade. The proper routing of the process is very important for milling operations.
There is a distinction between straight and reverse milling, and traditional milling theory describes that the use of reverse milling is conducive to reducing milling vibration, which is actually conducive to suppressing the vibration generated by the clearance of the screw.
Most of today’s milling machines are fitted with the ball or roller screws, so reverse milling damping is of little significance.
No matter it is down milling or up milling, as long as the direction of the milling force is consistent with the clamping direction of the workpiece, it is beneficial to eliminate the vibration of the bending plate parts.