Mechanical analysis during processing:
When the tool is processing the workpiece, a component force will occur in the radial direction, the entire tool is a tool body. Therefore, when the force is applied, the cutter body will be deformed, an error will be generated in the direction of the force. There is a displacement, so that the machining depth becomes smaller, the force becomes smaller, the displacement becomes smaller. Move in the opposite direction of the force. In this way, the depth of cut becomes larger larger, the knife body moves in the direction of force again, so the oscillation is formed repeatedly.
In a word: the so-called vibrating knife, the cutting force that changes during the machining process acts on the tool the workpiece, thereby oscillating.
There are three related elements of oscillation:
1. The strength of the blade itself
The strength of the knife body: the thicker shorter the knife body, the greater the strength, so shortening the knife body can handle the problem. If the processing length is required, then also pay attention to the following problems: the extension length of the steel shank is controlled below 3 times the diameter, the extension length of the heavy metal shank is controlled below 5 times the diameter. Arbor.
2. The size of the cutting force
Cutting force: The smaller the cutting force, the smaller the oscillation. The use of larger rake angles, smaller edge widths, reduction of feed cutting force can all deal with the vibration knife problem.
3. Strength of the workpiece
Another factor that affects the oscillation is the vibration frequency, which is the same oscillation frequency of the part tool machine tool during the cutting process, resonance occurs immediately.
How to deal with the oscillation problem the viewpoint of vibration frequency? It is the wrong peak, that is, the machine tool is at this frequency, the tool is at another frequency. The problem of turning vibration frequency is basically caused by the machine tool the workpiece, there is no good way to deal with it. The blade of a milling cutter has many teeth, it has a frequency of its own, so if the milling cutter vibrates, it can be changed to an unequal milling cutter, the function will be much better.
There are oscillations in the processing, even small oscillations will have a great impact on product quality life. It is more troublesome to deal with the vibrating knife in processing, which involves many aspects, such as tools, machine tools, parts clamping, programming, etc. What are the detailed treatment methods?
The simplest way is to adjust the processing parameters.
When we process parts, the parts appear chatter marks, the first thought is to adjust the cutting parameters, for example, to reduce the cutting linear velocity, etc. Today, we mainly explain how to deal with the vibrating cutter in milling the perspective of the tool. The potential oscillation factors are dealt with at the time of tool selection, which is more important than the occurrence of oscillations in the processing then thinking of treatment methods.
1. The thicker arbor can be selected for the thick one, the short point can be hanged as short as possible. After all, the thicker the shorter the stronger the tool. Increased tool life processing power have a significant effect.
2. The main declination angle: The main declination angle determines the force direction of the tool. The larger the main declination angle, the smaller the axial force the greater the radial force.
3. Number of teeth: The number of teeth directly affects the size of the cutting force. The more the teeth of the cutter, the greater the cutting force.
In order to improve the processing power, choose multi-tooth cutting tools as much as possible, the multi-tooth feed is large. However, under unstable working conditions, such as lack of rigidity of parts deep hanging, etc., in order to reduce the cutting force, try to choose sparse tooth tools.
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