In CNC machining, we often encounter problems such as bouncing, hitting, over cutting, etc. This paper discusses the solutions to these common problems, hoping to learn from each other.
1. Bounce
Bouncing tool refers to the large vibration caused by excessive force on the tool. The harm caused by tool skipping is to cause workpiece over cutting and tool damage. When the tool diameter is small, the tool axis is too long or the force is too large, the tool will jump. If reasonable tools and processing methods are used, the chance of tool jumping can be reduced.
There are three main factors affecting tool deformation:
1) Tool length
2) Tool diameter
3) Force on tool
1. Tool length
For the tools with the same diameter, when the tool length is doubled, its deformation will be increased by 3 times. During processing, shorten the tool length as much as possible to reduce the risk of tool bounce.
2. Tool diameter
For tools of the same length, when the tool diameter is reduced by one time, its deformation will increase by four times. During machining, large diameter tools or strengthened tools shall be selected as far as possible to reduce the risk of tool bounce.
3. Forces on tools
The deformation of the tool is proportional to the force it is subjected to during machining. Reducing the force on the tool can reduce the chance of tool bounce. In order to reduce the force on the tool, the contact area between the tool and the workpiece must be reduced.
2. Collision
Cutting means that the cutting amount of the tool is too large. In addition to the cutting edge, the tool bar also hits the workpiece. The main reasons for tool collision are that the safe height is set unreasonably or not set at all, the processing method is selected improperly, the tool is used improperly, and the allowance for secondary rough machining is set less than the allowance for secondary rough machining. First roughing setting, etc.
2.1 Too much cnc machining and cutting
Solution:
Reduce the amount of cutting. The smaller the tool diameter is, the smaller the cutting amount should be eaten. In general, the cutting amount of each rough opening of the mold is not more than 0.5mm, and the cutting amount of semi finishing and finishing is small.
2.2 Incorrect CNC processing method
Change the contour milling mode to cavity milling mode. When the machining allowance is greater than the tool diameter, the contour milling method cannot be selected.