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In CNC machining, problems often encountered include bounce, hit, overcut, etc. This article discusses the solutions to these common problems, hoping to learn from each other.

1. Bounce

Bouncing tool refers to the relatively large vibration of the tool due to excessive force. The hazards caused by tool jumping are overcutting of the workpiece and damage to the tool. When the tool diameter is small, the tool shaft is too long or the force is too large, the phenomenon of tool jumping will occur. If you use reasonable tools and processing methods, you can reduce the chance of tool jumping.

There are three main factors affecting tool deformation:

1) Tool length

2) Tool diameter

3) The force of the tool

1. Tool length

For a tool with the same diameter, when the length of the tool is doubled, its deformation will increase by 3 times. When machining, keep the tool length as short as possible to reduce the risk of bouncing tools.

2. Tool diameter

For a tool of the same length, when the tool diameter is reduced by 1 time, its deformation will increase by 4 times. When processing, choose a large diameter tool or use a reinforced tool for processing as much as possible to reduce the risk of tool bounce.

3. The force of the tool

The deformation of the tool is proportional to the force it receives during machining. Reducing the force on the tool reduces the chance of the tool bouncing. In order to reduce the force on the tool, the contact area between the tool and the workpiece must be reduced.

2. Collision

Hitting the knife means that the cutting volume of the tool is too large. In addition to the cutting edge, the toolholder also strikes the workpiece. The main cause of tool collision is that the safety height setting is unreasonable or not set at all, the processing method is improperly selected, the tool is used improperly, and the allowance for secondary roughing is set smaller than the allowance for secondary roughing. First roughing setup etc.

2.1 Too much cutting in cnc machining

  solution:

Reduce the amount of cutting. The smaller the tool diameter, the smaller the amount of cutting that 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 Improper cnc processing method

Change the profile milling mode to pocket milling mode. When the machining allowance is larger than the tool diameter, the contour milling method cannot be selected.

2.3 The safety height is not set properly, and the tool hits the clamp when lifting the tool

  solution:

(1) The safety height should be greater than the clamping height.

(2) In most cases, except for special workpieces, the "direct" tool advance and retreat mode cannot be selected.

2.4 Improper setting of secondary CNC rough machining allowance

The allowance for the second rough machining should generally be 0.05mm larger than the allowance for the first rough machining. If the allowance for the first rough machining is 0.3mm, the allowance for the second rough machining should be 0.35mm. Otherwise, the toolbar can easily hit the upper side wall.

In addition to the above reasons, tool collision may occur when trimming the tool path, so try not to trim the tool path. The most direct consequence of hitting the tool is damage to the tool and workpiece, and more seriously, damage to the machine tool spindle.

3. Over-cutting in cnc processing

Overcutting means that the tool also cuts the part that cannot be cut, resulting in damage to the workpiece. wait. In addition, if the operator does not set the knife accurately, it may also cause overcutting.

When programming, you have to be careful and meticulous. After completing the program, the toolpath needs to be checked in detail to avoid gouging.

As a professional, Xiehe not only produces metal precision parts, but also provides processing of plastic parts.

CNC machining service is the core business of Xiehe, from to mass production, our professional 3/4/5 axis CNC machining centers, CNC lathe equipment, CNC turning and milling equipment, CNC grinding machines, etc., are all operated by well-trained manufacturing engineers .