Vertical machining center is generally equipped with a vertical CNC lathe on the lathe, Vertical machining center some parts of the work will be installed on the lathe for processing. In the use of the process, because of the cutter reason, there will be over-cut, sub-not and so on, the following we will look at its solution.
1、 The numerical control system of the Vertical machining center does not set up tool setting program, nor does it set up tool compensation value. Solution: CNC tool set parameters will be modified to the required tool set parameters, or the use of automatic tool set procedures.
2、 When processing a part, the positioning accuracy of the workpiece is affected by the blank size of the workpiece or the positioning error of the tool. Therefore, the positioning and checking of the workpiece shall be carried out repeatedly during production to ensure the position relationship between the tool and the workpiece. Solution: After setting the tool compensation value, press the setting key of cutting parameters, press the Enter key to start the cutting process.
3、 When there is indexing error in the workpiece, over-cutting may occur. The solution is: the indexing parameters may be modified by programming instructions; the compensation may also be made by setting the value of tool compensation; the program segment in the program may also be set to code related to the workpiece, so that over-cutting does not occur during processing.
4、 When the indexing error of the part is large, the over-cutting phenomenon will appear. Solution: The processing error can be compensated by increasing the height of the workpiece.
Overcut
Over-cutting refers to the relative displacement between the cutting tool and the workpiece in the process of machining. After over-cutting, the cutting tool and the workpiece may collide and damage.
General over-cutting is caused by improper setting of process parameters, such as the actual size of the workpiece in processing than the set value, or tool tip speed than the set value will cause over-cutting.
The main reasons for overcutting are as follows:
1、 There are problems with the installation of machine tools in the processing center;
(2) There is any problem with the size of the rough parts;
3、 The positioning error is too large when the parts are clamped;
4、 The collision of tool tips and the size error of workpieces are not taken into account in the programming.
Score
The error after indexing is called dividing error. The dividing error refers to the difference of the size deviation between two adjacent processes in the same machining surface. The dividing error is an important factor for the precision of geometry and dimension, which is generally divided into two kinds: geometric precision and dimension precision.
Indexing error
A) Different positioning benchmarks for workpieces;
B) The relative position between the cutter and the workpiece is not well adjusted;
C) There are errors in the shape of the positioning datum, such as central hole, bridge, etc.
2. Solution:
A) If the workpiece has indexing error, it may be checked according to the size to determine the best indexing scheme;
C) The tool holder and tool holder shall be adjusted according to the degree of tool wear during processing.
3. Notes:
A) For the workpiece with complex shape, the processing method of “once clamping, once processing” shall be adopted as far as possible; for the workpiece with high surface roughness requirements, the rough processing may be conducted first, and then the precision processing may be conducted;
B) For finished workpieces, coarse processing shall be followed by fine processing.
Causal analysis
1、 When machining by vertical machining center machine, burr or fuzz appears on the surface of workpiece, which affects the positioning accuracy of workpiece.
2、 If over-cutting occurs during the cutting of the vertical machining center machine tool, it may be caused by the uneven speed or feed speed of the main shaft.
3、 When the gap between the cutter and the workpiece is relatively large, over-cutting will also occur, so the gap between the cutter and the workpiece shall be adjusted well before the workpiece is processed.
4、 If the indexing error of the cutter is large, it may lead to over-cutting.
Solution
1、 Setting the program segment in the program as the code related to the artifact, so as to avoid over-cutting;
2、 Modifying the parameters of the cutter;
4、 Changing the coordinate system of the workpiece to keep the cutter running on the workpiece origin.
5、 After the numerical control machine tool is installed, the rotation of the spindle and the tool rest shall be checked first to see whether they are normal. If abnormal, should be adjusted and re-check and adjustment. In addition, in the actual operation, to pay attention to safe operation, to avoid personal injury or equipment damage.
Post time: Mar-20-2023