The most commonly used verification method for 5-axis machining of impeller parts is: tool path display verification method. That is, display the wire frame of the tool position data (tool center coordinates and tool axis vector) to determine whether the tool path is continuous and verify that the tool position calculation is correct. Then it will display the tool position data and the wire frame of the machining position to determine whether the tool path is correct and whether the tool path and forward and backward methods are valid.
The basic idea is as follows.
Extract the contours related to all processed surfaces from the surface modeling results, extract the tool path information from the tool position calculation results (tool position files), and display them in combination. Or, place the tool model at the selected tool point and move the tool model along the trajectory. Therefore, determine whether the position of the tool core on the tool path, the vector of the tool axis, the relative position of the tool and the machined surface, and the forward and backward methods are reasonable.
1. Verification of tool path display
How to verify the display of the position track of the impeller blade: After the NC machining program of the impeller blade is generated, the tool position track is displayed on the graphic display to determine whether the tool position track is correct. Among them, CNC machining program feedrate, tool selection, program line number and other information should be removed first, and only the verification information is displayed. Next, perform “reverse post-processing” on the tool path information, obtain the NC machining program containing the tool path information, and draw the tool path. Next, I will explain this in a few lines of a 4-coordinate CNC machining program for machining the inlet and outlet sides of a large impeller.
Goal The three coordinate values of X, Y, and Z in this program are the values after the turntable is rotated by angle A. If you want to find the position coordinate of the tool when processing this point, you need to perform the following “reverse post-processing” calculation.
X1 = xy1 = ycos (-A) + zsin (-A) z1 = -ysin (-A) + zcos (-A)
The calculated (x1, y1, z1) is the coordinate of the tool location point, and this tool location file can be used to draw the tool path.
Judgment principle of tool path display verification
- 1. Whether the tool position trajectory is continuous.
- 2. Whether the tool path connection is smooth.
- 3. Whether the tool paths intersect.
- 4. Do you need to fly?
- 5. Is there a sudden change in the tool axis vector?
- 6. Is the tool path connection on the bumps valid?
- 7. Whether the tool path is valid when machining the combined surface.
- 8. Whether the cutting direction matches the surface shape.
2. Verification of combined display of machining surface and tool path
The basic method of combined display verification: simultaneously display the tool position track and the wire frame of the machined surface on the graphic display to determine whether the tool position track is correct, and the tool path and advance and retreat method are appropriate.
Judgment principle of compound display verification method
- 1. Whether the relative position of the tool path and the machining surface is appropriate.
- 2. Whether the offset direction of the tool path meets the actual requirements.
- 3. Does the tool interfere with the machined surface?
- 4. Are the positions and methods of the front and rear knives appropriate?
In summary, the display verification method is a good way to verify the contour of the impeller blade, especially the blade tip and blade root fillet. It is intuitive and easy to implement. When rotating on a computer monitor, it can be observed particularly accurately from three coordinate directions.