Accuracy Analysis of the Workpiece of CNC Lathe
Cause and Solution of Dimension Accuracy of Shaft Type Workpiece
1, because the operator is not careful, test the child when the error, or dial wrong and improper use
Therefore, in the measurement, to carefully, the correct use of the dial is very important to handle the dial tray, the various models of the dial is not the same lattice, each small grid dial can be calculated using the following formula :
Scale to a lathe tool movement distance = carriage screw distance / dial a total number of grid lines (mm)
Know the value of each grid scale, the use of attention also because there is a gap between the screw and nut, and sometimes dial although the rotation, but the tool does not necessarily move, and so the gap after the switch to complete the move. So in use, if the scale turned over the grid, and never allowed to only reverse a few cells, but to turn after a turn, and then re-aligned scale.
2, the gauge itself has errors or use is not placed positive
Before the use of measuring tools, to be carefully examined and adjusted, when used to put positive.
3, due to temperature changes, the workpiece size change
At the time of cutting, the chips are deformed, and the individual molecules of the chips move with each other, and they move friction and generate a lot of heat. In addition, the chip and the front of the friction occurs, behind the lathe and workpiece surface friction also produces heat, these heat directly affect the tool and the workpiece up. Of course, the highest heat is chip (about 75%), followed by turning tools (about 20%) and the workpiece (about 4%, and 1% in the air). When the workpiece after heating to increase the diameter (about 0.01 ~ 0.05 mm, cast iron change than the steel material), cooling diameter contraction, resulting in waste. It can not be measured when the workpiece temperature is high. If you must be the amount of side, in the turning when pouring enough cutting fluid, not to make the workpiece temperature; followed by coarse fine car separate method.
4, blank surplus is not enough
The blank itself is not bent straight, as well as the central hole deviation and other reasons.