One is machining accuracy and the other is measuring accuracy.
How to reflect the size required by the designer is the machining accuracy, and how to know the size completed by the machining is the measurement accuracy. Both of these accuracy are directly dependent on the accuracy of the machining machine or the working machine of the measuring machine.
The machining accuracy of machinery and equipment will only be lost rather than increased. Therefore, even if the assembly error is not taken into account, the machinery assembled by the parts processed by machinery with medium machining accuracy can only achieve low accuracy, and the parts assembled into medium precision machinery should be produced.
It can only be made using high-precision machining machines. According to this reason, to manufacture high-precision processing machinery, can only use ultra-high precision processing machinery.
It is the guide rail that has the greatest influence on the precision of machining machinery. The movement part of the machine is limited by the guide rail, the precision of the guide rail directly determines the precision of the mechanical movement. The sliding surface of the ultra-precision mechanical guide is called the “absolute plane”,
People who have seen the guideway sliding surface of high-precision machine tools all know that the so-called “absolute plane” is not a smooth mirror, but a plane with regular patterns all over it. The patterns are the traces left by the knife of the artisan who made this plane.
Absolute plane manufacturing process
Experienced artisans with a shovel knife to rough the plane to level, shovel out the needed plane at the same time also do a control plane, and then paint the color on the control plane, the processing plane on the control plane sliding.
At this time, the part of the processing plane stained with color and the part of the control plane dropped color are respectively the two planes on the higher part of the need to shovel off, this process is repeated until the two planes on the color completely uniform, at this time the plane left on the knife mark is just as the lubrication groove, killing two birds with one stone.
But this is not an absolute plane, because if two planes form the same radians, it will have the same effect, it just means that two planes are exactly the same, it doesn’t guarantee that they are a plane, so you need another reference plane.
Generally speaking, when processing the absolute plane, we need to process three planes at the same time. When any two of these three planes are consistent, we can calculate the absolute plane.