The higher accuracy of the mounting surface, the higher the price
In general, mechanical parts, once assembled, the components of the error will add up, most of the examples are the cause of the decline in accuracy after assembly. However, the use of ball linear guides, there is elastic deformation due to ball and absorb installation error, or the ball and the ball rolling groove by the contact between the structure, not only the accumulation of errors, but errors smaller than the original product type.
Do not understand this situation will improve over the mounting surface accuracy will increase overall manufacturing costs.
Absorb installation-error
Standard and non-rail width 25mm preload gap of ordinary 2-axis parallel to the product tolerance when comparing the radial form "SR25" as 50μm, four-way equal load type "HSR25" as 30μm, up and down the track to allow error according to standard 25mm rail width when compared to, "SR25" as 200μm, "HSR25" as 130μm, allowing a great value. Allowed value of large linear guides do not need to install the surface accuracy can be raised too high to meet the requirements. Therefore, to reduce machining costs, and assembly, alignment operation simple, reducing the processing, assembly work, the results can create a more competitive overall price of the device.
The larger model, the greater the tolerance. Whether from the load, the life of the selected point of view or from the mounting surface to absorb the amount of error point of view, it is important to choose a slightly larger model rail.
However, the choice should note that this value with the linear guide rail allows the manufacturer to another. Will soon exceed the allowable value end of life.
With the average accuracy of the results
After assembling the table, the linear guide rail to absorb errors, improve accuracy of the effect of movement on stage as the average accuracy of results. This effect by the rigidity of the machine table, or change, there are reports that the mounting surface can improve the precision error of the value of 1/4-1/7.
Ball of the Hertz theory based analysis of 1/4.4, which is theoretically the rail, slide, treated as a rigid body such as installation of nuts obtained similar results. With this in mind, the actual should be smaller than 1/4.4. Given the amount of alignment error and the table of the amount of actual change location accuracy than the average coefficient is called, and the experiment, the factor of 1/7.1. We believe that 1/7.1 of the test results have considerable reliability.
Therefore, the linear guide rail will be installed with the basic processing and assembly generated when the vertical flatness, parallelism and other alignment errors after averaging absorption characteristics.
Clever use of this functionality can create accurate table, using the general linear rail industry can get 0.6μm/110mm upper and lower accuracy (vertical), stringent accuracy requirements can be applied to semiconductor manufacturing equipment.
Because this value with the average of the results of the linear guide manufacturer varies, so it is necessary according to the chosen design of the corresponding linear guides.
Error of the linear absorption method rail
some consider the error of the linear guide is designed to absorb method. To be installed on difficult to obtain precision machining and parts of the plane, you can choose the contact structure for the ball DF (positive combination) product composition structure to absorb the error structure.
Because the "automatic adjustment" good DF construct linear guide rail will be installed inclined surface absorption by rail itself, so the slider assembly on the bench is not easy deformation.
To further improve the linear guides of "auto adjustment function", the need to improve the rigidity of table. Table is to increase the rigidity of the device using precision linear rails important factor.
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