The selection of the base tolerance grade of the automatic assembling machine determines the tolerance band of the Datum hole or datum axis, and the size of the tolerance band of the non-standard parts, so the matching selection is actually the location of the non datum parts, that is to say the basic deviation of the Non datum.
The calculation method is based on certain theory and formula to determine the required clearance or interference, so as to limit and match the design, mainly used for automatic assembly machine clearance and interference fit. For example, for the gap fit of a sliding bearing, the minimum allowable range is calculated according to the liquid lubrication theory. Then select the standard type of fit.
The basic deviation of all kinds of codes, under certain conditions, represents a variety of different cooperation, so the choice of matching is the basic deviation of the choice. The method of selecting and cooperating of automatic assembling machine has 3 kinds of calculation method, test method and analogy method.
The test method is to determine the gap or interference through test or statistical analysis. This method is reasonable and reliable, but the cost is higher, so it is only used for the key cooperation of the main products of automatic assembly machine.