Various single-factor processing errors can be divided into systematic errors and accidental errors according to their nature.
1. Cutting machine system error
When the hydraulic cutting machine processes a batch of parts in sequence, the error that the size does not change is a regular change is called system error monitoring. The former is a constant system error, and the latter is a systematic error that changes regularly (variable recovery system error). For example, use a diameter smaller than the specified size o. 02 reamer, the diameter of all holes reamed is smaller than the specified size o. 02, this kind of error is often a systematic error. In the case of an axle, due to the wear of the turning tool, the white diameter of the turning shaft is larger than one. The increase in the vertical diameter of the shaft is regular, so the error caused by the tool wear belongs to the systematic error of regular change (variation). Bai system error). The thermal deformation of Ran Ruding's system is also a variable system error.
2. The cutting machine is occasionally poor
In adding a batch of parts, the size and direction of this kind of error are irregularly changed, sometimes large, sometimes small, sometimes positive, sometimes negative. Such errors are called accidental errors. For example, when a four-column cutting machine uses a reamer to process a batch of holes for parts, under the same conditions, a batch of holes with exactly the same diameter and size are still required. This may be due to uneven hardness of the blank and AJJl' margin. Differences, the redistribution of internal stresses cause deformation and other factors, these factors are always changing. Although the causes of accidental errors are various, and the role of cutting machines is very complicated, the law of accidental errors can be found and controlled by the method of mathematical statistics.