In the processing of the exact error calculation method to minimize the error of the parts, is one of the important factors leading to the dimensional error of the parts during the processing of the panty sanitary napkin equipment.

1. Trouser sanitary napkin equipment geometric method of calculating the positioning error

Positioning error due to inaccurate positioning of trouser-type sanitary napkin machinery on the fixture caused by processing errors, in the use of adjustment method of processing, the positioning error of the piecework is essentially the process benchmark in the direction of the maximum change in the processing size. Therefore, when calculating the positioning error, the process datum of the process size should be identified first, and then the maximum change in the process size direction should be identified. Therefore, the set method or the differential method can be used.

The geometric method is used to calculate the positioning error. It is usually necessary to draw the positioning diagram of the piecework and exaggerate the limit position of the piecework change in the diagram, and then use the triangle geometry to calculate the maximum change of the process datum in the direction of the trouser sanitary napkin machine dimensions, i.e. the positioning error.

If the process datum of the trouser sanitary napkin machine piecework is the hole center, try to determine the positioning error when the hole-pin gap fit.

When the piecework has the largest hole diameter and the smallest diameter of the positioning pin, the maximum change of the hole center in any direction is the maximum gap between the hole and the pin, that is, regardless of the size direction of the process (as long as the size direction of the process is perpendicular to the axial direction of the hole, the positioning of the hole-pin gap is wrong in some special cases, the hole of the piecework can maintain a fixed contact with the positioning on the fixture, at this time, the contact point and the pin center in the The maximum variation of the hole center in the direction of the connection between, i.e. half of the hole tolerance. If the process marker of the piecework is still the hole center, and the process size direction is the same as the direction of the connection between the fixed contact point and the pin center, the

The above formula is the technical formula for positioning error in the case ofpanty sanitary napkin equipment hole-pin gap fit and maintain fixed variable contact, the formula Damx, Dmin are the maximum diameter and minimum diameter of the positioning hole, TD is the hole diameter engineering. In this case, the positioning of the hole on the pin has actually been transformed into the form of support positioning, and the positioning datum becomes a bus bar of the hole in contact with the fixed edge as the upper bus bar of the hole. As the positioning datum and the process datum part overlap earlier, the positioning error at this time is earlier and belongs to the datum part overlap error, which has nothing to do with the pin diameter tolerance.

2. Pants type sanitary napkin equipment differential method to calculate the positioning error

Differential calculation of block positioning to explain the positioning error of trouser-type sanitary napkin equipment differential calculation method is the same as the dimensional chain calculation method.

Considering that the dimensional error can be positive or negative and absolute values are used for each error, the positioning error of the process dimension H can be obtained in small increments instead of differentiation and the dimensions (including linear and angular dimensions) are considered as small increments.

If the angular error of the V-block is neglected (in fact, in the case of supported positioning, the error of the positioning element - in this case the angular error of the V-block - can be compensated by adjusting the position of the tool relative to the fixture), it can be compensated by adjusting the position of the tool relative to the fixture. When the process is based on the center of the outer circle, the positioning error in the vertical direction is :

If the process reference of the piecework of the panty sanitary napkin equipment is the lower bus bar C of the outer circle (the corresponding process dimension is H,), its positioning error can be found in the same way. the distance from the point C to the point A is

Full differentiation can be obtained, neglecting the V-block angle error (i.e., with α as a constant).

The same method can be used to find the positioning error when the process reference is the upper bus of the outer circle (the corresponding process dimension is H2).

In some cases, the differential method is used to calculate the positioning error more concisely than the geometric method.

It should be noted that the positioning error is always for mass production and adjusted machining. The same problem of positioning error exists when processing by the adjustment method (using a sample part or a tool for a tool gauge) in single-piece production, or when processing in a trouser-type sanitary napkin machine. If the trial cut method is used for processing, the positioning error is generally considered.