The new principle of the sliding (water tank) multi- drawing die is constructed after comprehensively correcting the mistakes in the traditional theory and supplementing a series of new concepts. It fully clarifies the characteristics of clear sliding and its role in stretching and other objective laws, and provides a scientific basis for planning a novel high-speed and high-efficiency sliding wire drawing machine.
Tungsten steel mold manufacturers introduce new accounting formulas and basic concepts
Slip exists between the wire being pulled and the surface of the drum (reel), and it occurs because the surface speed B of the drum is artificially made slightly larger than its actual line speed V. As long as there is no slip on the final drum, that is, B= Vk is an exception. The size of the slip can be obtained by the partial slip coefficient L and the cumulative slip coefficient Tn, indicating
In the process of piercing and normal stretching, the onset and existence of sliding can be analyzed as follows:
(1) When a certain length of thread is drawn from the n drum wheel by an external force after the piercing mold passes dn for the next piercing process, the n drum wheel generally does not slip temporarily, which can be recorded as;
(2) When a certain length of thread is drawn from the n+1 drum by the external force after passing through the mold through dn+1, there will be no slippage on the n+1 drum temporarily, which can be recorded as. But at the same time, there is sliding on the n drum (that is, because Bn is always slightly larger than Vn in the mold matching plan, when the aforementioned external force does not exist, the sliding will occur automatically, that is, it also has a temporary nature;
(3) Continue to wear the mold backward, and there will be a temporary sliding lift on the n+1 drum. O, and the cumulative sliding figure 7 on the knife drum at this moment is also temporary;
(4) In normal stretching, except for the "tk-1 period alone, so the -1 drum is alone, the r of each track only temporarily exists on each drum separately during the process of piercing." The mold is carried out one after another, tired
Product sliding T7. Just getting bigger and bigger
(5) After all the mold-piercing is completed, all the sliding amount on the knife drum wheel. It will be as shown in formula (5) and will exist in the knife drum for a long time during stretching;
(6) In theory, it is required that the wire take-up equipment of the wire drawing machine should have sufficient wire take-up tension to ensure that there is no slippage on the dot drum (ie Bk=Vt). Respectively 1.0.
The above-mentioned changes in the onset, temporary existence, and forward accumulation of sliding have been expressed in equations (4) and (5) in practice. During this period, the relationship between B and y and the cumulative situation of sliding forward are still
It can be expressed in tables.
The derivation process of formula (4) and formula (5) can be found in the literature [4][5]. They are all derived from the specific conditions of Bn/vn and fully show how slippage occurs, exists, and bulges forward. Round accumulation
The characteristics and objective laws of the new principle are the center and foundation of the new principle.
The formula (4) can be used for the calculation of the model matching: the drawing 8+1 is substituted into (4). You can get the common calculation formula of matching model
In the formula: "can be given in advance, yn+1. It can also be predicted. Therefore, when one of dn and dn+1 is known, the value of the other can be obtained.
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