How to set up wire drawing dies for wire drawing machine?

In the process of wire drawing, the main basis of die matching is the drawing process of the wire and the characteristics of the wire drawing machine. The drawing process also includes drawing route, drawing pass, drawing total compression rate and distribution part compression rate. Therefore, the influence and change law of the above factors must be considered when the mold is configured, according to the characteristics of different wire drawing machines.

1. The mold calculation principle of continuous wire drawing machine.

Because the continuous wire drawing machine has a multi-reel, it can realize the characteristics of multi-pass continuous drawing. When the metal wire is drawn by the continuous wire drawing machine, its diameter gradually decreases and the length extends, then the line speed of the drum should also increase in order to achieve continuous drawing. Therefore, it is necessary to understand the relationship between the change of wire diameter and the drawing speed when the mold is configured. According to the running characteristics of the wire drawing machine can be carried out mold calculation.

(1) The relationship between the diameter of the die wire and the drawing speed.

According to the drawing principle, the steel wire is drawn through each die hole, and the metal volume passed by each die hole in the unit time is unchanged. The following formula can be listed:

V=F₁L₁=F₂L₂=...... =FnLn   (1)

Formula: F1, F2...... FN is the first, second,...... The cross-sectional area of the wire in n passes.

L1,L2...... Ln is the first, second,... Length of wire for n passes.

V is the volume of wire passing through the die hole per unit time.

Because the wire length in each pass drawing die hole per unit time is the wire speed of each pass, expressed in V, the formula (1) can be written as: F1V1=F2V2..... =FnVn......... (2)

Substitute F=Πd2/4 into (2).

The result is d₁²/d₂²=V2/V1..... d_n-1²/d_n²=Vn/Vn-1  (3)

In equation (3), d_n-12/d_n2=u (elongation coefficient)

Vn/ VN-1 =i (ratio of wire speed before/after drawing)

Then: u=i=Vn/ VN-1 =dn-12/dn2

Since the broken area of the metal wire is reduced after the wire drawing die, and the length is extended, in order to achieve continuous drawing, the linear speed of the metal wire through the last reel must be greater than the linear speed of the previous reel, and the ratio of the speed should be at least equal to the elongation. This is the basic guarantee to achieve continuous drawing, and it is also the basic principle that continuous drawing machine mold should follow.

2. The matching point of pulley (integrated line) type wire drawing machine

The pulley type wire drawing machine ADAPTS to the extension of the metal wire on the front and back of the reel in continuous drawing by using the accumulation line. Therefore, the integrated wire drawing machine design has a fixed speed ratio, can not be arbitrary mold; The drawing process must be formulated according to the die matching coefficient.

According to formula (4), DN-1 =dn*i=dn (5)

Kn==i

Kn is called the mold coefficient (also known as the machine coefficient). It can be seen from the formula (5) that the wire diameter of the previous thread can be obtained by multiplying the mold coefficient Kn by the wire diameter of the (n) pass.

So D_n-1 = Kn*dn (6)

For the product line drawing machine, in order to maintain a certain amount of product line on the drum, the mold allocation coefficient can be increased by 0.01-0.05, that is, the product line coefficient is 1-5%