An algorithm for finding the ultimate drawing ratio of a rectangular deep drawn piece

The formula for calculating the material of the cylindrical deep-drawn part is d0 a, which is generally calculated separately by dividing the deep-drawn part into three parts. That is, the area of the straight cylinder, the area of the fillet at the bottom, and the area of the circle at the bottom.

Straight cylinder area a1 d h r ;

Bottom fillet area a2 [2 d 2r 8r ] 4 bottom circle area a3 d 2r 4

a＝a1＋a2＋a3

d0＝√a1＋a2＋a3 ／π

d0＝√4﹛d﹙h－r﹚π＋2πr﹙d－2r﹚＋8r²]π4＋﹙d－2r﹚²π4／π

d0＝√﹙d－2r﹚²＋2πr﹙d－2r﹚＋8r²＋4d﹙h－r﹚

Equal volume method!! Master an ultimate stretch factor. Drawing mold, debugging is very important. In practice, the tension height is often adjusted.

There are formulas to calculate, or pre cad calculations.

The deformation of the stretching process is characterized by the large cross-sectional area of the blank to the small cross-sectional area of the cylindrical piece, the so-called drawing coefficient, that is, the ratio of the cross-sectional area after each drawing to the cross-sectional area before drawing

i.e. m=an an-1

m – drawing factor.

an——cross-sectional area (mm) after drawing

an-1 - cross-sectional area before drawing (mm).

For cylindrical parts, the drawing factor should be:

m=an an-1=( dnt) ( dn-1t)=dn dn-1 where m - the drawing coefficient of the cylinder.

dn - diameter after drawing (mm).

dn-1 – diameter before drawing (mm).

t – the thickness of the material.

The drawing coefficient of the cylindrical part is the ratio of the diameter of the cylindrical part after each drawing to the diameter of the blank (or semi-finished product) before drawing. Namely:

First drawing m0=d1 d0

Subsequent draws m2=d2 d1, m3=d3 d2,......mn=dn/dn-1

where m1, m2, m3 ......m0 - each drawing coefficient d0 - blank diameter (mm).

d1，d2，d3，……d0 - the diameter of each semi-finished product or workpiece (mm).

The size of the deep-drawn part is calculated differently depending on the shape. Here's how:

1. Cylindrical deep-drawn parts, the blank is a disc, and the volume of the disc before drawing is equal to the volume of the rear cylinder, the head and the straw hat edge. Assuming the drawing process, the wall thickness of the material does not change, and the diameter of the blank disc can be calculated. In practice, the wall thickness of the material changes very little, and the calculation is relatively reliable.

2. The algorithm for the diameter of the blank of the round table-shaped deep-drawn part is similar.

3. The basin-shaped deep-drawn parts can be "cut" into discs, rings, barrels and several round tables for approximate calculation.

4. The length of the longitudinal section and the cross-section can be used as the length and width of the blank, and the length of the drawing is not large.

5. The blacksmith could not come up with an approximate calculation method for the shape and size of the blank of other deep-drawn parts. The blacksmith is estimated based on the experience of ironmaking, and the shape and size of the blank are corrected and determined after the drawing test, and he is incapable of summarizing and rising to theory.

The area of the blank is not constant when drawing, it is affected by the mechanical properties of the material, the geometry of the mold, lubrication, the geometry of the workpiece, the drawing coefficient and other factors. Therefore, there is no direct formula for drawing...

How to calculate the size of the stretched productHow to calculate the size of the stretched productHow to calculate the size of the stretched product? Thank you. 6 people Fu Doulei and his dad look at the social high fan answer2019-04-20Student consultation attentionThank you for your attention to the material size calculation of the drawing mold design:

The first step in the design of the drawing die is to calculate the material size of the product, which is mainly calculated according to the law of invariance of the total volume of the material. That is, the size of the product is calculated by the surface area of the product: the material formula of the round product of the drawing die, and the size of the stretched part with an outer diameter of 50mm and a height of 60mm material thickness on the right is calculated as follows:

The size calculated by the formula 50* *2 = 120mm is basically close to the actual size of the material. (Formula note: diameter d * height h = product cylindrical surface area, r square * = bottom area, the sum of the two divided by the re-opening square = radius of the product * 2 is approximately equal to the outer diameter of the product) in practical application should also consider that the trimming margin can be appropriate.

Hope mine is helpful to you.

Questions. Thank you.

The ratio of the end area of the material after each stretch to the end area before stretching is called the stretch coefficient of that time. The tensile coefficient actually reflects the degree of deformation of the stretched part. The ultimate stretch coefficient is the ratio of the end area of the material when it is stretched to its maximum extent to the end area before it is stretched.

When drawing, if it is not thinned and drawn, the size of the blank can be calculated according to the principle that the area of the blank before and after drawing is equal. Generally, the cylindrical parts are decomposed into: straight cylindrical shape, bottom R shape, bottom garden piece shape, and the area of the three parts is equal to the garden area of the blank.

m=m=diameter after drawing Diameter before drawing.

Appreciate this panacea answer.

(1) Determination of the number of drawing times.

a Find the drawing coefficient of the workpiece: mz=d d

b If mz> m1, it can be drawn and formed in one pass; If the mz < m1, it is necessary to draw it several times (two or more times).

c Find m 1, m 2, m 3 ......m n until the volume is less than m z, and the last n is the number of draws.

d Another method is determined by the relative height h d and the relative thickness t d of the workpiece.

e The purpose of multiple deep drawing is to prevent tearing.

There are several common ways to cut the edge of a deep-drawn piece. 1。The side of the car.

Generally, the deep-drawn pieces are relatively small. Instrument lathes are available. 2。

Stamping and trimming. Extend the edge of the punching part and make the trimming die. However, the catchy is relatively sharp and a bit fast.

3。Stamping and trimming. in the drawing of the punching piece.

External 3-5mm trimmed edges. Straighten it again. 4。

Rotate the trim. For square parts. The mold is a bit difficult.

It can be entrusted to our factory for processing. In addition, is there any other way to curl the edge besides spinning? Separately asked.