Stamping die design-layout and distance design method
The layout plan has a significant impact on the utilization rate of materials, the manufacturability of stamping processing, and the structure and life of the mold. According to statistics, in the cost of stamping parts, material waste accounts for more than 60%. Therefore, reasonable layout is of great significance for improving material utilization and reducing product costs.
1. Layout
1. Layout plan
There are many positions that parts can be intercepted on the sheet, which determines the diversity of the layout plan. Typical layout plan and characteristics.
According to whether waste is generated during nesting, nesting can be divided into nesting with waste and without waste. The waste during blanking can be divided into process waste and design waste. Process waste refers to the waste produced by the positioning holes of the edge material between the workpieces and between the workpiece and the strip and the inevitable material head and tail. Design waste refers to the waste generated due to the shape of the product, such as the existence of holes. No waste material layout, high material utilization rate due to no or less layup
But pay attention:
(1) There are lateral forces that affect the accuracy and life of the mold.
(2) The burr directions of the front and rear products are inconsistent.
(3) The temporary wiring of adjacent products is shared. If the positioning is not accurate, the problem of more cutting and less cutting is likely to occur.
2 layout principle
(1) The material utilization rate should be as high as possible.
(2) Meet the requirements of product parts blanking and subsequent processes, such as:
1. Requirements for fiber direction and burr direction;
2. Facilitate completion of subsequent processing procedures;
3. High productivity and easy operation;
4. The security is better.
2. Take the side
Overlap refers to the residual material set between the outline of the blank and the side of the strip and the outline of the adjacent blank during layout. The function of the lap is to ensure the separation of the blank from the strip, and to compensate the residual material required for the deviation of the strip during the feeding process due to the positioning error. Riding sides are divided into side and center sides. The basic requirement of the lap is to have sufficient strength, and the strength of the lap is mainly determined by the width of the lap.
The lap width is an important process parameter during layout. Factors to be considered in the selection of lap width:
(1) Material utilization rate (2) Punch strength (3) Rigidity of the strip (4) Product quality
If the edge value is too small, it is easy to warp or be stretched during punching, which will increase the burr of the punched part.
According to Table 3-10 of <<Ling Die Design>>, select the edge value a=1.5mm and a1=3.0mm.
3. Step distance
The step distance refers to the distance that the strip is fed forward each time during the stamping process, and its value is the minimum distance between two adjacent blanks in the feeding direction during layout. The step distance can be defined as
S=L+a=15.24mm
In the formula, S-blanking step;
L─Along the feeding direction of the strip, the maximum width of the outline of the blank;
a─The edge value along the feeding direction.
4. Strip width
The strip width refers to the minimum size in the width direction of the blank determined according to the layout result. In theory, the width of the strip is calculated as follows:
B=D+2b
Where B is the theoretical value of strip width;
D─The maximum contour size of the blank perpendicular to the feeding direction, which varies with the layout orientation of the blank;
b─Side value.
Due to mold processing errors, strip cutting errors, and feeding errors, the actual strip width should have a certain margin, and the specific dimensions can be calculated according to different feeding side positioning methods.
This mold is a mold without a side pressure device. When the strip is fed, it may swing between the guides, thereby reducing the overlap on one side. Therefore, when calculating the width of the strip, the reduction in the side overlap should be compensated. The width of the strip can be calculated as follows:
B=D+2(b+△)+Z=37.5mm
Where B is the width of the strip;
△─One-way (negative) tolerance of strip width, see Table 4-2;
Z─The gap between the strip and the guide plate, see Table 4-1.
Fives
Material utilization
Material utilization is defined as
Ч=A/（B*S）*100%
In the formula Ч─material utilization rate;
A─The area encompassed by the rough shape of the product;
B-strip width;
S-Blanking step.
The larger the Ч, the smaller the area occupied by waste. Therefore, Ч is generally used as an indicator to measure the quality of the blank layout plan.
and so
Ч=A/（B*S）*100%
=507.006/(37.515.24) 100%
=88.7%
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