Progressive die connecting rod type stamping parts in the electrical industry as a kind of connection is quite common, and the size accuracy requirements are high, it plays the role of force transmission even relay, if the size can not meet the requirements of product design, will cause serious impact on the whole product transmission mechanism may make the transmission mechanism can not work normally.

Secondly, its shape is more complex, a variety of different properties of stamping as a whole, so the formation of a certain degree of difficulty.

There are two ways to produce this kind of parts: one is to use the normal process scattered in the more simple mold, and the other is to concentrate the process in a progressive mold.The former need more equipment, mold and the number of workers, the labor intensity of workers, and because it is to pay more mold to complete the whole production process of parts, various factors will cause the accumulation of processing error, especially for some high precision, large output of connecting rod parts quality and quantity are difficult to be guaranteed in a single process mold.When the shape of the workpiece is relatively complex and small, the strength of the concave and convex die of a single process mold will be constrained, and it is difficult to deal with the positioning of the front and rear processes, and the interference between the front and rear processes.

This paper designs the progressive die for the parts shown in the air cover of the high-grade small round machine lighter, and emphasizes the superiority of CAD design in the progressive die for connecting rod parts.

Application of CAD software in progressive die of connecting rod

Part process analysis

The connecting rod parts shown in figure 1 are integrated with stamping processes of different properties, such as blanking, fixed extension, local polishing of bending, forming bending, etc.The diagram is the layout diagram of the part.From the point of the precision of parts, 2-3 + 0.05 D Φ symmetry requirement IT10 level, connecting rod high dimensional accuracy IT11 level, forming precision IT11 magnitude of bending deflection other sizes all IT16 grade precision.It is a common blanking, but the shape of the forming part is more complex and the forming direction is different.Because of the large output of parts, it is considered to adopt progressive die structure, and from the design point of view, it can be produced on the high-speed punch press, design shoulder type guide plate.

The main forming difficulty of this part is that the direction of definite extension and bending and the direction of sample delivery have 15° included Angle.Therefore, the arrangement of bending process is the key to layout design and the key to progressive stamping.According to the decomposition principle of multi-station progressive stamping bending process, first use the upper and lower action of the mold to complete the removal of excess waste parts shape, consider local repair before the fixed extension bending.After the above blanking and bending, the bar material is jacked up by 2mm higher than the fixed bending height through the blanking device to facilitate the smooth feeding.Once the bending scheme is determined, other processes can be arranged to make the layout diagram.

1.1 application of conventional manual design CAD software in progressive die of connecting rod

1.1.1 determination of each station and cavity

The bending parts were calculated by look-up table manually plate reinforcement, rendering the plane geometry, according to the geometry in each stage after decomposition, determine its size and relative position of each decomposition graphics geometry size, the working process of the theoretical calculation is a fairly complex numerous lock, it is more difficult, especially for random geometric figure as long as there is a location of computing a tiny error (error), so, progressive die for the larger impact on graphic design for each station.

1.1.2 pressure center determination

In order to ensure the correct balance of the work of the die, the punching pressure must pass the axis of the die handle and coincide with the center of the slide block of the machine tool.

For a single symmetric figure, the pressure center is located in the geometric center of its contour figure. For a figure with complex beginning, the pressure center can be solved by analytic geometry.

Formula:

For a number of graphs, the pressure center using the above formula is respectively solved, according to the polymorphic cavity to find the pressure center, textile machinery parts where the formula is the same as above.

1.2 CAD design (UG software)

1.2.1 mold the parts

In modeling, all kinds of modules and curves can be used to build the part entity model, and Feature use and edit the part model.

1.2.2 plate reinforcement deployment

BNDCL =(b+K*a)rad(c) enters the Application for plate reinforcement development, and the computer will automatically expand all the parts into a plane figure.