Online cutting process analysis
The cross-section of the product is not only closed but also complicated. The closed section is composed of a vertical surface, a horizontal surface and a curved surface, and the material is a galvanized steel sheet of 1.25 mm. It is required to ensure not only the quality of the section but also the galvanized layer and the speed of the production line. This brings a lot of trouble to the mold design. If the conventional cutting die is used for the overall cutting, it will not be cut off, and the product requirements cannot be met. According to the characteristics of the parts, a deep analysis is made, and it is decided to reserve a cutting amount of 6.8 mm before cold forming. Because the shape of the part is very special, the edge of the punch must be shaped, not only to cut the curved surface, the horizontal surface, and the vertical surface, but also to have no sag and scratches. According to the process requirements, in order to prevent the sag and ensure the convexity Intensity, it is decided that the process hole should be pre-punched in the middle of the part and at the corner, and the pre-punching hole must be punched out before forming, that is, before the cold bending, a process is added - pre-punching, so a pre-punch is designed. Hole mold. That is, two sets of molds are required to cut the workpiece: a set of pre-punching dies and a set of cutting dies.
Pre-punching die design
1. Position determination of mutual pre-punching
From pre-punching to cutting, there is a forming process in the middle, so that the position of the pre-punching is more complicated. Not only to ensure the quality of the cut surface, but also to choose the right position to improve the strength of the die of the cutting die, and also to ensure that the cold forming of the cutting die is not affected, and according to the requirements of the stamping process, the hole of the punching part The distance between the holes and between the holes and the edges should not be too small to correct the position of the holes and repeatedly simulate through the computer. The hole in the middle portion is to ensure that the intermediate portion of the punch is not too long and too sharp, and the formed chips are easily discharged when the top of the workpiece is punched. The hole at the corner is to ensure that there will be no sag at the time of cutting, and at the same time, it will not produce chips that are difficult to discharge.
2. Unfolding of the workpiece
Directly use the Pro/E expansion command to expand the part to get the expanded view. Expand the Expand Create Sheet Metal Unbend Regular by expanding the command, select a datum plane or edge (unmoved or edge) when unfolding, then select the Unbcnd All command, and then click OK.
3. Structural design and working process analysis of pre-punching die
①Pre-punching die structure design
According to the unfolding diagram and precision requirements, the diagonal guide column formwork is selected, and the formal form is adopted, the punch is on the upper side, and the concave mold is on the lower side. For economical processing and easy maintenance and replacement, the male and female molds are in a block-like structure, so that the insert can be replaced without removing the entire mold. After the two punches and the punch fixing plate are fixed, they are directly fixed on the upper mold base 7 by screws together with the punch pad, and the two concave molds are symmetrically set in the lower mold base.
In order to prevent the sticking of the scrap, the unloading rubber is specially designed on the punch, and after the scrap is punched off, the scrap is smoothly separated from the convex and concave molds under the elastic force of the rubber. In order to reduce the labor, the edge portion is made 1. S0 slope. In addition, because it is an online automatic production, the strip is automatically fed, so a fixed discharge plate is adopted, so that the discharge plate not only functions as a discharge plate but also functions as a guide plate, and the fixed discharge plate has a discharge force. Large, simple structure. Single features.
②Analysis of the working process of pre-punching die
In the working process, the plate guides the guide plate (the guide plate and the discharge plate 3 are the same plates), and the feeding process is automatic feeding, and the punching position is determined by the photoelectric switch. The plate is taken to the proper position. Under the action of the hydraulic machine, the upper mold base drives the punch downward, and the punch starts to work. Under the joint action of the convex and concave molds, the punching is completed. Under the elastic force of the rubber, the waste is smoothly leaked from the leakage hole, and the punch is lifted up, and one stroke is completed.