JPH03234321A - Burrless trim die for metallic plate and trimming method - Google Patents

Abstract

PURPOSE:To suppress the generation of a burr at the time of trim working by performing the rounding or the chamfering of a special shape to an edge of a punch or a die, and placing a plate pressing plate on the scrapping side. CONSTITUTION:In a state that the clearance is within a range of 5-50% of plate thickness, rounding or chamfering of >=0.10mm R radius is performed to a cutting edge of a tool 2 of the side for cutting away a scrap 4. As for a cutting edge of a tool 1 of the side which becomes a product, the rounding of <=0.05mm is performed. A plate pressing plate 6 is arranged on the plate of the side which becomes the scrap 4. By using this burrless punching die, punching such as piercing and trimming, etc., is executed. In such a manner, the trimming of a metallic plate can be executed without generating a burr.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a processing tool and a processing method used for trimming a metal plate.

[Prior Art] Processing of metal plates, such as automobile parts, always includes punching processes such as punching pierced holes and trimming using a press machine. However, in general, burrs (hereinafter referred to as burrs) are generated on the sheared end surface at this time, and when these burrs become high, they can cause poor assembly between parts and make it difficult for paint to adhere to them during painting, resulting in corrosion resistance. It has negative effects such as impairing sexuality. In order to keep the height of burrs that occur during punching of metal sheets within the allowable value, it is necessary to tighten the clearance of the mold in general punching and to strictly control the wear of the cutting blade during operation. Traditionally done.

However, these measures are not necessarily sufficient depending on the mold structure, part shape, etc. In reality, due to the precision issues mentioned above in mold machining, assembly, and installation, in the case of trim molds with irregular contours, it is extremely difficult to finish the entire body with a certain clearance, and the clearance may be large in some parts. It is inevitable that this will happen. Moreover, since many molded products are trimmed even after being molded into a three-dimensional shape, diagonal cutting in which the cutting edge is at an angle with the workpiece is often used. In this case as well, as the angle increases, the same phenomenon occurs as when the clearance increases.

In this way, improvement method 7 to tighten the conventional clearance
However, because there are parts with excessive clearance and diagonal cuts, parts of the molded product often have burrs that are outside the allowable range, and the smaller the clearance, the more the wear on the cutting edge increases. There is a greater possibility that serious problems such as chipping will occur. And in this case,
It is not unambiguously determined whether burrs occur on the product side or on the residual material side, and when burrs occur on the product side, it causes the aforementioned product defects.

The inventors have already devised a burr-free punching method in Japanese Patent Application No. 63-120713. This method is a simple burr-free punching method that uses a mold with a rounded or chamfered edge on one side (scrap side), which is conventionally used, and can be suppressed by burrs of 50 μm or less even in the case of excessive clearance. Although it is very effective for piercing holes and punching, when applied to normal trim processing, it may lead to poor punching, poor cutting, and deterioration of product accuracy. Therefore, it can be said that there is currently no suitable burr-free method for trim processing.

[Problem B to be Solved by the Invention The present invention solves the problems of the prior art described above by using a tool that can be used as is in a normal press machine and mold production can be done within the same range as in the prior art. It is an object of the present invention to provide a means capable of suppressing the occurrence of burrs during trim processing.

[Means for solving the problem] The present inventors have developed a steel plate, an aluminum plate, a copper plate, a zinc plate,
When trimming metal plates such as titanium plates and their alloys, the cutting edge of the tie, which is a trim type consisting of a single-action or double-action punch tie and a stripper plate, and which is to be scrapped, is used.
By using a burr-free trim type with a rounded or chamfered edge shape that is approximately the same as the thickness of the processed material, the cutting edge of the punch on the product side has a rounded or chamfered edge shape of 0.05 mm or less. It was found that the occurrence of burrs can be significantly improved. That is, in the present invention, the clearance is within the range of 5 to 50% of the plate thickness, the punch or die blade is rounded or chamfered within the above range, and the scrap side is set so that the material does not flow into the gap between the cutting edges. The present invention provides a burr-free trim type characterized in that a plate holding plate is arranged on the metal plate, and a burr-free trim method for a metal plate characterized in that trimming is performed using this type.

The present invention will be explained in detail below.

[Function] As a result of detailed study of the mechanical properties of the metal plate during cutting, the effects of clearance and lubricants, diagonal punching properties, etc., the present inventors reached the following conclusion. In other words, if the clearance is sufficiently medium, cracks will occur from both cutting edges of the punch and die, and as the cracks progress, they will come together, and a crack that started from one tool will grow to the tool cutting edge on the opposite side. In all cases, the burr is very small. On the other hand, if the clearance is large, cracks often do not propagate well, and the cracks propagate to the surface of the workpiece without joining with the cracks at the tip of the tool cutting edge on the opposite side, which prevents cracks from developing. A large amount of power is generated on the opposite side. In addition, cracks are easily affected by bending during shearing, and in double-sided shearing and punching with closed curved contours, cracks tend to enter from the cutting edge side of the die, but when a stripper plate is attached, cracks tend to enter from the cutting edge side of the punch. It depends on which side Bali takes. Furthermore, whether the burr is attached to the product side or the leftover material side depends on factors such as the wear condition of the cutting edge, the clearance, and the constraint conditions of the material, and if the burr occurs on the product side, the product will be defective.

The occurrence of burrs is greatly influenced by the clearance and punching angle. When cutting a metal plate under conditions with a large clearance, tensile stress acts on the surface of the steel plate opposite the cutting edge as the shearing progresses, resulting in necking. It was discovered that after cutting, the crack that occurred from the tip of the cutting blade propagated and caused the cut. In actual machining, diagonal cutting is often used, where the cutting edge has an angle with the workpiece, or in this case, when the angle becomes large, the punch tends to escape along the slope.
This is essentially the same as increasing the clearance, so the burr becomes larger as the inclination angle increases on both the die and punch sides.

When trimming automobile parts, etc., generally one side becomes a product and the other side becomes scrap in most cases.

In the present invention, the cutting edge on the scrap side is rounded or chamfered, and a plate retainer is placed on the scrap side to prevent the material to be cut from bending and escaping into the clearance during the trimming process. Even if the cutting edge is large or diagonal, the height of the burr on the product side can be extremely reduced by always creating a crack from the cutting edge on the product side and guiding the burr to the remaining material side. .

FIG. 1 is an explanatory diagram of a conventional trimming tool and a burr-free trimming tool of the present invention. Here, (a) shows the conventional trimming tool, 1 is the tool on the product side, 2 is the tool on the leftover material side (scrap side), 3 is the plate holder on the product side, and 4 is the side that will be scrap. 5 indicates the metal plate on the product side.Metal plates include steel plates, aluminum plates,
General metal plates such as copper plates, zinc plates, titanium plates, etc., and alloys thereof can be used. In addition, (b) shows the tool shape of the present invention, where 1 is a tool with a sharp cutting edge corresponding to the product side, 2 is a tool with roundness or chamfering corresponding to the scrap side, and 3 is a plate holder on the product side. , 6 is the plate holder on the scrap side, 4 is the metal plate on the scrap side, 5
indicates the metal plate on the product side. (Here, both (a) and (b) show the plate holder 3 on the product side, but if it does not affect the product accuracy, the plate holder 3 may be omitted.) Furthermore, according to the present invention, it is possible to concentrate the generated burrs on the side of the material without the blade, and it is possible to reduce the burrs on the product side.

Next, the limiting conditions of the present invention will be explained in detail. First, regarding the sharpness of the cutting edge on one side (product side), since the purpose of the present invention is to shear the material, it is naturally necessary to have the cutting edge as sharp as that required for normal shearing, which means 0.05 mmR or less. must be In addition, since the occurrence of burrs is determined by the roundness of the punch and die side cutting edges, the opposing cutting edge (remaining material side) needs to have a radius of at least 0.05 mm larger than the product side.
The cutting edge on the remaining material side must be at least O, lOm+nR.

In addition, when chamfering the cutting edge instead of rounding it, as shown in Figure 2, there is a shape (a) in which the cutting edge is rounded and a shape in which the round edges are connected linearly in the cross section of the cutting edge. Since chamfering (b) has the same effect in shearing, this is also treated as being rounded with radius R. Note that the dimension of the chamfer in the present invention is the second dimension.
In figure (b), T indicates the smaller value.

As schematically shown in FIG. 3, this shearing method using a processing tool has little difference from the conventional general shearing method when the clearance is sufficiently small, but it is effective at a clearance of 5% or more. However, as the clearance increases, the processing load increases rapidly, so a clearance of up to 50% is actually effective (the punching load of the press machine does not increase too drastically). Similarly, the roundness of the cutting edge
Chamfering and punching angles also impose a burden on the punching load of the press machine, so the effective range for roundness and chamfering is up to the thickness of the processed material, and for punching angles up to 60°. Regarding the plate thickness, if the clearance is too large, cracks will not form properly on the sharp cutting edge side, so it is inappropriate if the plate thickness is less than 0.2 mm.
If I+ is exceeded, the burrs and burrs caused by the burr-free trim method will become larger, so the applicable plate thickness range is 0.2 mm.
It is above 6III and below 111. Note that it is sufficient to apply pressure to the plate holder installed on the scrap material side to the extent that the material does not float from the tool cutting edge due to curvature during trimming.

FIG. 4 shows a schematic configuration diagram of a die when a cutting blade that satisfies the above-mentioned limiting conditions is incorporated into an actual press die. The press can be applied to either the double action method shown in FIGS. 4(a) and 4(b) or the single action method shown in FIGS. 4(c) and (d). In addition, Fig. 4 (a
) (c) is when the cushion bin is used, (b) and (d) are when the cushion bin is not used. Here, 11 is the punch, 12 is the punch side plate holder, +3 is the die side plate holder, 1
4 is a die, 15 is an inner, +6 is an outer, +7 is a bolster, 18 is a slide, 19 is a workpiece, 20 is a cushion bin, and 21 is a metal spring or a cushion made of urethane or rubber. Note that the punch side plate holder 12 may be omitted if there is no problem with product accuracy.

The present invention based on the above-mentioned limitations can be applied to the entire cutting edge of a trim tool, and can also be applied partially to corners of square cylinder punching dies and parts where it is difficult to reduce the clearance in complex irregular-shaped punching. These are sufficiently effective, and it goes without saying that these are included in the present invention.

[Example] The present invention will be explained in detail below.

Metal plates such as steel plates, aluminum plates, copper plates, zinc plates, titanium plates, etc., and their alloys can be used as metal plates, but among these, very mild steel plates, mild steel plates, high tensile strength steel plates, stainless steel plates, and semi-hard aluminum plates are applicable. I followed the board. For the trim mold, we adopted the method shown in Figure 4 when the single-action cushion bin was not used (metal spring). In addition, the tool cutting edge uses a straight-edged punch and die to vary the clearance from 0.05 mm to 1.00 mm, ■ a cutting edge with a roundness of 0.2 mmH, ■ 0.5 m
Trim angles of 0', 10°, and 20° were conducted using three types of cutting edges: m, 45-degree chamfered cutting edge, and normal cutting edge. As a comparative example of the conventional trim method, the same processing conditions were used, with both the punch and die having sharp cutting edges. Note that the burr height was measured for the largest burr on both the punch side and die side. The results are shown in Table 1.

Trim conditions: Straight edge shearing side nibless machine ft, :60 ton crank press punch: With straight edge cutting edge, ■0.2mmR, ■0
．． 5mm chamfering die: Straight edge ■With cutting edge, ■With 0.2aunR, ■0.5mm Chamfering clearance: 0.05mm to 1.00mm Lubrication
: Still coated with anti-corrosion oil. Also, as an example of an actual press, a 0.80 mm thick ultra-mild steel plate was used for the trim type of a car's front fender as shown in Fig. 5, and the double-action method shown in Fig. 4 was used. A burr-free trim method was carried out with a cushion bottle in use. The cutting edge roundness is 0.5mmH roundness and 0.51110 on the die side.
1T chamfering was carried out, and for comparison, trimming was also carried out using a normal trim mold, and the burr height was measured at the measurement location shown in FIG.

[Effects of the Invention] As described above, the present invention is extremely effective as a tool and method for trimming a metal plate without producing burrs, and has high industrial value.

[Brief explanation of drawings]

Figure 1 shows a burr-free trim tool (R
(attached) is shown. FIG. 2 is an explanatory diagram of a burr-free punching tool with an R and a burr-free punching tool with chamfering. FIG. 3 shows the relationship between the burr height and the clearance of the conventional cutting method and the burr-free trim method. FIG. 4 shows a schematic diagram of a burr-free trim method using an actual press die. FIG. 5 shows an example using an actual press mold, and shows the shape of the mold used and the measurement points. FIG. 6 shows the measurement results of the example using an actual press mold.

Claims (1)

[Claims] 1. In a metal plate trimming tool using a punch and die, the cutting edge on the side that cuts out scraps has a radius of 0.
The cutting edge is rounded or chamfered to a radius of 10 mm or more and equal to or less than the plate thickness of the processed material, the cutting edge on the side that will become a product is rounded to 0.05 mm or less, and a plate holding plate is placed on the side that will become scrap. A burr-free trim type. 2. In trimming a metal plate with a thickness of 0.20 to 6.0 mm using a punch and die, the claim must be made on the punch or die blade if the clearance is within the range of 5 to 50% of the plate thickness. 1. A burr-free trimming method for a metal plate, comprising punching using a burr-free punching die having a rounded or chamfered shape as described in 1.