One, the information from the waste situation
1, scrap is essentially the reverse of the forming hole, that is, the same position of the same position. By examining the waste material can be judged whether the correct or incorrect. If the gap is too large, the waste will appear rough, rough broken surface and a narrow zone of light. The larger the gap, the greater the angle between the fracture surface and the light zone. If the clearance is too small, the waste will present a small angle to the fracture surface and a wide area of brightness.
2, too large gap to form with a larger roll edge and edge tear of the hole, so that a thin section of a thin edge. Too small a gap formed with a slightly curled edge and large angle tear, resulting in more or less vertical profiles perpendicular to the surface of the material.
3, an ideal waste should be reasonable and uniform light with collapse angle. This can be maintained at a minimum of pressure and the formation of a small hole in the vicinity of the burr hole. From this point of view, by increasing the gap to extend the life of the mold is to sacrifice the quality of the finished hole in exchange for.
Two, the choice of mold gap
The gap between the mold and the type of material and thickness of the stamping. A reasonable gap can cause the following problems:
1, if the clearance is too large, the burr punching workpiece is relatively large, poor quality of stamping; if the gap is too small, although the good quality of punching die, but more serious wear, reduce the service life of the mold greatly, but also easy to cause the broken punch.
2, the gap is too large or too small to produce adhesion in punch material, resulting in stamping materials. The vacuum is formed between the gap is too small to the punch and the bottom surface of the plate material and waste rebound.
3, a reasonable gap can extend the life of the mold. Good discharging effect, reduce the burr and flanging plate, keep clean, consistent aperture do not scratch sheet, less grinding times, keep the flat sheet punching, accurate positioning.
Please refer to the following table to select the mold gap (the data in the table is a percentage).
Gap selection (total clearance)
Material Science
Minimum
Best
Maximum
Copper
8%
12%
16%
brass
6%
11%
16%
mild steel
10%
15%
20%
Aluminum (soft)
5%
10%
15%
Stainless steel
15%
20%
25%
%× material thickness = die gap
Three, how to improve the service life of the mold
For users, improve the service life of the mold can greatly reduce the cost of stamping. The factors that affect the service life of the mould are as follows:
1, the type and thickness of the material.
2, whether to choose a reasonable mode of the next gap.
3, mold structure.
4, when the material is a good lubrication of lubrication.
5, the mold is a special surface treatment.
6, such as titanium, carbon titanium nitride.
7, up and down the tower of the neutral.
8, adjust the appropriate use of gasket.
9, whether the appropriate use of oblique cutting edge die.
10, machine tool die seat is already worn.
Four, stamping special size hole should pay attention to the problem
1, the minimum aperture punching φ 0.8— — φ the range of 1.6 please use special punch punch.
2, thick plate punching, relative to the processing aperture, please use a large number of mold. Note: at this point, if the use of molds are usually the size of the damage will cause the punch thread.
Example 1, the following table of the processing conditions, although the processing aperture and A station corresponding to the mold, but please use the B station die.
Texture of material
Plate thickness (mm)
Aperture (mm)
Mild steel (40Kg/mm2)
Six
8.2-12.7
Four point five
11.0-12.7
Stainless steel (60Kg/mm2)
Four
8.2-12.7
Example 2, the following table of the processing conditions, although the processing aperture and B station corresponding to the mold, but please use the C station die.
Texture of material
Plate thickness (mm)
Aperture (mm)
Mild steel (40Kg/mm2)
Six
22.9-31.7
Four point five
30.6-31.7
Stainless steel (60Kg/mm2)
Four
22.9-31.7
3, punch edge part, the minimum width and length ratio shall not be less than 1:10.
In 3 cases, rectangular punch, when the length of the cutting edge is 80mm, the width of the cutting edge is ≥ 8mm is the most suitable one.
4, punch edge part and the thickness of the minimum size. Recommended punch edge part minimum size is 2 times the thickness of the.
Five, die grinding
1, the importance of mold sharpening
The regular sharpening of the cutting tool is the guarantee of the quality of punching. Regular sharpening of the mold can not only improve the service life of the die, but also can improve the service life of the machine.
2, mold needs the specific characteristics of sharpening
For the mold of the sharpening, there is not a strict number of blows to determine whether the need for sharpening. Mainly depends on the sharpness of the edge. Mainly determined by the following three factors:
(1) check the edge of the blade, if the radius of the corner to reach R0.1 mm (maximum R value shall not exceed 0.25 mm) on the need to wear.
(2) check the punching quality, whether there is a larger burr produced?
(3) to determine whether the need for sharpening by machine stamping noise. If the same pair of stamping noise when abnormal, that punch are blunt, need sharpening.
Note: the edge of the edge of the edge of the circle or the back of the rough edges, but also to consider the sharpening.
3, sharpening method
There are many ways to wear the die, and the special sharpening can be realized on the surface grinder. The frequency of punch, die grinding is generally 4:1, please adjust the die after grinding height.
(1) the harm of incorrect sharpening method: incorrect sharpening will aggravate the rapid destruction of the die cutting edge, resulting in a large reduction in the number of combat.
(2) the benefits of the correct sharpening method: the regular sharpening of the mold, punching quality and accuracy can be maintained stable. The edge of the mould is damaged slowly, and the life is longer.
4, sharpening rules
The following factors should be taken into account when the die cutting edge is worn:
(1) the edge of the blade in the case of R0.1-0.25 mm size to see the sharp degree of the blade.
(2) the surface of the grinding wheel must be cleaned.
(3) suggested that a kind of loose, coarse grain, soft grinding wheel. Such as WA46KV
(4) the amount of grinding time (depth) should not exceed 0.013 mm, grinding amount will cause overheating of the mold surface, the equivalent of annealing treatment, mold soft, greatly reduce the life of mold.
(5) a sufficient coolant must be added to the sharpening.
(6) grinding should guarantee the punch and die fixed smoothly, using special fixture.
(7) die grinding amount is certain, if the numerical punch will be scrapped. If you continue to use, easy to damage caused by mold and machine, The loss outweighs the gain.
(8) after grinding, edge to stone processing, remove excessively sharp edges.
(9) after grinding, clean up, demagnetization and oiling.
Note: the size of the tool wear is mainly determined by the thickness of the sheet metal.
Six, before use should pay attention to the punch
1, storage
(1) with a clean cloth to clean the inside and outside the die sleeve.
(2) surface scratches or dents don't care for.
(3) anti rust oil.
2, the use of pre prepared
(1) thoroughly clean the upper die set before use.
(2) to see whether there are scratches, dents in the surface. If, for stone removal.
(3 miles) oil.
3, the installation should pay attention to matters on the punch die sets
(1) clean punch, and gave a long handle oil.
(2) the upper die punch insert at the bottom of the sleeve in the die, can not force. Can't use nylon hammer. When installed, can not be fixed by screw bolts on the die sleeve