Calculation of sharpening and sharpening of CNC punching machine

●Sharpening of the mold

⒈The importance of mold sharpening

Regular sharpening of the mold is a guarantee of consistent punch quality. Regular sharpening of the mold not only improves the life of the mold but also increases the service life of the machine. It is necessary to master the correct timing of sharpening.

⒉The specific characteristics of the mold that need to be sharpened

For the sharpening of the mold, there is no strict number of strikes to determine if sharpening is required. It depends mainly on the sharpness of the cutting edge.

It is mainly determined by the following three factors:

⑴Check the rounded corners of the cutting edge. If the radius of the fillet reaches R0.1 mm (maximum R-value does not exceed 0.25 mm), sharpening is required.

⑵Check the punching quality for large burrs.

⑶The noise of the machine is used to judge whether it needs to be sharpened. If the noise of the same pair of the die is abnormal during stamping, the punch is already blunt and needs sharpening.

Note: The edge of the cutting edge is rounded or the back of the cutting edge is rough, and sharpening is also considered.

⒊Analysis of the relationship between the degree of edge wear and the number of punching.

⒋Sharpening method:

There are many ways to sharpen the mold, either with a special sharpening machine or on a flat grinding machine. The frequency of punching and lowering of the die is generally 4 to 1. Please adjust the mold height after sharpening.

⑴Hazards of incorrect sharpening methods:

Incorrect sharpening can exacerbate the rapid destruction of the die edge, resulting in a significant reduction in the number of hits per sharpening.

⑵The benefits of the correct sharpening method:

Regularly sharpening the mold, the quality and precision of the punching can be kept stable. The cutting edge of the mold is less damaged and has a longer life.

⒌Sharpening rules:

Consider the following factors when sharpening the mold:

⑴The edge fillet is to be sharper at the edge of R0.1-0.25mm.

⑵The surface of the grinding wheel should be cleaned.

⑶A loose, coarse, soft grinding wheel is recommended.

⑷The amount of grinding should not exceed 0.013mm each time. If the grinding amount is too large, the surface of the mold will be overheated, which is equivalent to an annealing treatment. The mold becomes soft and the life of the mold is greatly reduced.

⑸Sufficient coolant must be added during sharpening.

⑹When grinding, ensure that the punch and the lower die are fixed and stable, using a special tool holder.

⑺The amount of sharpening of the mold is constant. If this value is reached, the punch will be scrapped. If you continue to use it, it will easily cause damage to the mold and the machine, which is not worth the loss.

⑻After the sharpening, the edge should be treated with oilstone to remove the excessively sharp bobbin thread.

⑼After the sharpening, clean, demagnetize, and oil.

●Calculation of mold sharpening amount

The length of the punch edge portion, the thickness of the stripper, the material thickness, and the depth of the mold are as follows:

Sharpening amount = punch cutting edge length - stripping plate thickness - material thickness - mold depth

For the C/D/E station old-fashioned punch, if the height of the gasket is too large, the keyway of the punch and the positioning key on the punch cannot be matched, which may cause the abnormal mold to be used normally. Therefore, the maximum sharpening of the punch can only be 3mm.