Failure Analysis and Maintenance Method of Hydraulic Paper Cutter

The hydraulic paper cutter is popular with users because of its high pressure and good cutting quality. However, the failure of the hydraulic system is difficult to find. Once a failure occurs, it cannot be intuitively discovered that the fault is causing difficulties in operation and maintenance.

QZY-1150 hydraulic paper cutting machine produced by Shanghai Cutter Machinery Factory, had the phenomenon of failure: after the paper presser fell and contacted the paper product for a period of time, the paper cutter began to decline, and the pressure paper and paper cutting could not be used consistently. After the cutting is completed, the cutter is normally returned to its original position, but the paper presser bar cannot be lifted. After analysis, it is considered that the oil valve or the oil line is blocked or the change of the direction change valve is not smooth. For this reason, the relevant valve will be After the dismantling, clear the brush and clear the oil passage. After the oil is replaced, the fault phenomenon still does not disappear. Then check the circuit and everything is normal. Carefully analyze the oil circuit and suspect that the reversing valve at the bottom of the hydraulic cylinder is damaged (blocked or spring broken). After deducting all other doubts, remove the cylinder and check that the return spring of the hydraulic reversing valve is broken and replaced. After the spring troubleshooting.

In the cutting of the film, a vertical cutting method is generally adopted, that is, the cutting plane is perpendicular to the film plane, so that in the printing, the edges of the film are left with different degrees of marks. There are two main causes of edge marks: First, the dust in the working environment is large, and the film is stored for a long time, causing a large amount of dust to be stained at the incision, increasing the density here, and secondly, light is sparse from the light during the printing process ( When the air enters the dense matter (film), it will be refracted, and will also generate total reflection at its cut-out. The above two phenomena can occur alone or at the same time, so that there will be blockage when printing. As a result of underexposure, according to the circumstances, I took the condition of destroying the total reflection of the film to be empty. After several trials, the results were obtained by the oblique blade cutting method, and a special tool was made. The oblique blade cutting method was to cut the blade film. The plane is cut at a 45° angle. After such a cut, total reflection of the film can be effectively prevented. If a clean working environment is provided, edges and defects can be completely eliminated.

In addition, some of the small faults caused by the blade occurred in the cut paper should also be noted:

1. The newly grounded blade is put into use. If it does not touch hard foreign objects in the cutting, it will abruptly drop a little bit of the blade. The reason for this problem is mainly due to the fact that the cutting edge is not properly grasped by the blade during the grinding process (the feeding amount is large) and the temperature during the grinding process is too high (ie, the temperature of the contact point between the blade and the grinding wheel is too high). The blade burns.

2. The cutting knife does not cut in the end when cutting, mainly due to the sharpness of the cutting edge of the knife.

3. Immediately after the blade is sharpened, there is a knife cut on the cut surface of the cut paper product, or a bad cut occurs during the cutting process. This is mainly due to the blade being too soft due to overheating of the cutting edge, so long as the temperature is lowered .

4. In the cutting process of the paper cutting machine, the phenomenon that the insurance screw is broken sometimes occurs from time to time. There are several reasons for this phenomenon:

a. The edge of the blade is not sharp enough and should be sharpened in the correct way. After 8 hours of cutting time, the blade should be replaced in time. If the harder paper is cut, the time interval for blade replacement should be shortened.

b. The installation of the insurance screw is not suitable. When installing the insurance inspection, it must be installed on the side with small eccentricity. In addition, it is required to tighten the insurance screw inspection once per class 1-2 times.

c. The two left and right slides of the tool holder are worn, and a normal clearance of about 0.05 mm should be maintained between the tool holder groove and the slider.

d. The two ends of the insurance screw are not flat and need to be repaired or replaced.

e. Electrical reasons, such as the fact that the safety pin has not been withdrawn and the knife has been hit by a safety pin, can also lead to this failure.

In summary, the paper cutter has a variety of faults, which should be adjusted and resolved according to actual conditions.