During the use of printed guide belts, users often encounter the problem that the guide belt needs to be re-tensioned under the conditions of machine maintenance, guide belt maintenance and guide belt replacement. Here we should first understand the deformation process of the printing guide tape. Next, let's follow the Flat Screen Printing Machine Factory to learn more about this knowledge.
The main material of the guide belt TPU (thermoplastic polyurethane) is a synthetic material, this material will produce viscoelastic phenomenon under the action of tension. When an external force is applied to the guide belt, the guide belt will be extended according to its own hardness, and the hardness per millimeter of the width of the guide belt is represented by "K1% static state".
With the increase of time, the extension also has a small increase, until after a period of time to reach the final extension. When the external force is removed, the part extended in "K1% static state" will be released immediately, and the remaining extended parts will take some time to be released.
Normally, we will not tension the conduction band with a constant force, but with a certain elongation of the conduction band. Therefore, when tensioning the guide belt, the guide belt should be run slowly, and the tension should be gradually increased. Under certain tension conditions, the guide belt should be operated for a period of time, so that the tension of the entire guide belt can be evenly distributed.
The specific method is: Before tensioning the new guide belt, make the guide belt in a tension-free state, and make a 1000mm mark on both sides of the front edge of the guide belt. It is recommended that the user preferably make a 1000mm mark on both sides of the opposite edge of the guide belt Can be kept for a long time. Use the tensioning device to tension the guide belt and measure the length of the mark with a ruler.
Assuming that the guide belt needs to be extended to 0.5%, the tension will not be increased when the measured value reaches 1005mm. After a few rounds of operation, the mark is measured again. If the data has not changed, the tension is adjusted. Once the Habasit polyurethane belt is tensioned once, the elongation of the belt will stabilize and its elongation will not change after a long period of operation.
When the printing machine needs maintenance, the guide belt will be loosened. When the guide belt is tensioned again, sometimes it cannot be judged whether the guide belt is in a "permanent extension" state, so it can no longer be marked with the above-mentioned mode. It should be marked in the following way: Before the tension of the guide belt is not relaxed, make a 1000mm mark on both sides of the front edge of the guide belt.
The guide belt is relaxed, the distance between the 1000mm marks is shortened, and no measurement is necessary. Tension the guide belt and pull the mark back to 1000mm. If the mark made on the back when the guide belt is first tensioned is still there, the old mark can be used to tension the new guide belt.
If the machine has less maintenance work, you can also re-tension the guide belt by marking the tensioner. But don't judge the tension of the conduction band by feel.
Lead tangent. The deviation of the guide belt can be corrected when the tension of the guide belt is adjusted. At this time, the automatic deviation correction device and the rib device of the machine should be separated. The deviation of the guide belt can be corrected as follows: when the guide belt is deflected to the left, the right end of the roller can be tensioned, and vice versa.
Be patient enough when guiding the guide tape. You can fix the ballpoint pen on the frame and draw running traces on the printed guide tape. Generally, after 3 runs, if the traces are not thickened, you can cut the edges. Start the machine and let the guide belt run slowly. Carefully cut the blade into the guide belt until it penetrates the guide belt. If there are two cutting devices, you can cut from both sides of the guide belt at the same time, so that the lateral forces generated during cutting can cancel each other out.
After the completion of this work, you can install the correcting device and the guide belt stopper (board). These devices can assist in blocking the running deviation of the guide belt. If the guide belt always has a tendency to deviate in one direction, the guide belt edge and the stop (board).