Hard Screen Frame Selection Techniques in Screen Printing

The typical hard net frame is welded from a single metal strip. It is known for its stability. The method of fixing the silk screen is to glue on the metal frame. When selecting a hard frame, consider the following factors:

1. The size of the frame and the image;

2. Image Resolution;

3. Target wire tension;

4. Off-gauge

5. Screen type

6. Screen angle

7. Frame weight.

The frame size is a significant factor because it not only fits the size of the printing machine, but also fits the size of the image to be printed. Of course, in order to facilitate the accurate transmission of the image, a screen frame that is appropriately larger than the image size may be selected, that is, a part of the screen outside the image is in a blank state. The larger the area of ​​the blank screen, the less pressure is applied to the screen during printing, which is advantageous for maintaining the accuracy of the image.

The resolution of the image determines the number of lines used. The number of lines affects the size of the pull force. A good mesh frame should be able to withstand the tension of the screen, including the extra tension generated in order to overcome the off-gauge height when printing. It must also be able to withstand the extra tension created by the stretching to compensate for the slackening of the mesh. The force generated during printing or stretching is mainly related to the type of screen material.

Sometimes it is necessary to adjust the angle of the screen relative to the frame, but this happens rarely. However, when it is necessary to make adjustments, it should be noted that if it does not match the tension on the sides of the frame, it may cause deformation of the frame.

From the processing point of view, the weight of the frame is also important when transferring screens in the workshop. Furthermore, heavy frame weights on machines, especially roller presses, can reduce the printing speed, register accuracy and increase the wear of machine parts. Different hard frame characteristics can be obtained by various methods. Figure 4 shows some of the characteristics of the frame. Except for solid metal CD printing screen frames and similar screen frames used in the electronics industry, most are made of hollow metal strips pressed from various materials. Aluminum is the most commonly used material. Steel can also be used, it is cheaper than aluminum, but it is heavy, and if it is not stainless steel, it is also prone to corrosion.

Hard Frame Feature Description

These examples show the characteristics of the hollow metal strip used to make the frame. It comes in many types, including squares, rectangles and trapezoids (the trapezoid is designed for easy cleaning). When ordering a rigid frame, it must be ensured that the thickness of the metal strip satisfies the requirements of the screen tension. Also note that if too much metal strip material is removed when reusing the mesh frame, the performance of the mesh wall (where it is used to stick the mesh) may be attenuated.



Reprinted from: Dongguan Printing Network