During the operation of the CCD screen printing machine, there are several reasons for the occurrence of "mark spacing exceeding the standard and aligning NG":

1、 Equipment hardware aspect

CCD lens issue

CCD (Charge Coupled Device) lens is a key component used for identifying marks. If there is dirt, damage, or inaccurate focal length on the lens, it will affect the accurate recognition of the mark. For example, dust or ink splashes on the surface of the lens can block some of the light, resulting in incomplete image acquisition and deviation of the recognized mark position.

If the focal length of the lens is not adjusted properly, it is like the human eye being nearsighted or farsighted, which cannot capture the correct mark position clearly, resulting in errors in the calculated spacing.

Mechanical transmission component failure

If the transmission belt of the screen printing machine becomes loose, worn, or the motor malfunctions during the movement of the conveyor platform, it will cause a decrease in the accuracy of the platform movement. For example, a loose belt can cause the platform to shake or experience displacement deviation when transporting substrates (marked objects). When this deviation accumulates, it will cause the mark spacing to exceed the standard range.

If the screw and other components in the mechanical structure wear out, it will also affect the positioning accuracy of the platform. In high-precision screen printing operations, even minor mechanical wear can lead to inaccurate alignment.

Light source issue

A suitable light source is crucial for CCD to accurately identify marks. If the brightness of the light source is uneven or the intensity is insufficient, it will cause a decrease in the imaging quality of the mark. For example, when one side of the light source is bright and the other side is dark, the details of the mark in the dark area may not be clearly recognized by CCD, which affects the judgment of the position and spacing of the mark.

2、 In terms of software and parameter settings

Image processing algorithm error

The software in the CCD screen printing machine is responsible for processing and analyzing the collected images. If there are vulnerabilities or errors in the image processing algorithm, it may incorrectly identify the edges or center positions of the mark. For example, when processing marks in complex backgrounds, algorithms may mistakenly identify certain patterns in the background as part of the mark, resulting in incorrect spacing calculations.

Improper parameter settings

The working parameters of the screen printing machine include mark size, spacing standard value, recognition accuracy, etc. If these parameters are set incorrectly, such as setting the spacing standard value too small or too large, it will cause the system to erroneously determine that the mark spacing exceeds the standard. Moreover, if the recognition accuracy is set too low, it may not be possible to accurately capture the subtle positional changes of the mark, and there may also be situations where the alignment is NG.

3、 In terms of work environment and materials

Workplace vibration

If the screen printing machine is placed near a vibration source, such as a large stamping equipment or a traffic artery, the machine will be affected by vibration interference during operation. This vibration will cause slight displacement of various components of the machine, thereby affecting the alignment accuracy of the mark.

Substrate material issues

The flatness and material properties of the substrate can also affect the recognition of marks. If the substrate is uneven, it will cause the actual position of the mark on the plane to change. Moreover, the surface reflectivity or color of some substrate materials may interfere with CCD recognition, leading to errors in determining the mark spacing.