The feedback we often receive from customers with regards to the issues experienced in screen printing is the “bleeding of the ink and paste” when printing.
At Murakami, we have tackled this problem for many years, and we have worked on developing SP-H, in which the photosensitive materials themselves are liquid repellent, as well as FT processing, in which liquid repellence is added in the treatment after plate making. Please contact us for further inquiries.
FT processing is available if you want to add liquid repellence without significantly changing the specification of the plate that is being used.
Although this is a surface treatment for an insubstantial thickness, an improvement in the transferability of the ink and paste can be expected because the mesh surface will also become liquid repellent.
In addition, when you do not want the mesh to be liquid repellent or when the plate will be overused, it is suitable to use SP-H, in which the photosensitive materials themselves will have liquid repellence.
Depending on the printing conditions, there are cases in which the paste runs to the back when transferring, and this becomes a direct cause of bleeding.
The photo below illustrates a view of the plate’s surface condition during printing, and it concretely demonstrates the effects of FT processing in suppressing the paste from running to the back.
|Before printing||0 shot||5 shots||10 shots||After printing|
|With FT processing|
|Without FT processing|
In screen printing, the printing is literally supported by a screen mesh, so a mesh also exists in the openings. The advancement of extra fine line will make the permeability of the portion with mesh and without mesh greatly differ, thereby making it difficult to print evenly.
In FT processing, it is possible to add liquid repellence to the mesh surface as well and, as a result, the paste can be transferred without remaining on the mesh.
With the advancement of even finer line, characteristics of the opening section wall surface would affect the print performance.
By adding ｌiquid repellent treatment after plate making not only to the plate surface but also there will be possible to print with stable line width and height.
Although the advancement of even finer line would make it difficult to suppress bleeding and chipped parts due to stricter printing conditions, in FT processing, the straightness will improve and it will be possible to suppress chipped parts in printing by making it easier to transfer the paste from the plate.
Plate specification: SHCAL640-15_BL_IC-10000_M10
With regards to the mesh, if you do not want it to be liquid repellent or if you will be overusing the plate, it is suitable to use SP-H, in which the photosensitive materials themselves will have liquid repellence.