This article is for those who want to print “thick” coatings using screen printing!
Let’s explore the effect of printing thick coatings using a special screen mesh called “3D mesh” and specific measurement data!
About the “3D Mesh”
In screen printing, various types of printing, including fine line printing, thin film printing, and filling printing, are possible. With some ingenuity, it’s also possible to print thicker coatings.
To increase the thickness of the coating, this time we prepared a screen with a thick mesh fabric. We used a special type of mesh called “3D mesh“:
The “3D mesh” has a unique structure where only one thread is bent and processed, unlike traditional plain weave meshes. The thickness of the fabric is approximately three times that of the thread diameter!
It can create a printing film thickness about 1.5 times that of a plain weave.
Fill the Mesh with Plenty of Paste!
However, no matter how much you use the “3D mesh,” if the paste is not sufficiently filled inside the mesh during coating, the printing will not be successful. Especially for solid printing, if the paste is not sufficiently filled into the volume of the mesh “aperture” + “emulsion height” during coating, the film thickness may end up thinner than intended.
Let’s verify this with photos taken during actual printing.
[Coating: 1 time, incomplete filling]
This shows the filling condition of the paste when coated once with a squeegee.
It can be seen that the paste is not sufficiently filled, as there are exposed threads of the mesh and the side of the emulsion is visible in some areas.
[Coating: 3 times, sufficient filling, improved]
This shows the filling condition of the paste when coated three times.
It is confirmed that the paste is fully coated and firmly filled into both the mesh threads and the sides of the emulsion.
It was found that if you coat a lot, the paste can be filled firmly, but it’s troublesome to coat three times each time during printing. In that case–
[Coating: 1 time, sufficient filling, *scraper modified]
The tip of the scraper was slightly modified to make it easier to extrude the paste.
The result when photographed… was a great success! Plenty of paste was pushed out from the mesh openings.
Measurement Film Thickness Data
The printing film thickness results are as follows (calculated wet thickness at 3D 80/80 specifications = 120μm):
[Normal Scraper]
- 1 coat: 82μm (incomplete filling)
- 2 coats: 88μm (incomplete filling)
- 3 coats: 90μm (sufficient filling) *Average of N = 3
[Special Modified Scraper]
- 1 coat: 89μm (sufficient filling) *Average of N = 3
Printing Conditions Summary
- Screen Mesh: 3D 80/80, Fabric Thickness 225μm, Emulsion Thickness 10μm
- Clearance = 1.3mm
- Squeegee Speed = 50mm/sec, Scraper Speed = 50mm/sec
- Paste (Silver) Viscosity = 95pa.s (10 rotations)
- Printing Pressure = 0.22Mpa (Zero Point = 0.12Mpa)
For this printing, we maintained the above conditions and performed the printing under the same parameters.
As shown, by using 3D mesh, it’s confirmed that just by changing the coating conditions (number of times, scraper processing), the film thickness can be changed.
3D-mesh-Type 3D | Asada Mesh Co., Ltd. (asadamesh-global.com)
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Translation by GPT.