Screen Printing Mesh Count
The mesh serves as a net for holding the photo stencil and for metering the amount of printing medium applied. It should be flexible to adapt to the component’s surface changes to be printed with the squeegee.
It should be elastic so that it returns to its original shape after passing the squeegee, with an effect that allows complete removal of ink from the open mesh and minimal deformation of the printed surface. Screen Printing Mesh Count means The number of threads per centimeter and per inch, thread diameter, mesh size, open area or surface area, and fabric thickness are relatively self-explanatory.
Screen Printing Mesh Types
Nylon and Polyester Mesh is today used, here I would advise you, only to use Polyester Mesh. As Nylon absorbs more water and loses more tension, than a Polyester Mesh, be sure to use only Polyester!.
The number of threads per centimetre and per inch, thread diameter, mesh size, open area or surface area, and fabric thickness are fairly self-explanatory, but a comment or two might be in order.
Polyester mesh counts have the suffixes S, T, HD, and HD Super, and these refer to the thread diameter. The most common is T=Mesh for us screen printer on garments and the version with the thinner thread S. (When stencils were made from silk fabric, the T grade was the fabric used for textiles, while the S grade was used for serigraphs.) HD is suitable for heavy use, while the thicker version HD Super is even more robust.
S, T, HD and HD Super and these relate to the thread diameter
- “S” or “Serigraphic grade”
- “T” means “Textile grade”
- No need for us- just for the records, HD has heavy-duty applications and HD super it’s even heavier duty.
In spite of the “Serigraphic” name, the most frequently used of these mesh grades is T for screen printing on garments.
Screen Printing Mesh Count used
Most screen printing falls into one of three classifications.
Very heavy deposit, quality of outline not important Under 45-110 inch (18-43cm)
Heavy deposit, good definition 110–195 inch (43 – 77 cm)
Thin deposit, extra-fine detail 195–355 inch (77 -140cm)
Most special effect inks will need a big mesh, 18-30cm, ideal for sparkle or glitter inks, since these inks include particles that cannot pass through the finer mesh.
43-77cm for a good deposit of ink, puff ink like a 43cm Mesh.
and 77-140m is for fine ditails, halftones and so on.
Thread diameter and Ink Deposit
The main problem when printing fine details are the transfer of ink through the screen to the substrate.
In order for the ink to be easily removed from the stencil, it is important to have a larger area on the substrate compared to the area in the stencil.
The minimization of the thread mass as illustrated in the image, the use of thinner filament threads, and the reduction of the stencil thickness improve ink transfer and resolution. As you notice the EOM (Emulsion over Mesh) plays a role too.
As we use the T-Mesh mostly in screen printing and you understand the above. Would it make sense to use an S-Mesh? Yes of course! An S-Mesh fiber is much finer, so we have a bigger opening and less EOM.
The result is, the ink will release easily out of the mesh and are able to hold finer details and get more ink down. Here my little explanation T-Mesh verso S-Mesh. We used lately only S-Mesh for the under-base, or for very fine details. If you can get a hold on S-Mesh to give it a try.
Streching the Screen Printer Mesh
The fabric must be stretched evenly to ensure perfect uniformity during printing. A mechanical tensioning device is advantageous for carrying out this process. It can be done by hand, but this is not an option for a professional screen-printer.
Pneumatic systems are usually used for tensioning. These have a series of cylinders that perform the same pull in all directions, up, down, right, left.
But my favorite is this one
Yes I know, many will say the Pneumatic is much better, but I have the feeling I have more control over this once. And fewer parts to break, so this is a personal favorite for stretching the mesh, a simple manual device. Perhaps I have the feeling, to have more control over it, but hey, see what fits you best.
One advice here, when you stretch your frame, do it not to fast. Don’t try to pull in one go. Go slowly, pull, let rest, pull let rest, till you archive your desired newton. Give it some time!
How many newtons should a screen printer screen be stretched with?
The newton (symbol: N) is the International System of Units (SI) derived unit of force. One newton is the force needed to accelerate one kilogram of mass at the rate of one metre per second squared in the direction of the applied force. WIKIPEDIA
The measuring unit for stretching the screen printing mesh is called Newton. And this is depending on the mesh you use. A T-Mesh can take more Newtone than an S-Mesh, as we learned the diameter of the fibre is thicker. But not all T-Mesh get the same amount of newton when we stretch the Mesh. General speaking so finer the mesh count, so less newton it can hold.
A serios mesh suppliere, will provide you with a mesh Guide like above. itexplains you what percentage of mesh opening it have and how many newton it could hold.
Please ask for this, and not just blindly push your mesh to 40 newtons, as I hear very often, that 40 newtons would be good. My belief is, everything above 20 newtons, is good to work, less than that, will bring some problems concerning registration and sharpness. But please follow the Screen Printing Mesh Count guide from your supplier.
How to messure newton on your screen
For this we have a special tool called the newton-meter, positioned on the stretched mesh in the corners, to take the reading. Be aware, this thing has the tendency to fall down and break, use it with care!
Printing Mesh Adhesives
Here you have a wide choice, it starts from Liquid contact adhesive PATEX to the high professionals, what is chemically residence and has a short drying time from 30min or even less. A must is that the glue penetrates the mesh well, what can be difficult by a thick type of glue.
High-performance Adhesives have clear advantages and should be your first choice. Remember you need to hold a min. 20 Newton, there is some force! and nothing is worst, after stretching you mesh on the frame, that you see it loses its grip on some places. you will need to replace the mesh and do it again, and the cost of a proper mesh is not low.
What Screen Printing Frames to use
Wooden frames area cheap option, if you see screen printing as a hobby, yes, no problem. If you think and you are right, that metal is a better option, you are right too. But when it concerns normal metal frames, what you have any way to galvanise them, you are in the wrong way.
Invest in aluminium frame, it’s a lifetime investment, as they do not break, bend or set on rost. but be aware, of the thickness. Fin aluminium frame, have the tendency to bend when you add your newtons on the mesh. better invest in aluminium frame, with a 4x4cm diameter. I know, this is not a cheap investment, but did I mention that it is for a lifetime?
Yes, myself started with wooden frames, but it is just a pain in the …, think about it, well.
Mesh Calculator what is it
A Mesh calculator is used to identify the current mesh count on the frame. Some times people forget to write the mesh count on the screen and then it is hard and to see with the blank eyes, what mesh count it is, you use the mesh calculator.
A star will be formed, when you move this film over your mesh, this indicates what mesh count you have in front of you. Simple, but if you are unsure, get the confirmation, with this Mesh calculator.
Why we have colour Screen Printing Mesh?
You will see even Yellow mesh, but why it is yellow dyed?
First, The illuminated areas are cured by irradiating a direct stencil with UV light.
During exposure, the light passes through the screen emulsion and is reflected at the fabric surface. The light is also transmitted through the fibres themselves, resulting in even more undercut. Light rays hitting the white fibres of the fabric are reflected and scatter under the black edges of a film. This can lead to underexposure of the copy master (film) in the case of uncoloured “white” meshes. Thin lines or even halftone dots become even thinner due to the underexposure or are not imaged in the stencil at all. The obvious choice to achieve this is to use the complementary colour, which by definition absorbs the desired wavelengths. Absorption tests show that the most effective absorber is a warm yellow colour.
In other words, the yellow mesh should help to avoid light scatters or travels under the black film. So we would not have so sharp outlines.
Moire effect and how to prevent it
Moire is the superimposition of halftones and mesh. This interference results from meshes or mesh nodes that block some or all of the halftones in an image.
Generally, Moire is controlled by placing the halftones at a specific angle when creating the film with a RIP program and having four or more open mesh areas per halftone point. more info here
Screen Printing Mesh Count CONVERSION Chart
|Threads per inch||Threads per centimetre|