What is screen printing?

Silk printing method

Screen printing is a printing technique named when the printing screen uses silk to make. Silk printing can be used to print images on many different materials. Nowadays, in addition to silk, mesh frames are also created with cotton fabric , synthetic fiber fabric … The principle of silk printing technique is similar to oil ink printing on stencils. When printed, part of the ink will seep through the printing screen. Thanks to other specialized substances, some other meshes will be sealed. This technique can print on many materials such as:

• Nylon: Large and small packaging
• Fabric: Jeans, all types of shirts, handbags, school bags, scarves, backpacks
• Glass
• Clock face
• Electronic circuit
• Metal: Aluminum, zinc, iron
• Wood
• Paper: Cardboard paper, invitation cards…
• Plastic
• Mica

In addition, screen printing can also be performed on thick, thin, flexible, flat, and even rough material surfaces. Many people often refer to silk printing as screen printing, so how is silk printing different from screen printing? Lets discuss it and discuss the equipment that we use for screen printing in Dallas.

What is screen printing?

Screen printing is essentially a printing method that uses a printing frame and a printing screen. However, because screen printing uses silk mesh, the craftsman calls it that name. After more materials were used to create mesh, especially metal, it got the common name screen printing. We can understand that silk printing means screen printing. Both are printing techniques that use printing screens to create products. Both can print on a variety of surfaces, and produce similar quality finished products.

Principle of screen printing

The screen printing method will be based on the principle of ink absorption. Ink will be put into the printing frame. Aluminum or wood can be used in making the frame. Use a rubber blade to scrape off the ink. The impact of the scraper will help the ink penetrate the printing screen. And the ink is only absorbed through the part of the mesh where the image will be printed, then it will transfer the ink to the surface that needs to be printed. For the parts that do not have an image, the printing screen will be sealed with photosensitive glue, so the ink will not be able to come into contact with the printed material.

Is screen printing good?

Silk printing can still create beautiful, highly accurate images, but the durability is not as long. Many products are easily broken after a period of use, due to the elasticity of the fabric. So screen printing is still good, but if you want to print high-end products, you should not. The lifespan of the images is not prolonged and is easily affected by external influences, so the images quickly become old and peel off.

Silk printing steps

This is a printing method that can be printed manually or by a printer. Using the machine will save more time. New manual printing takes more effort and many stages. Therefore, below will introduce the steps of manual screen printing, helping you better understand the working principle of this printing technique:

Mix glue

First of all, to carry out this process, it is necessary to mix the glue successfully. Mixed glue cannot be too thick or too liquid. If the glue is loose when applied to the frame, it will be mushy. If the glue is thick, it will be difficult to coat the frame evenly. And note that when mixing glue, you must avoid light as well as spotlights. It is best to mix glue indoors, where it is least affected by light.

Remove the printing screen frame

The frame must be cleaned before printing. There are many ways to clean the frame, the most common way is to use a cloth soaked in oil or gasoline to clean off the paint stains. Some workers will use soap to clean. If the ink stain is too stubborn, you can use cyclohexenol gasoline to clean it.

To clean the inside surface of the frame, sprinkle the cleaner evenly on both sides. Then rub evenly so that the potassium permanganate penetrates into the glue layer on the frame. Finally, sprinkle more oxalic acid and rub vigorously to remove the glue. Rinse with water and hang the frame to dry.

Proceed with screen printing

Before printing, you need to prepare the following items:

• Silk shooting table
• Clean silk frame
• Glue trough
• Dryer
• The glue is already mixed
• Film or print to be taken
• 1 piece of black fabric, sized to fit the silk frame
• 1 2cm thick foam sheet the size of a black cloth
• 1 5-mm glass plate is the size of a Styrofoam plate
• 1 faucet with water

Step 1 : Apply glue to the frame

Step 2 : Place the film or print on the shooting table, then place the silk frame on the film. Line the frame with a black cloth and use the prepared foam to press it onto the cloth. Finally, the glass will be placed on top to fix it and dried

Step 3 : After drying for 5 minutes, take the film out and wash it. Be sure to spray strong water on both film surfaces.

Step 4 : Use tape and stick it to the 4 corners of the frame, then place the frame on the screen printing table

Step 5 : Put ink on the frame, use a knife to let the ink flow through the image to be printed

Step 6 : Once you have the finished product, you should clean the frame mesh

1. Learn the necessary equipment and supplies for screen printing
2. Silk screen printing frame

It can be said that when screen printing, a screen printing frame is indispensable. There are many different types of silk screen printing frames. Currently, there are 3 types of screen printing frames most commonly used: aluminum frames, wooden frames, and iron frames.

• Wooden frame : Wooden screen printing frame is the most used because it is cheap and easy to process. However, it can only print simple products with few colors. The frame also quickly becomes uneven or bent because it easily absorbs water.
• Aluminum Frame: Aluminum frames are used to print higher quality products. The aluminum frame makes color overlapping stable and easier to do. But the price of aluminum frames is much higher than wooden frames. Aluminum frame can be combined with machines during printing.
• Iron frame : Heavy iron frame, rarely used. But because of the low price, many people also invest in this type of frame. Iron frames come in a variety of sizes and can print large and bulky products.

Silk screen printing table

The screen printing table is a device that makes printing easier and smoother. The screen printing table must be flat and not rough. If the print bed is concave, the ink will not be printed evenly. If the print bed is convex, it will be difficult to remove ink. The height of the silk table will depend on the height of the printer. The printing table should not be placed too high as it will cause the printer’s hands to get tired, and the ink removal will also be uneven.

In addition to the height of the printing table, the width is also very important. Normally, the screen printing table will be 30cm larger than the printed product. Therefore, printing tables are manufactured in quite rich and diverse sizes to suit each different printing product. The screen printing table will have its own characteristics to help make printing more effective:

• The screen printed table top is smooth, flat, and sturdy.
• Tables are usually placed horizontally, or tilted at a 10 degree angle. That way it’s easy to use the knife to remove the ink.
• The printing table is made from a 2cm thick wooden board, 8cm – 10cm wide. Or it can also be made from thin metal panels or concrete. Nowadays, people use printing tables made from flat metal quite a lot. Maybe instead of using a printing table, the worker can use a large glass panel instead.
• For printing materials with uneven surfaces, the printing table will often be covered with an additional layer of fabric to increase elasticity.

1. Ink knife

The ink knife is used to help the ink penetrate the mesh and print on the product. The squid knife is composed of two parts: the blade and the handle. The material used to create ink scrapers is gradually changing, and depending on the screen printing specifications, the craftsman will use the scraper appropriately.

• Knife with wooden handle and rubber tapin blade : This type of knife was first used in screen printing. However, after many improvements, the handle was made of pine wood. The blade is made from heavy truck tires. This type of knife helps the ink handler avoid hand fatigue, as well as increase aesthetics.
• Plastic Polymer : This type of knife is considered the most advanced today. Use a mold to create a squeegee. The blade is created monolithic and seamless. This means that the handle and blade are both made of Polymer synthetic resin.
• Knife with aluminum handle, synthetic plastic blade : This type of knife is lighter, so it makes it more convenient for the worker to use. The knife also has a beautiful design, and is quite durable.

In addition, there are also semi-automatic scrapers and automatic scrapers. These are two types of knives used in automatic screen printing.

Glue coating trough

Silk-screen glue coated troughs are produced in two models: aluminum and stainless steel. And aluminum troughs are more commonly used, thanks to their durability and more affordable price. Glue troughs come in many different sizes to best serve each product that needs to be printed. The trough has sizes such as: 15cm, 20cm, 25cm, 30cm, 35cm, 40cm…

Copy glue

In the screen printing process, copy glue is indispensable. Currently on the market, photocopy glue is divided into 3 types. Type used for water-based ink , oil-based ink and amphoteric glue. Some types of silk screen printing glue commonly used today include:

• Plus series printing adhesive: This is an amphoteric screen printing adhesive that can be used for both water-based ink and oil-based ink. Plus series photo glue has a high price, but helps the product stay color-fast and sharp. The product does not contain heavy metals and is safe for users. In this line, Plus 7000 glue is used the most.
• Cao Thanh photocopying glue: A type of glue produced using American technology. Glue has a shelf life of about 2 years. However, the printed screen will be difficult to clean after printing.
• UDC-HV plate glue : A purple color plate glue, made in the US and of high quality.
• Unalo copy glue : Glue is used for both ink lines, and is of very high quality. Glue can print many of the smallest details on the drawing, helping to create the most complete print.
• Plate glue T101 : Plate glue T101 is quite easy to buy and can be used for both oil-based and water-based inks. The glue does not contain heavy metals, so it is also safe for users.

Silk screen printing ink

To create prints with colors consistent with the sample, it is necessary to use the appropriate ink and ink color. Screen printing ink will be divided into two types: water-based ink and oil-based ink. Printing ink contains resins, pigments, solvents and additives. Although ink is produced in many different types, the main ingredients are mostly the same. Currently commonly used screen printing inks include the following types:

• Water-based ink : These are inks that are mainly composed of water, safe but not very durable. The ink is water soluble, and does not need to be dried after printing.
• Oil-based ink : Is a type of ink produced from petroleum, has a strong odor, is not safe for users but is very durable. Printing ink does not dissolve in water, and is very water resistant.
• UV ink: This is a type of ink that needs to be dried with UV rays after printing before the ink can dry. Same oil-based ink, but lighter. Therefore, the ink smell is not too strong. When printing with UV ink, the image will have gloss and make the product more realistic.
• Plastisol screen printing ink: Plastisol ink is also an oil-based ink, but lighter. Once finished, the product needs to be dried at a temperature of 160 degrees Celsius for the image to dry. Ink can create many effects during the printing process.

Thus, screen printing is a printing technique that uses many different tools and equipment. Not only that, the method needs to be performed by a skilled craftsman to create the most perfect product. Screen printing, although handmade, always satisfies customers when producing a finished product. Although digital printing methods have now emerged, silk printing is still developing and popular with many people.