The manual screen printing process is simple to operate and can meet the requirements of screen printing without expensive equipment. It has low investment, good quality and high efficiency. It also has considerable advantages in the screen printing industry. Manual screen printing is now divided into three parts according to its process flow and is summarized as follows for the reference of colleagues who are beginners in screen printing.

Screen printing plate making

In terms of operation technology, screen printing plate making can be divided into engraving paint film plate making and photosensitive plate making. Different methods should be selected depending on the printing suitability of the substrate. Plate making method. For example, for screen printing with text and line patterns, you can choose to make a plate with engraved lacquered paper, and for screen printing with a continuous layered pattern, you can choose to make a plate using the hanging screen photosensitive printing method. The plate making method is introduced as follows.

1. Engraved paint film screen printing plate

(1) Formula and production of paint film paper

1. Formula and production of lacquer film paper

Recipe

Soft clear spray paint 100 grams

Super banana water or butyl acetate 200-300 grams

Castor oil 4- 6 grams

Operation

Put tracing paper or cellophane on a flat wooden board or glass, mix rubber water and gasoline evenly at a ratio of 1:1, and brush the paper with shading Brush as an isolation layer and spray paint after drying. When spraying, the spray gun should be about six or seven inches away from the paper; spray it seven or eight times. The thickness is up to you. Generally, wax paper can be prepared in three types: thick, medium and thin. Spray the first layer and let it dry slightly before spraying the second layer, the third layer... If the production quantity is small, you can also use a texture brush to make it.

Soft clear spray paint is colorless and transparent. When making wax paper, the spray paint must be dyed, that is, a small amount of royal blue, magenta, and magenta green pigments are added to the spray paint to facilitate identification during engraving. , the color should be light and not too thick, otherwise it will affect the view during carving. The dye should be dissolved with alcohol first.

The amount of castor oil should be increased or decreased according to the spray paint performance and weather changes. Dibutyl ester can replace castor oil, but is not as good as castor oil.

2. Formula and production of gelatin film paper

Formula

20 grams of special grade gelatin

100-300 grams of water

Glycerin 3-7 grams

Operation

Put the gelatin into the clear water in the container, cook and dissolve, then add glycerin and a little royal blue dye, and use a glass Stir thoroughly with a stick and filter through a 100-mesh or above wire mesh.

Attach the polyester film base to a very flat wooden board or glass plate, use a shading brush to apply perchlorethylene slurry and cyclohexanone solvent on the paper as an isolation layer, wait until dry It can also be sprayed or brushed with a shading brush (the method is the same as before).

Let it dry naturally and store it in a dry and ventilated place for later use.

When the temperature exceeds 180°C during preparation, 1 gram of sodium sulfate can be added.

3. Formula and production of nitro varnish modified paint film paper

Formula

Part A

Nitrocellulose 10 grams

90 grams of butyl acetate

50 grams of ethyl acetate

10 grams of butanol

40 grams of toluene

Part B

12 grams of melamine formaldehyde resin

20 grams of castor oil modified alkyd resin

Operation

Part A and B Mix well and mix thoroughly.

The operation method is the same as that of lacquered film paper, and the plate can be carved and plated by heating it at 120℃ for about 2 hours.

(2) Engraved paint film paper

Place the drawn ink draft under the paint film paper and paste it with transparent tape. Use an engraving knife to remove the paint film from the printed part. Remove from the backing paper.

For engraving with multiple colors, it is necessary to carefully examine the drawing and distinguish the order of overlapping colors. In order to prevent plate deviation, the first color range during engraving should be slightly larger than the original, and the second color range should be as large as the original, so that it will match exactly after printing. The engravings printed first should be wider, and the engravings printed later should be the same size.

In addition, when engraving the contour line, the color pressed by the contour line should be placed at one-half of the outer line, and the contour line should be engraved to be equal to the original pattern.

(3) Stretching screen

The selection of screen mesh and screen mesh should be flexibly selected based on the substrate, plate loading method, and printing material properties. Printing of fine graphics and text can be Use 130-150 mesh screen, and 100-120 mesh for printing thicker graphics and text. Gelatin film paper needs to be plated at a certain temperature, so silk screen can be used. Lacquer film paper needs to be plated with potion. No temperature is required, so it is better to use nylon mesh.

Use a stretching machine or manual stretching method to stretch the wire mesh on the frame. The stretched wire mesh should be flat and moderately elastic. Use glacial acetic acid to wipe off the oil on both sides of the wire mesh. and dirt stains.

(4) Placing the plate

1. Placing the plate on lacquered paper

Place the carved plate on the flat cellophane paper and place it Place the stretched screen frame on top. Use absorbent cotton dipped in a little banana water in your right hand to rub it on the screen. Use dry absorbent cotton in your left hand to press it to make the lacquer film adhere to the screen.

After the printing plate is completely dry, remove the lining paper, and use gasoline to clean the rubber water stains painted on the back of the printing plate and the lining paper.

If there are peeling spots on the plate, you can use banana water to repair them. If there are knife marks where the blades meet and small strokes that are peeling off, you can use a brush dipped in lacquer liquid to repair them.

2. Plate on gelatin film paper

Draw regular lines on the original manuscript. Many color plates use this rule as the binding rule.

Place the engraved plate together with the original manuscript at the appropriate position on the screen plate. According to the regular lines of the original manuscript, stick the regular binding pieces on the screen plate with milky white glue. And stick it firmly with paper. If there are several sets of colors, use several screen plates to set unified rules.

Place the original manuscript together with the engraved plate on a regularly arranged table, put down the screen frame, and use an iron on the screen to align the edges of the four corners of the engraved gelatin plate and iron them at fixed points. The gelatin version is pasted onto the screen and the original is removed.

Put some thick hard paper on the table, put down the screen frame to make the gelatin engraving paper pad flat, then cover the screen with a polyester film base to act as a spacer, and iron it back and forth with an iron. Several times, iron the gelatin film onto the screen.

After placing the plate, let it dry naturally, then remove the backing paper and use cyclic ketone to clean away the traces of perchlorethylene painted on the reverse side of the plate and the backing paper.

If the plate has fallen off, you can use glacial acetic acid to repair it. If there are knife marks where the blades meet and small strokes that have fallen off, you can use a brush dipped in gelatin to repair it.

3. Plating on nitro varnish modified paint film paper

The method of applying nitro varnish modified paint film paper is the same as before.

(5) Sealing the screen

Sealing the screen is to glue and block the screen other than the screen graphics and text with colloid so that the printing plate does not leak ink during printing. Lacquer paint screen can be sealed with nitrocellulose varnish, and gelatin liquid can be used to seal gelatin paint screen and nitrocellulose varnish modified paint screen. The sealed printing plate can be printed after it is dry.

2. Photosensitive screen printing

(1) Photosensitive printing formula and production

1. Gelatin chromium salt photosensitive glue formula and production

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Recipe

180 grams of special grade gelatin

30 grams of potassium red vitriol

1000 ml of water

Ammonium dichromate 10 grams

10 grams of citric acid

10 grams of barium sulfate

25 ml of alcohol

55 ml of ammonia

Operation

Heat, dissolve and filter the above-mentioned drugs, apply them on a 260-mesh nylon screen plate in a darkroom and let them dry naturally before use.

2. Formula and production of polyvinyl alcohol chromium salt photosensitive liquid

Formula

Nail nail solution

Polyvinyl alcohol 40 grams

Sodium dodecylbenzene sulfonate 0.5 g

Glacial acetic acid 4 ml

Water 250 ml

Liquid B

5 grams of ammonium dichromate

30 ml of water

A small amount of eosin

Polyvinyl acetate (or add 4 ml of dibutyl ester) 40 ml

Operation

The polyvinyl alcohol is preferably 1788, the polymerization degree is 1700, and the saponification degree is 88.

To prepare liquid A, polyvinyl alcohol, sodium sulfonate and water are mixed and dissolved in a water bath, and then filtered through a 180 mesh screen. Liquid B is filtered through filter paper after dissolution.

Mix liquid A and liquid B in the darkroom, stir thoroughly, scrape and apply onto the screen, scrape twice on the scraping surface of the screen, and scrape four to six times close to the printing surface of the substrate. Next, let it dry naturally or blow dry with a fan for later use.

Note: Glacial acetic acid can accelerate the dissolution of polyvinyl alcohol, facilitate development, and improve the resolution of photosensitive colloid. Eosin dye makes the colloid appear bright red after photosensitive curing, and the unsensitized part is washed with water. The screen is exposed for easy observation, and the polyvinyl acetate firmly combines the photosensitive adhesive with the screen to improve the resolution.

(2) Exposure and display

Place the positive negative film made by photography closely on the silk screen coated with photosensitive adhesive, and expose it with a fluorescent lamp or dysprosium lamp. 50cm-60cm, exposure time is 6 to 8 minutes.

Develop the exposed screen plate with warm or cold water for about 1 to 2 minutes, or rinse it with a nozzle. The pressure of the water flow should not be too strong to avoid destroying the photosensitive adhesive. Wait until the image is fully displayed. , rinse immediately with clean water and dry.

After the printing plate is repaired, a layer of varnish is applied to the non-inked parts to protect the plate in preparation for printing.

3. Printing suitability

Lake varnished paper engraving plates can be printed with thick lacquer, coatings, dyes, pigments, pulp, etc., and are suitable for varnished paper, varnished cloth, cloth Printing on class, paper, glass and other substrates.

Gelatin film paper engraving plates, nitro varnish film paper engraving plates and photosensitive printing plates are not only suitable for all the suitability of lacquer film paper engraving plates, but also can be solvent-based. Pigments, such as plastic ink, perchlorethylene, polyvinyl chloride, etc. are used as printing materials, suitable for printing on plastic products, leather and other substrates.

Print material performance and preparation

Manual screen printing covers a wide range of areas, and different substrates have different choices for printing materials. Here are several printing materials based on the printing of common substrates. Preparation method.

1. Performance and preparation of plastic printing materials

(1) Pharmaceutical properties

1. Polyvinyl chloride: powdered resin

The main raw material of plastic formula, it dries quickly and swells easily. It is easy to form a gel and is dull. It needs to be heated when dissolved in cyclohexanone.

2. Polyvinyl chloride: paste resin

Imported product, its transparency is better than that of powder. It can be dissolved in cyclohexanone without heating. It has the same functions as powder when used. Resin is the same.

3. Pervinyl chloride: floc resin

The main raw material of plastic, the drying time is slower than that of polyvinyl chloride, sticky and shiny, but it is more sticky than polyvinyl chloride resin after drying It is heavy, so it is not advisable to add too much in the formula, otherwise there will be adhesion after drying.

4. Perchlorethylene varnish

The varnish is used as a mixed varnish in Fanli water. Compared with the paint properties, it dries faster and can be used in printing paints and pigments. It has a stabilizing effect and can also play a drying role.

5. Cyclohexanone

Solvent is used to dissolve polyvinyl chloride resin and perchlorethylene resin. It is highly corrosive and slow to dry. If the amount is too much, poly(perchloride) chlorine will become When vinyl dissolves, it is best to discontinue use and use butyl acetate or xylene instead.

6. Butyl (ethyl) acetate

Solvent plays a diluting role in the formula. Ethyl ester dries faster than butyl ester, and both are shiny. Butyl ester is commonly used in formulas. ester.

7. Xylene

Solvent, used for dilution, is highly corrosive and volatile, and has high drying properties. Putting more in the seasoning can speed up drying, but when mixing with gold or silver materials cannot be used.

8. Dibutyl phthalate

Solvent plays a plasticizing role in the formula, dries slowly, and should not be used frequently in ingredients.

9. Nitrobenzene

Solvent is flammable and toxic, has low volatility, and can slow drying. Add a small amount to the prepared plastic raw materials to prevent sealing during printing. Version and sealed version can be used to unblock the version.

10. Various printing coating (slurry) materials

The powder is heavy and contains a lot of water. It is not easy to put too much when adjusting the plastic printing material. If it is too much, it will easily agglomerate and cause problems during printing. honeycomb.

(2) Preparation of printing material

1. Preparation of polyvinyl chloride pulp

Formula

100 grams of polyvinyl chloride tree finger

500 grams of cyclohexanone

500 grams of xylene

100 grams of dibutyl phthalate

Operation

Pour the medicines into the condiment container in sequence, and stir each medicine thoroughly with a glass rod or wooden stick to allow it to completely dissolve.

When mixing ingredients, it is necessary to isolate the seasoning vessels and place them in hot water to heat them to promote the dissolution of the medicine.

Note: The prepared polyvinyl chloride slurry is transparent and can easily form a jelly-like state in cold weather. When used together with other ingredients in winter, it needs to be heated with water to melt.

2. Preparation of perchlorethylene slurry

Formula

500 grams of perchlorethylene resin

500 grams of cyclohexanone

500 grams of dimethylbenzene

500 grams of butyl acetate

Operation

Pour the medicines into the seasoning vessel in order, pouring each one The medicine needs to be stirred thoroughly with a glass or wooden rod to completely dissolve it.

No heating is required when preparing this material. The prepared perchlorethylene slurry will be brown-red and transparent.

3. White material preparation

Formula

500 grams of polyvinyl chloride pulp

500 grams of perchlorethylene pulp

Titanium dioxide (titanium dioxide) 500 grams

Operation

Pour the above ingredients into the iron seasoning bucket in order, stir slightly with a wooden stick, and then stir with a mixer for 6 hours Above, stir the medicinal ingredients thoroughly and evenly, and add a little royal blue paint. The advantage of this is that the prepared white material will be brightly colored.

After filtering through a sieve of about 100 mesh, put it into a porcelain jar and store it with a lid. Pour a little cyclohexanone on the material surface to cover the surface to prevent drying.

4. Preparation of gold (silver) pigments

Formula

120 grams of polyvinyl chloride pulp

80 grams of perchlorethylene pulp

Gold (silver) powder (800 mesh or above) 100 grams

Operation

Before preparing gold (silver) powder, it needs to be soaked in cyclohexanone for a period of time.

Pour the ingredients onto the glass plate in order and use an ink spatula to mix.

Gold (silver) materials can be adjusted and used at any time, and should not be stored for too long to avoid the gloss darkening over time and affecting the printing effect.

If the gold (silver) material dries thickly or dries too quickly, you can add cyclohexanone to dilute it, but do not add xylene, otherwise it will easily cause gold to fall off.

5. Preparation of dark-colored materials

Formula

30 grams of perchlorethylene slurry

70 grams of polyvinyl chloride slurry

Appropriate amount of printing paste

Operation

Use an ink spatula on the seasoning board to mix according to the original color swatch, but the color is slightly lighter than the original. It can only be mixed with the original after the printing is dry. The colors are consistent.

6. Preparation of light color materials

Formula

Appropriate amount of white material

Appropriate amount of printing paste

Operation

Use an ink spatula on the palette to match the color swatch of the original, but the color will be slightly darker than the original. Only after the printing is dry can it match the color of the original.

(3) Common formula reference

1. ***Preparation of clothing pulp

Formula

Vinylidene chloride-vinyl chloride 200 grams of coating resin

500 grams of cyclohexanone

400 grams of butyl acetate

Operation

Pour the drugs in order Pour into the condiment vessel, and stir thoroughly with a glass rod or wooden stick for each medicine until it is completely dissolved, then add the pigment before use.

2. Preparation of ***jumbo resin

Formula

150 grams of vinyl chloride-vinyl acetate ***jumbo resin

Acetic acid 400 grams of butyl ester

500 grams of cyclohexanone

200 grams of methyl benzoate

Operation

Pour the medicines into the seasoning in sequence In the vessel, use a glass rod or wooden rod to stir each medicine until it is completely dissolved and add the pigment before use.

The above two formulas are easy to operate, do not need to be heated to dissolve, and do not need to be mixed. They can be used alone. The gloss and firmness are ideal, but the use must be flexibly controlled according to climate changes and the properties of the raw materials.

2. Performance and preparation of paints and thick paint printing materials

(1) Pharmaceutical properties

1. Various colors of thick paint

Printing The main material of varnished cloth and varnished paper is heavy in powder, less viscous than ink, shiny, easy to dry, and has a three-dimensional effect when printed on the surface.

2. Various resin-based inks

Highly sticky, shiny, and not easy to dry.

3. Drying oil

Promote the drying of thick paint and ink, quantitatively based on climate, add more when it is cold and less when it is hot.

4. Grease varnish (formerly known as Fanli Shui) is glossy, has good viscosity and can be used for dilution.

5. Turpentine

Used for dilution, it has low volatility, good decomposition power, and no luster. It is a good solvent for thick paint.

6. Glycerin

Colorless and odorless viscous liquid.

7. Gasoline

For dilution, it is highly volatile and non-sticky. Do not use too much.

8. Fish oil

It is shiny, not easy to dry, and slightly sticky. It can be used frequently when mixing gold powder.

(2) Printing material preparation

1. White paint preparation

Formula

Lithopone 15 catties

8 pounds of grease varnish

1 pound of glycerin

Operation

Use the ink press several times to press the mixture.

2. Preparation of black paint

Formula

15 pounds of carbon black

12 pounds of grease varnish

1 jin of glycerin

1.5 jin of black ink

Operation

Use the ink press several times to press the mixture.

3. Red paint preparation

Formula

3.5 catties of toluidine red

6 catties of grease varnish

1 jin of glycerin

1 jin of red ink

Operation

Use the ink press several times to press the mixture.

4. Preparation of thick paint printing materials of various colors

Formula

Thick paint 60-80

Printing ink 40-20

Drying oil 1-15

Appropriate amount of thinner

Operation

Use an ink shovel on the ink mixing table to mix according to the original color sample. The color should be lighter than the original color, and the light color should be darker than the original color. It will be consistent with the original color after it dries.

3. Preparation and operation of cotton textile printing materials

(1) Preparation and operation of cooked pulp

1000 grams of wheat starch, mix with cold water to make a uniform paste , heat and boil for a few minutes until the slurry is cooked, then add warm water to make it 5000 grams and set aside.

(2) Preparation and operation of printing materials

150-300 grams of powdery fast pigment

150-250 grams of neutral Taikoo oil

Caustic soda (40°Be) 100-150 grams

Industrial alcohol 150-250 grams

Cooked pulp (wheat starch) 3000-2750 grams

Cooked water (50-70°C) 1450-1300 grams

Weigh the dye first, then add neutral oil and caustic soda in sequence (if the oil is acidic, caustic soda should be added first and then the oil) , industrial alcohol, after mixing it into a slurry, pour it into 50-70℃ hot water and stir thoroughly until the dye is completely dissolved. Finally, add the dye liquid to the weighed slurry while stirring, and mix evenly to form cotton. Textile printing materials.

(3) Preparation and operation of chromogenic acid

Pour 100g of 66°Be concentrated sulfuric acid and 150g of Yuanming powder (also called anhydrous Glauber's salt) into 2000g of cold water respectively. Stir evenly and then add hot water until the total weight is 5000g. Be careful not to pour concentrated sulfuric acid into hot water or pure water into sulfuric acid, otherwise the acid will easily explode and splash onto the skin, causing corrosion and burns.

After the cotton textiles are printed with flowers, expose the cotton textiles to the air overnight (at least 18-24 hours), immerse them in acid solution at 70-80℃ for half a minute while stirring, and then take them out. Rinse with clean water several times until no acid remains on the cotton textiles.

(4) Preparation and operation of soap cooking liquid

5000g water

15g soap

Place the colored cotton textiles again Boil it in boiling soapy liquid, take it out and wash it with clean water after 10 minutes. The washed cotton textile print will be bright and firm in color.

4. Reference for common light-color formulas

①Pink: mainly white ingredients, with a little addition of orange and peach

②Meat color: mainly white ingredients , slightly add orange, medium yellow

③Beige: mainly white material, slightly add orange, medium yellow, black

④Lake blue: mainly white material, slightly Add peacock blue, if you need it darker, add a little royal blue, if you need light resistance, you can use bright blue

⑤Lake green: mainly white material, add a little bright blue and light yellow, if you need a darker color, add a little more Add medium yellow

⑥Light snow cyan: mainly white material, add a little pink and royal blue

⑦Grey: mainly white material, add a little black ink and royal blue, if necessary Yellow, blue, red, slightly darker yellow, bright blue, pink

⑧Emerald green: peacock blue plus lemon yellow

⑨Olive yellow-green: mainly white material , add light yellow and peacock blue, slightly add pink

⑩Dark green: dark yellow plus medium blue, then slightly darker red, if you need it to be more tender, add medium yellow and peacock blue

⑾ Silver gray: Mainly white material, add a little silver paste, black ink, if you need more blue, add a little royal blue

⑿Ivory yellow: Mainly white material, add medium yellow, peacock blue and orange red

⒀Fake gold: Mainly dark yellow, slightly darker red, medium blue, if the base is darker, add black ink, if it needs to be lighter, add white ink.

⒁Green lotus color: peacock blue plus pink

⒂Bronze color: mainly dark yellow, with a little red and black ink

5. Adaptation to printing materials

The prepared plastic printing material is suitable for printing on plastics, plastic products, synthetic leather and leather.

The prepared paint and thick paint printing materials are suitable for printing on metal plates, glass, varnished paper, varnished cloth and paper products and other substrates.

The prepared cotton textile printing material is suitable for printing on various types of cloth, vests, shirts and other substrates.

Manual screen printing method

When hand screen printing, hold a scraper and apply slight pressure on the screen surface to press the printing material to the inked part of the printing plate. The mesh is squeezed onto the substrate so that the substrate reproduces the same graphics and text as the original.

If you want to get perfect screen printing products, you must understand the entire process of manual screen printing. The basic steps of the screen printing process for substrates of different materials and shapes are the same, but the printing materials and printing adjustments used are slightly different. Now we will focus on their accuracy.

1. Manual screen printing operations

1. Check the printing plate

Check the sealing condition of the printing plate, whether there are blisters in the printing plate, and whether the printing plate is damaged by blisters. Whether the installation with the bottom plate is loose, whether the screen distance is appropriate, whether the printing rules are correctly positioned, and whether there is any deviation in the multi-color registration.

2. Selection of scraper

The length of the scraper should be slightly longer than the printed graphics and text, and different shapes of scrapers should be used for different substrates. The rubber scraper should have a certain degree of flexibility to improve the contact between the screen and the substrate and make the ink even. The scraper edge needs to be flat. If it is uneven, it should be smoothed with sandpaper. The scraper material can be made of 5mm acid-resistant rubber.

3. Printing material preparation

The type and composition of printing materials should be determined according to the printing material and printing requirements. The key to preparation is color adjustment, dryness adjustment, and Viscosity, and strive to adapt to the requirements of scratch printing. The printing material should be adjusted first and stored for one day to make its performance stable, except for gold coloring. You should also check whether there are any foreign objects in the printing material to prevent scratching the printing plate during scratch printing.

4. Dispense the printing material

The printing material is generally poured in front of the screen frame within the starting position and the width of the scraper. Do not place too much printing material in the screen frame and add it at any time. This makes it easy to control the amount of ink during scraping and printing operations.

5. Scratch printing

① Place the hand-held substrate on the platen with rules, put down the screen frame, and leave a certain screen distance between the printing plate and the platen .

② Press the hand-held scraper against the screen. When scraping, the angle of the scraper should be maintained at 50-60°. The scraper will scrape the ink at a certain speed, so that the printed material will be hollowed out under the pressure of the scraper. The screen holes in the graphics and text part are printed on the substrate, and the screen rebounds and separates from the substrate after being scraped by the scraper. Depending on the size of the printing area and the length of the scraper, one or two hands can be used to scrape the printing, but the amount of printing material must be controlled, the printing plate surface must be scraped clean, and no printing material should be left on the graphics and text of the printing plate.

③ Lift the screen frame and take out the printing substrate from the platen.

6. Scrub the screen

During the printing process, if you find that the imprint is blurred or the mesh is clogged, you must scrub the printing plate and gently wipe the screen with degreasing cotton wool or a soft cloth dipped in solvent. On both sides, when scrubbing, scrub the graphic area first, and then scrub the other areas. Both sides of the printing plate should be scrubbed clean, the blocked areas should be cleared, and the solvent on the printing plate should be sucked dry. The printing plate should also be wiped clean after printing.

7. Color registration printing

When using color registration plates for scratch printing, it is necessary to distinguish the ink color levels. Generally speaking, light colors should be printed first and then dark colors, and secondary colors should be printed first and then The printing process is important and should be arranged when making the printing plate. The color registration plate must be printed accurately, especially the first color version must be printed very accurately. When there is scraping printing with mixed colors, the loading mode of the printing plate should be changed according to the direction of the mixed colors to facilitate scraping printing.

8. Drying after printing

Drying is required after each printing, but the drying between the two colors only requires that the next printing will not contaminate the previous print. The final Drying should also consider the outer ink layer to be completely dry to ensure the adhesion fastness of the ink layer.

Some printing substrates are prone to expansion and contraction due to climate change. If overprinting is not timely or left aside for a long time, overprinting will be inaccurate. This should be noted when drying.

2. Adjustment of manual screen printing operations

After starting printing, problems of one kind or another often occur. To obtain ideal printing quality stably, some variable factors must be adjusted. Adjustment.

1. The printing plate is blocked.

When scraping and printing, you should avoid empty scraping without printed matter and excessive printing stop time. When the weather is hot, the printing material often blocks the mesh of the printing plate, making it impossible to print images and text. At this time, slow-drying agents such as dibutyl ester can be appropriately added to the printing material to solve the problem. However, dibutyl ester and the like are highly viscous, so the scraped printed materials should not be stored in excessive thickness to prevent adhesion of the printed materials.

2. The layout is sticky

The sticky layout may occur in the following situations:

① Too much plasticizer is used when making engraving paper. The engraving paper is soft and sticky, so you can use a hair dryer to dry the layout with cold air.

② If there is residue on the layout that is used as an isolation layer when brushing the engraving paper, it should be cleaned with solvent.

③The mesh spacing is too small and the elasticity is not enough, causing the engraving paper to become sticky. The mesh spacing should be appropriately increased, generally 3-5mm.

3. Ink leakage from the layout

The main reason for ink leakage from the layout is that some areas are not sealed with glue when sealing the screen after loading, or there are some areas on the printing paper when loading. After melting, the gelatin printing plate can be repaired with gelatin liquid, and the lacquer printing plate can be repaired with lacquer liquid.

4. The printing plate and imprint are smeared

The reverse side of the printing plate is smeared and the imprint is smeared. This is caused by the mixed printing material being too thin and the printing material leaking into the bottom layer when scraping. . If the imprint becomes mushy, the printing material can be appropriately thickened, or a scraper can be used to appropriately control the amount of printing material.

Manual screen printing involves stretching the screen, engraving or photosensitive plate making, preparing printing materials and printing. The equipment is simple and requires little investment. It is suitable for a wide range of applications. It is flexible and convenient to operate. It can produce large profits and quick results. It can flatten objects. It can be operated on spherical objects, curved objects, and concave and convex surfaces. It can be printed on various paper products, as well as leather, varnished cloth, varnished paper, and textile items. It can also be printed on metal, glass, plastic, porcelain, utensils, wood, etc. The ink layer after printing is thick. Strong three-dimensional effect, beautiful and eye-catching. Therefore, while the screen printing industry is developing towards high technology and modernization, manual screen printing is still widely used in a certain range. and is still in a fairly advantageous position.