Screen printing Applications

Applications

Screen printing is arguably the most versatile of all printing processes. It can be used to print on a wide variety of substrates, including paper, paperboard, plastics, glass, metals, fabrics, and many other materials. including paper, plastics, glass, metals, nylon and cotton. Some common products from the screen printing industry include posters, labels, decals, signage, and all types of textiles and electronic circuit boards. The advantage of screenprinting over other print processes is that the press can print on substrates of any shape, thickness and size.

A significant characteristic of screen printing is that a greater thickness of the ink can be applied to the substrate than is possible with other printing techniques. This allows for some very interesting effects that are not possible using other printing methods. Because of the simplicity of the application process, a wider range of inks and dyes are available for use in screen printing than for use in any other printing process.

Utilization of screenprinting presses has begun to increase because production rates have improved. This has been a result of the development of the automated and rotary screenprinting press, improved dryers, and U.V. curable ink. The major chemicals used include screen emulsions, inks, and solvents, surfactants, caustics and oxidizers used in screen reclamation. The inks used vary dramatically in their formulations (GATF 1992b).

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Screen Printing Tips & Techniques

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Tips To Improve Screen Printing Quality

Tips To Improve Screen Printing Quality

Ink Quality: The consistency of ink is a critical factor in the quality of screen printing. Inks can be classified as stiff or loose depending on their consistency. Some printers try to adjust the squeegee angle and pressure to compensate for the consistency of ink. This is likely to make the screen printing process much more difficult and if the process is manual, can even lead to carpel tunnel syndrome or sore joints.

The correct way to modify the way an ink prints is by using two products known as soft hand clear or extender base and curable reducer. The soft hand clear is used to adjust the pigmentation in the ink. In addition to adjusting the percentage of pigment in the ink, the soft hand clear also makes the ink more creamy and easier to screen print. The soft hand clear ink requires less squeegee pressure than regular ink and hence improves screen printing quality.

Curable reducer changes the adhesive quality of the ink and can be used anywhere from 2-4% to 10% depending on its texture. The curable reducer allows the ink to shear easily and thus print better.

Thus it is important to modify the inks as required so that you not only screen print easier and faster but also save ink and get better registration.

Screens: The rule of thumb with screens and meshes is that the tighter they are, the better the quality of output. The benefits of a tight mesh include a decreased likelihood of the mesh moving out of registration during printing and lesser chances of one color bleeding into another.

Tight screens also offer lower resistance when pulling the squeegee thereby reducing labor and cutting the ink cleanly.

A tight mesh also deposits the ink evenly onto the substrate. A soft mesh may have deposits of ink towards the edges thus printing with more ink in the center and less towards the corners. The uneven deposit of ink results in lowered printing quality.

Squeegee: It is vital that the blade of the squeegee is straight and sharp. The squeegee should be sharpened every day if need be to allow for even spreading of the ink.

Press: To get good quality screen printing, the platen must never move during printing. Even if you do everything else right and the platen shifts, the quality of the print will suffer. Also the color arm must not deflect when it in or out of the registration gate.

Curing: You cannot substitute the amount of time that the ink is cured for by increasing the heat. Sometimes inks need to be cured at lower heat for longer time for the ink to fuse with the fabric and get a full cure.

Thus, keep these tips in mind when screen printing to ensure high quality screen printing.

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Types of Sticker Printing

Types of Sticker Printing

Sticker printing has evolved greatly over the past several decades. While a black marker and white paper were once the tools of the trade, today's stickers are available in wide variety of stocks as well as a wide variety of color options.

Screen-printing is the oldest, but the most common technique of sticker printing. As the name implies, the process utilized silk, although today synthetic screens are now used. Screen-printing is the most basic form of printing stickers and is typically limited to very small amounts.

For screen-printing, ultra-violet cured pigment colors are used and the desired image is cut out onto a stencil. The stencil is then placed on the sticker stock. The screen is then laid over the top and ink poured on to the screen and pressed into place using a squeegee. If more than one color is required, the process must be done for each color and only after the last has dried. The process must only be completed once for one-color items.

Letterpress, also known as relief printing, is another form of printing where the image is taken from a raised surface. Letterpress printing is best understood if you think of it as something with ink being pressed down onto the sticker stock. Letterpress printing is used on simple projects that typically only require one color.

Flexography is a much quicker form of printing stickers and allows larger quantities to be produced. This method utilizes reverse master image transfer and is used most commonly in commercial label printing. This method was originally designed to allow for constant contact with the material being printed on. Flexography uses a master print that makes contact with the sticker stock and then leaves a print from the contact of being rolled over it. Flexography is fast becoming the most popular way to print stickers that come on rolls. This process is environmentally cleaner as well as being faster.

Offset printing involves transferring an image from a plate cylinder or rubber cylinder. Although offset printing uses an additional step, it allows you a lot of flexibility in terms of color options. Offset printing provides excellent color results. Offset printing and lithograph printing area often utilized together, as they can provide vivid colors and effects when combined.

The most common type of printing is 4-color process color that utilizes 4 ink colors to create the effect of full color photographs. The four colors are cyan, magenta, yellow and black.

Digital printing is the most advanced form of printing. Digital printing provides you the ability to make changes to the image until just before it is printed. Because the print is a reproduction of the digital image, this technique of printing also allows for color changes on the fly. The inks that are used in digital printing sit on top of the sticker stock rather than being absorbed into it.

Digital printing is one of the most common technologies used in producing personal, commercial and small business products. The biggest advantage to digital printing is that you don't have to have a master file and you can make adjustments to the image as necessary. However, digital printing is usually limited to quantities below 500.

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Printing Industry Overview: Screen Printing

Screen Printing

Many factors such as composition, size and form, angle, pressure, and speed of the blade (squeegee) determine the quality of the impression made by the squeegee. At one time most blades were made from rubber which, however, is prone to wear and edge nicks and has a tendency to warp and distort. While blades continue to be made from rubbers such as neoprene, most are now made from polyurethane which can produce as many as 25,000 impressions without significant degradation of the image.

If the item was printed on a manual or automatic screen press the printed product will be placed on a conveyor belt which carries the item into the drying oven or through the UV curing system. Rotary screen presses feed the material through the drying or curing system automatically. Air drying of certain inks, though rare in the industry, is still sometimes utilized.

The rate of screen printing production was once dictated by the drying rate of the screen print inks. Do to improvements and innovations the production rate has greatly increased. Some specific innovations which affected the production rate and has also increased screen press popularity include:

Development of automatic presses versus hand operated presses which have comparatively slow production times
Improved drying systems which significantly improves production rate
Development and improvement of U.V. curable ink technologies
Development of the rotary screen press which allows continuous operation of the press. This is one of the more recent technology developments

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Screen Printing Inks

Screen Printing

UV Curable

UV curable inks consist of liquid prepolymers, monomers, and initiators which upon being exposed to large doses of U.V. Radiation instantly polymerize the vehicle to a dry, tough thermosetting resin. They also require less energy, overall, to dry or "cure" compared to gas or electric driers.

The down side of UV inks is they can cost as much as three times that of regular inks and must be handled differently than conventional inks due to safety issues. Additionally, solvents are required for clean-up which results in some VOC emissions.

Plastisol Inks

Plastisol inks (both solvent and water based) are used in textile screen printing.

Solvent Inks & Water Inks

Solvent and water based screen printing inks are formulated with primarily solvent or water. The solvent evaporates and results in VOC emissions. Water based inks, though they contain significantly less, may still emit VOC’s from small amounts of solvent and other additives blended into the ink. The liquid waste material may also be considered hazardous waste.

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Rush Sticker Printing

There are necessary steps you need to endure before you experience the right printing process.

1. Provide your layout plan to your printing company.

The layout of your printing job can be your printer's guide in making your prints. Sticker printing companies are able to produce your desired sticker with this. Thus in order to successfully achieve the desired results, you must give a precise detail about your material to your chosen printing company. A well detailed process will facilitate your printing company to obviously know what you want for your stickers. Additionally, the experienced printing staff will make sure a quick and smooth printing creation that will assure clients that their projects are in competent hands.

2. Designing of stickers

Sticker printing companies provides you with various sticker printing plans and designs. From a variety of design samples to printing templates you can find what you want for your stickers. The illustration of designs and templates are very crucial mostly to those who are after short run printing or urgent printing jobs. However in case you were not able to precisely get what you wish for your sticker designs you can customize and do over the design of your stickers.

3. Production of the printing

There are different processes involved in the sticker printing production. If you are looking for fast printing service you can go for digital printing, in contrast if you want to go for huge number of prints in a single print run you can go for offset printing. Full color printing application is also used to add intensity to your stickers.

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Build your own t-shirt printing press

step 4Make your design

f you just want to have text then one of the simplest ways is to use wooden letters instead of making your own. Since Michaels was a kind contributor to a prior contest we recommend their wooden letter sets. On the other hand, if you want to make a design or image then there is a lot more work (unless of course, you own a laser cutter) to cut out a design. We decided to try an image of a 20 sided die along with the text "High Roller" (Copyright Kevin Dean and Ryan McFarland!) We experimented with materials that we had around the workshop. Red cedar smells good when the Dremel is put to it but the wood soaked up the paint. Laminate counter top was tough to shape and showed the blotting pattern because it was too smooth. Finally we tried using some foam from a set of alphabet foam letters that are used for a child's play mat. This was easy to cut with a hobby knife and took the paint well. It also was forgiving when pressed against the cloth.


step 5Ink and press

Use double stick foam pads to place your letters onto a board which is screwed to the LCD arm mount. We found that putting the letters on pieces for the foam allowed us to remove the entire word to position it or so you can ink different colors. You should be able to remove a cowling from the last hinge on the arm (closest to the print) and loosen a screw or nut to allow that hinge to move more freely. Now you can easily flip the press into position for inking and then rotate it back to parallel the shirt.

Use rags or old shirts for a few tries before putting your favorite shirt under the press. You'll get a feel for how hard to press, how much paint or ink to use, and how to apply the paint to the press. We tried using paper towels and brushes to dip into the paint and then apply to the "stamp" but we found that a sponge cut into smaller pieces worked very well - both for application and to mop up excess paint that may collect in the negative areas of the stamp.

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Build your own t-shirt printing press

step 2Prepare the table
This would best be done with a table that you don't really want to use for anything other than crafts or projects. You'll want to mount the LCD arm as low and far back as possible (most should have a variety of settings). You see that we put our arm on the corner so that the press can reach near or far depending on the thickness of the media pressed on the thickness of the object.

The LCD mount is great to use because it articulates but retains the orientation of the head so you can move the arm toward and away from the shirt while keeping the press parallel. You also can swivel the head to add ink or paint.

We bolted clear through the arm so that it is sturdy but if you wanted to be able to remove it you could use a threaded rod with a lag head with a wing nut so all you would have is the threaded rod emerging from the tabletop. Or you could mount the arm on a wall above a table or workbench.

step 3Build the platform
The LCD arm will probably not press all the way to the desktop so you may need to make a platform to raise the working area. If you have ever put in a counter for a bathroom or kitchen you might have a nice piece of laminate kicking around that will work well. Scrap wood will work well too - you just need to lift the shirt (and the piece of cardboard, acrylic, aluminum, or whatever you put in the shirt to keep the ink from bleeding through to the back) enough to make full contact with the press.

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Build your own t-shirt printing press

There are many other options for making shirts with great tutorials on this site about how to silk screen or make stencils. This stamping method has the benefit of being able to make more than one (a limitation of some stencil techniques). Also this style allows the use of multiple colors without waiting for a color to dry. You can have free-floating content (like the inside of an "O") which is difficult with some stencil techniques - and if you're just doing lettering the letters can be reused for another shirt design or another project entirely.

Step1: Tools and Materials
Table or flat surface you can bolt into
LCD desk mount arm
Scrap wood or counter top
Double stick foam tape
Foam
Scrap booking letters
Silk screening ink or specialized paint
Drill and bits
Screws
Hobby knife
Sharpie marker
Square, level, tape measure
Wood, acrylic, aluminum or cardboard to put inside the shirt
Cloth to print on

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Pen Type Readers and Laser Scanners

Pen type readers consist of a light source and a photo diode that are placed next to each other in the tip of a pen or wand. To read a bar code, you drag the tip of the pen across all the bars in a steady even motion. The photo diode measures the intensity of the light reflected back from the light source and generates a waveform that is used to measure the widths of the bars and spaces in the bar code. Dark bars in the bar code absorb light and white spaces reflect light so that the voltage waveform generated by the photo diode is an exact duplicate of the bar and space pattern in the bar code. This waveform is decoded by the scanner in a manner similar to the way Morse code dots and dashes are decoded.

Laser scanners work the same way as pen type readers except that they use a laser beam as the light source and typically employ either a reciprocating mirror or a rotating prism to scan the laser beam back and forth across the bar code. Just the same as with the pen type reader, a photo diode is used to measure the intensity of the light reflected back from the bar code. In both pen readers and laser scanners, the light emitted by the reader is tuned to a specific frequency and the photo diode is designed to detect only this same frequency light.

Pen type readers and laser scanners can be purchased with different resolutions to enable them to read bar codes of different sizes. The scanner resolution is measured by the size of the dot of light emitted by the reader. The dot of light should be equal to or slightly smaller than the narrowest element width ("X" dimension). If the dot is wider than the width of the narrowest bar or space, then the dot will overlap two or more bars at a time thereby causing the scanner to not be able to distinguish clear transitions between bars and spaces. If the dot is too small, then any spots or voids in the bars can be misinterpreted as light areas also making a bar code unreadable. The most commonly used X dimension is 13 mils (roughly 4 printer dots on a 300 DPI printer). Because this X dimension is so small, it is extremely important that the bar code is created with a program that creates high resolution graphics (like B-Coder).

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