If you had a money-printing machine, you would prioritise keeping it running. High-quality products often cost more because they are made from better materials than others. If utilised correctly, the assets that the more expensive product offers, may result in higher benefits.
When purchasing better-quality products, it is important to consider how their features and attributes can best be put to use. Otherwise, the screen-printing performance might not result in the highest profits.
High-quality ink is typically opaque, flashes quickly, minimises buildup and cures at the manufacturer’s recommended temperature. While saving money is important, focusing solely on cost can lead to increased screen-printing production time and potential issues.
Using lower-quality ink, might result in frequent screen cleaning, multiple-print strokes, longer flash times or curing problems. These delays can ultimately cost more time and money, especially if customers return shirts due to ink coming off in the wash.
Ultimately, clean screens will result in more profit
It is important to plan ahead to make sure screens for screen printing are tight before they are coated. Most screen mesh is not as tight as it could be or may loosen over time. The tighter the mesh, the better it will perform. In other words, if screens do not sound like a drum when flicked with a finger, then it may be necessary to take a closer look at that screen. The higher the drum pitch the better.
Before coating the screens, it is important to check if they were well cleaned and degreased. In addition, the room in which the coating happens needs to be clean and free of debris, dust and grease. These particles can cause pinholes and possibly a breakdown of the emulsion.
Prepare a clean rack so that after coating the screens, there is a place to store them while they dry. Note that the screens should be placed in a horizontal position with the ink side facing up. This will maximise the emulsion coverage on the shirt side to allow proper ink coverage during screen printing.
Try to avoid using a fan to speed up drying the coated screens or drying outside. The fan or wind can spread dust around, which may accumulate on the screen. Ultimately, clean screens will result in more profit.
The emulsion needs to be the correct type for the ink and light source used. In addition, it needs to be free of dust and debris. Many printers place the used emulsion back into its original container after coating the screens. In time, the original bucket may contain debris that can affect the quality of the screen-printed image. It is inevitable that a spot of dirt will show up exactly where the image lands on the screen.
To keep things simple, when coating a screen, as well as blocking or closing the pores of the mesh to create the negative image on the screen, there is also a need to create a gasket. The gasket means that there is more emulsion on the shirt or substrate side of the screen mesh.
The emulsion needs to be the correct type for the ink and light source used
To clarify, the mesh should not just block the mesh, but be thick enough to form a raised edge around where your image is burned. This edge acts as a barrier to prevent ink from spreading beyond the image boundaries. The extra emulsion creates a gasket that helps prevent the ink from going outside the image’s boundary.
Otherwise, there is no control of where the ink goes or what it is doing other than being pushed through the open area of the mesh. The extra emulsion acts as a guide for the ink. Without it, the ink can be pushed outside the image area, causing blurry edges (‘sawtooth effect’) and uneven coverage.
Keeping the glass clean of dirt and grease is essential where the screen is placed to be burned. This includes the inside portion of the glass. The inside of the glass can get dirty and affect exposure. Without LED lights, the light source might gradually become less powerful. Always keep a spare bulb on hand, whether using LEDs or traditional bulbs. With traditional bulbs, the exposure might need to be adjusted time over time, especially if there is not a light integrator that automatically compensates for changes in light intensity.
To determine the correct exposure time, always use an exposure calculator. Just as different screen-mesh counts are chosen for their ability to lay down less or more ink, they will also accept more or less emulsion given the same coating technique.
In other words, a shop needs to dial in the exposure time for every type of mesh.
Rubber-coated pallets absorb ink better, making prints appear brighter and more opaque. Aluminium pallets can heat up and cool down quickly, causing the ink in the screen’s ink well to gel or dry prematurely. This is especially problematic with newer, low-curing inks. To prevent this, consider using rubber mats on your aluminium pallets or adding ink and distributing them more frequently.
If the pallets get too hot, newer, low-curing inks may fuse while printing. With metal pallets, rubber mats can be used to coat them or add less ink more frequently. Importantly, continuously moving ink from the sides of the squeegee and putting it back into the centre means that it can be used up before it gels.
The entire ink film needs to achieve the stated temperature that the manufacturer recommends for the ink used. In some cases, that could be as low as 135°C, but in many cases it could be in the 160°C range. A key point is that, depending on the thickness of the ink film, it may require more or less time for the entire ink film to achieve the cure or fuse stage.
Heat is a necessary enemy, whereas time is an advantage. The heat needs to achieve the proper temperature for fusing (curing), but more heat than that can create problems on a print. Excessive heat can cause difficulties, such as bleeding (or dye migration). In some cases, ghosting and garment shrinkage and/or scorching can also occur. However, adding more dwell time in the heat tunnel – rather than increasing the heat – can be favourable.
It is essential to have an array of squeegee durometers available. If, in the middle of a screen-printing job, one of the colours needs more ink deposited, there are only a few quick-fix options once the screen is burned. One of those options – and the most speedy and profitable – is to swap the squeegee for a softer one.
The other option is to double-stroke that colour. However, that double stroke can cost a screen-printing shop a lot of money. It will slow down production time in the screen-printing process. Having an extra assortment of squeegee blades at the ready will avoid this.
If less ink deposit is required, the fastest fix is also to replace the squeegee. But in this instance, using a squeegee with a harder durometer will quickly have less ink deposited.
Otherwise, it may be necessary to burn a new screen with a higher thread count, which will cost an enormous amount of time. Burning one extra screen, once per month, not only increases overall costs, but also loss of time in productivity. Therefore, it is cheaper to have the extra assorted squeegees available.