About this section:
Find out more about the different printing processes that we supply and the products used and offered.
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HEAT TRANSFER PRINTING
Ireland's only supplier of pad printing products and equipment. Here, you will find a full range of pad printing products & services like: pad printing nylon & steel plates, pad printing inks, pad printing pads, pad printing equipment, pad printing chemicals, pad printing consumables.
WHAT IS PAD PRINTING
Pad printing is a relatively new printing process compared with screen printing and letterpress. It developed when it was possible to make printing pads out of silicone rubber, and has seen substantial growth over the past few decades.
Silicone rubber repels many substances (including ink), and by moulding itself to any given object, allows you to print on uneven surfaces. You can print on irregular surfaces, on sloping and vertical surfaces, with more than one side simultaneously.
It is the latest technique for printing on objects that are not flat or varied in size. It can be used on almost any surface including:
• Computer parts, micro chips, relays, panels, mobile phones, switches
• Rulers, scales on measuring instruments, radio and TV casings
• Electrical equipment, domestic appliances, publicity articles,
The following are the unique properties of the pad printing process:
• Printing almost independent of the shape, e.g. concave, convex, curved parts
• Printing of different surface structures, like uneven or structured surfaces
• Possibility to print into hollows
• Possibility to print mechanically sensitive products
• Variety of substrates, almost any material can be printed with suitable inks.
• Ability to print fine detail, resolution is far better than that of screen printing
• High resistance of printing inks, depending on ink type used extremely high resistances against mechanical abrasion or chemicals can be achieved.
• Easy handling and little maintenance, compared to other printing processes pad printing is easy to learn.
• Multi-colour printing: wet on wet - possibility to apply multiple prints without intermediate drying
• Short tooling-up times, plates and inks can be exchanged within a few minutes
• Low set up cost, plates can be produced in-house
• Relatively low space requirement, compared to other printing machines pad printing equipment is very small.
• Low drying cost, in the most simple case air drying at room temperature is sufficient.
• Integration into complex systems, inline production and assembly lines, or years now there has been a successful combination of pad printing systems with injection moulding equipment or assembly lines.
Size of motive
Motive sizes are limited by plate, pad and efficiency of the pad printing machine. The diameters of the largest efficiently printed motives are currently approx. 30 cm. Layer thickness of ink film. The pad process uses plates up to a depth of approx. 20-25μm (at the most 35μm). Thus conventional inks will result in printed ink films of approx. 7μm. This layer thickness can be increased correspondingly by multi-layer printing. Rough particles (e.g. glitter pigments) are difficult to print in an efficient manner.
Even substrates can be printed a lot faster with other printing processes. Whether pad printing is the only choice for a printing job, or if other printing processes would be better has to be evaluated individually. For printing of golf balls pad printing will continue to be the best method for some time, whereas for printing of T-shirts or beer crates screen printing will naturally be the more efficient choice.
a silicon pad
a device to hold the product in place for printing
a metal or plastic plate (plate) that contains the printing design, and
an inkwell with spatula and doctoring device, or a closed ink cup system.
In advanced models, this basic design is supplemented with mechanisms that load, unload and index (register) the parts at high speed.
The machines operate under reciprocal motion: The pad alternately picks up ink from the plate and then deposits it onto the product.
Rotary pad printers that print round and flat objects at high speed are also available. They operate on continuous rather than reciprocal motion - circular pads rotate constantly to transfer the design.
HOW DOES PAD PRINTING WORK
Regardless of the machine design, five basic steps occur during a print cycle. During these steps, special changes that take place in the ink help to explain why and how this unusual process works.
The entire plate which sits on the inkwell, is flooded with ink automatically.
A steel doctor blade then cleans excess ink from the plate surface, leaving ink only in the etched areas. Pad printing inks are similar to solvent based screen printing inks, except they have a higher pigment content for better opacity and higher tack (to promote adhesion to the substrate).
After the plate is wiped by the doctor blade, the surface of the ink in the engraving becomes more viscous and tacky as the solvents evaporate, improving the ink's ability to wet the pad.
The pad is positioned directly over the plate, pressed onto it to pick up the ink and then lifted away. The physical changes in the ink that take place during flooding, combined with the high surface tension of the silicone pad, account for the ink's ability to leave the recessed engraving in favour of the pad.
On occasion, printers have attempted to improve pad printing's limited ink deposit by increasing the plate depth, believing that more ink in the plate will translate into more ink on the pad and subsequently on the substrate. This theory is based on the incorrect assumption that the pad picks up 100% of the ink from the plate. Because of the surface changes in the ink after flooding, only a proportion of the ink is actually picked up by that pad. In other words, only a negligible increase in ink deposit can be achieved in this manner.
After the pad has lifted away from the plate to its complete vertical height, it moves laterally until it is positioned over the substrate. During this stage, the ink has just enough adhesion to stick to the pad (it can be easily wiped off, yet it does not drip) . The ink on the surface of the pad once again undergoes special changes: solvents evaporate from the outer ink layer (exposed to the atmosphere), while solvents on the inner surface migrate towards the pad, reducing the pad/ink adhesion.
The pad is pressed down onto the substrate, conforming to its shape and depositing the ink in the desired location. Even though it compresses considerably during this step, the pad is designed to roll away from the substrate surface rather than press against it flatly. A properly designed pad, in fact, will never form a contact angle with the substrate: such a situation would trap air between the pad and the part, which would prevent ink transfer
The pad lifts away from the substrate and assumes its original shape again, leaving all but a scant trace of the ink on the substrate.
As explained in Step 3, the ink undergoes special changes during the head stroke and loses its affinity for the pad. When the pad is pressed onto the substrate, the adhesion between the ink and substrate is greater than the adhesion between the ink and pad, resulting in almost complete deposition of the ink. This leaves the pad clean and ready for the next print cycle.
PAD PRINTING INK & SERVICES
Formulated to meet the adhesion requirements of most plastics, metals, woods, glass, fabrics and other natural or engineered materials, Serigraf offers a complete range of pad printing inks. We have standard colour shades available.
If you prefer not to mix ink yourself, we provide a colour mixing service. You can give us a Pantone or RAL colour reference, and we will produce that colour shade for you.
But Pad Printing Inks
PAD PRINTING PLATES & PLATE MAKING SERVICE
Pad Printing Plates are used to contain the desired artwork "image" etched in its surface. Their function is to hold ink in this etched cavity, allowing the pad to pick up this ink as a film in the shape of the artwork, which is then transferred to the substrate.
We can produce the following printing plates in various different sizes to suit your machine: Nylon/photopolymer and steel plates .5mm or 10mm thick.
Buy Pad Printing Plates
PAD PRINTING SILICONE PADS
Pads are available in an assortment of size, shape and hardness. The type of pad used depends on the printed material and the design that will be printed.
Harder pads generally offer longer life and better print clarity, though they are not always suitable for fragile materials. For multi-colour print to run, pad shape varies not only from part to part but frequently from colour to colour because of the different coverage requirements.
Buy Pad Printing Pads
PAD PRINTING ARTWORK PRODUCTS & SERVICES
We offer an artwork origination service using the latest graphics software and techniques. We can vectorise even the most complicated designs and save them or output them ready for printing.
We can create from scratch, your artwork in hi-resolution from technical drawings or pictures.
Send us your artwork files and we will output them for you at a high resolution with ultra opaque blacks, on high quality waterproof films. Whether it is single colour, spot colour separations or CMYK separations we can handle your files.
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PAD PRINTING MACHINES
Serigraf offers a line of pad printing equipment, featuring manual, semiautomatic and automatic 1- to 6-color sealed cup pad printers, with ink cup sizes ranging from 60mm to 150mm designed to meet any production need. These robust and user-friendly pad printers perfectly suit both start-up and experienced decorators
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