Tampo Pad Printing

The printing of finished parts is a very popular way of increasing the visual aesthetics of the part for a relatively low cost. At AKI pad printing is carried out on 1, 2 and 3 colour pad printers as well as on a 5 colour CNC printing machine. All machines are microprocessor controlled meaning that all parts will be printed to a very high standard. Each colour that is printed onto the parts is done using a separate pad so that the printing can be built up gradually, ensuring each colour is perfectly printed.

Pad printing is a cost effective way to print parts yet is also a highly reliable process and can produce parts to a very high standard. The most crucial part to the pad printing process is the plate on which the graphic is etched and this is called the cliché. The etching of graphics onto this plate is very important, as it will determine the quality of the final graphics once printed onto the component. Once this cliché is placed in its fitting in the machine the “cup”, containing the ink for the printing, is positioned on top of it so that while the pad is printing the component, the cup will distribute ink into the etch on the cliché. As the arm, controlling the pad, slides back the ink cup moves with it and slides away from the etch. This means that the only ink on the plate will be retained in the etch and so can be picked up by the pad. The pad is then lowered onto the designed graphic, formed by the etching and picks up the ink that is transferred to the next part. This is the printing process. The pad is made from silicon as this means it can pick up the inked pattern without the ink permanently becoming attached to it. The hardness of the pad will depend upon the texture of the surface that is to be printed. For example for a rough surface more pressure will be required to apply the ink on the surface, so a harder pad is required. The opposite is true for surfaces that have a smooth finish. The consistency of the ink is also very important.

Printing using a state of the art CNC machine ensures that graphics are printed to the highest possible standard. 6 pads, using 5 colours, are programmed using the touch panel interface so that the sequence of printing can be optimised. CNC pad printing also means that each part to be printed is lined up using lasers to ensure that it is in exactly the right position under the pads. This ensures that even when the machine is loaded with a number of mouldings at a time each one will be printed to the same standard. This helps reduce production time and keep costs to a minimum. CNC pad printing also benefits from having a 3-axis servo motor driven robot-printing arm. This means that it is possible to print very large parts or even parts that have an uneven surface to them. Since injection moulded parts are rarely perfectly flat this is a major benefit as it means any graphic can be printed onto the surface of the mouldings with little difficulty.

Benefits of Pad Printing

  • Attractive mouldings – the use of pad printing as a post moulding operation can significantly improve the visual aesthetics of a moulding. Complex graphics are possible and a plain moulding can be transformed into a very visually stimulating part.
  • Added component value – by using pad printing to add graphics to a part, after it has been moulded, a significant amount of value can be added to a component. Visually stimulating components are more attractive to the customer than plain coloured ones and this gives the part additional value.
  • High level of quality – as pad printing machines are controlled by microprocessor, the level of repeatability is very high, particularly when using the CNC printer. This means that each part will be printed exactly the same and all to a high level of accuracy.
  • Ease of handling – even with CNC controlled machines pad printing is relatively easy to learn and maintain. There are very few parts to change so jobs can be changed between very quickly. CNC machines are very easy to set up once the programming has been written. The use of lasers helps line up jigs so that parts can be set up in the correct place very quickly. To change the pad and cliché is a fairly quick process for both CNC controlled and manual printing machines.
  • Variety of printable surfaces – assuming that the correct ink is chosen, pad printing can be carried out on almost any material. So long as the ink is designed to stick to the surface of the material pad printers can be set up easily to print onto the material. Aki take pride in being particularly good at printing on Chrome Plated mouldings.
  • Printing on uneven surfaces – the pads of pad printing machines can be designed to be almost any shape and this gives the ability to print on surfaces of various shapes. For example on curved surfaces a flatter pad can be used to ensure print goes right round the surface. This helps to give designers greater freedom when designing graphics.
  • Wet-on-wet multi-colour printing – pad printing has the ability to print many colours without the need for intermediate drying time between each colour. This helps to greatly decrease the time to print multi-coloured parts as there isn’t the need to allow each colour to dry separately.

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