Understanding the Pad Printing Pad

Pad Printing Pad Life

Next to "What should I use?", the most difficult question to answer is "How long should a pad last?" Pads are like most things in life: The better you treat them, the longer they will last. Mechanical damage, aggressive solvents, and poor storage all take their toll. But the real killer is a careless operator. Some press operators have been known to pull a pad completely off its mounting plate during cleaning. If you make your staff aware of how much pads cost, they may treat them with more care. Use a softer pad if the power of your machine can? compress the pad sufficiently to achieve a satisfac-tory rolling action.

It isn't unusual for pads to last 50,000 prints. Going substantially over 50,000 prints isn't common, though. We know of one claim that a pad lasted 500,000 impressions, but we saw the 500,000th print and it looked pretty dreadful. Conversely, some pads are irreparably damaged before they print a single item. Usually, this results from a poor setup, when the downward motion of the pad during ink pickup or deposition is far too long, resulting in the destruction of the pad.

Although no hard and fast guidetines regarding pad life are available, you can take a number of steps to get the most life from all your pads:

  • Use a strong solvent only for initial removal of the silicone oil on the surface.
  • Use a mild solvent such as alcohol, or preferably an adhesive tape, if the pad must be cleaned during production.
  • Always use an adhesive tape to remove debris and dried ink before starting a production run.
  • Don't use too much pad pressure.
  • Ensure that the substrate is free of debris, particularly sharp particles, before printing.
  • With wooden-backed pads, don't allow the mounting screws to penetrate the rubber.
  • When possible, avoid printing near sharp substrate edges.
  • Use as large a pad as is reasonable for the job
  • Never store a pad on top of another.
  • If pads are supplied in a protective shell, use it when storing the pads in your shop.
  • Handle and store the pads very carefully.

One other point about pad life:

Certain inks have aggressive solvents that will be absorbed by the pad during printing, much as squeegees wiil absorb solvents during long print runs. This absorption will cause the image to "grow" on the pad, to the point that it will eventually affect the print quality. At this point, you must stop the machine and replace the pad. This isn't a permanent condition, though: If you allow the original pad to stand, the solvents that have penetrated into it will evaporate, returning the pad to tis normal surface finish. You can accelerate this process by warming the pad.

Conclusion

Although the importance of pads is sometimes overlooked in the field, remember that the process derives its name from these silicone-rubber image carriers. Correct selection and care of pads is essential. As with any process, pad printing has its limitations and its best to understand those before you choose a pad. Common sense and experimentation will guide you. Overall, keep the pad surface in good condition, and it should serve you well.

Shape and Size of The Pad Printing Pad.

Shape is the most important variable in selecting a pad.

Hardness of the Pad Printing Pad

The hardness of the pad is normally determined by the amount of silicon oil used when the pad is moulded.

Surface Finish of the Pad Printing Pad

Throughout the pad-printing industry, the custom practice among pad manufacturers is to furnish pads with a high gloss finish.

Material of the Pad Printing Pad

This topic refers not only to the material of the pad itself, but also the base onto which the pad is mounted.

Special Printing Pads for Large Images

In some situations, a large image area must be printed and the machine does not have the power to compress such a heavy pad in a smooth motion.

Quality Control of Pad Printing Pads

Poor-quality consurnables like pads can destroy the performance of the printing machine.

Pad Printing Pad Life

Next to "What should I use?", the most difficult question to answer is "How long should a pad last?"