Tech Tip Tuesday: Pad Printing – It’s All About The Pad!
The print pad is one of (if not the) most important aspects of the pad printing process. Made from silicone rubber, it is the perfect ink transfer medium when designed, used and maintained correctly.
The properly molded print pad will have the following features:
- Excellent adhesion
- Flawless Ink Detachment
- Perfect Ink Transfer
- Stability of Form
- Resistance to Solvents & Inks
Printing pads comes in all shapes and sizes and are often custom designed. This is because they are created for very specific applications, both unique and specialized. Below are some important things to keep in mind when it comes to the print pad.
The pad itself should be at least 20% than the image that it is printing on. If the height and width of the pad is less than this, the probability of distortion near the edges of the image is more likely.
The shape of the image itself is one of the most important factors in determining the shape of the pad. Use the following guidelines when considering your printing pad:
Rooftop shaped pad – for shorter, wider images (and straight text)
Round / cone pads – for flat surfaces with a round image area.
Square or Rectangular shaped pad – for square/rectangular shapes.
Half Moon pad – recommended for curved surfaces and longer text.
The other vital factor when it comes to the print pad is the contour (or angle) of the print pad. A steep, opposite angle of the print area is ideal, as to allow for clean transfer of ink by displacing air during pickup and transfer. The absence of a steep enough angle causes air to become trapped between the pad and cliché and damages the ink-to-image transfer.
The higher the number is, the harder the pad. This is also referred to as “shore”. It is determined by the amount of silicone oil when creating the pad. More silicone oil makes for a softer pad, while hard print pads are made using less silicone oil.
Hard pads – Produce sharper images (with less distortedness) and generally better coverage,
Soft pads – Produce longer image life due to more ink placement onto the image,
While it is easy to understand that softer pads last a little longer because of their flexibility, all pads eventually lose their image transfer quality due to silicone oil depletion inside the pad. At this point, surface application of oil is ineffective and drying out of the pad is inevitable.
While air blowers that produce clean and dry air will increase machine efficiency (and help with clean image transfer), it is important to know when your printing pad has reached its expiration.
Remember to keep your pad printing environment between 68-72 degrees Fahrenheit (which allows ink solvents to evaporate at a normal rate) and humidity between 50-60%. Maintaining this humidity level is crucial in the proper functioning of the ink and evaporation solvents.
Learn more about print pads by visiting our website at www.epsvt.com. There you can also find more information about Engineered Printing Solutions custom solutions, standard pad printers, industrial inkjet, consumables and other auxiliary equipment. Email firstname.lastname@example.org or call 1-800-272-7764 if you would like more information.