What Pad Printing Machines are right for my application?

Pad printing has many uses in a diverse set of industries. The uses range from printing on toys, appliances, electronics, medical devices and even automobiles. The process of pad printing focuses on the ability to transfer a 2-D image onto a 3-D object. This procedure is completed by using an indirect offset printing process which involves the image being transferred from a cliché on a silicone pad. From this pad it is then transferred onto a substrate.

When referring to pad printing applications they fall into three primary categories:

• Printing
• Decoration
• Coding

Printing is defined as the applied application of ink onto a substrate. This is a four color process and is usually used when printing multicolor symbols and lettering. Decoration it is generally used in collaboration with a design to enhance the looks of a product. These products are asymmetrical designs with single or multicolor pigments. Coding is used for informational printing only. This type of printing will be legible but not necessarily high quality like the other methods mentioned.

So how do you know which pad printing machines to purchase? The first question might be obvious, but ask yourself, does your application actually need the pad printing process? The dimensional tolerance, surface finish and frequency of batches are the primary areas of focus when deciding if you need a pad printing machine.

Basic Pad Printing Technologies in Use Today

We now take a look at the three basic technologies that are used in pad printing today: open inkwell, closed ink cup and rotary gravure.

Open Inkwell Pad Printing

• Requires the use of a spatula and doctor blade
• Very versatile
• Utilizes a cliche holder that uses an open ink reservoir

A feature that is commonplace with all machines is the need to flood the cliché image with ink. After this you need to doctor it clean. This type of machine uses a spatula and doctor blade. The spatula is used to flood the image with ink during the machine processing stage. The doctor blade then clears the excess ink from the surface of the printing plate. At the same time the machine completes this without removing the ink from the etched area.

Closed Ink Cup Technology

• Universally used
• Ink is contained in an inverted cup, reducing solvent evaporation
• Does not require a spatula

Closed ink cup technology was originally introduced in the mid 1980’s. Today it has been universally accepted with customers from around the world. One of the key features that makes it so popular is that the ink is encapsulated in an inverted cup. By doing this it limits solvent evaporation. Closed ink cup technology also does not require a spatula.

Rotary Gravure Technology

• Frequently used for printing around the circumference of a circular/spherical part
• Uses open inkwells

Finally we have the RTI system (otherwise known as rotary gravure technology). This technology is frequently used in applications that need printing on 360 degrees around a circumference of a part. Open inkwell technology and RTI technology are similar in design as they both use open inkwells and doctor blade assemblies. A cylindrical steel drum is used for the printing plate, which contains the etch on its surface. The RTI system also features a silicone transfer pad that is circular and is made from an aluminum hub.

What is Pad Printing?

Many times, we get the question: Well, what is pad printing?  If you happen to be wondering the same thing, read on!

Pad printing is a modern printing process that can be used to quickly transfer 2-D images on to all sorts of 3-D objects. However, before getting into a description of what pad printing is, it’s important to first define a few specific elements that pad printing relies on.

First, it’s important to understand gravure printing. Gravure printing, put simply, is printing that etches an image onto the surface of a metal plate. This places the images – in ink form – in the recesses of the metal plate, unlike relief printing (where the image is raised). By filling the recesses with ink, and leaving the raised portions of the plate dry, the image can be transferred from the plate to the substrate quickly and cleanly. Gravure printing can produce very fine and detailed images on short or long runs in multiple colors.

Beyond the gravure printing process, pad printing also relies on printing plates – or clichés. In traditional offset printing, printing relies on transferring an inked image from an offset (the plate) to a rubber blanket which then makes contact with the print surface. When compared to other modern printing methods, offset printing with plates is one of the best solutions when it comes to economically producing commercial quantities of high quality prints, without requiring much maintenance.  Today, clichés are made from metal or polyester.

However, pad printing is unique when compared to other gravure and offset printing methods in that the ink is transferred from the printing plate with a silicone pad, which then transfers the ink to the substrate. This allows pad printing to be used for printing on a number of products that would otherwise be impossible to print on, including medical products, electronics, appliances, toys, sports equipment, and more.

Crude forms of the basic premise behind pad printing have existed for hundreds of years. However, the popularity of the process enjoyed rapid expansion when the availability of modern manufacturing made widespread commercial use feasible. This expansion was felt first by the watch-making industry after the Second World War, which then gave way to pad printing being used for far more products. Since then, pad printing has experienced substantial growth due to the many applications that have found a use for it.

Partly to thank for the rapid growth of pad printing has been the increased availability of advanced silicone. The unique properties of the silicon pad in pad printing gives the process its highly sought after ability to pick the image up from a flat plate and then transfer it to a number of surfaces – including flat, spherical, textured, concave, and convex surfaces. This makes pad printing invaluable for everyone from appliance manufacturers to electronics manufacturers who need a better solution for membrane switch printing.