By Riley Mann, digital marketing strategist, Inkcups
Pad printing has been around for 200 years and has very much stood the test of time. It’s still a popular choice for all types of plastics decorating applications, with low start-up costs and low continuous operating costs. It provides flexibility to print on a wide variety of products and parts across numerous industries. One of the most important parts of the pad printing process is the pads used to apply the image to the part. Below are several common questions asked as related to pad printing pads.
What are pad printing pads?
A pad printing pad is a silicone stamp that transfers the pad printing ink from a pad printing cliché to the product. They are made of silicone to ensure the ink doesn’t stick and easily transfers to the part. A pad printing pad comes in many shapes and sizes and can be customized for all types of applications.
Are there different types of pads and what are they made from?
While most pad printing pads are made of silicone, the conditioning of the pad may be slightly oily or dry, depending on the application. There are pads made of more durable silicone with excellent ink transfer qualities that are resistant to abrasion and tears; there are pads made from an oilier silicone with very good abrasion, chemical and cut resistance; and there are pads which feature relatively dry silicone that are known for their instant break-in time and ability to get full ink release for high-quality prints.
There also are more general-purpose pads that can be used with many different types of inks for common applications and flexible silicone pads for printing on textured or concaved items, like golf balls, which feature a time-released conditioning agent that keeps the pad durometer consistent for the life of the pad.
How do I know which pads are best for which print job?
To produce high-quality pad-printed graphics, it is vital to select pad printing pads that are best for the printing job. Understanding pad printing pads, knowing how to keep pads in the best working condition and knowing how to restore them can have a major impact on the quality of a print job and decrease the overall cost of printing supplies.
Selecting the right printing pad is crucial for image quality. Pad printing pad characteristics that affect imprint are shape, size, hardness, surface and material. Pad printing pads play a crucial role in the pad printing process. They are responsible for picking up the image from the etched plate and transferring it over to the item that is being printed. Without general regard for shape, size and durometer (hardness), the printing process can produce incomplete images, skewed text and even a loss in adhesion. However, even when operators choose the right pad, normal wear and tear is inevitable with constant use.
How important is the pad shape and size?
The pad printing shape is the most important factor as it is mostly the shape that determines how well the pad printing pad achieves its rolling action. In general, the sharper the pad’s angle, the better the quality. If the item has a spherical surface (for example, stress balls), a flatter pad is recommended. Avoid pad printing pads with perfectly flat profiles as these can trap air during ink pickup or deposition. Operators also should look for pad printing pad shapes that extend the profile to cover the entire image as distortion of the image’s edges, in most cases, is caused by undersized pads.
Irregular ink pickup during the test print usually means that air is being trapped between the pad and the plate’s surface. Watch carefully as the pad printing pad is imprinting to make sure that a rolling action is occurring. Also try to avoid using the pad’s apex for ink deposit, when possible, as this tends to thin the ink at that point and cause a light spot on the image. Always use as little pressure as possible to pick up and print the image, because excessive pad pressure can cause distortion and poor ink transfer.
When it comes to the pad printing pad size, in general, the larger the pad printing pad, the less image distortion. The pad should be at least 20-30% larger than the desired image size. And for the best quality, use the largest pad size that is practical for the item to be printed. For larger items, the maximum pad size will be dictated by the printing machine’s parameters; namely, by the distance between the image and the machine’s body and its ability to compress large, hard pad printing pads.
How does the pad’s durometer (hardness) affect the print?
The durometer (hardness) of the pad mostly depends on the amount of silicone oil that is used for pad molding. Pad durometer is measured by a shore durometer tool and the same term refers to the measurement. “Shore 00” is a commonly used scale. Shore 35-40 typically suits soft pad printing applications, Shore 50 suits medium applications, Shore 60 suits medium-hard applications, Shore 70 suits hard applications and Shore 80 suits very hard applications.
When should I change the printing pad?
Wear and tear are common when pad printing a part or product non-stop; nonetheless, understanding when to change a pad printing pad is crucial. Although most pad printing equipment is built to last, there are some components that must regularly be changed to ensure a solid print, and one of the most important components is the pad. Think of pad printing pads as a stamp. When picking up the print from the plate, the pad will absorb a microscopic amount of ink. Over time, the pad print hardeners in the ink will break down the material of the pad, resulting in a smoother top to the pad and an overall discoloration of the pad. Depending on the type of pad used, the pad also may harden over time.
Operators will spend hours trying to find a “good” spot on an old pad. However, purchasing a new one is easier and saves time. It is recommended to speak to a pad supplier to calculate how many prints a specific type of pad will achieve and how often an operator should change them. It also is a good idea to keep an assortment of pads in the production facility as applications arise.
Inkcups is a leading supplier and manufacturer of direct-to-object digital inkjet equipment, pad printing equipment, laser platemakers and corresponding supplies. Inkcups manufactures high-quality industrial machines for a wide range of industries including apparel, drinkware, promotional, electronic, medical, sporting goods and automotive markets. Inkcups’ portfolio includes a range of pad printing and UV inkjet printing solutions, inks and pre-treatment systems. For more information, visit
www.inkcups.com.
