Pad printing head selection and daily maintenance: five pitfall avoidance points summarized by the manufacturer

In the pad printing process, the rubber head is the core component that receives the stencil ink and transfers it to the substrate. Many printing defects - such as blurred patterns, rough lines, and light ink - are often not rooted in machine accuracy, but in improper selection of rubber heads or lack of maintenance. As an automated pad printing equipment manufacturer, we combined our front-line debugging experience to sort out the key precautions when using the rubber head.

First, the hardness matches the fineness of the pattern. The hardness of the rubber head is usually divided into three grades: soft, medium and hard. When printing fine lines or dots, a harder rubber head should be used to avoid pattern distortion caused by deformation; while the surface of the substrate is uneven, a soft rubber head can better fit the curved surface to ensure complete transfer. If the hardness of the rubber head is insufficient, the edges of printed fine characters will easily appear blurry. At this time, switching to a slightly harder rubber head will often have immediate results.

Second, the extrusion depth cannot exceed the limit. When the rubber head is imprinting, the pressing depth should not exceed one-third of the total height of the rubber head. Over-limit extrusion will accelerate fatigue damage of the rubber head and cause pattern deformation or blurring. Many operators increase the pressure in pursuit of 'more solid printing', but this is counterproductive.

Third, the new glue head must be cleaned first. There is often a layer of release agent left on the surface of a newly purchased rubber head. Direct printing on the machine will cause the ink to fail to adsorb properly. Before use, use a clean cloth dipped in ethanol or special plate cleaning agent to wipe the surface, and wait until it evaporates before putting it into use.

Fourth, pay attention to daily cleaning and storage. After each shutdown, cleaning agent must be used to wipe off the remaining ink on the surface of the rubber head to prevent damage to the rubber surface after curing. If the rubber head is stained with dirt or becomes sticky and deteriorates, it should be cleaned or replaced in time. When out of use for a long time, the rubber head should be stored in a dry and ventilated environment at 5-25°C to avoid exposure to sunlight or moisture.

Fifth, the wear of the rubber head needs to be checked in time. When the prints repeatedly show rough lines, lack of ink or bubble marks in the pattern, you should first check whether the surface of the rubber head is damaged, oily or insufficiently curved. If the center point of the rubber head is exactly at the position of the pattern defect, it usually means that the rubber surface there is damaged, and the fault can be eliminated by replacing the rubber head.

Pad printing seems simple, but in fact the cooperation of rubber head, ink and steel plate is indispensable. By managing the rubber head well, most common printing defects can be avoided at the source.