Pad Printing
Pad printing is a printing method that uses an elastic pad to pick up ink from a plate and transfer it onto curved or uneven products to print text or patterns.
Contents6 sections
Definition and Overview
Pad printing is a printing method that uses an elastic pad made of silicone or similar material to pick up ink from an engraved plate and press it onto the substrate to transfer the design. Because it uses the deformation of the pad, it is easy to print not only on flat surfaces but also on gentle curves and areas with steps.
It is used more for logos and product number markings on small, three-dimensional parts such as buttons, zipper pulls, buckles, cord stoppers, and name accessories than for large-area printing on the apparel product itself. “Tampon printing” is a common term for the same process.
Position in Product Manufacturing
Pad printing is a type of secondary processing often performed after components are molded and surface-treated, and before sewing or assembly. Since printed components are supplied to sewing factories, the printing specifications are finalized when the components are ordered, and the production schedule includes the processing lead time and inspection process.
Compared with prints that express patterns on flat, wide areas such as a garment body, it differs in the objects it targets and the expressions it is best at. Pad printing is suitable for small logos, symbols, and text, but for fine multicolor gradations or large solid areas, another method is considered, including the product shape and compatibility with the ink.
Items to Decide When Ordering
When ordering, share the material, color, surface condition, printing position, orientation, and print area of the target part using the actual item or a drawing. Curvature, irregularities, changes in thickness, and molding boundaries such as parting lines affect pad contact and how the design appears, so reference points should be clearly defined when specifying positions.
As a rule, the submitted data should include contour data suitable for plate making, and the minimum line width of text and the size of knockouts should be confirmed with the processor in advance. Since a plate and printing process may be required for each color, the color specification, print order, whether spot colors are possible, and the approval method for samples should also be written in the specification sheet.
- Actual sample of the target part, material specification, and whether surface treatment is applied
- Print color, color sample, and artwork data for logos or text
- Dimensions of the print position, reference points, and front/back side and orientation
- Quantity, delivery date, and whether extra units are needed
- Quality standards to be checked with samples before mass production
Quality Checks and Points of Attention
Before mass production, trial pieces are made using the same material and surface condition as the actual parts, and position, color tone, missing areas, bleeding, fading, and misregistration are checked. On glossy surfaces, uneven surfaces, soft resin, and painted surfaces, ink adhesion changes, so not only appearance but also abrasion resistance and water resistance under the intended usage conditions must be checked.
Fine logo lines, very small text, and large solid areas are parts where reproducibility can vary depending on the ink amount and how the pad makes contact. If pressure during sewing or contact with other parts is added to the printed surface, check after assembly that there is no rubbing, transfer, or peeling, and agree on the acceptable range in advance.
Differences from Similar Terms
Screen printing is a method that prints on flat surfaces by passing ink through openings in a screen, and is suitable for relatively wide areas on apparel and fabric. By contrast, pad printing transfers through an elastic pad, so it is suited to printing on curved or uneven surfaces of small parts.
Stamping is a process that gives text or patterns relief or recess through pressure or heat, and its finish generally differs from pad printing, which transfers ink. Since printing and stamping may be used together, it is important to separate whether color expression is required and whether relief is required when defining specifications.
Frequently Asked Questions
What kinds of materials can pad printing be used on?
It is used on resin, metal, painted surfaces, and more, but suitability depends on the material, surface treatment, shape, and usage environment. In particular, poor adhesion can occur on soft resin or parts with release agents, oil, or irregularities on the surface. It is important to make a trial on the actual part and confirm the required durability tests.
Can fine logos and small text be reproduced with pad printing?
It can be used for relatively fine logos and text, but line thickness, text size, curved surfaces of the part, and the ink color and base color affect visibility and reproducibility. After submitting contour data, a trial is made, and before mass production it is checked whether blurring, missing areas, or fading are within the acceptable range.
How can printing position shifts be prevented during mass production?
Fixtures that hold the part in place and reference points that determine the position are important. On the drawing, specify not only dimensions from the edges but also the front/back side, top/bottom, logo orientation, and reference holes or corners. Since the apparent position also changes on curved surfaces, keeping an approved sample that shows the viewed-from-the-front condition makes verification easier.
