Pad Printing for Stainless Steel Cutlery Inside a Jieyang Factory

Introducing a new post-processing technique adopted by the Garbo factory: Pad Printing.

The 5 steps of pad printing:

At its core, pad printing is an indirect transfer process that utilizes a silicone rubber pad as an intermediate carrier.

1.Loading: Products are placed into fixtures on a rotary indexing table, enabling a multi-station, continuous workflow.

2.Inking: The design is etched into a steel plate (or ink cup); a doctor blade wipes across the surface, leaving ink only within the etched recesses.

3.Ink Pickup: A soft silicone pad presses down, utilizing the material's viscoelastic properties to "pick up" the ink from the recesses.

4.Transfer: The pad presses against the curved spoon handle; the silicone conforms to the curvature, transferring the design intact—a feat that standard flat-screen printing or conventional stamping cannot achieve.

5.Curing: The product enters a curing oven, typically baked at 150–180°C for several tens of minutes (depending on the ink system), allowing the ink to cross-link into a durable, wash-resistant film.

Quality control in pad printing:

Defects can occur in pad printing, primarily manifesting as blurred pattern edges or uneven ink thickness. To ensure high-quality results, the Garbo factory implements the following controls:

Pad selection: Pad hardness is matched to the product handle and the complexity of the custom design.

Customized fixtures: Specialized fixtures are designed to position the product accurately. Combined with vacuum or mechanical clamping and CCD vision-assisted alignment for multi-color registration, this ensures consistent positioning accuracy

Differences between pad printing and other processes

Laser: Requires no consumables and offers permanent, indelible marking. However, it is generally limited to monochrome and compromises the local passivation layer, necessitating an anti-rust assessment. It is ideal for permanent traceability codes.

Chemical/Laser etching: Creates a recessed pattern in the metal with a premium, tactile feel; however, the mark itself is colorless (requiring paint filling for color), and both costs and lead times are relatively high.

Water transfer/Thermal transfer printing: Suitable for full-surface patterns and gradients, though registration precision and wash durability are inferior to pad printing.

PVD: Offers superior wear resistance. Faux gold finishes, achieved via pad printing with metallic gold ink, offer a similar visual effect at a fraction of the cost, making them suitable for promotional items or seasonal designs.

Factors affecting pad printing costs:

For the same pattern, processing costs are higher for non-magnetic stainless steel (304/201) than for magnetic grades (410/420/430). 

Three additional considerations include: ink compliance with food-contact regulations (LFGB/FDA); adhesion verification via cross-hatch and 3M tape testing; and the inclusion of dishwasher cycle durability requirements in acceptance standards to prevent large-scale color loss after production.

Pad printing enables the printing of crisp patterns onto the curved handles of stainless steel spoons. While it resembles stamping, it is actually the most practical solution for printing on curved surfaces. It is particularly advantageous for high-volume production of small-scale designs, offering high speed, excellent results, and cost-efficiency.