Technique → Dial & Display

PAD PRINTING – TAMPOGRAPHY

Pad printing, or tampography, is a printing method used to apply graduations, numerals, logos, or graphic elements onto watch dials, discs, crystals, and even other components such as movement parts. This technique allows for exceptional precision in transferring intricate and fine details, making it particularly valued for producing clean and detailed prints on the varied surfaces found in watchmaking.

Principle of Pad Printing

Pad printing involves the use of a silicone pad to transfer ink onto the dial’s surface. This indirect printing method is commonly employed to apply patterns or inscriptions to flat or slightly curved surfaces, such as watch dials. It is particularly well-suited for small production runs and components requiring high precision.

Printing Process

  1. Preparation of the Design and Ink
    The process begins with creating an ink film using an engraved cliché of the desired pattern or inscription. The matrix (engraved cliché) is perfectly flat and chemically etched with the pattern to be printed. The ink used for this type of printing is typically solvent-based, ensuring optimal adhesion to metallic or lacquered surfaces commonly found on watch dials. Ink colours are selected to meet the aesthetic or functional needs of the watch design and may include a wide palette, as well as metallic or luminescent finishes.
  2. Applying the Ink to the Cliché
    Ink is deposited onto the cliché, which is a metal plate engraved with the pattern to be printed. A doctor blade removes excess ink, leaving a uniform layer that matches the pattern to be transferred.
  3. Transfer with the Silicone Pad
    A soft silicone pad is pressed against the cliché to pick up the ink. This flexible pad adapts well to the shape of the dial, even if it has slight curves (domed surfaces) or irregular textures (e.g., guilloché). The ink-laden pad is then pressed onto the watch dial, transferring the ink with high precision and faithfully reproducing the design or numerals on the dial’s surface.
  4. Drying and Finishing
    After the ink is applied, the dial is left to dry, often in controlled conditions to prevent imperfections. The dial may be placed in an oven (approximately 80°C) to accelerate drying and eliminate air bubbles trapped in the ink. In some cases, an additional protective layer, such as a transparent lacquer, is applied to ensure the longevity of the print and protect it from scratches or wear over time.

Types of Designs and Applications

Pad printing allows for a wide range of expressions on watch dials, whether for aesthetic, functional, or readability purposes:

  • Numerals and Indexes: Printing numerals (Arabic, Roman, or stylised) or indexes (lines, batons, or dots) is common. These elements are crucial for ensuring dial readability and can be produced in various colours and sizes to match the watch design.
  • Graduations: Some graduations (e.g., chronograph scales displaying 1/10th of a second) require extreme precision and fineness. Pad printing is typically the most suitable method for such detailed graduations.
  • Logos and Branding: Manufacturer logos or other brand symbols can be printed using pad printing. This technique ensures the reproduction of complex patterns or fine details with remarkable accuracy.
  • Date Discs and Other Complications: Indications for date discs, day discs, or other horological complications can also be printed using this method. Numerals or symbols for apertures are easily transferred with a pad, ensuring perfect positioning.
  • Decorative Patterns: Beyond functional elements, pad printing is also used to apply more intricate decorative patterns, such as fine lines, geometric shapes, or special textures. It adds artistic touches to the dial while maintaining the intended aesthetic.

Colours and Luminescent Materials

The colours used in pad printing on watch dials can vary widely. In addition to standard colours such as black, white, gold, and silver, special inks can be used to achieve unique effects. Common colours include:

  • Metallic Colours: Various gold tones or a broad range of metallic hues can be used to give the dial a luxurious and refined appearance.
  • Luminescent Colours: Luminescent or phosphorescent inks, which absorb light and emit it in the dark, are frequently used for dial elements that need to remain visible in low-light conditions, such as indexes, numerals, or hands. These inks often contain substances like Super-LumiNova or similar compounds, enabling the ink to glow in the dark after exposure to light.
  • Luminescent Inks: These are often chosen for elements requiring high visibility in low-light environments, with long-lasting emission properties, making them ideal for use on dials in sports or diving watches.

Advantages of Pad Printing

Pad printing offers several advantages for printing on watch dials:

  • Precision and Detail: The method allows for printing extremely fine and detailed designs, essential for complex dial elements such as numerals or logos.
  • Adaptability: The flexible silicone pad enables ink transfer onto curved or irregular surfaces, making it particularly useful for printing on dials with slight curves.
  • Material Versatility: It can be used on a variety of materials, including metals, ceramics, sapphire, painted or lacquered surfaces, stone, wood, and more.
  • Durability: Once dried and cured, the ink used in pad printing offers excellent resistance to ageing and UV exposure, ensuring the longevity of the print even after prolonged use.