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Rich Smylie, GMN
By Richard Smylie | Dec 18, 2018
Pad printing at GMN

Pad printing is an offset printing process where ink is transferred from a cliché to the required component via a pad. Bringing together a blend of consistency, repeatability, and durability, pad printing can help you achieve intricate patterns and designs. While most decorative techniques such as screen and lithographic printing require a flat surface, pad printing is one of the very few processes that is well suited for decorating gently curved, irregular, textured, and/or cylindrical surfaces. Predominantly seen in the automotive, electronics, appliance, personal care, and medical industries, pad printing is often chosen for applications that will endure significant handling and need to withstand the test of time.

Our latest video was created to not only equip you with the essentials of pad printing, but also to walk you through the step-by-step process. First, the artwork is etched onto the cliché (flat plate), and ink is deposited into the etched recess. Next, a silicone pad picks up the inked image and descends onto the part to transfer a clean, crisp, and lasting image. Then, the pad is pressed on a polyester film to remove any excess ink. Comprising of a low-tack pressure-sensitive adhesive, the polyester film removes any residual ink from the pad prior to the next printing cycle.

From standard to programmable multi-axis printers, this video offers a glimpse into the different pad printing presses utilized at GMN. Armed with a rotating fixture, the programmable multi-axis printer is capable of numerous hits in multiple color combinations on different axes, all in a single set-up. This capability eliminates the need to transfer the part manually from one station to the other, resulting in significant time and cost savings.

Pad printing is compatible with a broad range of substrates including stainless steel, polycarbonate, polyethylene terephthalate (PET), glass, polyvinyl chloride (PVC), acrylic, and acrylonitrile butadiene styrene (ABS). Very few plastic materials such as low (LDPE) and high-density polyethylene (HDPE), and polypropylene aren’t cohesive with pad printing inks and require a pre-treatment to ensure good adhesion.

For every project, custom fixtures are designed and built to register the component to the pad printing head. The alignment of the ink pad with respect to the size and geometry of the part is specifically engineered to ensure exact registration. As seen with the Nissan badge in the video, the pliability of the silicone pad allows for printing with extreme precision, preventing the ink from coming in contact on the inside walls of the recessed letters. Maintaining the viscosity of the ink is extremely crucial to ensure the ink deposition accuracy and consistency. While the ink needs to be fluid enough to deposit on the substrate, it should not bleed out of the impression area. Thinners and adhesion promoters can be added to inks to achieve the desired viscosity level. Most of the inks used for pad printing at GMN are air-dried and are usually cured in conveyor ovens. Several other factors including the shape, material and durometer of the pad, location and color of the etched artwork, and tilt of the ink pad, are critical to the success of any project.

To see the pad printing process in action, watch our video here.

By Kenny Pravitz | Jun 12, 2018
Plastic decorating options at GMN

What makes plastic decoration at GMN unique? Along with dedicated engineers to support your projects from concept to creation, state-of-the-art equipment, a robust quality system, and complementary capabilities to plastic injection molding like value-added assembly, GMN provides all the decorating options for plastics under a single roof.

To determine the most appropriate plastic decoration technique for any application, there are multiple factors that go into consideration, including the plastic type, environmental requirements (exposure to fluctuating temperatures, humidity, and moisture), component dimensions, cosmetic requirements, regulatory requirements, and production volume. In this blog, we will be skimming over all the plastic decorating options available at GMN to understand their core advantages and pitfalls.

1) Pad printing - In this printing process, the image is engraved on a plate which is then coated with ink and transferred to the desired surface via a silicone pad.

Advantages:

    • Same set-up for multi-color
    • Can accommodate fine artwork and detailed graphics

Disadvantages:

    • Difficult to print on heavy textures or surface finishes
    • Cannot pad print on swooping or curved surfaces
    • Cannot use metallic inks
    • Size restrictions

 

2) Screen printing - In this method, the artwork is transferred on to the plastic surface using a mesh screen and a squeegee.   

Advantages:

    • Quick set-up time
    • Can accommodate larger artwork
    • Ideal for high-volume production

Disadvantages:

    • Can only be performed on flat surfaces
    • Needs different screens for different colors
    • Longer curing times
    • Challenging to achieve finely detailed graphics

 

3) Hot stamping - This dry printing technique utilizes heat and pressure to transfer colored foil onto the plastic surface.     

Advantages:

    • No ink-mixing or curing of part required
    • Can accommodate metallic colors

Disadvantages:

    • Ribbon can be expensive due to the minimum order of quantity (MOQ)
    • Raised surfaces only
    • Size restrictions

 

4) Laser etching - As the name indicates, this technique employs a laser beam to etch a design on the plastic surface which would have otherwise been difficult to mark mechanically.

Advantages:

    • Details are permanently etched into the surface of the part
    • Ideal for products with barcodes, lot numbers, backlighting, or intricate artwork

Disadvantages:

    • Longer cycle times depending on size and detail of the image
    • Size restrictions

 

5) Spray painting - Often used in conjunction with laser etching, spray painting utilizes either an automated robotic spray or manual hand-spray method to apply the ink on the desired parts. 

Advantages:

    • Can hide flaws on the plastic surface
    • Can utilize the manual method for low-volume to mid-volume production and utilize the automated method for high-volume production
    • Can accommodate multiple colors and materials

Disadvantages:

    • Detailed masking may be required, making the process labor intensive
    • Requires a clean environment
    • Requires longer lead time

 

6) In-mold decoration (IMD) - This advanced technique allows for the printing of highly durable and complex three-dimensional shapes.  

Advantages:

    • Can achieve compound curves and complex 3D forms
    • Well suited for designs incorporating small windows or backlighting  
    • Offers versatile decoration options
    • Ideal for high-wear applications

Disadvantages:

    • Development phase can be long depending on the design
    • Automation can be expensive
Denys Sanftleben, GMN
By Denys Sanftleben | Jun 29, 2016
Pad printing at Elite Plastics

At GMN Plastics, we go beyond the standard injection and compression molding processes to offer full solutions to our customers through secondary processes. Within these secondary processes, we offer a range of plastic decorating capabilities in-house in our Beaverton, Oregon facility. These decorative technologies include pad printing, screen printing, hot stamping, vacuum metallization, painting and laser etching, and insert mold decorating.

One of the standard decorative technologies at GMN Plastics is pad printing. Through this printing process, ink is transferred from the cliché and is applied to the part via the pad. To do this, the artwork is etched onto the cliché, a flat plate, and ink is deposited into the grooves of the image. From there, the pad comes down on the cliché and picks up the image before transferring it to the part. At GMN Plastics, there are two types of pad printing machines including a programmable micro printer and standard pad printers. The difference between the two types is that the standard machine is equipped with stationary fixtures while the programmable printer is able to move the fixture so that the part can be printed on at multiple angles. Another major strength of pad printing compared to other decorative processes is the ability to print multiple colors during one set-up rather than through individual set-ups per color. This saves crucial time and money for the program. Pad printing is able to achieve fine print graphics as well.

Considerations when evaluating pad printing as a decorative option include the type of plastic material and the size of the artwork. If the plastic material being printed on has a heavy textured finish, the ink may not print as crisply or thoroughly as it would on a smooth material. Some plastic materials aren’t cohesive with inks and require a pre-treatment to ensure good adhesion. After production, a post-treatment is done to ensure that the ink is cured quickly. Despite these considerations, pad printing technology is highly recommended for its ability to achieve multiple colors and angles in one run.

In our next article we will discuss screen printing technology and its application for plastic parts.