In-Mold Labeling & Pad Printing for Medical Devices

August 15, 2022 • Posted in Events

Printing and labeling for medical devices requires a high level of precision, testing, and quality control. With the need for clear user interfaces, stand-out branding, and durability in highly sanitized environments, medical parts stand in a specialty category all on their own. At Sanwa, we have over 40 years of experience partnering with customers to provide high-quality medical parts, assemblies, and devices using both pad printing and in-mold labeling technologies.

medical equipment iml parts

About Pad Printing

Pad printing involves taking a two-dimensional graphic and depositing it onto a three-dimensional part. During the process, a flexible pad is dipped onto an etched plate with ink and then applied to an object. On a highly tuned-in assembly line, this allows for accurately applying images and text on medical instruments such as syringes, tubing, inhalers, and even the surfaces of pharmaceutical tablets and capsules.

The benefits of pad printing include the ability to print onto curved or irregular-shaped surfaces with fine detail, and a low overall cost. Its versatility and precision make pad printing a good fit for single-use or short-lifespan medical devices, especially for use in hospitals and high-turnover settings.


About In Mold Labeling

As opposed to pad printing, in-mold labeling (IML) satisfies the need for a part’s longevity, durability, and chemical resistance. We recommend this method for equipment with longer lifespans, such as dashboards, control panels, display windows, and high-use push buttons.

Think about all the buttons in a hospital. Buttons to adjust beds, machines, controlling the amount of medicine going into an IV, or the button to page a nurse. Some types of buttons fail to last more than 10,000 or 20,000 pushes before beginning to crack or peel. At Sanwa, we have experience with producing in-mold labeling with push buttons that pass a 100,000 push button test.

The IML process involves more than printing on a surface — instead, IML is designed to outperform most other post-production printing methods by applying the label during the injection molding cycle. Therefore, the design becomes part of the object rather than ink printed on top of an object.

The benefits of IML for medical devices includes:

  • Longevity

  • Durability and hardiness

  • Chemical resistance

  • Flexibility in design

  • Customization and branding

  • Aesthetic excellence

Additionally, IML can work with many different types of resins that meet the needs of a medical setting, including PET, ABS, PC, or PMMA. Resins are chosen to withstand environmental factors (such as harsh sanitizing detergents), and techniques are available to seal corners and edges to reduce the occurrence of bacterial/viral contamination or peeling.

Lastly, IML ink selections can also be based on performance specifications, including opacity, transparency, transmissivity, chemical resistance, or contrast.


quality control in mold labeling medical devices

Quality Control & Testing


Quality control and testing throughout the entire printing and IML processes ensures consistency from the first product to the last. We understand that even slight variations in printing location, 3-D shapes, or print sizes can lead to waste and sub-par performance.

Part testing can be either performed in-house, or done in a manufacturer’s controlled facilities. Testing categories for medical parts can include chemical resistance, water resistance, adhesion, flammability, water discoloration, abrasion resistance, and more.

At Sanwa, our quality management system ensures that we meet ISO 9001 and ISO/TS 16949-2009 requirements.

Medical Equipment Printing & Labeling with Sanwa

Sanwa continuously innovates materials, processes, tooling, and equipment for the successful execution of printed and labeled parts for medical grade devices. From very small (the size of a quarter) to nearly 30 inches wide, we are able to deliver a wide range of parts to meet your needs. And if more complex molding structures are needed, processes like two shot molding and dead-front labeling are also possible.

Get in touch to speak with our team about developing your next high-quality medical part.