In Mold Decoration at Metro Plastics: A Guide to Our Decorating Techniques

A molded plastic part often needs more than just a good mold to be market-ready. Logos, labels, branding, and identification marks all have to hold up to handling, moisture, and everyday wear, without adding unnecessary steps to your production line.

To make that easier, Metro Plastics offers several in-mold decoration options for molded parts as part of our plastic injection molding services. Here’s a look at each option, so you know what’s available and can have an informed conversation with our engineering team about what fits your project.

In-Mold Labeling (IML)

In-Mold Labeling embeds a pre-printed label into a plastic part during the injection molding cycle itself. The label is placed inside the mold cavity before resin is injected, and as the plastic flows around it, the two fuse together. The result is a label that’s part of the component rather than something applied to its surface afterward, which means it holds up far better against peeling, fading, and moisture than a traditional adhesive label.

We cover IML in full detail, including a step-by-step breakdown of the process, in our In-Mold Labeling guide.

PolyFuze™

PolyFuze™ is Metro’s technology for creating strong, molecular-level bonds between molded parts and decorative labels, without the need for adhesives. Rather than applying a label to the surface of a finished part, PolyFuze™ fuses the label directly into the component.

Because there’s no adhesive layer involved, there’s no glue line to break down and no edge to lift over time. PolyFuze™ tends to be a good fit for parts that need a decorated finish to hold up under real-world conditions, like repeated handling, washing, or chemical exposure.

Hot Stamping

Hot stamping applies decorative elements to a molded part using heat, pressure, and metallic or pigmented foil. During the process, foil is transferred onto the surface of the component to create logos, text, or metallic accents. It’s a strong option when you want crisp, eye-catching branding or accent details added after molding.

Logo Inserts

Logo inserts are custom inserts placed inside the mold to create raised or recessed branding as part of the part’s own geometry. Rather than adding a separate decorating step, the logo becomes a built-in feature of the molded component itself.

Engraving

Engraving uses controlled material removal to add permanent text, serial numbers, or identification details directly to a part. It’s a straightforward option when a part needs durable, functional markings rather than decorative branding.

Choosing the Right In Mold Decoration Method

With five decorating options available, the right choice comes down to your part’s design, material, application, and production volume. A part that needs to survive frequent washing and handling might call for PolyFuze™ or IML, while a part that just needs a crisp logo or serial number might be better suited to hot stamping, logo inserts, or engraving.

Our in-house engineering team typically walks through these options with customers early in the design process, since it’s easier to plan for the right decorating method before tooling begins than to add it after the fact. You can see the full lineup of decorating and finishing options, along with the rest of our capabilities, on our value-added plastic services page.

Why Work with Metro Plastics for In Mold Decoration

Metro Plastics has been perfecting the craft of injection molding since 1975. Our in-house engineering team works with you from concept through production, helping you choose the right decorating method, material, and process for your specific part.

We’re also ISO 9001:2015 certified, which means our quality management system goes through annual audits against internationally documented standards. Combined with our on-site Metrology Lab and real-time production testing, you can be confident that whichever decorating method you choose, it’s backed by a rigorous quality process.

Whether you’re dealing with label durability issues, looking to add branding without extra production steps, or just weighing your options, our team can help you figure out which decorating method fits your project. Contact Metro Plastics today to get started.