Cable Marking Printing Methods

In modern industrial applications – from telecom networks to aerospace harnesses and automotive assemblies – cable marking is essential for identification, traceability, and safety. Printed or embossed text on a cable jacket makes installation and maintenance much easier. One cable industry guide notes that “cable markings make identification and branding easy”. The challenge is choosing the correct printing method for your specific cable type and application. Factors like jacket material, cable diameter, speed requirements, and industry standards all play a role.

In this article, we break down the three main marking processes—gravure (ink-wheel) printing, embossing, and inkjet printing—explaining how each works, their pros and cons, and what to watch for with different cable materials (like thick vs. thin jackets and TPE outer layers).

Gravure (Ink-Wheel) Printing – High-Speed Contact Marking

Gravure printing (also called ink-wheel printing) is a contact printing method. An engraved metal wheel or drum picks up ink and rolls a fixed legend directly onto the cable surface. This happens inline (often right after extrusion), so it’s swift. Gravure is widely used for long cable runs where the markings don’t change (e.g. product names, ratings).

• Advantages: With the right specialised ink, gravure marks are highly durable, standing up to abrasion and solvents. It also offers high speed – some machines can print over 3,000 feet of cable per minute. The process also has low maintenance and integrates easily into automated production lines.
• Disadvantages: The significant trade-off is flexibility. The print legend is hard-coded into the engraved wheel. That means fixed content only—you must use a different wheel for each message or number sequence. On-the-fly text changes or serial numbering are essentially impossible. Gravure also requires inks and periodic wheel cleaning.

Engineers use gravure printing when they have a stable, repeating marking requirement on large cable volumes. For example, a manufacturer might emboss the company logo and rating on every meter of a long run of identical wiring. But gravure is unsuitable if you need to print batch codes or unique IDs (you’d switch to inkjet or laser instead).

Embossing – Permanent Raised Marking

Embossing is a mechanical marking method that creates raised (convex) characters on the cable jacket. An embossing unit – typically placed right after the extruder (when the cable is still hot and malleable) – uses a male/female die set to deform the jacket. The process “indents” the plastic around the characters, leaving the printed text raised from the surface. This creates a permanent 3D mark without any ink or consumable material.

• Advantages: Embossed marks are permanent and tamper-proof. They require almost no ongoing maintenance and no inks or foil (so operational cost is very low). Because the mark is physically moulded into the jacket, it can withstand extreme temperatures, chemicals, and abrasion – ideal for harsh environments. Raised characters remain legible even if the cable is painted over or gets dirty, which is a big plus for aerospace or industrial motor applications.
• Disadvantages: The most obvious drawback is legibility/colour: embossing doesn’t add pigment, so the mark is the same colour as the jacket. Raised text can be complex to read on a black or dark background unless perfect lighting. Also, you need a sufficiently thick and ductile jacket – thin or brittle cables will crack under embossing pressure. Experts note that mechanical methods “do not work for thin-jacketed cable as indent would damage the jacket”. This means excellent wires or jackets thinner than about 1 mm may not be embossable. Finally, changing the embossed legend requires making new dies, limiting flexibility (similar to gravure).

In summary, embossing is used when extreme durability is required and legends are known in advance. It’s common in aerospace/military cable where MIL-specs demand permanent, indelible markings. (By contrast, hot-foil stamping – which indents colored foil – is similar to embossing but adds contrast via colour and works on many jacket types.)

Inkjet Printing – Versatile Non-Contact Marking

Inkjet printing sprays tiny droplets of ink onto the moving cable jacket. It’s a non-contact method, much like a desktop inkjet printer, but industrialised for wire. Inkjets can print text, serial numbers, barcodes, logos – virtually any graphics – directly on the cable on the fly. Because the image is computer-generated, you can easily change the text or print serialised data without stopping the line.

• Advantages: Inkjet printing is highly flexible. With no hardware change, you can print different data for each cable (batch/serial numbers, time stamps, custom labels). It’s also widely used and relatively easy to program—most cable makers have inkjet systems integrated into their production. Inkjets handle high line speeds well, and modern systems even support multiple lines of text or logos. There are minimal moving parts, and the setup time (for changing the text) is very short.

• Disadvantages: The ink’s adhesion can be an issue on some surfaces. Certain chemicals, such as abrasion or hand rubbing, can remove the print if it isn’t properly fixed. For instance, standard inkjet inks might smear or rub off on flexible elastomer jackets. One practical example: TPE (thermoplastic elastomer) cables are known for “low adhesion” – in one case, an industry engineer pointed out that print on TPE “does not stay on as long as on a PVC jacket”. To address this, manufacturers use UV-curable inks, preheat the cable slightly, or even treat the surface. For example, plasma or corona pretreatment can dramatically improve ink wetting on low-energy plastics (PE, TPE, XLPE, etc.), making the print indelible. In practice, inkjet requires consumables (ink cartridges or fluids), and printheads must be cleaned regularly. It also generally produces less contrast on dark jackets (unless special inks are used). But its versatility and speed make it the preferred choice for many plant-floor applications (like control cable, building wire, custom harnesses).

Material and Sheath Thickness Considerations

Material matters as much as method. As noted, cable jacket material and thickness can favour or rule out specific marking processes. For example, PVC jackets (standard in telecom and automotive cables) work well with inkjet or hot-foil printing. In contrast, untreated polyethene (PE) or XLPE often repels inkjet inks unless treated. Likewise, rubber or TPE jackets (used in industrial automation or robotics) have very low surface energy; any ink (jet or wheel) will have trouble sticking.

A few key points:

• Surface Compatibility: A wire manufacturer’s guide highlights which methods suit which materials. For instance, hot-foil stamping (similar to embossing) works on PVC, PE, PTFE, etc., but not on rubber. Inkjet works efficiently on PVC but not raw PE/XLPE unless the cable is pretreated. An ink-wheel (gravure) can handle most materials if the ink is right.
• Sheath Thickness: Embossing or foil indent printing requires a minimum jacket thickness. If a jacket is too thin, the die will tear it. One industry source warns that hot-foil (indent) printing “does not work for thin-jacketed cable as indent would damage the jacket”. In practice, cables thicker than ~1–1.5 mm can be easily embossed or stamped. By contrast, inkjet and gravure only require enough thickness to absorb the ink – skinny films (like PVC insulation under 0.5 mm) may show through.
• TPE and Low-Energy Plastics: As mentioned, TPE material (and other elastomers) will quickly rub off regular inkjet prints—a fix is a surface treatment. For example, plasma or corona treatment “activates” the jacket, dramatically improving the wettability and bonding of ink. After treatment, inkjet marks become extremely abrasion-resistant (one company saw a print survive 10+ bend cycles, compared to failing in 1–2 cycles before treatment).

In short, always consider your jacket material: PVC/PVC blends are generally easy to mark with any method, while hard plastics (XLPE, PTFE) often need thermal or laser techniques, and soft elastomers (TPE, silicone) usually need embossing or special ink treatment.

Choosing the Right Method

So, which method should you choose? Here are some practical guidelines:

• Production Volume & Speed: Gravure (ink-wheel) excels at high-speed, high-volume runs where the marking doesn’t change. If you’re extruding thousands of meters of identical cable, gravure gives durable marks at top speed. Inkjet can also run fast, but very high line speeds can challenge ink drying. Embossing is typically slower (stamping cycles) and best when throughput is secondary to permanence.
• Data Variability: Do you need serial numbers, time/date codes, or batch data? Inkjet (or laser) is your friend. Both support dynamic data generation, whereas gravure/embossing is static.
• Durability Needs: If markings must survive harsh environments (heat, chemicals, abrasion) and stay legible for decades, embossing or hot-stamping has the edge. These create permanent deformation rather than relying on ink adhesion.
• Legibility & Contrast: Inkjet and gravure (with black or colored inks) produce high-contrast text on most jackets. Embossed text is the same colour as the jacket, which can be a drawback in poor lighting. If readability is critical (barcodes, fine print) on a dark cable, consider adding a backing paint/ink or using hot-foil stamping (which adds colour).
• Material Constraints: Check the jacket material. Avoid embossing or hot stamping if it’s a soft rubber or thin cable (you’ll tear it). If it’s a low-energy plastic like PE or TPE, plan for pretreatment or choose embossing or laser over plain inkjet. For standard PVC jackets, most methods work fine.

Ultimately, many companies standardise on one method per product line to simplify manufacturing. For example, building cable makers often use inkjet printers post-extrusion, while aerospace harness makers rely on indent/emboss markers. If in doubt, test samples are invaluable: print samples and see which best meets your legibility, durability, and cost requirements.

Conclusion

Each cable marking method has its place. Gravure printing offers proven high-speed durability, embossing gives tamper-proof permanence, and inkjet delivers ultimate flexibility. You can ensure clear, long-lasting identification by matching the method to the cable’s construction and the application’s needs. And when you’re ready to implement, Romtronic’s experienced team can help. With decades of cable assembly expertise and ISO-certified processes, Romtronic offers integrated marking solutions (or pre-printed harnesses) tailored to telecom, automotive, aerospace and automation standards. In short, we know how to make your cables perform reliably and arrive fully labelled and traceable for the system’s life.

Sam Wu

Sam Wu is the Marketing Manager at Romtronic, holding a degree in Mechatronics. With 12 years of experience in sales within the electronic wiring harness industry, he manages marketing efforts across Europe. An expert in cable assembly, wiring harnesses, and advanced connectivity solutions, Sam simplifies complex technologies, offering clear, actionable advice to help you confidently navigate your electrical projects.