Rex Hang
By Rex HangDirector Consultant Expert, HeatSign · 10+ years in industrial marking · LinkedIn

One of our customers runs a 100 W fiber flying laser on a cable line. On black cable, 30% power gives a clean, readable mark. When the line switches to red cable, the same text needs about 80% power.

Same machine. Same text. Only the jacket color changed.

That is the first thing to know about a laser wire marker. The cable jacket decides which laser you need and how much power it takes. The line speed comes second. This guide shows which laser fits which jacket, how a laser compares with a wire printer, how to fit a flying laser on your line, and which HeatSign machine to pick.

What Is a Laser Wire Marker, and How Is It Different From a Wire Printer?

A laser wire marker changes the color of the cable jacket, or removes a very thin layer of it, with a laser beam. It marks while the cable moves along the line. A wire printer usually means an inkjet coder or a sleeve and label printer, which needs ink, ribbons or sleeves.

The laser never touches the cable. The mark is part of the jacket itself, so it lasts as long as the jacket does. There is no ink to refill and no sleeve to slide on.

On a production line, the laser works “on the fly.” A sensor or an encoder tells the laser how fast the cable moves. The laser then writes the text across the moving jacket, so the line never stops.

Cables and pipes

Four words you will see

Jacket (insulation)
The plastic outer layer of the cable. This is what the laser marks.
Flying marking
Marking a product while it moves, without stopping the line. Also called on-the-fly marking.
Encoder
A small wheel sensor that measures line speed, so the text does not stretch or squash.
Tensioning device
A set of rollers that holds the cable steady under the laser head.

Which Laser Works on Which Cable Jacket?

Fiber lasers suit dark PVC and PE jackets. UV lasers suit white and light jackets, fluoropolymers like PTFE and ETFE, and thin wire. CO2 lasers suit non-metal jackets and pipes on a tight budget. Jacket color changes the power you need, so always test each color.

Jacket
Laser
What the mark looks like
Watch out for
Black or dark PVC
Fiber
Light gray to white mark
Low power is often enough. Too much can bubble the surface.
Colored PVC (red, blue, yellow)
Fiber or UV
Varies by color
Needs more power than black. Test every color.
White or light PVC
UV
Dark mark on a light jacket
Works well when the jacket has white pigment (TiO2).
PE and XLPE (cross-linked PE)
Fiber or UV
Depends on color and additives
Test first. Some grades mark weak without additives.
PTFE, ETFE, FEP (fluoropolymers: slippery, heat-proof plastics)
UV
Dark, fine mark
Used on aircraft wire. Test to your own spec.
Silicone
UV or CO2
Light or frosted mark
Soft surface. Check the mark after flexing.
PVC pipe, thick jackets
CO2
Engraved or light mark
Lowest cost. Not for fine text on thin wire.
Thin hook-up wire
UV
Small, sharp text
The small spot size helps on small diameters.
CO2 laser marked text on orange, green, blue, black and red cables
CO2 laser marks on five cables of different colors and sizes. Each color needs its own settings.

Why does UV work on white wire? Most white jackets contain titanium dioxide (TiO2), a white pigment. UV light turns these particles dark, so the mark forms just under the surface. Industry tests show 2–4% TiO2 by weight is enough for good contrast. Only light-colored wire gives this dark mark.

UV marking of aircraft wire has its own SAE standards: AS5649 for the process and AIR5558 for measuring contrast. If you make aerospace wire, test the HeatSign UV laser against your customer’s spec before you buy. For more on UV, see our guide to UV laser marking.

laser wire marking

Shop note: color changes the power

Same 100 W fiber flying laser, same text, from one of our customers’ cable lines

Black cable30%

Red cable80%

Black absorbs more laser light than red, so it marks with less energy. If your line runs several colors, pick more power than your darkest cable needs, and save one set of settings for each color.

Laser marked text on a black cable jacket and on a red cable jacket
Black jackets give a bright mark at low power. Red jackets need much more power for the same text.

Laser, Inkjet or Sleeve Printer: Which Wire Printer Do You Need?

Choose a laser for high-volume, in-line marking that must last. Choose an inkjet coder if you need the lowest upfront cost. Choose a sleeve or label printer for wires that are already cut and terminated, field repairs, or small batches.

Method
What you keep buying
How long the mark lasts
Good for
Laser wire marker
Nothing (power only)
As long as the jacket
In-line production, many meters a day
Inkjet (CIJ) coder
Ink, solvent, filters
Can rub off with solvents or wear
Low upfront cost, fast lines
Sleeve or label printer
Sleeves, labels, ribbons
Good, but a sleeve can slip or get lost
Terminated wires, panels, repairs, small runs
Hot stamping
Foil, heated type
Good, but it presses into the jacket
Older lines. Hard to use on PTFE.

Inkjet coders can print black or white ink on wire from about 20 AWG to 8 AWG (wire gauge sizes), and on cable up to about 13 mm across. They are quick to install and cheap to buy. But you keep paying for ink and solvent, and the printed mark can wear off.

Sleeve printers, like the heat-shrink sleeve printers used on control panels, do a different job. They label wires after cutting. If you mark a few hundred wires a week for panels or repairs, a sleeve printer may suit you better than a laser. We would rather tell you that than sell the wrong machine.

A laser pays off when you mark many meters every day, need a mark that cannot rub off, or want to stop buying ink.

Inkjet Printer For Cable

How Do You Fit a Flying Laser on a Cable Line?

Mount the laser above the line with a tensioning device that keeps the cable from shaking. Set the laser head at 90° to the cable, match the line speed with an encoder, focus with the red aiming light, then run the line and fine-tune the settings.

A moving cable is not like a box on a conveyor. It sways, twists and bounces. If the cable moves up and down under the laser head, the text blurs. That is why HeatSign builds a tensioning device for each cable line, sized to your cable diameter.

  1. Fix the tensioning device to the line frame. We use M10 × 30 bolts.
  2. Thread the cable through the rollers, from left to right.
  3. Set the laser head at 90° to the cable path, right above the tensioning device.
  4. Adjust the roller bolts until the cable is held firm but still runs freely.
  5. Focus the laser. Turn the two handwheels until the red aiming dot meets the reference line on the cable.
  6. Match the line speed, run the line, mark a test length and adjust.
Cable tensioning device with guide rollers for a flying laser marking line
A HeatSign tensioning device. The cable winds through the rollers. The arrows show the mounting holes.
Cable held between tensioning rollers with the red aiming dot of the laser
The tensioning rollers hold the cable steady. The red aiming dot shows where the laser marks.

The video shows a HeatSign flying laser marking text on a moving cable. Watch how steady the cable stays under the head.

Three settings do most of the work. Start with the values below, then fine-tune on your own cable at full line speed.

Watch it: a flying laser marking a moving cable
Setting
What it does
Where to start
Marking speed
How fast the beam writes
Match it to line speed. Too slow: letters distort. Too fast: marks look faint.
Jump speed
How fast the beam moves between letters
Text and logos: 2,000–5,000 mm/s. Serial numbers and QR codes: 6,000–10,000 mm/s.
Power
Laser energy, 5–100%
Set it for each cable color and save it.

How much time does the laser get? Here is a simple check. Say the marking window is 110 mm long and the cable runs at 60 m/min, which is 1 m/s. Each point on the cable stays in the window for about 0.11 seconds. More text or a faster line means you need a longer window, more power, or shorter text. Send us your line speed and text, and we will test it.

Flying laser marking head above a moving black cable, showing the marking window and line speed
The laser writes only while the cable passes through the marking window. Illustration.

If the line is in a closed room, plan a fume extractor too, because marking PVC gives off smoke. See our industrial laser fume extractor. For the difference between fixed and flying setups, read static vs flying laser marking.

Which Flying Laser Should You Choose?

For dark PVC and PE cable, or lines that run many colors, choose the HS-FLY60 fiber laser, or 100 W for extra power. For white, light or PTFE wire and thin wire, choose the HS-UV10. For non-metal jackets on a tight budget, choose the HS-CLY40 CO2 laser.

The tensioning device is made for your cable size and quoted with the machine. Standard machines take about 5 working days to build, plus 4–6 working days by air express. All three are in our flying laser marking machines range.

What Should You Send Us Before a Test?

Send a short length of each cable color you run, with the jacket material, outer diameter, line speed, the text you need and its height. Tell us if your line has an encoder, and send a photo of the space above the line.

7 things to send us

  1. One sample of each cable color, about 1 m each
  2. Jacket material: PVC, PE, XLPE, PTFE, silicone…
  3. Outer diameter of each cable
  4. Line speed in m/min
  5. The exact text, and the character height you need
  6. Whether the line has an encoder
  7. A photo of the space above the line where the head would go
Fiber flying laser marking machine

Planning laser marking on a cable line?

Send us your cable details. HeatSign will suggest the laser, the power and the tensioning setup for your line.

Request a quoteSee flying lasers

Laser Wire Marker FAQ

Does laser marking damage the insulation?

No, when the power is set right. The laser changes the color of the jacket surface or removes a very thin layer. A good mark never cuts through the jacket. Too much power can bubble or cut into thin jackets, so test first.

Can a laser mark black cable?

Yes. A fiber laser makes a light gray to white mark on black PVC and PE, often at low power. It is easy to read without any ink.

Can a laser mark white cable?

Yes, a UV laser makes a dark mark on white and light jackets that contain white pigment (TiO2). A fiber laser usually gives weak contrast on white.

Do I need a tensioning device?

For in-line cable marking, yes. It keeps the cable steady under the laser head. Without it, the cable moves and the text blurs.

How much does a laser wire marker cost?

HeatSign flying lasers start at $3,800 (CO2), $4,000 (fiber) and $7,000 (UV). The tensioning device and any custom mounting are quoted with the machine.

Where to Start

The most common mistake we see is choosing a machine from a sample photo on someone else’s cable. Then the buyer’s red or white cable marks weak, and the power runs out.

Start with your own cable, every color you run. Then check your line speed and text. The laser choice usually becomes clear after one test.

Send us your cable samples and line speed. We will reply with the laser, power and setup that fit.

Sources

  • Tri-Star Technologies, “UV laser marking of wire insulation materials” (Wiring Harness News)
  • SAE AS5649, Wire and Cable Marking Process, UV Laser
  • SAE AIR5558, UV laser marking and mark contrast measurement of aerospace wire
  • Linx, wire and cable coding application notes
  • HeatSign flying laser marking operation guide