Which laser marking machine for glass do you need?
Three questions decide which laser marking machine for glass you need. How thin and how costly is the glass, and does it run on a line?
HeatSign · CO2 and UV lasers
Laser marking machines for glass
A laser marking machine for glass puts batch codes, dates and data matrix codes straight onto the container. No ink, no labels, and the code survives washing and the autoclave.
Thick bottles take almost any laser. Thin walls and crystal do not. Tell HeatSign what glass you use and we will tell you which machine is safe for it.
Just tell us the glass type and the wall thickness. That is enough for a HeatSign engineer to start, and you will have an answer within one business day.
Cold marking · 355 nm
UV laser marking machine
The one for thin and costly glass. It marks walls under 2 mm without cracking them, and the glass keeps its strength.
10W UV galvo · for lines
10W UV galvo laser
More power, so it marks faster. For production lines and higher output, with start and finish signals to work with your controller.
CO2 · 40W or 60W
CO2 laser marking machine
Cheaper and fast on thick bottles and jars. Not the right choice for thin walls, lead crystal or anything under pressure.
Running it on a line needs work on your side too. HeatSign supplies the start and finish signals. Your controller stops the container in position, sends the start command, waits for the finish signal, then moves the line on. Tell us early if you need this, because it is a planning job as much as a machine choice.
Which glass can a glass laser marking machine handle?
Some glasses can shatter under a laser. Check what your glass is before you buy a machine.
One code, three kinds of glass. The glass decides the machine.
Glass Laser What happens
Soda-lime, thick wall
CO2 or UV
Bottles and jars. The easiest glass to mark, and CO2 is cheaper here.
Thin wall, under 2 mm
UV
Perfume and cosmetic bottles. HeatSign UV machines handle this. CO2 cracks it.
Borosilicate
UV
Vials and lab ware. It resists CO2, so UV is the practical choice.
Lead crystal
UV only
Lead lowers the softening point, so CO2 heat cracks it.
Quartz glass
UV, test first
Very high melting point. It marks, but the settings are narrow.
Painted or coated glass
Either
The laser lifts the coating and clear glass shows through. High contrast.
Tempered glass
Do not
It is held under tension. Heat can shatter the whole panel.
Cold or wet glass
Warm it first
Glass straight from a washer or a fridge cracks far more easily.
Does the mark weaken the glass?
Every pharmaceutical and bottling buyer asks this, and most suppliers avoid answering. The answer depends on which laser you use.
CO2 — heat
- The surface heats fast, then cools fast
- That leaves stress behind in the surface
- Stress creates tiny cracks you cannot see
- On a thick jar this does not matter
- On a thin wall or a pressurised container it matters a great deal
UV — cold
- It breaks the surface without heating the glass
- No heat means no stress left behind
- No stress means no tiny cracks
- The wall keeps its strength
- This is why vials and ampoules are UV marked
What laser marking glass puts on the container
Six things go on glass products. Most makers need two or three, and one HeatSign machine does all six.
Content What it is for
Batch and lot code
Ties the container back to a shift and a run
Date and expiry code
Required on food, drink and medicine
Data matrix or QR code
Serialisation, UDI and anti-counterfeit checks
Brand and logo
A permanent mark that no label can replace
Cavity and mould number
Shows which mould the container came from
Volume and fill marks
Graduation lines on lab glass and measuring ware
Where you see it
These are the common ones, not the full list.
Pharmaceutical glass
Vials, ampoules and syringes. Codes that survive the autoclave and the washer.
Beverage bottles
Date and batch codes on beer, wine and spirits, including returnable bottles.
Cosmetics and perfume
Brand marks and batch codes on thin walled bottles and jars.
Laboratory glass
Volume lines, catalogue numbers and lot codes on borosilicate.
Flat and building glass
Panel numbers, batch data and supplier marks on sheet glass.
Awards and glassware
Names, dates and logos on trophies, tumblers and gift glass.
Four things that go wrong with glass laser engraving
These four cause almost every complaint we hear about a laser engraving machine for glass. None of them needs a more expensive machine.
01 The mark chips and looks sandblasted
Turning the power up is the most common mistake on glass. More heat does not give more contrast. It breaks bits off the edge, and the mark ends up rough instead of clean.
Less heat, not more. Drop the power, raise the speed, lower the resolution. If the mark still has to look clean or be read by a scanner, the answer is UV rather than CO2.
02 Thin glass cracks under the beam
On a wall under 2 mm the heat cannot escape sideways. The stress goes right through, and the bottle can crack while you watch or an hour later.
Use UV on thin walls. HeatSign UV machines mark glass under 2 mm without cracking it, which is why perfume and cosmetic bottles are UV marked. Let cold glass warm to room temperature first.
03 The data matrix will not scan
A rough mark has broken cells. The reader cannot find the grid, the code fails its grade, and the line stops while somebody works out why.
Clean edges, not deeper marks. A UV mark keeps every cell square, so the code grades well and the line keeps running. On glass, a scannable code is a UV job.
04 Painted glass does not mark the way people expect
On coated or painted glass the laser removes the coating. It does not frost the glass underneath, which surprises people who ordered a sample without telling us the glass was coated.
That is usually a good result. Clear glass showing through paint gives very high contrast. But it changes the settings completely, so tell HeatSign if your glass is coated before we run a test.
Glass engraving equipment questions we get most
Why does borosilicate barely mark, when the same setting works on a bottle?
Because borosilicate is built to resist exactly what a CO2 laser does. It is made to survive sudden temperature changes, which is why it is used for lab ware and oven dishes. That same property stops the surface frosting.
A setting that gives a bright white mark on a soda-lime bottle can leave almost nothing on borosilicate. Use UV Laser Marker instead. It does not rely on heat, so the glass type matters far less. Send HeatSign your vial spec and we will confirm it before you order.
Do we have to coat or wet the glass before marking?
With CO2, often yes. Many shops lay a damp paper towel or a thin film over the area so the mark comes out white instead of flaky. On one piece that is fine. On ten thousand pieces it is a person standing at the machine all day.
With UV you skip it completely. The laser marks bare glass directly. If you are costing a production line, count that labour, because it often closes the price gap between the two machines.
Our expensive crystal marks worse than cheap glass. Why?
That surprises most people, but it is normal. Cheaper glass usually gives a brighter frosted mark than premium crystal. Hand-blown and crystal pieces also carry more stress inside them from the way they were made, so they crack more easily.
Price does not predict how glass marks. Always test the exact item you will sell, not a sample of something similar.
Will the code survive bottle washing and reuse?
Yes. The mark is a change in the glass surface itself, not a layer on top of it. Caustic washing, high pressure jets and repeated handling do not remove it.
That is why returnable bottle systems move from ink to laser. Ink has to come off at the wash, which means it also comes off in normal handling.
Why did a bottle crack an hour after we marked it?
Because the stress was already there and took time to release. CO2 heat leaves stress in the surface, and on thin or already stressed glass the crack can appear later, not while you watch.
If that is happening, stop using heat on that container. It is a wavelength problem, not a settings problem, and no amount of tuning will fix it.
How does the machine connect to our production line?
Through simple input and output signals, wired between the laser and your own controller. The cycle is described in the machines section above.
The wiring is straightforward. The planning is the real work, because your line has to hold each container still long enough for the mark. Tell HeatSign your units per hour and how long you can stop each one, and we will say whether one machine keeps up or you need two.
Can you engrave inside the glass rather than on the surface?
That is a different process and a different machine. A green laser focuses inside the block and leaves the surface untouched, which is how 3D crystal photos and awards are made.
If that is what you need, look at our crystal laser engraving machines instead. Everything on this page is surface marking.