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Fibre galvo

A fibre galvo laser is a device where the mirrors that steer the beam rotate, but do not move, as opposed to a plotter device in which the mirrors move, but do not rotate.

Fibre is the laser source, and unlike a CO2 laser, saying "fibre" does not specifically imply only one wavelength of light being produced, generally speaking it means 1 micron wavelength, although there are variations from source to source, whereas CO2 *always* means 10 micron wavelength light energy being produced.

UV galvo lasers are used to mark glass and soft plastics, and green galvo lasers are used to mark glass, we do not own any UV or green lasers at EL at this time.

This image shows the electromagnetic spectrum, and you can see that while fibre and CO2 sources both produce IR (Infra Red) light energy, the wavelength of fibre is ten times shorter than CO2, and that does make for some significant differences in how it reacts with different materials.

For example CO2 laser beams are great for cutting or engraving clear acrylic, which despite being optically clear to the human eye, is almost completely opaque to a CO2 laser beam, but, that same piece of clear acrylic is almost completely transparent to the fibre laser beam, so you can't cut or engrave clear acrylic with it... nor can you use sheets of acrylic to safely absorb and block any stray beam reflections.

On the other hand, you can make beautiful black marks on polycarbonate with a fibre beam, whereas the CO2 beam just engraves it and leaves a textured surface, and when it comes to various metals you can directly mark or engrave them (mostly) without using any extra chemicals or compounds.

You can put a high power fibre source in a plotter style machine, add all sorts of specialist assist gases, and you have a metal cutting laser.
Exeter Laser do not cut metal.

But (from September 2017, it should have been *much* sooner, but foolishly we delayed things hoping to find better workshop premises first) here at Exeter Laser when we talk about fibre we mean a fibre galvo, which, depending on the material, can mark, or anneal, or engrave, but not necessarily all of the above for any single material, for example Titanium metal can be marked extremely well, but it can't be engraved well, whereas aluminium can be both marked and engraved very well.

Currently our new fibre galvo machine is "Gordon" and when open on three sides in Class 4 mode with the protective cover raised, can take quite large items, and has 450 mm of Z travel, but you have to subtract a fair chunk from that for the focal length of the final lens used, the bigger the work area lens, the longer the focal length... for the 180 mm lens the Z height is 175 mm. Using the rotary table will of course eat into this somewhat as well.

In Class 1 mode "Gordon" has an XY limit of 400 x 260 mm for the work *piece* with the protective cover lowered... the work *area* is still 180 x 180 with the 180 lens.

Class 1 mode means you can stand next to it and no laser energy can escape because the doors are shut, so you could use it in a public space, Class 4 mode means the doors are open to get larger work in, and everyone (man and beast, dogs and cats etc have optic nerves and eyes too) in line of sight needs to be wearing appropriate protective eye gear etc.... 1 mW laser pointers can cause permanent eye damage, even the lowest power fibre machines are 20,000 times more powerful than the most powerful legal laser pointers.

The standard lens in "Gordon" has a 180 x 180 mm work area "per shot" and of course there is full rotary capability, and 70, 110 and 220 mm lenses are available for larger run jobs should they be required, in addition to the 180 fitted as standard.

Maximum work / part / piece weight is 30 Kg, unless the rotary is being used in which case it is 2 Kg.

By mid to late September 2017 we will have added an 800 mm X axis linear table to Gordon, which means after each section is marked, the whole worl piece is moved under CNC control left or right for the next piece to be marked, which will increase Gordon's potential work area from say 180 x 180 mm in one shot to 180 x 890 mm in several shots. Repeatable positional accuracy of the X axis linear table is of the order of 0.030 mm or 30 micron which compared favourably with the focus dot size of a 180 x 180 mm f-theta lens.

"Gordon" is a fibre source producing 1 micron wavelength IR light, and the galvo head can scan at up to 3 metres per second, so "Gordon" is ideal for deep engraving many metals including the usual ferrous ones.

Fibre laser materials list :

CHROMIUM ***    ✔
COPPER ***    ✔

 This is a list of materials that the EL Fibre laser will mark or engrave *excellently*

Of course anything that can be engraved can be "cut" after a fashion, because the definition of engraving is to remove material... however we are in reality talking about sheet metals 0.5 mm thick or less

In between this list of materials that a fibre galvo laser is excellent at marking or engraving, and the list of materials that are basically unaffected by it (such as clear acrylic, white paper, most woods and MDF, and so on) there is a whole raft of things where you get "variable" results, so for these materials feel free to ask and feel free to ask for a test or demo on a material sample supplied by you, the results may be just what you were looking for.

One of the other interesting applications of a fibre galvo is cleaning metal objects, there will be a whole bunch of videos on this added to the EL vimeo channel in due course, so it isn't *just* marking and engraving that such a machine will do.

Because of various technical details, "Gordon" is capable of incredibly fine levels of detail, for example pin sharp perfect clear text that you literally require a magnifying glass to read, again, there will be plenty of 1080p quality videos uploaded to the EL vimeo channel in due course.

Fibre galvo lasers are eminently suited to such things as marking firearms, marking surgical instruments, marking metal components (eg branding car parts, bearings, etc etc), marking hygiene or culinary components, the list is almost endless.

Generally speaking fibre galvo lasers mark or engrave metals, and marking metals is usually an annealing process, that is permanent until that item is heated up to red hot, or an engraving process (also sometimes called ablation) which is the permanent removal of material, so it is a permanent mark no matter what.

"Gordon" is not a MOPA fibre machine, in *theory* MOPA lasers can alter the pulse width, as well as pulse frequency and pulse power, and in *some* metals, notably Inox, you can use this to produce an effect that can look coloured from certain angles, in our opinion this faux colour marking is a novelty at best, it isn't proper annealing and it isn't as permanent as proper annealing and it only works at all in direct sunlight from certain angles.... perhaps in a few years time this technology will have advanced to the point where it marks as well as a "standard" frequency and power pulsed fibre like "Gordon", but it isn't there yet and so it is not commercially viable.

As well as single items and small runs, "Gordon"  is ideally suited for batch production jobs, and can directly import lists of data such as serial numbers etc from such sources as spreadsheets and CSV files, and automagically increment each mark on each piece.


This last image shows the EM spectrum plotted against the reflectivity of various materials.

The blue arrow is the wavelength of the CO2 plotter, George.

The red arrow is the wavelength of the fibre galvo, Gordon.

What is *important* to understand is when you look at for example Al (aluminium) the graph is talking about *pure* aluminium, not an alloy.

"Gold" as is bullion and electronics is not the same as "gold" in jewellery or money, the latter are impure, and it is the impurities that mean that for example Gordon works on my silver napkin ring, but doesn't work on 100% pure silver, or copper, or gold..... this may matter to you if for example you wanted to have a PCB layout etched from a copper sheet on a resin base, Gordon won't ablate away the copper leaving a perfect PCB layout (you need a 355 nano UV laser for that, and no, we do not have one) so all we could do is coat the copper with paint and ablate that away to create a mask so you could then chemical bath etch the remainder.