I think I need a laser engraver

[northwest]

I have always in the past engraved stuff using the little mill and a 1mm ball nose cutter, this is proving:

a) very time consuming
b) expensive (broken cutters, though I am breaking fewer)
c) difficult on odd shaped stuff

So I have been thinking about a laser engraver. I need to engrave ally and stainless and mild steel, round, flat and curved shapes. What do I need to buy and can it be had for less than £400? I don't need a very big working envelope.

 

[BrokenBiker]

something like this maybe?

80W Laser Engraver Machine - DIY CNC Engraving Cutting Machine | eBay

40W and 80W refer to the power going into the laser. The laser itself has an output power, which is a fraction of this (the rest of the energy is lost through heat). This is pretty normal and seems consistent across manufacturers: a 40W laser will have 5 to 5.5W actual output, an 80W laser will...

www.ebay.co.uk

it says it will do stainless, assume it will also do ally and mild. curved shapes may be an issue though

 

[My Old Landy]

You need something in the 1064nm range for steel and ally (non anodised) a blue light will do for stainless. In reality a fibre laser is the best for metal.
Sadly, I don't know of any IR or fibre that is £400 (if you find one, I will buy one too).
My dual blue light / IR laser is now on sale https://uk.xtool.com/products/xtool-f1 I paid a tad more than that!

 

[Agroshield]

...round, flat and curved shapes...

Could you expand on the above. Are all of these items planar in plan view (i.e. 2D curvature or 3D curvature)?

When you say 'round', do you wish to engrave on the curved surface of a cylinder or the flat face a circle?

Thus far, the suggestions are only suitable for plane surfaces. On anything non-planar keeping the laser the same distance from the surface being burnt is an expensive challenge.

 

[My Old Landy]

Could you expand on the above. Are all of these items planar in plan view (i.e. 2D curvature or 3D curvature)?

When you say 'round', do you wish to engrave on the curved surface of a cylinder or the flat face a circle?

Thus far, the suggestions are only suitable for plane surfaces. On anything non-planar keeping the laser the same distance from the surface being burnt is an expensive challenge.

My xtool S1 has a motorised head and tracks curved surfaces. It can have an IR head fitted to do metal. It is all more expensive than £400 but is available. It also has a rotary that allows you to do mugs etc. With the lasers I have (around £3k in investment) I can do most materials.

 

[Keith 66]

Basically you need a fibre laser to engrave metal. They were many thousands of quid but prices are coming down, principally for machines made by a Chinese company you will never have heard of, Might be good but might not be!
Normaly available lasers are diode or Co2 the latter either DC glass tube jobs (cheap as chips) or RF ceramic/metal core. They will cut & engrave organic materials, wood, acrylic, leather, bone, paper, slate, they may engrave some metals if coated with expensive marking solution but it isnt as good & is hit or miss.
Apart from Acrylic plastics are a no no as nasty by products are produced particularly PVC. You will need good extraction as lasers produce fume from what they are burning, its on a nano scale & is not good to breathe in. If you can run a pipe outside you need a stand alone extractor & the cost of the filters is eye watering, our school one used 2 filters at £265 & £245 each, two sets a year & it still stank the prep room out.
Then there is the time factor, by the time you have some design software that you have to learn to use & produce dxf files for the laser to read, the laser will have its own control software loaded you have to learn, lots of practice required before you try to ruin a good part!
I used to use one nearly every day in a school for 5 years, I could do basic stuff but never got fully to grips with its capabilities, simply wasnt enough hours in the day.

 

[northwest]

You need something in the 1064nm range for steel and ally (non anodised) a blue light will do for stainless. In reality a fibre laser is the best for metal.
Sadly, I don't know of any IR or fibre that is £400 (if you find one, I will buy one too).

Having done a bit more research now I have a better understanding of what I am looking for I realise my budget is unrealistic. I will have to either up the budget or forget the idea.
It really is a minefield as the usual suspects are making fanciful claims of machines that are barely capable of burning your name on paper.

 

[Agroshield]

My xtool S1 has a motorised head and tracks curved surfaces. It also has a rotary that allows you to do mugs etc.

What about a doubly-curved surface, like an egg? What would be the minimum setup needed for that and how automatic could the 'curve detection' be?

Another maybe useful thing to give us an idea of is maximum part size - say I wanted to engrave a logo 1" square but on something quite big or long. Is it practical to have parts of the item being engraved overhanging the machine enclosure?

 

[My Old Landy]

Basically you need a fibre laser to engrave metal. They were many thousands of quid but prices are coming down, principally for machines made by a Chinese company you will never have heard of, Might be good but might not be!
Normaly available lasers are diode or Co2 the latter either DC glass tube jobs (cheap as chips) or RF ceramic/metal core. They will cut & engrave organic materials, wood, acrylic, leather, bone, paper, slate, they may engrave some metals if coated with expensive marking solution but it isnt as good & is hit or miss.
Apart from Acrylic plastics are a no no as nasty by products are produced particularly PVC. You will need good extraction as lasers produce fume from what they are burning, its on a nano scale & is not good to breathe in. If you can run a pipe outside you need a stand alone extractor & the cost of the filters is eye watering, our school one used 2 filters at £265 & £245 each, two sets a year & it still stank the prep room out.
Then there is the time factor, by the time you have some design software that you have to learn to use & produce dxf files for the laser to read, the laser will have its own control software loaded you have to learn, lots of practice required before you try to ruin a good part!
I used to use one nearly every day in a school for 5 years, I could do basic stuff but never got fully to grips with its capabilities, simply wasnt enough hours in the day.

My xTool F1 is portable and I take it to shows. The filter unit does a good job and you can't smell the fumes from any wooden items I engrave. Its filters are £100 twice a year which I think is reasonable.

 

[My Old Landy]

What about a doubly-curved surface, like an egg? What would be the minimum setup needed for that and how automatic could the 'curve detection' be?

Another maybe useful thing to give us an idea of is maximum part size - say I wanted to engrave a logo 1" square but on something quite big or long. Is it practical to have parts of the item being engraved overhanging the machine enclosure?

The amount of points you probe gives the resolution. The focus is quite forgiving within a millimetre or two. I have used the S1 to good effect and the F1 is a galvo laser and handles curves well. I have been pleasantly surprised at the capability of the pair of them.

 

[My Old Landy]

What about a doubly-curved surface, like an egg? What would be the minimum setup needed for that and how automatic could the 'curve detection' be?

Another maybe useful thing to give us an idea of is maximum part size - say I wanted to engrave a logo 1" square but on something quite big or long. Is it practical to have parts of the item being engraved overhanging the machine enclosure?

To answer your second question, whilst you can run larger items I personally don't. There are open frame fibre lasers but my eyes are too important to me to use a laser in that way.

 

[Bki26]

Desktop fibre lasers have become stupidly cheaper last couple of years, perhaps worth looking into one

 

[My Old Landy]

Desktop fibre lasers have become stupidly cheaper last couple of years, perhaps worth looking into one

I see Omtech now off an enclosed 30w fibre for just over £2k. I am planning on getting the F1 Ultra in April as I am an xTool fanboy

 

[Robotstar5]

Could you expand on the above. Are all of these items planar in plan view (i.e. 2D curvature or 3D curvature)?

When you say 'round', do you wish to engrave on the curved surface of a cylinder or the flat face a circle?

Thus far, the suggestions are only suitable for plane surfaces. On anything non-planar keeping the laser the same distance from the surface being burnt is an expensive challenge.

Pick up a used small industrial robot?, they have a useful parameter called TCP (tool centre point) which is normally defined as the tip of the tool (welding torch etc.) but if you define it as the centre line of a cylinder the robot can be programmed to move a tool (engraver, laser etc.) over the surface of the cylinder keeping a constant distance from the surface.
There was a university using a robot to engrave glass vases, tumblers etc. using the method in the 80's.

 

[northwest]

Pick up a used small industrial robot?,

I tried to show in my initial post that I am hoping to keep to a minimal budget, You are not helping. Now how much would a robot cost and where the hell would you buy one? Second hand robot shop? On the other hand, I do know someone with experience of them

 

[Agroshield]

Pick up a used small industrial robot?

In a way, the iron to move stuff around is the cheap part of the purchase. It is the software (CAM) and motion controller that coordinates the movement that will cost. It is possible to build a 5-axis machine in your garage, but making it dance is expensive.

 

[Robotstar5]

I tried to show in my initial post that I am hoping to keep to a minimal budget, You are not helping. Now how much would a robot cost and where the hell would you buy one? Second hand robot shop? On the other hand, I do know someone with experience of them

I used to work with the chap that started Global Robots - example

 

[Keith 66]

The college i worked at got given an ex Fords Dagenham production line robot, the Head of dept acquired this thinking it was a good idea. No way to drive it without a hundred grand hydraulic power pack, It sat outside the workshop & became a magnet for the oiks to climb & hang on, bit like a scene from planet of the apes. A few months later it was ignominiously scrapped!

 

[Robotstar5]

The college i worked at got given an ex Fords Dagenham production line robot, the Head of dept acquired this thinking it was a good idea. No way to drive it without a hundred grand hydraulic power pack, It sat outside the workshop & became a magnet for the oiks to climb & hang on, bit like a scene from planet of the apes. A few months later it was ignominiously scrapped!

Sounds like a Unimate robot, they were the first industrial robots launched in the 60's, the robot arm is normally mounted on top of the power pack so it sounds like he just got given the top bit.
Useless fact: the robot was invented by Joseph Engleberger who was working for Westinghouse at the time so they set up the Unimate company to market them.

 

[m_c]

In a way, the iron to move stuff around is the cheap part of the purchase. It is the software (CAM) and motion controller that coordinates the movement that will cost. It is possible to build a 5-axis machine in your garage, but making it dance is expensive.

There are fairly cheap options available, provided you've got the correct equations for the kinematics.
I use a few Dynomotion controllers, and their software can be configured to handle non-cartesian machines, which has reminded me of their demonstration 'robot' -

It can be programmed in basic XYZ G-code, and the software Kinematics will convert it to the required non-linear machine movement.

Although for CNC, the usual use is for A/B/C axis, so the controller handles any tool offsets, unlike some other software/controllers, where although they can drive multiple axes, they don't actually handle any of the kinematics and rely on the CAM being able to produce the correct movements for a specific tool length.