Noob - Help with machine selection to engrave and cut 0.5mm metal

Community Laser Talk
1

Greeting all.

Complete noob at laser stuff. I have been researching what machine I need but am having some trouble…can you help?

I’m a hobbyist and the plan is to create engraved watch dials. These will be created from sheet metal, be it stainless steel, brass, bronze, copper, titanium, or aluminium with a maximum thickness of 0.5mm. Surface relief will be 0.1 to 0.2mm. This type of thing:

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So I guess a fibre laser is what I need but what power? I have seen videos of people cutting steel with a 30w fibre laser but OMtech said no when I asked. will it suffice or is there an alternative? It needs to cut to create the dial disk, so can it get through 0.5mm?

Thanks in advance!

2

I have a M60 JPT M7 MOPA, it is an engraver.

The only difference between engraving and cutting is how deep can you engrave. If you can engrave deeper than the material we call it a cut.

As stated it’s an engraving machine not a cutting machine.

These arrows are 0.254mm brass. I cut them out after about 20 - 30 passes. The heat from cutting them has an excellent tendency to warp the metal

To cut something 0.50mm with a laser will take lots of power in the big dollar area.

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What you want is something that cuts well through 0.50mm, and has the delicate touch to engrave.

I don’t think there is any such animal…

Let us know what you come up with…

Good luck

:smile_cat:

3

Thanks for the info…it’s kind of where I got to.

I reached out to this guy (5Red) but no response as yet. Here he is apparently cutting and deep engraving:

I guess the alternative is to purchase a blank disk and engrave that. Similar to coin relief engraving, which appears to be a thing.

If I arranged a jig to hold the dial, perhaps securing 0.5mm on the edge of the dial disk I assume this would help to keep it flat. I could engrave this. Is it possible to centre (frame?) the laser accurately?

When you mention cost - what are we talking about. In the UK we do kwhs.

Found that a 50w laser used 750w/h, so 450w for a 30w laser. That’s £0.15 per hour. Pretty cheap. Assume consumable for the laser cost too, however.

4

After pondering this, I think a fiber might not be a bad idea. As long as you understand the limit of doing or what you want to do… I’m not a expert, but I’ve run mine enough to know I still don’t know much… :crying_cat_face:

I think the video was good and confirmed my suspicions.

I hoped you asked him about the thickness he uses and how long it took.

If you note, I stated you can do it also, but it takes lots of passes. I did a 3d coin that took 2 hours and is relatively deep. That was 256 passes in 3dslice mode.

The brass I cut was done in about 30 passes and it did distort. It was 1/2 the thickness of what you are after. 60 passes would be an easy task … but it will depend on the material.

Fiber lasers are fast for many things, but there are lots of passes a small interval to get the results you want, so it’s take time.

I doubt you’ll find actual disks the same size as you need. There are so many watch sizes… Am I incorrect in the observation?

If you want to do a lot of cutting, then the bigger the better, wattage wise. I ended up with the 60W, but they are solid state pumped and triggered, they are pulse lasers.

I’d suggest staying under 100W… the lenses for these go up by about 8 times. :exploding_head:

Are these, that you are looking at a q-switch or mopa types? A mopa gives you much more control and is better than q-switch for oxidizing/annealing for a colors type visual result.

About 30:20 into the Sadler video he explains fiber lasers. The whole video (~1 hour) is a good watch if you don’t know how some of the works.

For coins, mostly I use a circle engraved out that will seat the coin. It’s pretty shallow. If I move anything on the machine or table, I just do another one…

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Good luck… keep us informed.

:smile_cat:

5

Thanks - will do more research. I am looking at Seiko NH35 dials (may mean nothing to you I realise, this is the watch movement and dials are a standard size) but the good news is that this is a big industry, with a vast modification community around it looking for bespoke or interesting items. I can get 28.5mm blanks for next to nothing and there are a great deal of people looking for NH35 dials at 28.5mm. I t will also enable me to create bespoke watches with my own dial designs.

edit

the guy in the video above is using a 50w split fibre laser.

6

If you can buy the size and type of metal you want, it would sure make life easier…

Most fibers have a source/controller and a fiber transmission line to a separate head. Mine is also a split fiber.

Good luck

:smile_cat:

7

By looking at your photo of the watch dial it looks like your graphics might be 3D

3D means dynamic focusing. Compared with ordinary 2D fiber laser machines, like @jkwilborn referred to.

3D laser marking machines use a different laser heads. Regular 2D fiber Laser Machines like the 30W OMTECH use 2D galvo scanning head which have only two mirrors, while the 3D fiber Laser machine uses a 3D Dynamic focus scanning head .3D scanning heads have three mirrors. The third mirror can be moved back and forth. This is the key technology of 3D laser engraving machine.

There are three main applications for 3D laser marking machines. Including curved engraving, Embossing laser engraving and large-working Area engraving.

  1. Curved laser engraving

The 3D fiber laser Machine working area is usually below 300x300mm. It can be used to engrave curved and Ball surfaces. Unlike rotary engraving, 3D curved surface engraving has a very high accuracy, automatically adjusts the focal length,Mainly 3-axis dynamic focus technology and layered engraving technology. According to the different points in the working area, the focus is automatically adjusted through the machine software control, so that the 3D fiber laser marking machine can make molds and stamps, copper coins, mold steel and other materials. and works faster.

  1. Embossing laser engraving

Embossing laser engraving is as popular as Curved laser engraving. It can be used to make many things like molds , Retro coins and watch faces like the example you showed, etc. The purpose is mainly for deep engraving material.

The 2D laser machine can do deep engraving however all the depths are the same, on the same plane. 3D laser engraving can reach different depths, behaving like a three-dimensional pattern, with a three-dimensional effect. It makes a pattern more vivid like the dragons in your watch example.

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  1. Large-working area engraving.

The maximum working area size of the 2D laser engraver is 300*300mm. Using a 3D laser engraver machine, working area can be up to 600x600mm.

NOW for the bad news. Lightburn will not be able to run a 3D fiber laser however other users have been able to print STL files which give you a 3D effect.

Read more in this post:

Hope this information helps you and others

Cheers

Sas

8

Your video with the fiber shows you can do what you want with a fiber.

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I think you can see here, using the 3dslice option in Lightburn seems to work well. You are dependent on the depth of field of your lens.

EZCad3 has Z control, for deeper engraving, same machine with a stepper on the Z axes.

I can’t imagine how the 3d with mirrors works that @Sasquatch stated, but I think I see big bucks and no software to drive it that I could afford.

:smile_cat:

9

Not a cheap option indeed and no Lightburn is a deal breaker for me as well @jkwilborn

Where the 3D excels is in the crispness of the deep engrave

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And in the ability to engrave on non plane surfaces .

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The level of detail in @B3auf watch image is greater the detail image @jkwilborn shows in his example. That is why I mentioned the 3D. Since @B3auf is still doing his research.

Cheers :beers:

Sas

10

Thanks for all the input - have loads of work on so will digest it all this weekend!

11

These images appear to have relief - is this without Z axis control?

The maximum engraving depth will be 0.2mm I guess.

I think it’s a greyscale depth map - presumably, this means you don’t need a Z-axis laser. I can go for a 70mm x 70mm lens.

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12

Absolutely correct… 3dslice mode in Lightburn. This was the source.

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Lens selection is rather critical.

There are many calculators that specify the depth of filed or how much Z direction the beam stays in focus, along with the spot size.

If you use an F110 (70x70mm coverage), spot size of 16um and the depth of field is 0.22mm.

Conversely an F254 (175x175mm) has a spot size of 31um but a depth of field of 0.67mm.

When you figure this, the input beam size is in the denominator, so a larger entrance beam generates a smaller dot (spot) size.

Keep in mind if you purchase a machine with an F110, it will probably have a relatively short column. Mine is 800mm and will handle an F420 lens.

These are all variables that you get to pick and choose…

Good luck

:smile_cat:

13

Next question - where do you learn how to use the machine?

14

Don’t know if I ever will learn it completely… Lots of videos, along with thinking what’s going on at the material…

I’d like to plug into the MATRIX and learn all there is to know about it :crazy_face:

Laser Everything is a good source, they also have some free settings you can use to work from.

Good luck

:smile_cat:

15

I have seen a video (Trotec perhaps?) explaining we can do that in multiple passes, with lower power.
One day, I will try to do this with my diode laser, not sure it will be good (I fear too much burning, but worth a try?).