First engraving trials

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dirtyhanfri

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Hi

I've been doing some engravings in aluminium using a spare piece I has lying around.

I've used a V-bit 0,1mm tip, 45º. 0'05 machining depth in just one pass. Highest possible spindle RPM(about 20000), cutting feed: 75, plunge feed: 20 (mm/min)

In 3mm letters everything looks fine, but when doing 2'5mm or less, the holes inside the letters dissapear.

Also, I'm not sure if the tip was broken, the traces look much wider than I calculated (those tiny tips are hard to see clearly for me after some hours working).

Any suggestion is welcome
 

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joaquins

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Trying 0.2mm 60º?

I don't have experience with that but I guess the 0.1mm tip is quite brittle, probably good for doing PCBs or engraving multicolor plastic sheets but I don't know about Al, remember you are working the anodised while very thin layer is quite hard.

Also the shallower the angle of the tip the less thickness error with Z same axis error. Of course you need to be cutting something but not much I guess. If Z axis error is a problem a floating head may be a good option.

JS
 

jwhmca

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5000 or 6000 series Aluminum?

5000 series is VERY soft and gummy, I've had it break many tips.

I had to do a surface run first to, well, resurface. Then I started having really good results.

1. Lay the raw face down with double sided sticky tape.
2. Surface mill flat.
3. Spray with your black spraypaint and let cure.
4. Engrave.
 

dirtyhanfri

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joaquins said:
Also the shallower the angle of the tip the less thickness error with Z same axis error. Of course you need to be cutting something but not much I guess. If Z axis error is a problem a floating head may be a good option.

JS

Maybe 0.2mm 60º would work better, cutting at 0.12mm depth give me a bit wider cut than I would like according to calculator, but I have to try.

Anyway, I tried to engrave again, with anodised aluminium, and with a sharp 0.1mm tool and being careful looks better... I will get some 0,1mm 60º tips


jwhmca said:
5000 or 6000 series Aluminum?

5000 series is VERY soft and gummy, I've had it break many tips.

I had to do a surface run first to, well, resurface. Then I started having really good results.

1. Lay the raw face down with double sided sticky tap.
2. Surface mill flat.
3. Spray with your black spraypaint and let cure.
4. Engrave.

I think it's 6000 Series aluminium, not sure.

About spraying the surface with blackspray and then engrave, I have a pair of questions:

You just spray paint on bare aluminium? no other treatment?

Do you use this method for front pannels or anything that has a bit of use, meaning friction from fingers turning the knobs, plugging connectors etc?

I suppose after the engraving you use some kind of varnish to protect it?

My experiences painting aluminium are not so good, and even worse if I don't use any primer prior to the paint...

Thanks
 

jwhmca

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Paint sucks. I hate it... I use Front Panel Express now, but then I just went with RAW aluminum the engrave and do my own Black infill...
 

dirtyhanfri

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jwhmca said:
Paint sucks. I hate it...

;D I'm not alone then...

I just spent 11€ in a aluminium primer spray can, it's my last trial on painting. I've found a shop locally who can anodise my pannels, not so fast (being not so much pieces I've to wait to be part of bigger run, not so much problem with black colour) but cheap enough to don't complain.

 

Gene Pink

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dirtyhanfri said:
I've found a shop locally who can anodise my pannels,
Have you considered anodizing in your garage?

There are many tutorials on the net, and most people that frequent this board likely already have the most expensive component of the setup, a hefty power supply in the 16-20V range.  I use a large roll-around car battery charger that can do 50 amps at 14 volts, and then variac it up a bit. Figure on 1 amp per 2.5 square inches of aluminum, less current just takes longer, it is a forgiving process. The only thing critical is temperature control, between 45-50 degrees F.

The rest can be obtained on a saturday morning shopping trip for 100 bucks, and these are non-consumables. Once you are set up, the consumables are distilled rinse water, dye, ice, and electricity.

If anyone is interested, I'll start a thread on anodizing, but there are plenty of articles already out there.

Gene
 

dirtyhanfri

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Gene Pink said:
Have you considered anodizing in your garage?

Actually yes, but my shop doesn't have any water intake or drain system, also I'm in the process of learning about machining and a few other things, so I think it will take some months until I get bored and try to learn something new.

I'm moving in January and my new house has a balcony next to the kitchen which looks perfect for make a little anodising jig

I've been looking at some tutorials (in spanish) and seems doable.

About engraving, I've been doing PCBs and I'm having nice results, got some Bungard boards and they are flatter than the chinesse ones I started milling.

Also I noted Autoleveller software is not working propperly, I got a lot of flying cuts when using it, setting Z axis 0 manually just once is working better for me.

Today I'm gonna try to engrave some aluminium again...
 

gyraf

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Autoleveller software

Could you explain? I'd very much like some kind of auto-levelling - when engraving I have to babysit the machine very closely as I'm depending on a 0,15mm +/-0.05mm depth for decent work (with a 0.3mm bit). And sadly the frontpanel aluminum plate material has bigger tolerances than this - across single panels..

Jakob E.
 

dirtyhanfri

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Autoleveller is a Java software for take height measurements of the piece before start the milling process, it needs an electrical probe (one wire in the piece and other in the tool, when tool touches piece it closes circuit and Mach3 detects piece height) Not sure if it will work on anodised pieces, I use it for pcb's and I'm not pleased with it.
 

gyraf

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Aah - for mach3.

Some day I'll hopefully have the time to start using that - it looks very good. But for now, I'm too pressed for time to experiment, regrettably..

Jakob E.
 

joaquins

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gyraf said:
Autoleveller software

Could you explain? I'd very much like some kind of auto-levelling - when engraving I have to babysit the machine very closely as I'm depending on a 0,15mm +/-0.05mm depth for decent work (with a 0.3mm bit). And sadly the frontpanel aluminum plate material has bigger tolerances than this - across single panels..

Jakob E.

Have you tried a floating head? Kind of the same thing but mechanic  ;)

I've heard good and bad things about those, I guess it would need some experimentation as well but may worth it. One of the things to consider is the chip removal, if the head is a small closed circle around the bit the chips would scratch the surface. You can't make it too big or it won't work as well and will take too much working space from the clamping to the tool (unless working with vacuum clamping or double sided tape)

JS

PS: I mentioned it twice in this topic  :eek: it's time to restart my CNC build.
 

mattamatta

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dirtyhanfri said:
ot sure if it will work on anodised pieces

I expect it will give you problems on anodized parts.  The anodic layer is a decent insulator.  You may get some conductivity as it scratches around through the layer, but that's not going to be very ideal.
 

gyraf

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Have you tried a floating head? Kind of the same thing but mechanic

Yes, I have one and use it on painted surfaces. But on anodized, even the smallest piece of cut-off material caught under the depth-adjusting nose will scratch and look really bad. I tried with a LPKF nose floating on pressurized air, and even that won't really do it without messing up..

Jakob E.
 

joaquins

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gyraf said:
Have you tried a floating head? Kind of the same thing but mechanic

Yes, I have one and use it on painted surfaces. But on anodized, even the smallest piece of cut-off material caught under the depth-adjusting nose will scratch and look really bad. I tried with a LPKF nose floating on pressurized air, and even that won't really do it without messing up..

Jakob E.

Optically floating would be cool... floating on laser  ??? Maybe there is something, maybe it will be at some point.

One problem with the electronic mapping is the wobbling of the material, if you got a PCB supported by the sides it might wobble enough in the middle to cause problems in thin traces. I guess with 3mm Al is less of a problem specially for light engraving. The floating head applies some pressure on the work pice which is nice and small scratches on PCB are hardly a problem.

JS
 

Gene Pink

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joaquins said:
Optically floating would be cool... floating on laser  ??? Maybe there is something, maybe it will be at some point.
Interesting idea. If a DC/DVD laser head can follow a warped disc in the Z axis to stay in focus, why not?

Gene
 

dirtyhanfri

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Hi

I've been engraving and cutting some aluminium yesterday, with much better results.

I've been lubricating with alcohol , and it helps A LOT, the engraving comes out much cleaner, even with bigger tips (0.4mm) I get decent results with 3mm. letters. Also for cutting or pocketing it makes much easier the process.

The advantage with this is the alcohol dissolves with the air, the only residue is that grey mush formed by aluminium and alcohol, easy to take out with compressed air.

Time to make some plumbing for a coolant system...
 

toffifee

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Jakob, CNC Graf is able to do this (Remember? We have chatted about this at "Musikmesse Frankfurt" two years ago... and three years ago...)  ;)

Check boenigk.eu ...

I am running two machines with it and love it. For a probe you can get Baumer My-Com switches on EBay relatively cheap - repeatability of 1y!! Really  :D

Cheers, Christoph (aka Toff)




gyraf said:
Could you explain? I'd very much like some kind of auto-levelling - when engraving I have to babysit the machine very closely as I'm depending on a 0,15mm +/-0.05mm depth for decent work (with a 0.3mm bit). And sadly the frontpanel aluminum plate material has bigger tolerances than this - across single panels..

Jakob E.
 
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