Blackhole 60W Laser

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Re: Blackhole 60W Laser

Postby Greolt » Mon Jan 16, 2012 9:23 pm

My understanding is that the head from CNCOLETEC has different length air assist nozzles for different focal length lens.

I bought mine with a 63mm focal length lens and had wondered if I should try to purchase a nozzle and lens holder for 50mm lens.

Then it would be a very quick change from one focal length to the other as required by the cutting or engraving job.

Greolt
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Re: Blackhole 60W Laser

Postby educa » Mon Jan 16, 2012 9:28 pm

Thanks Greot, but can I ask you (like I asked iGull) if I do need a moveable Z table of I only itend to cut/engrave on plate material with thickness < 10mm ?

I suppose if I could position my nozzle correctly and then mount the table fixed, then I will at least have about 10mm of playing distance with putting the nozzle up and down ? This could lead to a dramatically easier design for me since it would eliminate all the stuff to move z axis table.

but I'm not 100% sure if what I say here makes sense.
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Re: Blackhole 60W Laser

Postby iGull » Mon Jan 16, 2012 9:36 pm

There's no reason at all why you can't have a fixed bed if your material is going to be 10mm or less - either a 50 or 63.5mm lens will be fine - the mechanical adjustment for both lenses will still be 30mm. If the nozzle lengths are different between lens focal lengths then you'd just need to have two gauges (or a 'duogauge [tm]' :lol: ) as the focus position will be different from the end of the nozzle.
Certainly makes the machine much more rigid - not to mention cheaper :D

Cheers

Neil
EMOs are a sign of weakness ...
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Re: Blackhole 60W Laser

Postby educa » Mon Jan 16, 2012 9:48 pm

And if I don't use a moveable Z table, what distance should I then best leave open below my machine?

I could make the machine very with little height, but I suppose if I leave too little space below it, then the laser can reflect on the bottom and bounce back up ?
Or can I cover the ground of my machine with some kind of material which absorbs the light/energy somehow ?

If I can make the machine fixed height, then this would dramatically ease the way how I need to make it + reduce the height of the machine at all.


So any advice on how much space I oucht to leave on the bottom + what material I best place at the bottom ?

Kind regards,

Bart
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Re: Blackhole 60W Laser

Postby Greolt » Mon Jan 16, 2012 9:55 pm

Yes I am with Neil on this one.

A fixed table would be a big saving in complexity and size of the machine.

I mostly built a moving table so that I can fit a rotary axis under the laser head.

30 plus mm of adjustment in the head itself would cover many different material thickness.

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Re: Blackhole 60W Laser

Postby educa » Mon Jan 16, 2012 10:26 pm

Ok so now to be 100% sure, can you please tell me if what I say below is 100% correct?

Image


1) laser light enters the laser head at point A

2) At point B it bounces on the mirror and turns 90° downward

3) At point C it gets to the focussing lens where the light begins to colimate

4) At a distance of 50.8mm awat from the lens (I use a 50.8mm lens) there will be the focal distance and also the focal point to burn.

5) Point F is the tip of the nozzle and this tip lies between points C and D, where the focal point will always be the same distance away from this tip (downward)

6) If you use a gauge block then this block has the hight of the distance between F and D ?

7) So if I put a plate of for example 4 mm onto the table (which does not move) then all I actually have to do is put the gauge block on my plate , loosen screw E so the nozzle goes up and down. Position the laser head above my gauge block , lower the nozzle until it touches the gauge block and then tighten screw E again ? When I then remove the gauge block I will always have the correct focal distance (where focal point will be at the top of my material ?

8) Suppose I want to have focal point in middle of material (4mm thick material) , then I just use a gauge block which is 2mm less high ?



Is this all correct? If it is (which I hope) then this would be sooooo nice. I would not need moveable Z axis on the machine then.
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Re: Blackhole 60W Laser

Postby iGull » Tue Jan 17, 2012 7:22 am

Yes, that is all correct.

Useful graphic to have too.

Cheers

Neil
EMOs are a sign of weakness ...
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Re: Blackhole 60W Laser

Postby educa » Tue Jan 17, 2012 7:59 am

Here is another (also handy) image which I just received from cncoletech.

By the way, the laser head comes with a nozzle matching the focus lengt you ordered, but if you order another lens they send the extra (other version) of the nozzle with it to match

Image
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Re: Blackhole 60W Laser

Postby iGull » Sat Mar 24, 2012 8:13 pm

It's been a wee while since I did any updates on the buildlog, so I took a few pix today ...

P1010050.JPG
Electronics Drawer

P1010051.JPG
General View

P1010048.JPG
DSP LCD Mount


The main update recently has been the installation of the Lightobject 2012 DSP controller. I have been using the Lasersaur controller since I started the build, but I really needed to get this machine making some pocket money, so opted to purchase the DSP. I have to say, even though it's PC based (I'm all Mac really), the controller and LCD interface have been exceptionally good - it really runs well (ethernet and USB both). I'm having a few hiccups with the LaserCAD software (it's not Adobe Illustrator is it :-)) - the interface could really do with an overhaul and get up to the standard and features that other similar laser control software systems have (LaserWorks etc). They all look much the same, but there are definite differences in the operating quality.
I'm running LaserCAD using Virtualbox (free) on the Mac - it's running Windows XP in a solo window - works very well and integrates with the rest of the Mac OS without having a complete XP screen. I use Illustrator as the main graphics app, but have many different graphics and CAD apps on the Mac. Again, a few issues with importing, it doesn't like illustrator files, but the DXF output is a workaround that works - I believe there is an update to improve the illustrator importer (like I said, it falls behind other similar apps). Overall, I'm VERY pleased with it's operation - I can actually do raster engraving now - even producing a Mayan Calendar LOL.

I installed a SS relay to the exhaust fan today as the DSP can control that now - much nicer than having it on all the time (although it would be good to have it stay on for 20s or so after cutting to clear the last of the smoke before opening the door).

That's the laser cutter pretty much complete now - although I may install a refrigeration unit to keep the water at a constant for cutting/engraving consistency. I wonder if there is an open source refrigeration system ? I guess an air cooled system could be made to work in this country as it's never that hot in summer :D :D

Cheers

Neil
EMOs are a sign of weakness ...
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Re: Blackhole 60W Laser

Postby daveczrn » Sun Mar 25, 2012 2:57 am

i really like how the extruded aluminum shows with the covers, looks really unique.

As far as a cooler goes to cool the water. I took apart a mini refrigerator once that was designed for a car. had a cigarette lighter adapter plug on it. It had a Peltier cooler in it. Basically it had a heat sink on one side with a fan blowing on it and the other side mounted to the base of the mini fridge. the fridge side got really cold, and the other side with the heat sink got really hot. i think it would work exceptionally well at cooling off the water. only issue with it was it was very inefficient and kinda power hungry.
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