Blackhole 60W Laser

[iGull]

Hi

Thought I'd start a quick buildlog as my metalwork should arrive today.
System has a Coletech 60W laser along with their better quality optics etc. Laser and ancillaries arrived a few weeks ago - end jacket broken on the laser unfortunately, but another arrived within 5 days. I have to mention the excellent service I have received from Coletech - at all times the communication has been rapid and accurate ('Shirley' must be a great worker to have in the office ). I ordered my parts from China on the Wednesday afternoon - they were on my doorstep on the Friday afternoon - from China - and using DHL !!! That is outstanding service - I can hardly get that service from suppliers here in the UK.

My machine is similar to the 2x and the Lasersaur (among others) - 1220x610x200mm (48x24x7.8 inches) cutting area. It is floor standing with all the ancillary stuff underneath - air assist pump/cooler/electronics and extract. There's a 'pod' on the front which will contain an LCD and some control buttons eventually.
Rails are vee rails (RS) with Barts original acetal vee wheels - I'd have liked to use the new makerslide rails, but the shipping would be horrendous. It's conceivable that I might convert at a later stage as the bosch stuff is compatible.

Skins are set into the frame using magnets rather than outside with screws (the magnets are let into the dibond skins [similar to aluply]). The side skins are quickly removeable to allow access for long material. There's also a lower 'crumb tray' to catch all those parts that you forgot to add tags for

I'm using Bosch/Rexroth extrusions rather than misumi - I can get it all cut from KJN without having to buy stock 3 metre lengths and work out my own wasteage - all online ordering too.

One annoyance is having to use 6mm chain and sprockets for the Z axis lift - I just couldn't source a closed belt that was big enough. I'm sure it'll be fine (if a tad noisy )

I'm currently at a crossroads regarding the controller - I really want to be able to use it with the Mac (and definitely NOT using a PC emulation ) Current options are the LAOS board - I have one of the beta boards which I'm building - it's essentially a CUPS printer which converts to a form of gcode - acts like a normal printer interface - mBed controller onboard. Other option is the Lasersaur unit which is arduino based with a web based interface and importer - I lashed one up - it worked first time and has a VERY clean interface - currently uses svg format files as input - converts to gcode and thence to grbl on the arduino. How this will shape up to 'engraving' will remain to be seen (the arduino isn't that powerful), but the vector work is very clean and fast.
I don't want to go down the DSP OEM board route at present as they are all PC only (and will probably remain that way for some reason). I have a DeskCNC board (PC based ) which works REALLY well on my old CNC router and I have been reliably informed that there are Mac and Linux versions to appear. It has PWM laser output and can also handle 'engraving'.

I'll attach some rough renderings (definitely not up to the 'Bart Dring School of Industrial Design' standard LOL but they'll suffice for my needs )
They're also partially incomplete as I don't get too anal about small things like shaft coupers etc.

Cheers

Neil

PS Blackhole was chosen for a couple of obvious reasons, it creates blackholes and that's where all my funds have gone

[TLHarrell]

Very nice. I'll be keeping an eye on this one as I too would like to build a 24"x48" machine once I get my little 40W unit producing a stream of revenue (total income so far... $65). I've got an interesting idea for the table lift though. I intend to use Sarrus linkages in the table corners instead of rods or rails, and use a dual cam lift in the center of the table.

[iGull]

Should never have mentioned that the metalwork was to arrive today - obviously cursed - despite emails to the contrary, the stuff is not going to arrive now until Monday - a pox on them I say )
Maybe that'll give me time to do a dummy run on some cheap 6mm MDF before I run the semi-precious acetal sheet through my CNC router.

Forgot to mention that the table centre can be easily replaced with various tops - I'm looking for some cheap alternatives to honeycomb. My experiences with honeycomb section is that it gets 'dinged' very easily - a simple steel grid would probably be better (10mm?) - could then use magnet hold-downs if necessary.
I was looking at the Lasersaur site tonight and noticed they are using what looks to be drywall corner bead for a base - quite a practical idea if you can get a small enough section (20mm ?). However, checking the local cost of corner bead would put it in the same ballpark as aluminium honeycomb and firstborns.

I'm fortunate to have a lathe to turn the 8mm steel shafting down to 6.35mm to suit the bearings - 1/4", <rant> why do we still use these archaic imperial measurement systems ) </rant>

Cheers

Neil

[iGull]

While waiting on my test MDF parts being cut this morning, I've been searching through alternatives for honeycomb. One of the lasersaur machines in the US has been using aluminium eggcrate - used for lighting and ventilation in suspended ceilings. I've found a fairly local company that sells it 'up here' ...

http://www.clanma.co.uk/eggcratecore.php

Probably cheaper places too - haven't seen it on evilBayUK 'though. I'll make some enquiries on monday - looks like a good alternative - steel would be nice.
I've also seen it used in vertical cleanroom partitions for laminar flow.

[TLHarrell]

I've actually considered messing around with some metal slat blinds from IKEA. They're way cheap. I picked up a small one for like $5. Just haven't had the heart to chop it all up yet.

[iGull]

Finished cutting the test parts from MDF yesterday (took a while, my leadscrews are only 3mm pitch). Something I haven't really noticed before are the number of facets on circles/arcs etc in Sketchup - the default is 24 and it telegraphs into the finished cut of course. FWIW, you can change the default value easily - when you select say a circle, just type in the number of segments you want - I tried 48 and 72 - to be honest, 48 is fine enough for this sort of job. I use the phlatscript (or sketchUcam as it's called now) - produces gcode from the sketchup file - works extremely well - and good for me too as I use a Mac One of the nice features of sketchUcam is that it produces 'tabs' to keep the objects in situ while cutting. Only found a couple of minor errors in the cutfile, but worth doing just to check tolerances etc.

I'll overdraw the parts to up the facet count, but I don't think I'll bother recutting a test set. I found a new sheet of 6mm clear polycarbonate I forgot I had - maybe I'll make them clear rather than white

[naPS]

That aluminum egg crate looks very similar to the en-gravs product. You can find that here : http://www.cuttinggrid.com

[iGull]

Nice link, I like this part ...

Exclusive new powder coated surface reduces bounce back and makes clean-up even easier

It's probably powder coated anyway when they buy it (most likely it's lighting grid) - let's turn this into a feature

I'm not sure what plastic is in powder coating - maybe some chemists among us can help - and whether it has any 'nasties' in it?

Unsure about those "economical prices" 'though

I'll be actively looking for the powder coated stuff in the UK - I was keeping away from coated stuff because none of the big laser manufacturers seemed to use it on their machines - thanks for that.

[BenJackson]

The 1/2" honeycomb from honeycommcore is actually quite economical if someone wanted to resell it. An unexpanded 4x8' sheet is $80. You can easily saw that in thirds (down to 16" x 8') and with some effort you can split those into 16"x4' which you can expand by hand and still get two full tables (plus waste due to expanding by hand). So a $80 purchase yields 12 table surfaces, or about 6 resellable (unexpanded) units.

If I had it to do again (and I didn't have a lifetime supply of 1/2" cell table material!) I might try to get smaller cells just to have more even support, but I suspect it would be harder to expand and MUCH harder to trim.

[iGull]

Aluminium extrusion eventually arrived this evening - took two of us to lift it all into the workshop
Using Bosch Rexroth rather than Misumi - the supplied stuff looks pretty good and the cutting is certainly as good as I can do on my chopsaw with an aluminium cutting blade. KJN were substantially cheaper than the other suppliers and the stuff was cut, not raw lengths. I haven't checked the accuracy of their cutting yet - fingers crossed

I need to lash up a drilling jig for the extrusion as I am using mainly core screws rather than brackets. There are a few reasons for this, brackets get in the way of skins and stuff if you want a clear access to the frame. The brackets are also about 1.30 GBP each including fixings, whereas a core screw is only 0.29 GBP - quite a saving when you add up the sizeable number of connections needed. I guess that using brackets makes it a bit of an easier 'meccano' type construction 'though
It shouldn't take long to drill all the access holes using the jig (only about 500 ) - it'll have a distance gauge stick built in. I'm using a few 'corner cubes' - on the lid and the table - leaves a neat finish and allows full access to the corners. I'll post some pix of course when the construction gets underway.

I don't have the issue with having sufficient nuts set into the frame to attach the skins - the skins will be held in with cheap 8mm neodymium magnets - the magnets are let into the back of the skins (skins are 3mm) - the fixed magnets are held in a 6mm strip of MDF (I may use some acrylic sheet if I have some scrap lying about - I suppose I could cut it with the laser really ). The strips are then just dropped into the extrusion slots and held in place with a little flexible adhesive - the corners are clear as there are no brackets.

Something that no-one seems to have mentioned (at least I haven't seen it ?) is tapping of the extrusion ends - bosch rexroth have small 'wings' in the holes which means that you can't use a regular tap - the flutes get jammed in the wings - you need to use a 'spiral tap' where the flute is a spiral not unlike a twist drill - the thread remains the same of course. I'm assuming that the Misumi stuff is similar ?

One thing I couldn't find was a decent set of substantial feet for the system - the ones I got are just the regular 25mm diameter plastic 'buttons' and M6 metal thread that are supplied for 6mm slot extrusion.

Looking forward to getting some real building done now rather than virtual stuff on the computer !

Cheers

Neil