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Messages - Stonemull

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1
Projects / Re: PCB solder mask
« on: February 27, 2018, 03:58:09 AM »
I finally got around to assembling the board from a few days ago and this mask stuff is sooo unforgiving!
It needs a far more thorough stripping than I gave or the 'clean' copper is basically unsolderable. It looked clean but it must have had microscopic film or blobs of resist and about the only thing that helped was scratching away with a stanley knife.
That means the resist has to be exposed well to allow a good cleanup, something that will be impossible with the 2 wavelengths I have tried so far.
Maybe it would be possible if the laser had no side flare, as it is off when travelling over the areas to be unexposed, however it still partly exposes, enough to be the major issue. So it must just be speckle off the lens surface .. perhaps dropping the lens down really low ? I need a point source .. might be worth finding a more precision lens.
The other thing that might help is just using a much thinner layer of mask, clutching at straws here :(

2
Projects / Re: PCB solder mask
« on: February 24, 2018, 06:19:07 PM »
I have tried kapton to use as a solder paste stencil and the 2.5W does cut it, it had some issues that I can't remember off hand, being orange it absorbs the energy just fine. I think I needed to do more research, are nuked polyamide fumes dangerous ?
I was doing it in situ though on the pcb and the power needed burnt the fibreglass too, I then found that black insulation tape gave better performance with cleaner edges .. apart from being vinyl with nasty fumes.
I might revisit it with a mask in mind.
The main issue is that masks are larger than the pads, stencils are same size or smaller, so you often end up with only a few microns of material between pads on the mask with smaller pitch devices.
I will update after more researching..


3
Projects / Re: PCB solder mask
« on: February 24, 2018, 07:14:13 AM »
Solder mask, would help with 0.5mm pitch components.
Etched a board last night and spent the last few hours trying to get it right, no luck so far.
Mainly due to lining up the mask with the pcb on the laser, you have to add some lines on the mask layer at 0,0 and the diagonal corner to assist in alignment as T2 will trim the gerber to the pad extents if you dont, the 0,0 is no longer where you expect it to be.
Despite the misalignment I still let it expose and "developed" it, I got it partially right only once.
I think the issue is that the laser is on most of time and scattering from the lens is enough to partially set the resist.
My first attempts were at 0.05mm resolution, at 6000 mm/min the resist falls off, at 5000 mm/min .. none of it comes off unless you use acetone, then it all comes off.
Dropped to 0.1mm resolution to reduce the time spent over the board, still nogo, photo shows the best i managed it so far, simply not enough setting of the UV resist, I think I need a different wavelength, all I can find so far is it should be 350-400nm.
UV sunlamp set the resist hard in a few minutes though, I may have to use a film technique which I do not want to do or I might as well use it for the whole method.

Only a protype design so I did not really want resist on this one as it will have wires tacked all over it, also big pitch an no need for it, but good to experiment on, now I am depressed :(


4
Projects / Re: PCB solder mask
« on: February 23, 2018, 07:14:07 AM »
will zap it with extra UV afterwards, either leave it in the sun or hit it with my mercury lamp. just been wiping it off and trying again so far, I did have to use a paint scraper at one point, even steel wool wasnt getting it off.
The laser is not fully hardening it, however the pads were not clearing if I zap it more.
It says to use petroleum or petroleum based solvent to use to wipe it off, hence trying isopropyl, dry cleaning fluid and acetone so far..
Some people use thinners.
Still experimenting a bit. its only a little over $2 delivered for a tube of this stuff so worth an effort.


5
Projects / PCB solder mask
« on: February 23, 2018, 02:33:02 AM »
UV curable solder mask, dab a little on the pcb, squish with transparent film and smooth out with a bearing. Use T2, import solder mask gerber and then invert, need a negative.
Tried a few exposures using my plotter with the 405nm 50mW laser and the 2.5W laser.
Speeds down to 1000mm/min and power 100 on the higher powered laser, no curing occured.
On the 405nm at full power, 5000mm/min left me darker patches over the pads (where there shoukd be no mask) however even acetone would not remove resist, increased to 10000mm/min and had first success, excess removed with isopropyl alcohol, acetone still too violent and removed exposed material easily.
So somewhere between 5000-10000 mm/min at 50mW 405nm will be the magic spot.
Will toughen it up with further exposure to UV later.


6
Grbl Controller / Headless GRBL
« on: February 14, 2018, 07:31:31 PM »
Still have my CNC plasma cutter concept in the thinking machine but getting the hardware together.
Recently made a battery pack adapter to drive it with https://www.thingiverse.com/thing:2770920
Reason being is plasma cutters etc are pretty awful on the noise front, also requires my fairly large air compressor to cycle and between the 2 it iften blows the breaker to the shed, so decided I want the controller headless (no PC) and battery operated, if I stick a SD card on it, need a way to select files and home the machine etc, so a display and sone sort of input device is required.
I now have a PC just for going in the shed and wired the shed up with the house ethernet, its an old touch screen HP, I added a dual boot to it as I thought running LinuxCNC might be a future option, since decided to go headless on the plasma though. The PC is now setup with Eclipse and I have it compiling grbl for the Ramps 1.4 though, so good for dev work currently.
Today the rest if the hardware arrived, everything I should need.
Hoping someone has already done the hard work but not found anything driving these graphic displays with grbl yet.
Anyway, still alive and doing stuff o/



7
Mini CNC / Re: Sieg ?
« on: January 16, 2018, 09:57:50 AM »
I will pull it down soonish, it seems pretty well setup atm though and I wanted to get some data first so if I reassemble and its not as good, I know I can make it betterer if you know what I mean  :)
Will probably wait till I have a dial indicator to start with, really need some gauge blocks, surface plate, scrapers and prussian blue to really tune one.
Used some luggage scales to roughly check torque on the X and Y axii just tugging on the handle, around 600g on the X and up to 2kg Y, handle is about 35mm from axle so I reckon even a nema 17 could spin it geared down 5:1 or something. Plan is to get some nema 23's ultimately.
I have some 150mm loop belts and 16T pulleys and a couple of larger ones, 64T?, thought I might have a muck around with nema 17's first.

8
Mini CNC / Re: Sieg ?
« on: January 16, 2018, 02:08:11 AM »
Yay, it arrived .. only have limited tooling currently, my largest end mill is 6mm, plus the mill only comes with 2 T-nuts and no bolts to screw into them, so I bolted my drill press vice to the thing and got my feet wet on a piece of aluminium I melted into a muffin tray some time back.
Will be looking at automating it soonish, will need some experiments. It seems backlash on the X and Y slides are not as bad as I expected,  will be ordering a bunch of new stuff I guess, dial indicators, clamps etc etc..

Just checked basic backlash by lightly clamping my digital verniers in the vice, X is an astounding 0.01mm and Y a fair bit worse at 0.14mm.
Not bad straight from the crate though, now going to read the manual..


9
3D Printer Software / Re: 3D Printer Slicers
« on: January 08, 2018, 01:37:50 AM »
no love for skeinforge ?

:)


10
Mini CNC / Re: Sieg ?
« on: December 20, 2017, 08:07:38 PM »
Bought the Sieg

11
Mini CNC / Re: Sieg ?
« on: December 20, 2017, 07:16:40 PM »
I got the email on that too, that is actually what started me hunting for parts, free shipping within the US, with motors this is still more expensive without delivery than the Sieg X2. That is what got me thinking .. ok it can do thin aluminium, slowly .. I would rather have one that can do steel if required. I could then use it to make brackets and stuff and make me own little mill :)


12
Mini CNC / Re: EleksMaker 555 Spindle Motor
« on: December 20, 2017, 06:31:49 PM »
It doesnt look like there is any switching on the motor pcb, just spike suppression caps, I would say connecting 12v to the barrel connector on the motor will run it flat out and the 2 wire connector will be connected in parallel with it. So if you have a control board with a decent mosfet on it then just use the motor output on the board and forget about the barrel connector.



13
Mini CNC / Sieg ?
« on: December 20, 2017, 08:43:15 AM »
I was pricing bits to make an aluminium capable mill, still no idea, tossing up c-beam, sbr16, sbr20 etc etc.. looking like not much going to happen under $1000 in reality .. bits add up.

Then I saw these on ebay https://www.ebay.com.au/itm/Sieg-X2-Variable-Speed-Dovetail-Milling-Drilling-Machine-Mill-Drill/391945151546?hash=item5b41c0643a:g:rckAAOxyVaBStM0B

These sieg machines are rebranded as lots of others, including harbor freight, so now I am wondering how hard it would be to add some nema23's to something like this instead, might need gearing down but so what, pretty easy to come up with something I reckon.
One thing that has me wondering .. backlash, I see the fine Z axis winder on the front has half a turn of backlash before it engages the coarse spindle.

couple of example videos in action https://www.youtube.com/watch?v=II_1xK_6m34

and oh .. here is one converted to CNC .. https://www.youtube.com/watch?v=Ve43EJHYGNo

and one doing 1/4 steel plate with CNC https://www.youtube.com/watch?v=VHw0cG5EzG8

comment by uploader
Quote
Exactly, I have not using a chuck, just a end mill holder made by my self, you know, to convert the X2 machine is very easy and not so expensive, have good kits on market like little machine shop.

ok, looking for sieg x2 cnc turns up like this kit http://www.cncfusion.com/minimill1.html
which is nearly as exxy as the mill and includes new ballscrews .. but not the motors or mounts, damn. I still wonder if its doable without exxy added bits.

found a thread with a dude doing a conversion https://forum.ausrocketry.com//viewtopic.php?t=4002

So .. what ya reckon.
Can you see disadvantages of going this route ?


edit: forgot to mention this guy too .. https://www.ebay.com.au/itm/Sieg-M1-Vari-Spd-Multi-Function-Metal-Lathe-Milling-Drilling-Mill-Drill-Machine/382310729057?hash=item59037ec561:m:mz2H6T9xW4O7N3dZ2DdK0ww

combo lathe mill, dunno, might do neither well ..







14
T2 Engraving / Re: Thanks Zax
« on: December 20, 2017, 05:27:41 AM »
Good luck. It takes some practice but with some patience, you will be putting us all to shame.

except for that one guy with the PhD in burningology.

15
Projects / Re: JTICE - My Engravings
« on: December 18, 2017, 09:33:49 PM »
dude, I think you might be the first PhD in laser engraving.

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