Finally... The Perfect Etch... 8)

[Mechatrommer]

anyone into waving dick contest?

[Jay_Diddy_B]

It looks very good. It looks you have a resolution of '1/2 a bee's dick'.

Are you going to share how you did this board?

Regards,

Jay_Diddy_B

[Psi]

Im sorry

[Mechatrommer]

Are you going to share how you did this board?

i followed the path of this guy...


i'm making pcb for my psu project. i bought another new laser printer just for that. still it failed miserably like my previous printer due to not enough solidity at large copper pour area. this will result in bee or ant nest holes everywhere if you know what i mean, worst if it happens in tracks or circuit sensitive area. so i ditched out my new laser printer idea and build my own pcb printer for the past few weeks. i can see a promise to this new "3d or cnc printing" idea. i'm using environment friendly blue etchant anyway, not ferric chloride method.

searching... there are new invention breeds of pcb engraving/printing machine (like below), but those are in $2K range average, and their demo at most doing DIP or large traces packages or some useless tree embleemed watch with led blinking and probably a 555 chip inside, not so impressive for $2K price. i'm thinking of at least soic package and lots of traces, board up to 20cm x 20cm size and machine cost somewhere $500 or less than $1K, my 1st prototype very crude made out of wood woobling everywhere machine show some promises, i believe i can refine further. the smallest tracks in the OP is 0.5mm. i had one failed board, that shown is the 2nd board after making 2 prints, not really a challenge and its already show some promise after tinkering with some few print parameters, i'm aiming at etching 0.25mm traces consistent or even lesser, well i will experiment further after my psu project i believe. there are more other non ee projects to come next week so i will not 100% pace on EE, sadly...


https://www.kickstarter.com/projects/voltera/voltera-your-circuit-board-prototyping-machine
etc

Im sorry

good sharp eye. i know i can rectify that. i've eye louped any problematic area and make some ink resist rectification, like in the attached image, it was a broken track i dab a litlle ink resist and etch out isolation part. your snapshot is not really a problem in term of connectivity when i drill and solder the part's lead in later. my main objective is to get a solid copper pour / ground plane without bee nest's holes everywhere, which cheap laser printer toner transfer method failed to do... i know there are some example of success of toner transfer but meh photo resist and ironing/hot laminate can be too tedious for me... i'm tired of all that and what i get is bee nest on the ground plane and traces, just because of laser printer failure/limitation.

[KL27x]

Nice.  I imagine you can get top/bottom registration quite close without much fuss!

I never found a marker that worked nearly that well with ferric or chloric. Maybe it's your pen, maybe it's your ammonium persulfate etchant... but that looks quite nice.

anyone into waving dick contest?

I've posted some toner transfer boards, before. I have not any problem with ground planes. But edges of traces are not as clean as what you have there. Partly that is due to etchant. Persulfate is more accurate than any of the acid etchants. I wonder if you ever tried Pulsar transfer paper. It's hard to not get perfect results. I did 300 square inches of board last week. All perfect. Registering top and bottom is a pain, though.

[Mechatrommer]

Nice.  I imagine you can get top/bottom registration quite close without much fuss!

i dont think its a problem for both toner transfer and that printing method, few sub mm of misalignment is ok for me as long as traces are not shorting out to another net. i just drill two holes on pcb as reference, and the matching holes on both transfer papers and align them with pins, iron the top part and it will stick there, redo again on bottom layer, done.. i used hand cloth iron anyway, not hot laminate. my hot laminate are stacked under many items in the store, and transfer paper usually slide a little bit when entering laminate machine, so its a problem for double sided pcb, not good, i prefer hand iron, easier to align and stick put.

I wonder if you ever tried Pulsar transfer paper.

never that i know of... last time i bought china paper, and now i used back of photo cold lamination. 100% toner transferred, its better than china's paper. looking toner on the paper was ok, but when transferred to pcb, its a total dissapointment. you can see through the toner the copper below. no i wont risk another copper board again with that, enough is enough. i erased it with thinner and replace it with permanent marker ink and print away.. sorry i dont quite get your other comments.

[Kean]

If you're going to use a CNC to remove the marker/resist, why not just mill the copper with a V cutter, and drill accurate holes at the same time. 
Here is an example 2 layer board I did recently for a 0.8mm pitch QFN GPS module, with a 1mm pitch connector at the left, and chip antenna at right.
Worked really well for a prototype.

BTW, with laser toner transfer the Pulsar FX transfer paper plus TRF foil does work really well, but I still prefer using my CNC.

[Mechatrommer]

If you're going to use a CNC to remove the marker/resist, why not just mill the copper with a V cutter, and drill accurate holes at the same time. 

i will have problem with bed/platform levelling as what i built is cheap machine, putting in bed levelling mechanism will complicate things and took much longer to build. i use spring loaded tip, like the guy above, so bed unlevel is taken cared of.

Here is an example 2 layer board I did recently for a 0.8mm pitch QFN GPS module, with a 1mm pitch connector at the left, and chip antenna at right.
Worked really well for a prototype.

that using CNC? thats nice, care to tell what CNC machine? diy build or bought CBU?

and those via stitches are really nice i always dream of that, i havent found a place to buy those, maybe wrong name. where did you get those?
edit: ok i got it, the name is pcb rivet/Grommets thanks..

[Kean]

And a pic of the assembled board.
A bit messy with the ground plane rivet soldering and without solder mask, but it was really just to confirm the footprint and interfacing before doing a production PCB.

[Kean]

will have problem with bed/platform levelling as what i built is cheap machine, putting in bed levelling mechanism will complicate things and took much longer to build. i use spring loaded tip, like the guy above, so bed unlevel is taken cared of.

I place a piece of thick plastic on the bed, and then run a 1/4" milling cutter over that to get it level.  I then use very thin double sided tape to hold the PCB down as flat as possible.
I mill the two sides separately on 0.8mm thick PCB, and because they are CNC'd they align almost perfectly.

that using CNC? thats nice, care to tell what CNC machine? diy build or bought CBU?

Thanks!.  It is a "6040" CNC from China that I've done a few upgrades on.
It is probably the 8th CNC I've set up, but most were for friends. 

ok i got it, the name is pcb rivet thanks..

Yes, I use ones from LPKF (EasyContac).  They're 0.6 & 0.8mm, and go into 0.85 & 1.05mm holes.  They punch down really flat.
They're a bit expensive, but I only use them on the occasional prototype.  Otherwise just a bit of fine wire soldered on both sides.  I can do 0.35mm vias that way, but not under a device.

[Kean]

Now that I think about it, I did have a short circuit on that board due to the rivets.  I didn't make the via pads big enough, and there wasn't quite enough clearance on a couple once they were punched down.  Fixed pretty quickly with a sharp knife, but annoying at the time.

[Mechatrommer]

and what i built is incapable of doing a serious engrave since very minimal metal involved. a steady engraver needs beefier metal and iron and hence = $, i will see if i can make improvement on that in later revision. but engraving is in my last list since a real cnc/engraver its very remote relevance with ee pcb making, more toward mechanical. i've ordered 1W laser cutter head, which i hope of making stencil. lets see if that can engrave copper out too.

[Kean]

Here is a photo of another one I did a month or so ago to check a quick design before ordering the PCBs.
This has smaller components include 0402's, but still could supply 6A output.
Tweeted about it: https://twitter.com/KeanM/status/768673907717001216

[Kean]

and what i built is incapable of doing a serious engrave since very minimal metal involved. a steady engraver needs beefier metal and iron and hence = $, i will see if i can make improvement on that in later revision. but engraving is in my last list since a real cnc/engraver its very remote relevance with ee pcb making, more toward mechanical. i've ordered 1W laser cutter head, which i hope of making stencil. lets see if that can engrave copper out too.

Not really, except maybe for the cutting out the mechanical outline and levelling the bed.
You are only engraving a very shallow V cut, so you just need a very fast (10,000+ RPM) spindle.
I've thought about adding a small laser diode head to the CNC, but anything less than 40W isn't that useful, and you need a lot more than that for metal.
I quite enjoy the mechanical in addition to the electronics.  A nice diversion from software as well 

[KL27x]

ry i dont quite get your other comments.

Regarding your etchant. Ammonium persulfate has the least amount of undercutting of any popular etchant. I don't know what the units mean, but persulfate is like 1:7 IIRC. Whereas ferric is only like 1:4. And acid copper has like 1:3.  Something like that, anyhow. Muriatic and peroxide is particularly horrible. The more undercutting, the more ragged the edges of the traces. This is more noticeable on a thicker pour.

Also regarding permanent marker. I have tried many of them. I have tried on scrubbed degreased boards. Pre etched board. I have tried baking the board before etch. I have got very poor results no matter what I tried. I suspect they get eaten away by the acid. And that your persulfate basic solution is one key to why your boards are so great! Anyhow, that's why I use pulsar paper. Perfect transfer every time.... hundreds of boards. I can't trust permanent marker to fix even small defects with my etchant.

[Whales]

Using a 3D printer is a very interesting method.  I use toner transfer and my copper fill areas always end up pitted (probably due to toner thickness):



There is only one punishment I can give that is strong enough to offset my jealousy.  Keyboard criticism!

Why do you even bother?  PCB services are so cheap nowadays you are wasting your time by making your own.  Making your own PCBs is stupid, it's holding you back.  Think of all the new people on this forum you are misleading into doing the wrong thing.  Now you're getting them to play with chemicals too?

I recently found out that it's easy to etch veroboards too, which can have its uses.  Simple electrical tape is perfect as an etch-resist.  I might try 'taping out' some circuits on plain copper boards some time too, see how it goes.

[Mechatrommer]

Also regarding permanent marker. I have tried many of them. I have tried on scrubbed degreased boards. Pre etched board. I have tried baking the board before etch. I have got very poor results no matter what I tried. I suspect they get eaten away by the acid. And that your persulfate basic solution is one key to why your boards are so great!

i'm not sure whats the chemical i'm using, its from China, whitish salt like, becoming blue when etching. manual is in chinese i cannot read. but i think it is what you say... all i know is my result is worse if its laser printer toner transfer compared to this latest 3d/cnc printer method, same chemicals, same chemicals.

I use toner transfer and my copper fill areas always end up pitted (probably due to toner thickness):

this is exactly what i'm talking about as "bee nest holes". most of the times my result is worse than your picture.

Why do you even bother?  PCB services are so cheap nowadays you are wasting your time by making your own. Making your own PCBs is stupid, it's holding you back.  Think of all the new people on this forum you are misleading into doing the wrong thing.  Now you're getting them to play with chemicals too?

on the contrary its the other way around in my situation, imho... last time i made order from itead, about $30 cost, 2-3 weeks wait time on manufacturing and delivery. 10 boards 100 x 50mm maxed each. my board was small i need to panelize 5 of them in one board to utilize all the cost. i decided to not do the diy prototype board first because i thought the idea was right and i dont have a working laser printer around to diy. when the board came, assembled and tested, i figured out the idea was wrong, so now i have useless ~50 boards subjected to premature obsoletion all of this for $30 down the drain.

that was before i bought the new laser printer for another $60 few weeks ago. my previous laser printer's drum has become unacceptable with ink scorching and all after just few times of use but years of just sitting on the desk. hopeless. and i thought my latest printer with latest tech can print much thicker toner, i was wrong, again its hopeless! so i looked for another way in google luckily i found that guy and with the OSHW 3d/cnc firmware, 3d/cnc printer can now be made by homebrewer easier than before.

to sum it... Why do you even bother?  PCB services are so cheap nowadays? no, they are not yet cheap, both in term of cost and time. you need to pay shipping, you need to wait weeks for it to arrive, you dont expect to order just a single proto board for under than $5 shipped, and you have to obey their rules esp board size limitation and quantity.

here is another 2 boards i etched this morning. later i will drill holes with the same machine who etched the ink-resist layer on it. another 1 board to etch, all 4 boards in my psu one-off project. each different design, not multiple of the same design. 3 boards 100 x 130mm size, 1 is 200 x 85 mm. try that with online pcb manufaturer how much is cost? i guesstimate all my boards incl etchant will be around less than $10 of cost. maybe 1 or 2 days lead time if i want to. but now other than other stuffs i'm doing for my family life, i'm also populating the 1st board in the OP after i got it drilled (last attached pic). so it took time the whole process, but no, not weeks just to wait for the delivery. and another point on why diy? you will get a lot of things to learn and skills to develop, perharps that you can put in your resume and raise higher than others. fwiw.

[KL27x]

becoming blue when etching

Yes, this is a basic etchant. Most likely persulfate.

Sound like you are set. But for anyone else that suffer holes, I suggest pulsar. Heck, I don't even know why I bother cutting up the sheets to save money. Considering the time/work involved, the stuff might as well be free. But as is, what I do is precut the whole 10 sheet pack into 4.25" x 3.4" squares. Then I print 4x3" square onto a stack of 60 sheets printer paper. Then tape the pieces on with paper tape. Stick in my dedicated pcb printing laster printer. And I'm set for months. HP 1102w, FWIW. I think it cost around $100.00.

Also, I find it vital to pre-etch the board. This greatly increases the adhesion and reduces fattening/waviness of traces. No holes, I promise.

I initially purchased some of the foil second step, but I found it to be completely redundant, at least with my toner and cupric etchant.

[Harvs]

that using CNC? thats nice, care to tell what CNC machine? diy build or bought CBU?

Thanks!.  It is a "6040" CNC from China that I've done a few upgrades on.
It is probably the 8th CNC I've set up, but most were for friends. 

Can you tell me what bits you're using?  I've just recently got a 6040 and interested in giving it a try...

Thanks

[Kean]

Can you tell me what bits you're using?  I've just recently got a 6040 and interested in giving it a try...

Bits as in "tooling", or bits as in "bits & pieces"?
I'll asume the latter, but any more detail needed just ask.

On my primary 6040:
- ripped out all the cheap cabling and replaced it with shielded cables
- put the Chinese stepper drivers aside and replaced with a Gecko G540
- got a USB smoothstepper, but currently still using Mach3 (or grbl) via parallel port
- threw away the awful spindle controller & brushed spindle, and replaced it with a brushless one [1]
- added a pair of Meanwell 350W 48V PSUs
- added a decent E-stop button that is easy to access
- made clamping bars using 1" square steel tube, 6mm threaded rod, & wing nuts
- got some proper T nuts (M6 ones for a Sieg mill)
- plastic (HIPS 10mm) sacrificial bed that covers the useable work area, and milled flat as needed
- added some limit switches, but they're not currently wired
- two different pendants - a Modbus one with MPG [2] (unused) and a brilliant but simple USB one [3]
- purchased a huge variety of PCB drills and small milling cutters over the last 10 years
- vacuum cleaner - quite critical!  I use a small Ryobi one
- also had several attempts at a spindle dust collector, but not found a good compromise for my usage

In reality, it is all about what you want to do with it.
I mill lots of plastic and Aluminium parts for front panels, prototype mechancial parts, small production runs of parts for scientific instruments, plus the odd PCB and test jig.

[1] This is the brushless spindle I'm using:  www.ebay.com.au/itm/121581247413
It is a little gutless, but at least it doesn't keep blowing fuses, wearing out brushes, and generally trying to electrocute me.
Every now and again the new one will slow down for a second and then restart.  I suspect a compatibility or configuraion problem with the G540 PWM output.
If it does that at just the wrong time it can break a tool  so I really need to put a scope on the PWM and enable signals and find the culprit.

[2] www.homanndesigns.com/index.php?main_page=product_info&cPath=54_15&products_id=74

[3] https://www.kickstarter.com/projects/1651082654/jog-it-open-source-controller-pendant-for-emc2-and

[T3sl4co1l]

 

This is the best one I ever made.  Haven't made any for /years/, because screw that. 

http://seventransistorlabs.com/ClassD1/

Etch was okay (20/20 rules, toner transfer with marker over the top), but registration was perfect, within 5 thou across the board I think.

Tim

[Harvs]

Can you tell me what bits you're using?  I've just recently got a 6040 and interested in giving it a try...

Bits as in "tooling", or bits as in "bits & pieces"?
I'll asume the latter, but any more detail needed just ask.

I was actually asking about the former, but some good info in there, thanks for that.

But can I ask what size cutter that is?  Or any recommendations?

I largely bought my machine to modify off the shelf enclosures, but having a go at milling a PCB could be interesting.

[Kean]

But can I ask what size cutter that is?  Or any recommendations?

I use a "45 degree spade mill" to do the copper "etching" on the mill.  I bought a bunch of these many years ago from a guy in the USA who ground them himself (drewtronics).  He doesn't seem to be around any more, probably because of all the cheap "V engraving" bits you can get from China.  Although you can get really sharp ones, like 10 degrees, after trying those I'd recommend sticking to a wider angle.

Just search ebay for keywords like "degree engraving carbide" - these are similar to what I use http://www.ebay.com.au/itm/201672655025
The "0.2mm" in the title is an indication of the minimum engraving width, but obviously it will get wider depending on how deep you cut.  So you need to be quite careful about having a flat PCB and sacrificial surface, and with your Z height zero adjustment.  The narrower angle engravers can help here, but are likely to leave stringy little islands of copper between cuts, requiring more manual clean-up or having to do numerous cut passes.

For other 1/8" shaft PCB drills and milling cutters, here are my two favourite suppliers:
http://drillbitsunlimited.com/
http://drillcity.stores.yahoo.net/

They have large selections of drill bits (new and resharpened) plus small milling cutters.  All the ones I've bought have been excellent quality, and much better than those I bought from China, although I do buy larger milling cutters from China (e.g. >2mm for Acrylic or Aluminium).  If you're still new to using the CNC, you'll probably break quite a few tools, especially the really small ones.  The V engravers last a long time, so I prefer them over the tiny milling cutters.  The 1.27mm or 1.6mm milling cutters are great for PCB routing.

Also you can get "stop rings" you can put on the shafts.  Then you can have all your drill and mills/engraver bits set with the same fixed height, making for quick manual tool changes which is really important for PCBs which could have several different hole sizes.

I also use a 1/4" end mill for surfacing the sacrificial bed.  So I only need two collets for the spindle, 1/8" and 1/4".