pcb drilling

[John Lyons]

Martin
I understand what you are saying but I don't think the etchant has much to do with the traces lifting.
The etchant can't get under the board unless it's water soluble and I don't think any are.
Water soluble meaning porous enough for liquids to penetrate. I use Hcl/H202 by the way.
The only down side is that sharpie isn't enough of a fix for toner flakes and touch ups. I use enamel model paint and a tooth pick nowdays.
Usually I can etch a single board in 5 minutes or less with a fresh batch of etchant. I have been reusing it now and it takes 20 minutes or so depending on the copper thickness I'm using.

My experience with dull HSS bits is that they leave a burr around the drilled hole and a rough edge on the not copper side as well as the copper side. With the 1/8" shank carbide bits I use from "drill bit city" I get no burr around the copper, the bit does not skate around or drift at all and the holes are clean and show no sign of white rough edges in the board material. I drill very fast paced, faster than I should and still retain nice holes. I get several hundered or more holes from each bit, not that I count, but it's been a a good month and a half on the same bit and I etch a lot of boards with an el cheapo Delta $99 10" drill press.
I would never think that a bit would make much difference but when I started using carbide bits with the thick shank it REALLY made the difference.

John

[jrem]

yeah, I think the trace lifting is due to the hss bits pushing the copper out of the way.

I picked up a Dremel drill press today (but kept the receipt!), and am going to give it  a whirl.  If I have to buy a jewelers drill press then so be it, although I don't know what one is.

Thanks for all the advice, although I don't listen to art garfunkel any more.  Jeesh, talk about the second best job in rock and roll (behind john oats) . . .

[frank_p]

As said before, I have trace lifting when using acetone for too long, so Soulsonic, you confirm my results.  As for muriatic/peroxyde solution it's the one that I've ever used so I can't compare for now with ferric chloride per ex.  I bought some however, so I might try it, and see if I note a difference.  As for drill bits, carbide is better, but not not necessary for paper/thermosed clad.  If you are putting out quantities of board, and longevity before resharpening, is a cost issue, you can go for diamond bits.   That is what they do in the wood industry !  But I guess it's a solution if you are a robot that work very fast !!!  For my HSS bits, it's just that I've saw too many carbide tools (in machining at work) and I like to support my local supply store where I can take a walk to.  So for me, trace lifting is acetone + bits that I've not sharpened for too long (for now).  Note that with HSS you can be sharper than with carbide (having less burrs/tears), but you get dull much faster.

[R.G.]

Note that with HSS you can be sharper than with carbide (having less burrs/tears), but you get dull much faster.

N.B. The theoretical edge radius with HSS is indeed smaller than with carbide. However the glass fiber in the fiber-glass boards is extremely abrasive to steel (the glass is harder, as hardened HSS will not scratch it). They are much less abrasive to the harder carbide particles in solid carbide bits, so the carbide lasts much longer.

Expect a working life of 50-100 holes of PCB size in 0.062" glass-epoxy before getting a new HSS bit if you want good holes.

[GREEN FUZ]

I`ve got to say, I can`t see where the length of time the PCB is immersed in the etchant has any bearing on the quality of the traces.

As a point of interest, particularly for those on a budget, this is what I`ve been using to bore holes, with great success.


For the occasional PCB it`s ideal.

[frank_p]

Yes, sure, carbide for fiberglass.  But I don't use fiberglass clad board when drilling holes.  Maybe I should try soon.

I wan't to stay away from PBC for now, I need a more easy way to probe.  I have an impression of learning nothing when doing PCBs.
Do anybody have a hint on this:
http://www.diystompboxes.com/smfforum/index.php?topic=66513.msg528597#msg528597
Sorry for plugging myself. 
But I find it hard to study with a PCB. 

[merc]

A Dremel drill press? That's a good idea! Much cheaper than a regular drill press.  Maybe I should try that.

How did it turn out?

[Morocotopo]

I use this (awful cell phone picture):

Around here it´s called a "berbiquí". Don´t ask for an english translation... I think it´s the same thing as what GREEN FUZZ shows. It´s basically a mini hand drill. You position the bit in the hole, then push down the little collar below the top with two fingers while holding the top with another finger. The axle has a thread and a spring around it, so when you push down the collar it makes the "head" (I think you english speaking people call it the chuck) spin, so you get a hole! Bought at a jeweller´s supply house. I use it with 0,7 to 1 mm bits, bought there also. Requires steady pulse and good lightning, what I do is put the PCB over a stack of newspapers as a "kitchen table protector", and also won´t break the bits if you bend it a little from vertical. Slow. Very slow. You need patience. Also, I don´t use fiberglass, might be harder than what I use (pertinax). I never, repeat, never broke a bit, since I started to make/drill PCB´s. Maybe because rotation speed is looow (5 RPS(econd) perhaps?  I´m not a fast guy:P)
Oh, and I never had a lifted trace...

Morocotopo

EDIT: it requires good LIGHTING, not good LIGHTNING...

[jrem]

A Dremel drill press? That's a good idea! Much cheaper than a regular drill press.  Maybe I should try that.

How did it turn out?

dunno yet.  Need to get some carbide drills.  First look at it,  though, and I can see what some others are stating about it, it might be a bit loose, i.e., I can see the drill being a bit wobble-y.  I would think though if one takes time to drill it might work out, though.  Like I said, I kept the receipt, so if it doesn't work out I'll get my $40 back from Lowe's.

[juse]

Etching could have a part to play if the traces get under-etched. This is when the etchant eats underneath the edges of the traces and is not usually visible to the naked eye. It looks kinda like a fulcrum when viewed in a cross-section, like a triangle. This could be caused by being in the etch too long, not cleaning it soon enough after being etched or by not cleaning the board properly or quick enough.



Also, I have never had problems cleaning boards with acetone. I rinse them good with running water after etching then clean the gunk off with the acetone.

[culturejam]

A Dremel drill press? That's a good idea! Much cheaper than a regular drill press.  Maybe I should try that.

How did it turn out?

I've been using one for a couple of months, and it works just fine for me. Note that if you get the tiny bits that Smallbear sells, you'll need to get the super-small collet for the Dremel (your local big-box hardware store should have these in stock). Or get the adjustable chuck instead. Or get bits that have the 1/8" shaft.

[jrem]

ok, got the dremel drill press set up and running, I bought an engraving bit (hss) to use until the carbide drills show up.  Pics are at http://www.jrem.com/080406

works good.  the board with the solder on it is the one I complained about (etch then drill), the ones without solder are big muff boards I made a while ago that were etched but never drilled.

[slymonkey]

I have been using a cheap rotary tool from Harbor Freight Tools for a while now.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94076
I have done about 30 boards with it.  I put a small piece of particle board under it and work at the kitchen counter.  My wife loves the noise.  haha!
I have to be very careful not to slip but I haven't ruined a board yet.  It's just a hobby for me so I probably won't upgrade for a while.
The micro bits are cheap also. Here is a link to some bits, though I found smaller, cheaper kits by going to the actual store.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=34640

Would love to have a better rig, but I only build a few pedals a year.