pcb drilling

[jrem]

ok, I know we've been over this, but I have to ask again, how do you guys drill after etching?  I can't seem to get it done without lifting traces . . . 

[brett]

Hi
Lifting traces sounds a bit like the quality of the board might be bad.  But if the board quality is ok -

I used to use a drill stand to hold my drill ($10 second hand).  But I'm lucky enough to have a proper drill press ($80) these days.

I have a 100W light bulb located about 1m away from the drillpress, so that I can see without straining my eyes.  I use 2 size drills - 1 mm (resistors, caps, etc) and 1.2 mm (about 3/64ths, for power diodes etc.).  A good etch job leaves a tiny etched hole that the drill tip will find if you are close.

I set the drill press up so that the tip is only about 3mm above the board.  As I lower the tip, I make minor adjustments to the position of the board, so that the holes are right on target.  About 1 in 50 holes still go a bit "wrong".  I support the PCB with a piece of fibreboard (MDF).  With a fairly good setup like this, it takes about 5 minutes to drill a moderately complicated board, like a tubescreamer, and 30 seconds to do a fuzzface.
cheers

[bkanber]

I have access to a drill press, but I use that only for drilling enclosures. For PCBs, I go with a much simpler route (that requires very steady hands). I have a 1/32" drill bit (a little smaller than 1mm) and a dremel. You can't really find 1/32" or 1mm in stores, you usually have to mail order them. McMaster-carr is always great for stuff like this.

I just power up the dremel, hold the board in one hand, drill with the other I find it easy, and I can drill about 60 holes a minute without any mess-ups, but then again I'm young and I have solid dexterity. The drill press method is definitely easier (I tried it once) but it's a little more tedious and time-consuming. (But then again, we're talking 5 minutes versus 1 minute).

Be careful with the small drill bits, they break easily!

And I second the notion that lifting traces is either due to a bad board or a bad drill bit.

And, I never knew this, but apparently PCB dust is toxic? Does anyone know anything about that?

Burak

[R.G.]

If you want to do PCB drilling right, not always be scrabbling around trying to compensate for not having the right stuff and always ruining a certain percentage of your boards,

(a) get a jeweler's precision drill press (about $140.00), NOT a bench or floor standing drill press or a Dremel drill press. Both the last will be OK for hacking around, but cannot be relied on for the necessary precision
(b) get solid carbide 1/8" shank PCB drills at a local tool supplier or by mail order. They're about $2.00 each. The precision drill press will not wobble and break them like a Dremel or other hatchup rig will. It's essentially impossible to drill with PCB size carbide by hand without breaking them about every third hole.
(c ) run them at about 8K RPM or more to get good, clean cuts.

I'm building another PCB microscope drill. This one has a USB camera/microscope held in a frame over a bottom-mounted 1/8" collect air drill which moves up from the bottom. The camera puts a picture on a screen, and crosshairs mark where the point of the bit comes up. In use, you align it, put the PCB on the stage facing the camera, then move a pad to be centered in the crosshairs. Press the pedal to move the drill bit up, release the pedal, move to the next pad.

[Solidhex]

Yo

  If you're holding the pbc in one hand and drilling with the other a simple slip up could result in drilling through your palm or fingers. Just clamp the thing down on some scrap wood or something. I've been using the dremel press lately but I might have to invest in something better. Since drilling pcb's is on the more boring side of the pedal building process it pays to make it quick and easy and safe.

--Brad

[RedHouse]

ok, I know we've been over this, but I have to ask again, how do you guys drill after etching?  I can't seem to get it done without lifting traces . . . 

One thing that can help with the trace lifiting thing is to make sure you use sharp drills (bits). If the drill (bit) is dull it heats up the copper pad too much trying to force it's way through and that can lead to lifting because the bonding of the copper to the fiberglass gets weak.

When using carbide PCB drills you can inadvertantly achieve lifting if your drill speed is too low, the carbide bits can "catch" as they penetrate and peel up the pad so if you use those keep the drill motor speed up high.

I use both the carbide and the standard HSS drill types and I like the carbide best ...but... find that using the HSS #65 or #68 drill from the local hobby supply store (usually about $/ea) can be quite effective if one makes sure the etched pads have a fairly good pad-hole etched into them. In other words try to get the etched hole close (but not the same size) to the size it will be after drilling, that seems to reduce the opportunity for a bit to "catch" or "over heat" the pad's copper.

[John Lyons]

+1
High speed, sharp bits, carbide bits even better, Drill press of some kind is a must.
The material needs a high speed, too low and the bits just chew through the board and make for a rough hole.
Go to drill bit city and buy a 10 pack of resharpened carbide bits for $8. You won't look back.

John

[culturejam]

I just power up the dremel, hold the board in one hand, drill with the other I find it easy, and I can drill about 60 holes a minute without any mess-ups, but then again I'm young and I have solid dexterity.

You can hand-drill 1 hole per second? You must be part robot or something.

[Mark Hammer]

Wide shank carbide bits....YES!!

A drill press with a laser sighting feature....YES (cheaper than you'd think)

A spring-loaded centre punch.....YES!!

Very often the blanks left in the centre of the solder pads in PCB layouts can be your best friend.  With the etched opening in the centre of the pad a lower level than the copper around it, this can often stop the bit from wandering.  If the pattern itself does not provide them, then make an effort to insert them either digitally, or by some post-transfer scratching.  Just keep your finger-juice off the copper.

[bumblebee]

i just use good quality drill bits (1mm/1.2mm) and an cordless hand drill. its not the best method but its one of the cheapest and works fine if you have patience.

a tip: always have spare bits readily available.

[bkanber]

It's essentially impossible to drill with PCB size carbide by hand without breaking them about every third hole.

I disagree =) I use a dremel @ 30,000 rpm and 1/32" carbide bits. I broke two early on, but now I've drilled probably 200 or 300 holes without breaking a bit.

Granted, a drill press is always better... however, I'm happy with my technique. I'm super quick with it and my holes are always nice and clean.

You can hand-drill 1 hole per second? You must be part robot or something.

Haha.. that's why my girlfriend said! =P
Yeah, I've gotten my drilling technique down pat, and can do about 1 hole a second. I'll time my next board for you, and let you know. But sitting here looking at my watch, 1 second each feels about right. Maybe it's more like 1.2 seconds: 5 holes/6 seconds. Something like that ...
Remember Gene Wilder in Blazing Saddles? That's me..

Burak

[jrem]

maybe I should reword the question . . .


first, I'm using a dremel and a 0.038" high-speed bit (or so), I press-n-peel the board, then center punch, then drill (I put the board in a small vice and hand drill them), then touch up with a sharpie, then etch. 

The last couple boards I tried to eliminate the center punch, etch, then drill, and they don't turn out so well.  When I try to drill I tear the traces up off the board, or when I go and solder, funky things happen.

Now I'm back to punching, drilling, then etching, but I don't think the boards look as clean as they would if I etch then drill.

So what's the secret?  Smaller carbide drills?

[soulsonic]

How long are you etching for?
In industrial situations, one of the main reasons for trace lifting is inadequate etching time.
What kind of acid do you use to etch?

[R.G.]

I disagree =) I use a dremel @ 30,000 rpm and 1/32" carbide bits. I broke two early on, but now I've drilled probably 200 or 300 holes without breaking a bit.
Granted, a drill press is always better... however, I'm happy with my technique. I'm super quick with it and my holes are always nice and clean.

Kewl. I think we should nominate you for Driller of the Year.

However, not everyone is blessed with such dexterity and vision. I think I'd be happy if I had your technique, too. There's lots of stuff other than drilling I could use the sharp vision and dexterity for.

Plus, 200-300 holes per bit is good, but not by bit life standards. A good carbide bit will go several thousand holes before needing replaced due to dullness. The point is not to break carbide bits period, or so infrequently you don't have a bundle of bits sitting there just in case.

Of course, my view is jaundiced. I'm thinking back to when I was the only place on the internet to get clone boards and I'd sit down and drill maybe 2000 holes before taking a break. One board at a time is easier to stay fresh.

I think my advice stands for beginners, perhaps modified by "... of course, you may be the kind of person who is just so good that you'll never break a bit. In that case, ignore this, and only buy one carbide bit and use it free hand in your Dremel."

[John Lyons]

So what's the secret?  Smaller carbide drills?

Yes, as stated above at least twice. 

[frank_p]

So what's the secret?  Smaller carbide drills?

NO! This is THE ULTIMATE MACHINE !


This is my old setup for drilling PCBs.  :

Old broaching press.
Flexible shaft and Dremel.
1mm HSS drill bit that I keep on using...

Now this is Hi-Tech !

Maybe I could install a lazer and web camera on this one. 

I bought a press-drill instead of that Teisco guitar.
http://www.diystompboxes.com/smfforum/index.php?topic=66052.msg524193#msg524193

Jeweler press-drill, DAMN! I should have know this before buying my general purpose drill !
Oh! it will serve for enclosures!

[soulsonic]

I don't think my observation should be ignored.

[R.G.]

Quoting my Nashville friends, I smell what you're steppin' in. It's a real downer isn't it? Howzat Simon song go? "still people hear what they want to hear and disregard the rest, la-la-la-la la..."

Remember - you can lead a horse to water but you can't make him think.

[frank_p]

I don't think my observation should be ignored.

Yes and also, how long you rub with acetone to clean the transfered toner...
So, with what solution are you etching with Soulsonic, so it don't fragilise the bond to the copper trace ?  And for how long?
(I am not teasing)

Quoting my Nashville friends, I smell what you're steppin' in. It's a real downer isn't it? Howzat Simon song go? "still people hear what they want to hear and disregard the rest, la-la-la-la la..."
Remember - you can lead a horse to water but you can't make him think.

C'mon R.G. don't be tempted to sing the same song too often .  Conditionnement is the ways we tame the horses.  Habits is the way we make humans stupid and lifeless.  Don't be alieanated too much by your own toughts.  Identifying your feelings on other constatations is the action of the ego toward stigma.  And social concensus in that way is not always a good thing...  I know it's hard not to let our knowledge, experience and intelligence run over the fence of the technical domain. I try to keep my horses in the paddock and work with them, or let them go wild and happy. However, I understand your frustration when you see people not be attentive on good advice, and then, after, propagate nonsense on the net.  What I see is that not a lot of folks have your experience, so they are blinkered by what they do not know (even if they are free or in the paddock).  I am often one of those.  All my respect for pointing me in the right direction again !  Who knows, if I drink at your source perhaps, one day I will be able to think by myself. PCBs is archetypal of what you say...
   

[soulsonic]

I've used Ferric Chloride and Sodium Persulfate and never had problems with trace lifting from either. I'd say a 3"x4" piece of board generally takes at least 1 hour to  1½ hours depending on ambient temperature.
I don't usually use acetone on the boards if I don't have to. I usually just use denatured alcohol. If I absolutely have to use acetone to remove something stubborn, I try to get it done as quickly as possible and use the absolute minimal amount on a cloth, taking care not to saturate the board with the stuff... since it does bad things to the board material.

I just don't understand why people are getting all worked up over the bits. Sure a good bit is going to make a nice clean hole, but I've used all kinds of junky bits with various hand drills and never had problems with traces lifting; so, to me, it seems that bits have less to do with lifting than other variables. You can actually see along the edges of the traces if they are going to be prone to lifting - I've seen ones where they look really sharp and a little raised on the edges - that's not good. The ones I do look "blended in" to the board on the trace edges - and that must be good because they almost never lift. I'm not going to say that I do the best boards, or that I even do great boards - I think my home-etched boards are pretty amateurish, and that's why I like to stick to hand-wiring on perf... BUT, I've never had trouble with trace lifting, and that's what we're talking about here, so I'm throwing my 2 cents in and saying that this "5 minutes with Muriatic acid" foolishness I keep seeing around here is absolutely begging for bad etches.