[OT] Using a Dremel tool for drilling PCBs

thats a lot of holes by hand, hope its not many boards you are doing.

IME the solid carbide drills dont last long unless you have a good chuck and stand. cos they break so easily, although depends what size >1mm is probably ok the ordinary HSS last a while before they go blunt, but probably work out cheaper for hand use.

carbide coated are somewhere inbetween.

I was interested in the direct ink jet printing of etch resistant ink.

Colin =^.^=

Depending on the circumstances, I very often find for 1-off stuff its easier and cheaper to get boards from ExpressPCB. The money end of that makes sense IF (Repeat "IF"), the board dimensions can be kept to exactly 3.8" x 2.5". They call it their "Mini Board" service.

You get QTY-3 boards for $51 + $8 to ship them 2nd day. (You have them in 3 days.) Double-layer, plated through holes, but no solder masks or silkscreens.

They are not paying me to say this. In fact, there are probably "better" deals out there??

But from the sound of it, you'd be spending a lot of time using the Dremel. Unless you enjoy that activity of course, your time is probably more valuable. Just a thought. Plus, the plated-through holes should add to reliability.

They have free layout software, as to most of their competitors. And for $60 more, they will come off the Gerbers (for those interested in that..)

Keep in mind larger, or differently dimensioned boards will cost a lot more. This restriction may not apply to other vendors who offer a small run prototyping service.

-mpm

(snip)

Can the expressPCB software generate Gerber files?

Thanks. I forgot to ask---what speed should I use?

I hear dental burs are the best for hand drilling pc boards.

I've got a solid pedestal drill - running at about 2000 or 3000 RPM and HSS bits it works better than the Dremel at any speed. Carbide bits work really well in the dremel at higher speeds but are very easily broken. Try running the vacuum cleaner continuously to grab the dust.

Thanks for the expressPCB link. I may use them, but I will still need to make at least some boards by hand.

Should I solder from both sides if the holes are not plated? Would I need to stick a piece of wire through for hand-drilled vias, or would a plug of solder establish the connection?

Sigh.

HSS will be getting dull after around one board or two. They are cheap, you can buy an envelope of them. Cobalt should be slightly better (but more expensive).

They generally have a shank the diameter of the hole they make. Professional PCB drilling generally uses solid carbide drill bits with a 1/8" shank. They are easy to break with a cheap drill press setup, but some people have been successful using the Dremel.

As with any cutting tool, buy only good name-brand bits, cheap junk like the TiN stuff sold to hobbyists will bring you only grief. Some of them are amazingly soft, barely suitable for hardwood.

You can drill 150 holes pretty quickly with good lighting and proper RPM-- just a few minutes for the bulk of them which will probably be around 0.8mm.

Best regards, Spehro Pefhany

--
"it\'s the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

Use wire, bent over on both sides and soldered.

--
Cats, coffee, chocolate...vices to live by

Oh yeah, it's very practical. I use the same process for all my boards. A drill press is an absolute necessity! Without one you WILL break your bits. Use the standard collet, it fits the carbide bits with a 1/8" shaft. I have never dulled a bit. I always get in a hurry and break them before they get dull. I've never measured the speed, but just set it till it sounds right. It is fairly slow for the Dremel tool. A few practice holes will tell you.

150 holes in a board is not problem. I can do 100-200 before I need to take a break.

Three things that really help:

1 - A #10 Optivisor. A #7 might be ok you have good enough eyes. 2 - Lots of light. I use a gooseneck lamp with a 23W screw in fluorescent bulb. You need the light adjustable because reflection from the board changes when I have to rotate the board and the light position makes a big difference. 3 - Make sure your layout is printed with drill guide holes etched in the center of the pads. I set my software to print 0.025" dia guide holes.

I drill all the holes to.032 then go back and enlarge all the holes that need it. This works much better. The larger bits don't tend to fall into the etched guide holes nearly as well, but fall nicely into the .032 holes. They don't follow the guide holes well if the speed is too high either.

I also setup my shop vac just behind the Dremel tool to keep the fiberglass debris down. This makes it easier to see the guide holes and results in much less of a mess. Use a fairly small nozzle and get it close as possible without interfering. Don't forget to use breathing mask! It's much easier on the lungs.

Mike

When truth is absent politics will fill the gap.

Matt wrote: (snip)

Solder will not reliably form a thread through an unplated hole. Definitely, use a wire. Silver plates wire wrap wire works well. Strips and wets very easily. Good for at least an ampere.

Depends on drill diameter and drill material. Up to 0.05" or so, with carbide, the Dremel can't go too fast. Try about 1/3 the speed for HSS (so about 10,000 RPM at 0.05" and 20,000 at 0.025" etc.) You can always go slower than the recommended RPM, but that reduces the optimum feed rate (takes longer to drill each hole).

Best regards, Spehro Pefhany

--
"it\'s the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

You NEED a stand.

Collet is best for aligment - must be metal collets though, not plastic.

Must use carbide - PCBs eat HSS in no time. You MUST use a stand when drilling with carbide bits otherwise they will snap very easily. A carbide bit should last many hundred holes easily. HSS maybe a few dozen.

see

for plenty of info on making good homemade PCBs.

Yup. I made my own:

I can use 13 mil drills with it, without breaking them, and with reasonable accuracy.

No, it cannot. Here's how it works:

You place an order with them. (Using their free layout software, which is actually pretty good*) Then you call them back with the order confirmation number and tell them you want the Gerber Files. They charge your credit card $60 US, and email you the Gerbers.

A few threads back, someone was going to post an alternate solution involving raster-to-Gerber conversion. (The ExpressPCB has 300dpi output capability, but I don't know if this alternate solution would provide acceptable results as I've never tried it...)

It just seemed that Matt was about to embark on a fairly involved creation effort, and I wanted to give him the heads-up. In small quantities, these little PCB fab houses are hard to pass up.

And honestly, I no longer have the patience or eyesight required to thread wire for "plated-thru" holes. I do however, has enough aspirin for same....

Does it occur to anyone that there might be fewer of these "little PCB fab houses" making "pretty good" software if you create software (a raster to gerber converter) that forces them all to compete strictly on price and no longer on what tools they provide?

Just something to think about...

I make my own PCB's... I could almost write a book on the subject.

I use as much SMD as possible...I hate drilling holes. Maybe use more SMD. I also hate hand soldering..That's why I hot plate. But when I do drill holes..Yes..I use a dremel on a dremel drill press. I buy bits at the local hobby shop. Dunno what type they are but it's cheap and I have no idea how long they last.. I seldom drill. As soon as I sense slow drilling or burning, I change to another bit.

By the way, I also hate toner-transfer paper :) D from BC

You'll find centering to be a problem unless the art provides for etched centers. Many gerbers do not do this, simply relying on electronic drill file.

RL