how do i drill holes in pcb easily.

well, he will explain, wont you, kinjal?

Well, I use screen-printing process to print the tracks. I never use markers because its just impossible to draw IC foot-print without any errors. It can work only if you are an artist or your circuit only has transistor and other stuff. No ICs.

Coming back to screen printing, in this process
1) A silk screen used which is coated with a photo-sensitive chemical. The screen is then allowed to dry for 5 minutes.
2) Then for transferring the PCB image, a good quality print-out on tracing paper is used. This printout is then sandwitched between a plain glass and the screen and couple of fluorescent-lights are placed bolow the glass platform.
3) This way the screen isexposed to filtered light (from PCB printout) for about 5 minutes. This process turns the exposed part into hard layer while the parts below the tracks remain soft and can be washed using water.
4) The screen is ready. Screen printing ink is now poured on one side of the screen and this screen is kept on the copper-clad. Using a rubber squeezer, the ink is pressed hard over the screen which causes it to flow from tiny mesh of the screen and go on to the copper clad.
5) The board is the etched and drilled. Thats it!

Sounds a tedious way of creating PCb isn't it? But in these years I found this method to be the most economical and produces near professional quality PCBs in less time than getting it developed from professional PCB manufacturers.

An observation

Kinjal,

Your board looks good, but I might point out a few things for those just getting started in this stuff.

I would appear that the holes in your board are coned out on the copper side, like tiny volcanos. If you're drilling from the component side, that would be one cause. If you're drilling from the copper side, your drill bit is getting dull or the drilling speed is too slow. The hole position accuracy is good, primarily because of either center-punching first or because your pads have voids in the center, creating an automatic center-punch mark.

I use a Dremel tool, Dremel drill press stand and carbide bits for drilling my boards. That way, you get high speed (10,000 rpm), accurate control, perfectly perpendicular holes, very few broken bits and bits that can stand the rigor of that abrasive G-10 board substrate. It takes about 2 seconds per hole to drill if you're working IC pads. And this setup isn't that terribly expensive.

G-10 dulls HS (high-speed steel) drill bits quickly, usually after only 10 holes or so, while the carbide bits will last through a 200-300 holes. OF course, you certainly CANNOT use carbide bits in a hand (manually-operated or electric) drill at all, for they'll break nearly instantly since they can't stand any side-thrust or angle change after the hole is started.

pkshima, glass epoxy (G-10) boards refer to the fiberglass insulating material upon which the copper is clad. It's usually green in color, but I've seen it also in blue, tan and ..... (ugh!) pink. The other common material is phenolic. Phenolic is usually cheaper, but has a lot of shortcomings: (1) it easily warps; (2) the copper does not adhere as well and often is easily damaged when drilling out or soldering small pads; (3) it can absorb moisture and change it's dielectric constant and create leakage, makeing it less than preferable for RF work. But is it usually less expensive and is less abrasive to drill bits.

Dean

Sorry to interrupt guys, but back to the topic on easily drilling holes on the PCB. I would like to share my experince, which I think is the easiest way, since I've tried all the methods mentioned and ended up with many broken drill bits.

The method is by attaching a piece of metal with the aid of two screws to attach to a small electric motor. The other end of the metal piece is attached to a drill bit by two screws as well. To operate the drill, the motor would be held in the hand, attached to a power supply and operated on the PCB.

I know the holes are coned out and I also know the why it has happened. Coning out is also the reason why this bare PCB is lying with me unused.
This happened because by mistake I attached a 0.9mm drill bit instead of 0.7mm which raised the copper part to some extent. This has also destroyed the pads at some places if you can see them. Due to this I had to make another PCB . After completing the drilling I came to know what mess I had created.

To drill my boards, I use 30,000 RPM/30W mini-electric drill with speed controller and is mounted on a stand. All the bits I have are carbide ones because normal one are seen to be unhappy when rotated at this speed. :lol:

kinjal can u give us an idea how much such a drill costs.

vernon i didnt quite get ur idea though it sounds interesting.
a bit more explanation would help a great deal

Hi Pradeep,
I bought this drill for around 1500 Rs. Its made in U.K. but you can find it in Indian stores too.
The drill specifications are:
Make: Minicraft **broken link removed**
Model: MB150
RPM: 30,000 Max.
Voltage: 18V DC Max.
Power: 30W
Chuck Capacity: 0.4 - 3.2 mm (diameter)

well your pcb loooks well kinjal. thats because you do it with the optical method, wich is very accurate.
i make them useing markers and feric clorhide , because i cant find the methods you talked about here.
but still i make them quite well for qhat i need. but as i will adbvance, i will have to change the method.
now, what softwere do you use?
i use eagle now, but the limited edition makes it not so usable. i am struggelig to use orcad, but like i said i need help, because i dont know where to start. i made the schematic, but i dont know how to set the packages and transfer the schematic to the layout program.

i thought u had a a bench drill someting like the one shown on the bottom the page u sent the link of.

by the way, though this is slightly off topic do u know of a mini (micro) lathe well suited for robot hobbyists ?
i saw taig tools website and also sherlines. they r marvelous
but i dont think they r available in india.

I use ExpressPCB, PCB123, EasyTrax (DOS) and if my PCB is small enough to fit, I use Eagle Demo. All these are free! Many thanks to the companies which offer them.
For simulation I use Circuitmaker Student Version.
I don't have any big commercial softwares as I can't afford them

pkshima said:

i thought u had a a bench drill someting like the one shown on the bottom the page u sent the link of.

by the way, though this is slightly off topic do u know of a mini (micro) lathe well suited for robot hobbyists ?
i saw taig tools website and also sherlines. they r marvelous
but i dont think they r available in india.

Click to expand...

You can enquire about these tools at the hardware store. I guess you will get them!

The tools.

Pradeep, here in the U.S., "Unimat" was the brand name of a miniature metal lathe. As I recall, they handled a 12 inch length of material maximum and about a 3" diameter. It's a fully manual metal lathe. However, I don't even know if they are being made anymore.

Lindsay Publications is a good place to find books on the subject of building your own metal lathe. I don't recall their web address but a Google search will find them out for you.

The Dremel Mototool is a hobbiest rotary grinder that uses collets with an optional chuck. They're available in several versions, varying in single-speed, dual-speed or variable speed or whether they have bronze or ball bearings. Sears (Craftsman) sells a similar tool that I suspect is made for them by Dremel, since it is mechanically compatible with all the Dremel accessories. Also, Black & Decker has competing models. All these operate from 120 vac rather than dc power. The high-end models of the Dremel costs around $65 U.S. at discount stores.

Carbide bits (they're solid carbide with a 1/8-inch shank, and about 1.5 inches long overall length, available in a variety of number drill sizes) can be had as resharpened bits for about $3.50 U.S. from a variety of "surplus" mail order outfits, such as Hosfelt Electronics here in the U.S.

I made boards "by hand" for years and years before I finally started using the Press 'n' Peel PnP Blue toner transfer sheets and a laser printer. Back in the "old days", I used Testor's 1103 flat red model paint as my etchant resist and ferric chloride as the etchant. I've since graduated to using ammonium persulfate as the etchant and prefer it over the ferric chloride simply because it doen't stain everything it touches. When it's a fresh, warm solution that's vigorously agitated, it is just a aggressive at etching as is ferric chloride.

Dean

You piqued my interest, so I did a google search and found this: https://www.unimat.at/index_e.php They still make the Unimat. They also make these. I knew someone made something like these tools but didn't know who. Thanks for pointing these guys out.

hey, i found that the best way for me is using a cordless drill. I have a cheap 12 volt cordless drill with a keyless chuck and that's about as quick as anything. All i do is clamp the pcb in the bench vice just enough to hold it tight and guide the end of the bit with my left hand and hold the drill with my right. I usually do it with the copper side up. Hopefully that gives you an idea.

Holding the drill in hand will increase the chances of breaking your bits beacsue even a small degree of deviation at high speeds is enough the break it into two.

HS, not carbide.

It's the carbide bits that snap off with the slightest deviation of the drill. If you're going to use ANY hand-operated tool for drilling (i.e., not mounted in a "drill press" frame), you MUST use high speed steel (HSS) bits since they are more forgiving of flexing -- within reason. They'll just quickly dull in fiberglass board material.

I own a good machinist's drill press (1/2" chuck) and even it has too much vibration to use the tiny carbide bits. I have the best luck with the Dremel tool and its associated drill press stand.

Dean

How I do it

I use a Dremel Tool other makes will work as well mounted in a drill press with piece of plywood underneath. You have control of pressure and can hold pcb with one hand while feeding the bit on the PCB.

Hope this helps

i have a cheap 6v hand drill that can bore up to 1.3 mm holes in pcb. i like using it since its very handy - lightweight and small (can be held by index finger and thumb). the 90° angle of holes is just a matter of "getting used to it" factor for this kind of drill.

for the mounting holes, i use the regular hammer drill (too heavy for through holes)

I normally use the CNC mill at school to do the drilling but since i'm on holidays i've had a bit of luck with a hand-held drill (cordless).

just try to keep the tip of the drill as far in as it can go into the chuck, this minimises snapping of the drill bit.

if u use a PCB program to design your pcb, and all the holes go by a 2.5mm grid, use a piece of stripboard over the PCB and drill through that (more useful for when you need a row of holes in a straight line (e.g for a chip, row headers etc)