All about mini drilling machines: principle of operation, characteristics, drills. Simple PCB Drilling Machine DIY Mini PCB Drilling Machines

Tired, in general, of drilling boards with a manual drill, so it was decided to make a small drilling machine exclusively for printed circuit boards. There are plenty of designs on the Internet, for every taste. After looking at several descriptions of such drills, I came to the decision to repeat the drilling machine based on elements from an unnecessary, old CD ROM. Of course, for the manufacture of this drilling machine, you will have to use the materials that are at hand.

From the old CD ROM, for the manufacture of a drilling machine, we take only a steel frame with two guides mounted on it and a carriage that moves along the guides. In the photo below, all this is clearly visible.

The drill motor will be mounted on the movable carriage. To mount the electric motor to the carriage, an L-shaped bracket was made from a strip of steel 2 mm thick.

We drill holes in the bracket for the motor shaft and the screws for its fastening.

In the first variant, an electric motor of the DP25-1.6-3-27 type with a supply voltage of 27 V and a power of 1.6 W was chosen for the drilling machine. Here he is in the photo:

As practice has shown, this engine is rather weak for drilling work. Its power (1.6 W) is not enough - at the slightest load, the engine simply stops.

This is what the first version of the drill with the DP25-1.6-3-27 engine looked like at the manufacturing stage:

Therefore, I had to look for another electric motor, more powerful. And the manufacture of the drill has stalled ...

Continuation of the manufacturing process of the drilling machine.

After some time, an electric motor from a disassembled faulty Canon inkjet printer fell into the hands:

There is no marking on the engine, so its power is unknown. A steel gear is mounted on the motor shaft. The shaft of this motor has a diameter of 2.3 mm. After removing the gear, a collet chuck was put on the motor shaft and several test drillings were made with a drill with a diameter of 1 mm. The result was encouraging - the “printer” engine was clearly more powerful than the DP25-1.6-3-27 engine and freely drilled textolite 3 mm thick at a supply voltage of 12 V.

Therefore, the manufacture of the drilling machine was continued ...

We fix the electric motor with the L-shaped bracket to the movable carriage:

The base of the drilling machine is made of fiberglass 10mm thick.

In the photo - blanks for the base of the machine:

To prevent the drilling machine from fidgeting on the table during drilling, rubber feet are installed on the underside:

The design of the drilling machine is of a cantilever type, that is, the supporting frame with the engine is fixed on two cantilever brackets, at some distance from the base. This is done in order to ensure that sufficiently large printed circuit boards are drilled. The design is clear from the sketch:

The working area of the machine, the white LED backlight is visible:

This is how the illumination of the working area is implemented. The photo shows excessive brightness of the lighting. In fact, this is a false impression (this is a camera glare) - in reality everything looks very good:

The cantilever design allows drilling boards with a width of at least 130 mm and an unlimited (within reasonable limits) length.

Measurement of the dimensions of the working area:

The photo shows that the distance from the stop to the base of the drilling machine to the axis of the drill is 68mm, which ensures the width of the processed printed circuit boards is at least 130mm.

To feed the drill down when drilling, there is a pressure lever - visible in the photo:

To hold the drill over the printed circuit board before the drilling process, and return it to its original position after drilling, a return spring is used, which is worn on one of the guides:

The system of automatic adjustment of engine speed depending on the load.

For ease of use of the drilling machine, two variants of engine speed controllers were assembled and tested. In the original version of the drill with the DP25-1.6-3-27 electric motor, the regulator was assembled according to the scheme from the Radio magazine No. 7 for 2010:

This regulator did not want to work as expected, so it was mercilessly thrown into the trash.

For the second version of the drilling machine, based on an electric motor from a Canon inkjet printer, on ham radio cat website another circuit of the motor shaft speed controller was found:

This regulator provides the operation of the electric motor in two modes:

When there is no load, or, in other words, when the drill does not touch the printed circuit board, the motor shaft rotates at a reduced speed (100-200 rpm).
With an increase in the load on the engine, the regulator increases the speed to the maximum, thereby ensuring the normal drilling process.

The motor speed controller assembled according to this scheme worked immediately without tuning. In my case, the idle speed was about 200 rpm. At the moment the drill touches the printed circuit board, the revolutions increase to the maximum. After drilling is completed, this regulator reduces the engine speed to the minimum.

The motor speed controller was assembled on a small printed circuit board:

The KT815V transistor is equipped with a small radiator.

The regulator board is installed at the rear of the drilling machine:

Here, the resistor R3 with a nominal value of 3.9 ohms was replaced by an MLT-2 with a nominal value of 5.6 ohms.

The testing of the drilling machine was successful. The system of automatic adjustment of the frequency of rotation of the motor shaft works clearly and without fail.

A short video about the work of the drilling machine.

In amateur radio practice, it is often necessary to make printed circuit boards, in which it is necessary to drill many holes with a diameter of 0.5-3.0 mm, which cannot be drilled manually, with a drill or on a large drilling machine.

Therefore, for drilling printed circuit boards, many radio amateurs make home-made desktop or manual mini drilling machines. I bring to your attention the design of a desktop drilling machine, designed and made by hand, made from improvised parts.

Design

The basis of the bed of the mini drilling machine was a stand for linear measurements with a digital indicator with a little refinement. The object table with adjusting screws was dismantled and a part of the movable rod for fastening the dial indicator was removed to the length of the slot.

At the base of the stand, two holes were drilled for attaching the table and an M4 thread was cut into them. In the rod itself, in the center of symmetry, with a 15 mm indent from the edge of the cut, a hole with a diameter of 10 mm was drilled for the guide bolt.

After preparing the base, you can begin to manufacture parts. The table is made of duralumin and has dimensions of 100 × 120 mm and a thickness of 15 mm. It can be made from almost any material, aluminum, iron, fiberglass, chipboard, hardwood. Choose the table size of your choice. The table is attached to the base of the mini drilling machine with two M4 screws with countersunk heads.

The next part of the mini drilling machine is a movable plate in which the engine is fixed. The plate is made of duralumin measuring 50 mm by 130 mm, 15 mm thick. The thickness is not critical, it can be from 5 mm and thicker. The narrow ends of the plate for aesthetics are rounded with a radius of 25 mm. Two large holes are made in the plate at a distance of 80 mm. One for sliding on the stand while drilling with a diameter of 30mm, and the second for fixing the motor with a diameter of 36mm. Between the large holes along the line passing through their centers, another hole was drilled, in which an M10 thread was cut. The center of this threaded hole, when the plate is put on the post, must be in line with the hole drilled in the rod.

It was possible to fix the engine in the plate by simply clamping it on both sides with screws, into the drilled threaded holes, but I wanted to do better. I made a slot in the plate and the engine is fixed by crimping the plate with an M5 screw. Thanks to this solution, the engine is easily removed from the plate and the mini drilling machine turns into a miniature hand drill, which is sometimes necessary. If the need for a mini hand drill is frequent, then a thumbscrew can be installed.

The next detail is the lever handle, which ensures the travel of the drill during drilling, which is about 7 mm. The lever handle is a duralumin plate 5 mm thick and 50 × 120 mm in size. One oval large hole is made in it, with a size that ensures the passage of the motor of a mini drilling machine without touching and the ability to look at the entry point of the drill into the part when drilling for aiming.

You will also need a bolt 60 mm long with a thread at the end equal to the thickness of the plate of the mini drilling machine, a Morse taper a1 for fitting the cartridge onto the motor shaft and a spring of sufficient rigidity to return the plate with the motor to its original state.

Assembly

It remains to assemble the parts together and the mini drilling machine will be ready to go. The bolt is first threaded through a 10 mm hole in the lever handle, then inserted into the rod. A spring is put on and the bolt is twisted into a movable plate. It is advisable to cover the friction points of the parts of the mini drilling machine with a thin layer of any thick lubricant before assembly, in extreme cases, you can get by with ordinary engine oil.

The assembled assembly is mounted on a cylindrical stand of a mini drilling machine, and the rod is fixed with a standard clamp. It remains to install the engine, adjust the height and you can start drilling. It is enough to press the lever-handle with a little effort and the drill will go down.

If the spring force is not enough to lift the movable part of the mini machine up, then you need to stretch it a little or replace it with a stiffer one.

Details

I used the DPM-35N1 electric motor for a DC supply voltage of 27 V. To power the engine, I made a simple power supply, which is a step-down transformer, a diode bridge and an electrolytic capacitor. You can use almost any DC or AC motor, but preferably with a rotor mounted on rolling bearings (ball bearings). The higher the engine speed, the better the holes will be and the faster the work will go.

Job

If you are interested, watch a short video showing a mini drilling machine in operation.

About PCB Drills

As a rule, desktop mini drilling machines are used for drilling printed circuit boards for radio structures. The basis for printed circuit boards is foil fiberglass, which, due to the presence of glass in the material, very quickly blunts the cutting edges of the drill. After hundreds of drilled holes in fiberglass, the drill becomes unusable. Filling a drill with a diameter of 0.7 mm is almost impossible at home. There are carbide drills specially designed for drilling fiberglass. They are available in different diameters from 0.5 mm to 2.0 mm and all have a 2 mm shank.

A single carbide drill without cutting edges can drill tens of thousands of holes. One disadvantage of such a drill is that it is very fragile and breaks easily if a lateral force is applied. If a carbide drill is clamped in a hand drill, then at the first touch to the surface of the part, the drill will break. I have been drilling with one drill for many years in a mini drilling machine, and it still drills like new.

I wanted to assemble a machine for drilling printed circuit boards and other small things, options like a collet chuck right on the motor shaft did not suit me. Something more serious was needed, but he did not dare to start building a machine from scratch. But then a broken (after a fire) home-made micro-drilling one successfully turned up, which I took as a base for my craft, or rather restored it.

I did not photograph the initial view of the machine, the condition was very deplorable. There was a headstock, a spindle jammed in it, a spindle movement mechanism, a column and a base.

First of all, a new column was carved, the old one was severely deformed:

Screwed rubber feet onto the base:

ShB. The old m4 locking screw was broken when trying to unscrew it. I made a new handle from an M6 bolt:

At first I wanted to put a 220 volt 6 watt asynchronous, but then a 12 volt 12 watt collector was bought. It will be attached to the SB through the adapter plate:

A toggle switch is installed on it:

Pulley for the engine picked up ready:

Got a new spindle. He killed the most time, he made a hexagon with a file:

New pulley machined from ebonite:

Spindle movement mechanism:

Everyone is here:

LED lighting that turns on with the engine:

Refurbished machine:

Satisfied with the machine. I put a collector electric motor to control the speed with voltage (in the PWM plans), but the power turned out to be back to back, and I abandoned this idea. With an asynchronous machine, the machine would work many times quieter ...

The first version of a desktop machine for drilling circuit boards was made three years ago. He did it purposefully, specifically for drilling boards (it is not intended for another) and exclusively from improvised materials, he did it “quickly” as a temporary device, spent a day off on manufacturing. And he took it and "got accustomed" - it turned out to be unusually convenient in work.

The diameter of drills that can be used is from 0.5 to 1 mm inclusive. Sprint start, finish without inertia. He summed up the board, pressed it - the hole was ready, released it - the drill returned to its original position by itself. For all 2-3 seconds. Six months later, once the thing came "to the court", I spent another evening and gave it a more appropriate and acceptable look.

The device and the principle of operation, as you can see, remained the same. Two more years passed, but I was not going to do something more solid, although the components for this were selected. From good, good is not sought. But he allowed himself the modernization.

There have been significant changes:

lowering occurs by pressing the handle
the electric motor is switched on when lowering at the moment the button is pressed against the stop
a table for drilling on threads and can be raised - lowered to adjust the distance from the surface of the board being drilled to the "point" of switching on the electric motor
electric motor powered by direct current

WITH tank for drilling boards - wiring diagram

The basis of the entire frame and guides.

The bushings, their inner diameter is only one - two tenths of a millimeter more than the diameter of the guides, the material - ebonite (dielectric), was not chosen by chance, this is a kind of "decoupling" from the electric current. What the belt is made of, which later fixes the traction, is not difficult to guess.

The button - switch is fixed on a plastic corner with 2 screws and nuts, the corner itself is connected to the bushings with glue.

There is an M2 threaded hole in the motor shaft, it was not difficult to fit the collet. And the felt seals (on both sides of the shaft) waited for the oil.

As a "bearing" element, to which the engine is attached and which, in turn, is attached to the bushings, a furniture corner was chosen (light, durable and easy to process). Diode bridge and capacitor in a protective casing.

The stop consists of a spring, on one side of which the rubber stop itself is glued, on the other, a nut is soldered, which is screwed onto a screw that is mounted on a thread in the hole in the bed.

The drilling table is mounted on a screw (its additional function is described above).

And finally, how it all works:

Video of the drilling process

For those who liked it: everything from which this machine was assembled for, previously lay in cans, boxes and just corners. I think the hint is more than obvious. I wish your drills never get dull, Babay.

Discuss the article MACHINE FOR DRILLING PCB

Somehow the author decided to make a drilling machine for printing. boards, but an option such as a collet chuck around the motor did not suit anyone and will not suit. He needed something better and heavier to assemble, but he did not undertake to do it from the bottom. Somehow, fortunately, he came across a worn old mini-drill, which he took as the basis of his homemade work and restored.

At the beginning, the machine looked very deplorable, the author did not want to look at it, let alone touch it. There was a headstock with a jammed spindle, a mechanism used to move the spindle (spindle) and a column with a base.

First, he had to carve a new column, because the old one, sorry for the expression, was in a wretched state:

On the base, rubber bipods or legs were replaced and screwed on, it's your right to call them:

The old M4 stop screw broke during the initial attempt to disconnect and, moreover, not so weakly. He had to make a new stop. handle with M6 bolt:

At first he decided to put a 220V 6W asynchronous, but then, after an unsuccessful attempt, he was replaced and bought a collector - 12V 12W. It is attached to the SB very simply, without any effort through the transition. plate:

A toggle switch is installed on it:

He immediately took the pulley for the engine ready, in order not to bother with its manufacture:

Then he had to machine a new spindle. The time that he spent on it took the most, he had to make a 6-ik with a file, as he said everything turned out fine: