When faced with the need to drill numerous fine holes in printed circuit boards for electronic devices, it was found that a power drill in this case is not such a good assistant she is loud, and the power of it excessive. Then decided to make a small tabletop drill press is more suitable for such work. The present machine has a small size, low power consumption and, importantly, virtually silent — you can work even when all the household slept. And drilling the holes with diameter from 1 to 6 mm permissible even in aluminum workpieces.
Structurally my table drill press, like most of his “brothers”, consists of a table-base, a rack, a console with a working body and arm. And is characterized in that its working body (jig and drill) is mounted on a “single shaft” with a drive motor (shaft motor inserted directly in a blind hole end of the working shaft of the machine and connected by the dowel). In addition, the motor has its own “personal” power supply.
Table base used duralumin plate size 320×220 mm and thickness 10 mm mounted on shock absorbers — rubber glides with a height of 25 mm. is mounted On a table stand made of steel rod with a diameter of 20 mm, and the rack wearing adjusting focus, the spring and the console. The stop is made of 16 mm steel sheet. Spring total height of 100 mm is wound with a pitch of 15 mm on the bar of high carbon wire (grade 70 steel). Console — welded detail: two bushings (running and working) are connected by a pipe section of rectangular cross section 40×26 mm To chassis bushing welded to the side of another boss thread on the end for mounting the lever arm.
Move console along with a work on stand up-down handle is effected via a lever.
The working shaft of the machine in the working bushing of the console is mounted in two bearings No. 100 in the glass, which, in turn, is mounted in the working bushing of the console. On top of the glass is attached with screws M4 flange motor.
Desktop miniature machine tool for drilling holes in printed circuit boards (mounting screws at the position not selected):
1 — table-base (dural plate 320×220, s10); 2 — absorber (rubber, 4 pieces); 3 — front (steel, circle 20); 4 — console; 5 — the stop (steel, sheet s16); 6 — lever handle (steel, lap 16); 7 — lever (steel, strip 16×4); 8 — thrust (steel, strip 16×4); 9 — coil spring (wire Ø2, spring steel 70); 10 — motor DPR-72, N = 20 W, n = 6000 Rev/min; 11 — working shaft (steel 45, range 14); 12 — Cup (duraluminum D16); 13 — cover (duraluminum D16); 14 — the bearing № 100 (2); 15 — power supply; 16 — a stopper-console (screw М8х20); 17 — a stopper cap (screw М6х16); 18 — axle hinge pin (bolt M8 with washer); 19 — thrust axis (screw M8 with washer); 20 — mount arm (M8 nut with washer); 21 — strut (nut M16 with spring washer); 22 — of tool cartridge No. 1; 23 — dowel (steel 20)
The scheme of power supply of the motor
1 — the bushing (steel, range 46); 2 — jumper (pipe 40×26); 3 — way bushing (steel circle 40); 4 — threaded boss (steel, round 16)
Motor — brand DPR-72, flanged, with the number of revolutions of 6000 per minute. With a well sharpened drill holes in work pieces are obtained without burrs.
The scheme of power supply of the electric motor shown in Fig. Voltage is removed from the secondary winding of the transformer is 24 V. If the complement diagram power supply a variable resistor to regulate the voltage to 15 V, it is possible to change (reduce) the speed of the motor.
The Assembly structure to reduce friction in moving joints and lever rod stop and the console it is advisable to put ftoroplastovye or nylon gasket-washer thickness 0,3 — 0,5 mm. Before operation, the rack lubricated with a thin layer of machine oil.
Y. KURBAKOV, Tula