CN203003203U

CN203003203U - Back drill drilling device

Info

Publication number: CN203003203U
Application number: CN 201220712788
Authority: CN
Inventors: 陈蓓; 任小浪
Original assignee: Shenzhen Fastprint Circuit Tech Co Ltd
Current assignee: Shenzhen Fastprint Circuit Tech Co Ltd
Priority date: 2012-12-21
Filing date: 2012-12-21
Publication date: 2013-06-19
Anticipated expiration: 2022-12-21

Abstract

The utility model discloses a back drill drilling device comprising a drilling rig, a bakelite plate, a plate to be processed and a conductive cover plate, wherein the bakelite plate is fixed on a drill floor of the drilling rig; the plate to be processed and the conductive cover plate are sequentially fixed on the bakelite plate; and a drilling tool of the drilling rig is fixed on a main shaft above the drilling rig. A back drill stubs exists on the plate to be processed after the back drill of the drilling tool of the drilling rig on the plate to be processed. The deviation value of the back drill stub is the difference between actual stub value and the theoretical stub value, and the formula is (R/2) x cotangent (Theta/2), wherein R represents the diameter of a back drill through hole, while Theta represents the angle of an sharp angle of the drilling tool of the drilling rig. Through the diameter of the back drill through hole and the angle of the sharp angle of the drilling tool of the drilling rig, the deviation value of the back drill stub is obtained, and then the depth of the hole is adjusted, and thus, poor precision problem of the back drill stub can be well solved, and application range of printed circuit boards on high-speed signals is extended.

Description

The back drill drilling equipment

Technical field

The utility model relates to the printed circuit board (PCB) production field, refers in particular to a kind of back drill drilling equipment.

Background technology

Along with the high speed development of electronics technology, the applying frequency of printed circuit board (pcb) is also more and more higher, and this has proposed new challenge to the signal integrity control technology.

The back drill technology is exactly to utilize major diameter to bore cutter the via hole of completing plating is carried out secondary drilling, reducing the unnecessary part of via hole hole wall, eliminates via hole to impacts such as the reflection of signal, ring, resonance thereby reach, and ensures signal integrity.But the existence of back drill hole stub makes improvement forever can't reach optimal state, thereby back drill stub precision is the key point of assessment back drill quality.Usually stub length is controlled in 20mil and just can guarantees signal integrity preferably, high-precision requirement need be controlled in 10mil, therefore need to carry out special control for the principal element that affects back drill stub precision, in the hope of realizing high accuracy (in 10mil) requirement.

The dark principle of rig control is that main shaft touches conductive cover plate with drill point and forms current loop and begin to calculate in going down process, and motor system is controlled and got into the set depth value under main shaft and stop.Control dark starting point place's drill point and conductive cover plate contact point and be apex point most advanced and sophisticated, control dark destination county drill point and back drill stub end breaking part contact point is the apex point chisel edge, this causes actual back drill stub value and theoretical value that certain deviation is arranged.

Conventional back drill technique will be to causing the whole deviation tens of back drill stub length to hundreds of micron (the back drill depth offset causes), and mostly adopting the measure of ignoring for this influence factor in industry at present, this is with the applying frequency scope of serious ground restriction PCB back drill plate.Thereby solution is eliminated the depth accuracy error of conventional back drill technique for improving back drill partitioned signal integrality, improving the applying frequency important in inhibiting.

Summary of the invention

The present utility model purpose is to provide a kind of back drill drilling equipment, and it can overcome the defective of prior art, and the technical problems such as it can solve, and the back drill degree of depth is partially shallow, back drill stub low precision improve the dark precision of control and back drill stub precision.

The purpose of this utility model is achieved in that

A kind of back drill drilling equipment, it includes rig, bakelite plate, plate to be processed and conductive cover plate, described bakelite plate is fixed on drill floor, described plate to be processed and described conductive cover plate are fixed on described bakelite plate successively, rig bores cutter and is fixed on the main shaft of rig top, and rig bores cutter and has the back drill stub after back drill on described plate to be processed;

Wherein, back drill stub deviate=actual stub value-theoretical stub value=(R/2) * ctg(θ/2), R is the diameter of back drill through hole, θ is the wedge angle angle that rig bores cutter.

Preferably, the angle of the wedge angle angle of described rig brill cutter is 130 °-165 °.

Preferably, the diameter of described back drill through hole is 0.4mm-2.4mm.

Preferably, the thickness of described conductive cover plate is 0.15-0.2mm.

The utility model back drill drilling equipment compared with prior art has following beneficial effect:

The utility model passes through the deviate of the diameter of back drill through hole and the wedge angle angle acquisition back drill stub that rig bores cutter, control deep degree by adjusting more afterwards, can be good at solving the problem of back drill stub low precision, expanded the scope that printed circuit board (PCB) is used at high speed signal.

Description of drawings

Fig. 1 the utility model back drill drilling equipment structural representation;

Fig. 2 is the utility model back drill depth compensation process structure schematic diagram.

The specific embodiment

As shown in Figures 1 and 2, the utility model back drill drilling equipment, it includes rig, bakelite plate 10, printed circuit board (PCB) to be processed 11 and conductive cover plate 12; Wherein, described bakelite plate 10 is fixed on drill floor 13 by nut, described printed circuit board (PCB) to be processed 11 and described conductive cover plate 12 are fixed on described bakelite plate 10 successively, described printed circuit board (PCB) to be processed 11 is fixed by a pin to the upper surface of described bakelite plate 10, described conductive cover plate 12 is fixed on described printed circuit board (PCB) to be processed 11 by U.S. line glue, described rig bores cutter 14 and is fixed on the main shaft of rig top, and rig is controlled main shaft according to default depth value and holed downwards.

usually more than the large 0.2mm of back drill boring ratio through-hole diameter reaches, when rig brill cutter 14 bores the cutter target location, the apex point tip that rig bores cutter is in the center of back drill through hole 15, apex point please be write exactly with back drill stub end and contact, apex point this moment tip is exactly the back drill stub deviate 18 of back drill stub actual value 16 and theoretical back drill stub value 17 to the vertical range (Z-direction distance) of the contact point of apex point inclined plane and back drill stub end, actual back drill stub value 16 is greater than theoretical back drill stub value 17, its departure is subject to the impact that back drill through-hole diameter R and rig in structure bore the wedge angle angle theta of cutter, concrete deviation relational expression is: back drill stub deviate=actual stub value-theoretical stub value=(R/2) * ctg(θ/2).

In this preferred embodiment, the span of back drill through-hole diameter R is 0.4mm-2.4mm, 130 °-165 ° of the angles of the wedge angle angle theta of described rig brill cutter, and the thickness of described conductive cover plate 12 is 0.15-0.2mm.

Before back drill boring, can bore the numerical value of the wedge angle angle theta of cutter according to the value of back drill through hole 15 diameter R and selected rig, utilize above-mentioned deviation relational expression that the depth compensation table is calculated and be organized into to the back drill deviate, as shown in the table:

During back drill boring, according to the wedge angle angle theta numerical value of back drill through hole 15 diameter R numerical value and rig brill cutter, inquiry compensation in above-mentioned compensation meter, then, the drilling depth of controlling the deep drilling machine by control compensates, and solves the problem of back drill stub low precision.

The above embodiment has only expressed several embodiment of the present utility model, and it describes comparatively concrete and detailed, but can not therefore be interpreted as the restriction to written or printed documents utility model patent scope.Should be pointed out that for the person of ordinary skill of the art, without departing from the concept of the premise utility, can also make some distortion and improvement, these all belong to protection domain of the present utility model.Therefore, the protection domain of the utility model patent should be as the criterion with claims.

Claims

1. back drill drilling equipment, it is characterized in that, it includes rig, bakelite plate, plate to be processed and conductive cover plate, described bakelite plate is fixed on drill floor, described plate to be processed and described conductive cover plate are fixed on described bakelite plate successively, rig bores cutter and is fixed on the main shaft of rig top, and rig bores cutter and has the back drill stub after back drill on described plate to be processed;

2. back drill drilling equipment according to claim 1, is characterized in that, the angle that described rig bores the wedge angle angle of cutter is 130 °-165 °.

3. back drill drilling equipment according to claim 2, is characterized in that, the diameter of described back drill through hole is 0.4mm-2.4mm.

4. back drill drilling equipment according to claim 1, is characterized in that, the thickness of described conductive cover plate is 0.15-0.2mm.