WO2008139472A2

WO2008139472A2 - Dual spindle system

Info

Publication number: WO2008139472A2
Application number: PCT/IL2008/000661
Authority: WO
Inventors: Yitzhak Oz
Original assignee: Colibri Spindles Ltd.
Priority date: 2007-05-15
Filing date: 2008-05-13
Publication date: 2008-11-20
Also published as: IL183224A0; WO2008139472A3

Abstract

A dual spindle system for a drilling machine for printed circuit boards has a low speed spindle head and a high speed spindle head. The low speed spindle head and the high speed spindle head may be spaced apart to perform low and high speed drilling actions along parallel axes, or may be attached one to the other to alternately perform low and high speed drilling actions along a similar axis.

Description

DUAL SPINDLE SYSTEM

FIELD OF THE INVENTION This invention relates in general to spindles used in the printed circuit board (PCB) industry, and more particularly to spindles that are used for drilling a PCB.

BACKGROUND OF THE INVENTION The PCB drilling industry is leading towards PCB drilling machine tools which provide the ability to drill both large diameter bores (up to 6 mm) as well as very small bores (up to 0.05 mm), using the same machine.

Large diameter bores are typically performed at a low rotational speed range (125 to 160 Krpm) and high torque / power, while the small diameter bores are typically performed at a high rotational speed range (200 to 350

Krpm) and low torque / power. The (theoretical) optimized rotation speeds for the smaller bore diameters is approximately 450 Krpm.

A single spindles which would provide the abilities described above, is not known in the art. It is an object of the present invention to provide a spindle system having the capability to drill both large and small diameter bores.

SUMMARY OF THE INVENTION

In accordance with a first embodiment of the present invention there is provided a dual spindle system for a drilling machine for printed circuit boards comprising a low speed spindle head and a high speed spindle head, the low speed spindle head being adapted to perform a low speed drilling action about a first axis of rotation and the high speed spindle head being adapted to perform a high speed drilling action about a second axis of rotation, wherein the first axis is parallel to the second axis.

Typically, the dual spindle system further comprises a first drive and a second drive, the first drive being adapted to bias the low speed spindle head forward along the first axis to perform a drilling movement and the second drive being adapted to bias the high speed spindle head forward along the second axis to perform a drilling movement.

If desired, the high speed spindle head comprises a vacuum sleeve being moveable between a rearward retracted position and a forward extended position, wherein at least during the drilling movement of the high speed spindle head the vacuum sleeve is urged forwardly to bear against the drilled material to remove drilling debris away from the drilled material.

Preferably, the high speed spindle head comprises first and second channels that are formed therein, the first channel communicating with at least a portion of the vacuum sleeve located upstream and air flowing through the first channel upstream is adapted to urge the vacuum sleeve rearward, the second channel communicating with at least a portion of the vacuum sleeve located upstream and air flowing through the second channel upstream is adapted to urge the vacuum sleeve forward. In accordance with a second embodiment of the present invention there is provided a dual spindle system for a drilling machine for printed circuit boards comprising a low speed spindle head, a high speed spindle head and an axis of rotation, the low speed spindle head extending axially to a forward end and being adapted to alternately receive at the forward end a drill bit for performing a low speed drilling action about the axis and the high speed spindle head with a drill bit for performing a high speed drilling action about the axis, wherein when the dual spindle system performs the high speed drilling action only the high speed spindle head has portions that rotate about the axis.

Typically, the low speed spindle head comprises at least one socket at the forward end and the high speed spindle head comprises at least one pin, wherein when the low speed spindle head receives the high speed spindle head the at least one socket receives the at least one pin to form a flow path between the low and high speed spindle heads.

If desired, the high speed spindle head comprises a pneumatic turbine that is adapted to rotate the drill bit and air flowing through the flow path bears against the turbine to thereby rotate the turbine about the axis to perform the high speed drilling action.

Optionally, the at least one socket comprises a ball that is initially biased towards the socket to block the socket for flow of air therethrough, and wherein the pin when received in the socket biases the ball away from the socket to form the flow path.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding the invention will now be described, by way of example only, with reference to the accompanying drawings in which: FIG. IA is a perspective top view of a dual spindle system in accordance with a first embodiment of the present invention;

FIG. IB is a top view of a portion of the system shown in FIG. IA; FIG. 2A is a perspective top view of the system shown in FIG. IA with a high speed spindle (HSS) head in a working position; FIG. 2B is a side view of the system shown in FIG. 2 A;

FIG. 3A is a perspective top view of the system shown in FIG. IA with a low speed spindle (LSS) head in a working position;

FIG. 3B is a side view of the system shown in FIG. 3 A; FIG. 4 is a section view taken in the plane IV-IV of Fig. IB showing the HSS head with a vacuum sleeve in a retracted position;

FIG. 5 is the section view taken in the plane V-V of Fig. IB showing the HSS head with the vacuum sleeve in an extended position;

FIG. 6 is a perspective bottom view of a dual spindle system in accordance with a second embodiment of the present invention; FIG. 7 is an exploded view of the system shown in Fig. 6 showing a low speed spindle (LSS) head and a high speed spindle (HSS) head; FIG. 8 is a perspective bottom view of the LSS head of the second embodiment;

FIG. 9 is a perspective top view of the HSS head of the second embodiment; FIG. 10 is a bottom view of the LSS head of the second embodiment;

FIG. 11 is a partial cross sectional view of the LSS head taken in the plane XI-XI of Fig. 10;

FIG. 12 is the partial cross sectional view of Fig. 11 shown when the HSS head is attached to the LSS head; and FIG. 13 is a cross sectional view of the HSS head of the dual spindle system in accordance with the second embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Attention is drawn to Fig. IA. In accordance with a first embodiment of the present invention there is provided a dual spindle system 10 in which a low speed spindle (LSS) head 12 and a high speed spindle (HSS) head 14 are paired together to form a spindle system that may be mounted in a drilling machine (not shown) for drilling printed circuit boards (PCB's). The LSS head 12 has a first axis of rotation Rl and the HSS head 14 has a second axis of rotation R2 that is parallel to the first axis of rotation Rl.

The LSS head 12 is adapted to provide a low rotational speed in the range of for example 125 to 160 Krpm and high torque / power, while the HSS head 14 is adapted to provide a high rotational speed in the range of for example 200 to 350 Krpm and low torque / power. The LSS head 12 is typically adapted to drill bores having a diameter of up to several millimeters and the HSS head is typically adapted to drill bores having a diameter of up to several tens of microns. The dual spindle system 10 in accordance with the first embodiment of the present invention has a first drive 15 that is adapted to bias the LSS head 12 along the first axis Rl and a second drive 16 that is adapted to bias the HSS head 14 along the second axis R2. The first and second axes Rl, R2 define each an axial forward direction in the direction of drilling and an opposing axial rear direction. During use, each one of the spindles 12, 14 is independent to perform a drilling action along its respective axis Rl, R2.

Attention is drawn to Figs. 2A to 3B. To perform a high speed drilling action the second drive 16 biases the HSS head 14 forwardly to perform the drilling action (Figs. 2A, 2B) and to perform a low speed drilling action the first drive 15 biases the LSS head 12 forwardly to perform the drilling action.

In the PCB drilling machine industry, vacuum is required in order to absorb powder that is generated from the drilling process. Such a vacuum is provided in the vicinity of a point along the axis where drilling is designed to occur. In the dual spindle system 10 in accordance with the first embodiment of the present invention drilling is designed to occur at two separate points along axes Rl, R2 that are linearly displaced one from the other. The drilling machine therefore may be able to provide vacuum suction for only one of the spindles. The LSS head 12 for example may be that spindle, Attention is now drawn to Figs. 4 and 5. The HSS head 14 is provided with a vacuum sleeve 18 for absorbing powder that is generated during drilling. The vacuum sleeve 18 has a cylindrical body 20 that extends axially forwardly along the second axis R2 to end at a forwardly facing cap 22. The cap 22 has an aperture 24 that is formed therethrough along the axis R2 that is adapted to surround the point where drilling is designed to occur in the HSS head 14.

The body 20 of the vacuum sleeve 18 surrounds a housing 26 of the HSS head 14 and is adapted to slide axially thereupon. A turbine 28 of the HSS head 14 is located within the housing 26 along the second axis R2 and is adapted to rotate about the second axis R2. An automatic tool change (ATC) device 30 that is located rear of the turbine 28 is designed to releasably retain therein drilling bits 32.

First and second channels 34, 36 of the HSS head 14 are formed therein and are adapted to provide paths for air flowing upstream into the HSS head 14. The first channel 34 (see Fig. 4) extends initially forwardly and then rearward to end at a forwardly facing side of an annular ridge 38 of the sleeve's body 20. The second channel 36 (see Fig. 5) extends forwardly to end at an opposing rearward facing side of the annular ridge 38 of the sleeve's body 20. Air flowing upstream through the first channel 34 (indicated by arrows 40) is adapted to bear against the annular ridge 38 to thereby bias the vacuum sleeve 18 to a rearward retracted position and air flowing upstream through the second channel 36 (indicated by arrows 42) is adapted to bear against the annular ridge 38 to thereby bias the vacuum sleeve 18 to a forward extended position.

During a drilling movement, air provided through the second channel 36 urges the vacuum sleeve 18 forwardly to bear against the PCB that is being drilled to thereby remove drilling debris away from the drilled material. During tool change, the vacuum sleeve 18 should be in a retracted position. It is noted that vacuum is formed within the vacuum sleeve by a suction tube (not sown) that may extend through the housing 26 or may be external to the housing 26.

The HSS head 14 design in accordance with the present invention is a cost effective design that optionally utilizes pneumatic turbines for providing rotational speed and torque as opposed to those spindles typically used in the PCB industry that utilize electrical motors for providing rotational speed and torque. Pneumatic turbines for example may not require driver units and thereby the cost of systems incorporating such turbines is reduced.

Pneumatic turbines that may be used in the HSS head are optionally similar to those used in the dental industry such as those manufactured by KaVo Dental GmbH. Pneumatic turbines are suitable for high speeds - low torque applications and have a vibration level that is lower than typical spindles that are used in PCB drilling machines due to their lower moment of inertia which results from their small shaft diameter. The small shaft diameter of the turbine also reduces the centrifugal forces that are imposed upon the turbine which thereby enables the use of ball-bearings in the HSS head in place of the air-bearings that are typically used within the conventional PCB drilling spindles. Ball-bearings are less expensive and less sensitive to external crashes, although may have a limited lifetime as compared to air bearings. Due to the low mass of the HSS head 14, higher acceleration rate around the axis R2 may be achieved, as well as the use of low power drivers. Once again, this accounts to reduction in system cost, in addition to a significant increase in counted unit per hour (UPH).

Attention is drawn to Figs 6 and 7. In accordance with a second embodiment of the present invention there is provided a dual spindle system 44 having an axis of rotation R3 that defines an axial forward direction in the direction of drilling and an opposing axial rear direction. The dual spindle system 44 has a low speed spindle (LSS) head 46 that may alternately receive at a forward end 47 thereof a drill bit (drill bit mounted in LSS head is not shown in the Figs) for performing a low speed drilling action about the axis R3; and a high speed spindle (HSS) head 48 with a drill bit 32 for performing a high speed drilling action about the axis R3.

Attention is additionally drawn to figs. 8 and 9. The LSS head 46 (Fig. 8) has three channels 50 (one of the channels is shown in Figs. 11 and 12) that are formed therein that open out to the forward end 47 of the head at three sockets 52, respectively. The LSS head 46 has in addition at the forward end 47 a chuck 54 that is located about the axis R3 and is coupled to a motor (not shown) of the LSS head 46 that is adapted to rotate about the axis R3 at a low rotational speed. The HSS head 48 (Fig. 9) has at a rear end thereof three pins 56 and a rod 58. The rod 58 extends rearward along the axis R3 and each pin 56 communicates with a respective air way 60 (one air way is shown in Fig. 13) of the HSS head 48 that is formed in the HSS head 48. When the LSS and HSS heads 46, 48 are attached one to the other, the rod 58 is received within the chuck 54 and each pin 56 is received within a respective socket 52. It is noted that that chuck 54 may receive therein also a drilling bit 32 for performing a low speed drilling action.

Attention is now drawn to Fig. 11. A plug mechanism 62 is provided at each socket 52 in order to block the path for air out of the channels 50 when the LSS and HSS heads 46, 48 are not attached or disconnected. The plug mechanism 62 includes a ball 64 and a spring 66 wherein the ball 64 is biased towards the socket 52 by the spring 66 and is adapted to block the socket 52 for flow of air. Attention is now drawn to Fig. 12. Each pin 56 is provided with a lumen

68 that passes therethrough. In the attached state of the HSS head 48 upon the

LSS head 46, each pin 56 of the HSS head 48 biases the respective ball 64 of its socket 52 away from the socket 52 to thereby open a flow path for air between the LSS and HSS heads 46, 48 that passes, inter alia, via the lumen 68.

Attention is now drawn to Fig. 13. Air flowing through the air paths that are formed between the LSS and HSS heads 46, 48 may power an automatic tool change (ATC) device 30 of the HSS head 48 or may bear against a pneumatic turbine 28 of the HSS head 48 to thereby rotate the turbine 28 about the axis R3 and perform a high speed drilling action thereabout. It is noted that during high speed drilling, the motor of the LSS head is kept still and not in rotation about the axis R3; and only the turbine 28 of the HSS head 48 is in rotation to thereby provide the high speed drilling action.

Although the present invention has been described to a certain degree of particularity, it should be understood that various alterations and modifications could be made without departing from the scope of the invention as hereinafter claimed.

Claims

CLAIMS:

1. A dual spindle system (10) for a drilling machine for printed circuit boards comprising a low speed spindle head (12) and a high speed spindle head (14), the low speed spindle head (12) being adapted to perform a low speed drilling action about a first axis of rotation (Rl) and the high speed spindle head (14) being adapted to perform a high speed drilling action about a second axis of rotation (R2), wherein the first axis (Rl) is parallel to the second axis (R2).

2. The dual spindle system (10) according to claim 1, further comprising a first drive (15) and a second drive (16), the first drive (15) being adapted to bias the low speed spindle head (12) forward along the first axis (Rl) to perform a drilling movement and the second drive (16) being adapted to bias the high speed spindle head (14) forward along the second axis (R2) to perform a drilling movement.

3. The dual spindle system (10) according to claim 2, wherein the high speed spindle head (14) comprises a vacuum sleeve (18) being moveable between a rearward retracted position and a forward extended position, wherein at least during the drilling movement of the high speed spindle head (14) the vacuum sleeve (18) is urged forwardly to bear against the drilled material to remove drilling debris away from the drilled material.

4. The dual spindle system (10) according to claim 3, wherein the high speed spindle head (14) comprises first and second channels (34, 36) that are formed therein, the first channel (34) communicating with at least a portion of the vacuum sleeve (18) located upstream and air flowing through the first channel (34) upstream is adapted to urge the vacuum sleeve (18) rearward, the second channel (36) communicating with at least a portion of the vacuum sleeve (18) located upstream and air flowing through the second channel (36) upstream is adapted to urge the vacuum sleeve (18) forward.

5. A dual spindle system (44) for a drilling machine for printed circuit boards comprising a low speed spindle head (46), a high speed spindle head (48) and an axis of rotation (R3), the low speed spindle head (46) extending axially to a forward end (47) and being adapted to alternately receive at the forward end (47) a drill bit (32) for performing a low speed drilling action about the axis (R3) and the high speed spindle head (48) with a drill bit (32) for performing a high speed drilling action about the axis (R3).

6. The dual spindle system (44) according to claim 5, wherein when the dual spindle system (44) performs the high speed drilling action only the high speed spindle head (48) has portions that rotate about the axis (R3).

7. The dual spindle system (44) according to claim 5, wherein the low speed spindle head (46) comprises at least one socket (52) at the forward end (47) and the high speed spindle head (48) comprises at least one pin (56), wherein when the low speed spindle head (46) receives the high speed spindle head (48) the at least one socket (52) receives the at least one pin (56) to form a flow path between the low and high speed spindle heads (46, 48).

8. The dual spindle system (44) according to claim 7, wherein the high speed spindle head (48) comprises a pneumatic turbine (28) that is adapted to rotate the drill bit (32) and air flowing through the flow path bears against the turbine (28) to thereby rotate the turbine (28) about the axis (R3) to perform the high speed drilling action.

9. The dual spindle system (44) according to claim 7, wherein the at least one socket (52) comprises a ball (64) that is initially biased towards the socket (52) to block the socket (52) for flow of air therethrough, and wherein the pin (56) when received in the socket (52) biases the ball (64) away from the socket (52) to form the flow path.