JPH09192993A - Vertical twin head surface grinding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vertical twin head surface grinding machine which can simultaneously polish both surfaces of an ultra thin workpiece with a high degree of accuracy. SOLUTION: A workpiece conveying device 17 comprises a conveying belt 16 having several holes 35 with which a workpiece W is rotatably held and advancing horizontally, and upper and lower spindles 11, 12 which are adapted to be rotated in one and the same direction and which are arranged in the workpiece conveying direction with a predetermined space therebetween. A distance D between the center axes of both spindles 11, 12 is set so that the polishing surfaces of two grinding wheels 14, 15 overlap with each other as viewed in a plan view, and the width (d) of the overlapping parts is set to be greater than a maximum width of the workpiece but smaller than the radius of the rotary grinding wheels. Further, the conveying belt 16 is arranged so that the widthwise center line C of the belt passes through the center axes O1, O2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention holds a pair of vertical upper and lower spindles, a pair of upper and lower rotary grindstones fixed to the lower end of an upper spindle and the upper end of a lower spindle, respectively, and a work. The present invention relates to a hard-type double-sided surface grinder that is equipped with a work transfer device that transfers between two grindstones and that grinds two parallel surfaces of a work simultaneously.

[0002]

2. Description of the Related Art In recent years, this type of rigid double-sided surface grinder has been widely used for grinding ultra-thin works such as base materials for electronic parts.

FIG. 4 shows an example of a conventional structure. A pair of upper and lower rotating grindstones 1 and 2 facing each other are aligned on the same vertical axis O, and rotate in opposite directions. As a work transfer device, a carrier disc 3 having a large number of work holding holes 5 at its outer peripheral end is rotatably arranged, and the outer peripheral end of the carrier disc 3 is placed between both grindstones 1 and 2. It is supposed to pass.

As another conventional example, as shown in FIG.
No. 0-249563), there is a rigid double-sided surface grinder utilizing an endless belt 6 having an opening 7 as a work transfer device.

[0005]

When both surfaces of a work are simultaneously ground, a carrier disk thinner than the thickness of the work is required. In the carrier disk method of FIG. The work is very thin (for example 0.2 mm
If the thickness is about the same), the rigidity of the carrier disk 3 becomes insufficient, and smooth processing becomes impossible. By the way, the limit of current technology is to reduce the work thickness to about 0.8 mm.

On the other hand, in the endless belt system of FIG. 5, by using a thin steel plate or the like as the belt 6,
It enables continuous double-sided grinding of thin workpieces. However, the work does not rotate but passes between the grindstones with the posture fixed.

Further, since the upper and lower main shafts are arranged in series on the same vertical line O, the grindstones 1 and 2 are formed in an annular shape, and the belt 6 passes through the shaft center O portion, the work W is the grindstone 1. After being ground at the inlet side portions of the grinding wheels 2 and 2, they are once released in the space portion at the center of the grindstone, but are again ground at the outlet side portions of the grindstones 1 and 2. Moreover, when the second grindstone is being performed on the grindstone portion on the outlet side, the first work of the next work W is being performed on the grindstone portion on the inlet side. Therefore,
It is difficult to adjust the distance between both grindstones and the angle of the spindle in order to finish many workpieces with uniform accuracy.

[0008]

In order to solve the above-mentioned problems, the invention according to claim 1 is fixed to a pair of vertical upper and lower spindles, a lower end of an upper spindle and an upper end of a lower spindle, respectively. In a vertical double-sided surface grinder that includes a pair of upper and lower rotary grindstones, and a work transfer device that holds a work and transfers the work between both whetstones, and grinds both upper and lower end surfaces of the work at
The work transfer device is equipped with a transfer belt having a large number of holding holes for rotatably holding the work so as to move straight in the horizontal direction. The distance between the spindles of the two spindles is such that the grinding surfaces of both grindstones partially overlap each other when viewed from above, and the width of the overlapping portions in the workpiece conveyance direction is equal to or larger than the maximum width of the work and equal to or smaller than the radius of the rotating grindstone. The conveyor belt is characterized in that the center line of the belt width passes through both main shaft cores.

[0009]

1 is a vertical cross-sectional schematic view of a vertical double-sided surface grinder to which the present invention is applied, which is fixed to a pair of vertical upper and lower spindles 11 and 12 and a lower end portion of an upper spindle 11. Annular upper grindstone 14, an annular lower grindstone 15 fixed to the upper end of the lower spindle 12, a work transfer device 17 having a steel belt transfer belt 16, and a loading device 18
And an unloading device 19. The upper and lower grindstones 14 and 15 having the same diameter are mounted, and the surfaces facing each other are horizontal grinding surfaces.

The upper spindle 11 is rotatably supported by the upper spindle stock 21 and is linked to an upper drive motor 27 via pulleys 23, 25 and a transmission belt 24. The drive motor 27 is connected to the upper spindle. It is fixed to the table 21. The lower spindle 12 is rotatably supported by the lower spindle stock 22, and is linked to an upper drive motor 31 via pulleys 28, 30 and a transmission belt 29. The drive motor 31 is connected to the lower spindle stock. It is fixed to 22.

The conveyor belt 16 is arranged in a horizontal straight line along the workpiece conveying path passing between the two grindstones, and
Drive pulley 32 at the end of the transport path and other driven pulley 3
It is hung over 3 and moves endlessly in the direction of arrow R.

Both the spindles 11 and 12 are set so as to rotate in the same rotation direction (for example, a clockwise direction when viewed from above), and are arranged at a constant interval D in the work transfer direction. The distance D between the axes of both spindles 11 and 12 is such that the grinding surfaces of both grindstones 14 and 15 partially overlap each other when viewed from above as shown in FIG. It is set so that it is larger than the maximum width and smaller than the radius of the rotating grindstone.

The conveyor belt 16 has a large number of circular work holding holes 35 formed at equal intervals in the conveying direction over the entire length, and a conveyance center line C connecting the centers of the respective holding holes 35 is formed. It is arranged so as to pass through both main spindle cores O1 and O2. The thickness of the conveyor belt 16 is, for example, 0.05-0.
Various changes can be made within the range of 4 mm, which enables double-side grinding of ultra-thin workpieces of 0.1 to 0.5 mm.

In the central space portion of the lower grindstone 15, as shown in FIG. 1, a horizontal inlet side guide plate 40 having substantially the same height as the grinding surface of the lower grindstone 15 is arranged. On the top, we want the outlet of the loading device 18,
The work W is sequentially supplied into the holding hole 35 of the conveyor belt 16.

On the work outlet side of the lower grindstone 15, there is disposed an outlet side guide plate 41 extending horizontally rearward at substantially the same height as the grinding surface of the lower grindstone 15, and the outlet side guide plate 41.
A discharge hole 43 is formed at the rear end portion as the unloading device 19, and a carry-out conveyor 44 is arranged below the discharge hole 43.

The operation will be described. In FIG. 1, by starting the drive pulley 32, the conveyor belt 16 is moved to the arrow R
By rotating the motors 27 and 31 in the same direction and starting both motors 27 and 31, both grindstones 14 and 15 are rotated clockwise in FIG. 2 at the same rotational speed.

The unprocessed work W is sequentially supplied from the loading device 18 into the holding hole 35 of the conveyor belt 16 on the inlet side guide plate 40.

The upper and lower end surfaces of the work in the holding hole 35 are projected from the upper and lower end surfaces of the conveyor belt 16, respectively. In this state, the work is conveyed on the guide plate 40 in the R direction and the upper and lower grindstones are conveyed. It is supplied between 14 and 15.

While passing between the grindstones 14 and 15, the work W
The upper and lower end surfaces are simultaneously ground, but during this process, a rotational force in the direction of arrow M is applied to the work due to the difference in grinding speed between the inner and outer ends of the rotary grindstones 14 and 15, and the work rotates.

The reason for the above rotation will be described in detail. FIG.
6 is a plan view perspectively illustrating a state in which the work W is sandwiched between the grindstones 14 and 15. The lower grindstone 15 contacts the lower surface of the work to apply a grinding force. Since the grinding speed becomes faster on the outer side in the radial direction in proportion to the distance from the axis O2, the grinding force (black thick arrow) P1 applied to the circumference of the work W on the conveyance center line C of the lower grindstone 15 is shown. , P2
Becomes P1> P2, and the difference in grinding force (P1-P2) acts as a rotational force in the direction of arrow M1.

On the other hand, the upper grindstone 14 abuts on the upper surface of the work W to apply a grinding force, but the grinding speed of the grindstone 14 becomes faster in the radially outer side in proportion to the distance from the axis O1. , The work W on the transport center line C of the upper grindstone 14
Grinding force (white arrows) P3 and P4 on the circumference of
P3> P4 and the difference in grinding force (P1-P2) is indicated by arrow M
Acts as a rotational force in the direction.

The above two rotational forces (P1-P2), (P3
-P4) has a rotational force in the same direction with respect to the work W, so that the work W rotates in the M direction.

The work W ground on both sides while rotating is
The upper grindstone 14 is transferred onto the outlet side guide plate 41 of FIG.
After passing through the central space portion and the lower side of the grinding surface on the arrow R direction side, it is discharged from the discharge hole 43 onto the carry-out conveyor 44.

[0024]

[Other Embodiments]

(1) The upper grindstone 14 may be arranged on the conveyance start end side and the lower grindstone 15 may be arranged on the conveyance end side.

[0025]

As described above, according to the present invention, (1) the work is conveyed linearly by the conveyor belt 16 having the work holding hole 35, and both surfaces are ground while passing between the grindstones 14 and 15. Therefore, even an extremely thin work piece can be ground easily and accurately.

(2) The spindles 11 and 12 are displaced in the workpiece conveying direction with a space therebetween, and the distance D between the axes is determined so that the width d of the workpiece conveying direction at the overlapping portion of the grindstones 14 and 15 is the maximum width of the workpiece W. Since the radius is set to be equal to or smaller than the radius of the rotating grindstone, the work belt W is used to allow the work W to pass through the shaft core portions of both the grindstones 14 and 16 while performing accurate grinding. Also, compared with the conventional coaxial core arrangement in which the grinding wheels are intermittently passed twice, it is easy to adjust the grinding wheel interval or the grinding wheel angle, and uniform grinding performance can be exhibited.

(3) Both spindles 11 and 12 are shifted so as to be spaced apart in the workpiece conveying direction, the rotational directions of both grindstones 14 and 15 are the same, and both surfaces are simultaneously ground at the overlapping portions of both grindstones 14 and 15. Therefore, the workpiece being ground can be easily rotated by utilizing the difference in the grinding force due to the difference in the distance from the axis of the grinding surface, and the uniformity of the grinding accuracy is further improved.

[Brief description of the drawings]

FIG. 1 is a schematic front view of a vertical double-sided surface grinder to which the present invention is applied.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a perspective view for explaining an operation showing a relationship of a grinding force of a grindstone overlapping portion.

FIG. 4 is a perspective view of a conventional example.

FIG. 5 is a front view of another conventional example.

[Explanation of symbols]

 11 Upper Spindle 12 Lower Spindle 14 Upper Grinding Stone 15 Lower Grinding Stone 16 Conveying Belt 17 Work Conveying Device 35 Work Holding Hole

Claims (1)

[Claims] 1. A pair of vertical upper and lower spindles, a pair of upper and lower rotary grindstones respectively fixed to the lower end of the upper main spindle and the upper end of the lower main spindle, and a work is held and conveyed between the two grindstones. In a vertical double-sided surface grinder that is equipped with a work transfer device and grinds both upper and lower end surfaces of the work at the same time, the work transfer device moves a transfer belt having a large number of holding holes for holding the work rotatably straight in the horizontal direction. Thus, the upper and lower spindles are driven to rotate in the same rotation direction and are arranged at a constant interval in the work transfer direction.The distance between the spindles of both spindles is such that the grinding surfaces of both grindstones are viewed from above. The width in the work transfer direction of the overlapped part and the overlapped part is set to be equal to or larger than the maximum width of the work and equal to or smaller than the radius of the rotating grindstone,
A conveyor type double-sided surface grinder characterized in that the conveyor belt is arranged so that the width center line passes through both spindle cores.