Method for the simultaneous double-side material-removing processing of at least three workpieces

• US 8,851,958 B2
• Filed: 09/04/2012
• Issued: 10/07/2014
• Est. Priority Date: 09/16/2011
• Status: Active Grant

• Current Assignee: Siltronic AG (Dr. Alexander Wacker Familiengesellschaft Mit Beschrã¤Nkter Haftung)
• Original Assignee: Siltronic AG (Dr. Alexander Wacker Familiengesellschaft Mit Beschrã¤Nkter Haftung)
• Inventors: Pietsch, Georg
• Primary Examiner(s): NGUYEN, GEORGE BINH MINH
• Application Number:
  US13/602,436
• Publication Number:
  US 20130072093A1
• Time in Patent Office: 763 Days
• Field of Search: 451/5, 451/41, 451/57, 451/262, 451/268
• US Class Current: 451/57
• CPC Class Codes: B24B 37/28 for double side lapping of plane surfaces
• CPC Class Codes: B24B 47/12 by mechanical gearing or electric power B24B47/16 takes precedence

Abstract

A method for simultaneous double-side material-removing processing of at least three workpieces includes disposing the workpieces in a working gap between rotating upper and lower working disks of a double-side processing apparatus. The workpieces lie in freely movable fashion in respective openings in a guide cage and are moved under pressure in the working gap using the guide cage. Upon attaining a preselected target thickness of the workpieces, a deceleration process is initiated that includes reducing an angular velocity ωi(t) of a respective drive i of each of the upper working disk, lower working disk and guide cage to a standstill. The reducing is carried out such that ratios of the angular velocities ω_i(t) with respect to one another as a function of time t deviate by no more than 10% from initial ratios of the angular velocities ω_i(t) corresponding to when the preselected target thickness was attained.

Claims

1. A method for simultaneous double-side material-removing processing of at least three workpieces, the method comprising:

disposing the at least three workpieces in a working gap between a rotating upper working disk and a rotating lower working disk of a double-side processing apparatus, each workpiece lying in freely movable fashion in a respective opening of a guide cage;

moving the at least three workpieces under pressure in the working gap using the guide cage; and

upon attaining a preselected target thickness of the workpieces, initiating a deceleration process including reducing an angular velocity ω

_i(t) of a respective drive i of each of the upper working disk, the lower working disk and the guide cage to a standstill, the reducing being carried out such that ratios of the angular velocities ω

_i(t) with respect to one another as a function of time t deviate by no more than 10% from initial ratios of the angular velocities ω

_i(t) corresponding to when the preselected target thickness was attained.

2. The method as claimed in claim 1, wherein the the reducing is carried out such that ratios of the angular velocities ω

_i(t) with respect to one another as a function of time t deviate by no more than 5% from initial ratios of the angular velocities ω

_i(t) corresponding to when the preselected target thickness was attained.

3. The method recited in claim 1, wherein the working disks are ring-shaped, and the method uses at least three circular guide cages each having at least one cutout for a respective workpiece and each having a toothing extending circumferentially on a circumference of the guide cage, wherein the toothing engages into an outer and an inner drive ring, which are respectively arranged concentrically with respect to a rotational axis of the working disks, and wherein the two drive rings constitute the drives of the guide cages by means of which the guide cages are moved circumferentially with simultaneous inherent rotation about the rotational axis of the working disks, such that the workpieces describe cycloidal trajectories relative to the two working disks.

4. The method recited in claim 1, wherein the working disks are circular and the method uses exactly one guide cage, which covers an entire area of the working disks and is driven by eccentrically rotating guide rollers arranged on a circumference of the working disks to effect an orbital movement such that in a resting reference system for each workpiece there is a respective stationary area which is completely covered by the workpiece at any time.

5. The method recited in claim 1, wherein the angular velocity ω

_i(t) of each drive i is reduced in accordance with ω

_i(t)=ω

_i,0−

k_i/J_it, wherein ω

_i,0 denotes an initial angular velocity at a beginning of the deceleration process, J_i denotes a moment of inertia where J_i=∫

ρ

_i(τ

)r²d τ

, ρ

_i(τ

) denotes a density distribution, r denotes a distance from an axis of rotation, k_i denotes a deceleration capacity of the drive i, dr denotes an infinitesimal element of a volume r that encompasses rotating parts of the drive i, and t denotes time.

6. The method recited in claim 1, wherein a magnitude of a change in the angular velocity ω

_i(t) of each drive i per unit time increases in a course of the deceleration process.

7. The method recited in claim 6, wherein the angular velocity ω

_i(t) of each drive i is reduced in accordance with

8. The method recited in claim 1, wherein a duration t_br of the deceleration process is determined by the respective drive i with a greatest angular momentum L_i=J_iω

_i,0, wherein ω

_i,0 denotes an angular velocity at a beginning of the deceleration process, J_i=∫

ρ

_i(τ

)r²d τ

denotes a moment of inertia, ρ

_i(τ

) denotes a density distribution, r denotes a distance from an axis of rotation, dr denotes an infinitesimal element of a volume τ

that encompasses rotating parts of the drive i, and t denotes time.

9. The method recited in claim 1, wherein the pressure exerted on the workpieces by the upper and lower working disks is reduced during the deceleration process.

10. The method recited in claim 9, wherein the pressure at the end of the deceleration process is greater than zero.

11. The method recited in claim 1, wherein each working disk respectively carries a working layer containing fixedly bonded abrasive which, through contact with the workpieces, brings about material removal from the workpieces by grinding.