Cutting device with a pair of cutting blades and elements for detecting and controlling wear of the cutting blades

• US 7,484,444 B2
• Filed: 02/01/2005
• Issued: 02/03/2009
• Est. Priority Date: 02/02/2004
• Status: Active Grant

• Current Assignee: Disco Corporation
• Original Assignee: Disco Corporation
• Inventors: Tokumitsu, Naoya
• Primary Examiner(s): Ashley; Boyer D.
• Assistant Examiner(s): LEE, LAURA MICHELLE
• Application Number:
  US11/046,801
• Publication Number:
  US 20050166745A1
• Time in Patent Office: 1,463 Days
• Field of Search: 838/84, 838/81, 834/253, 83/621, 83/72, 83/74, 83/75, 83D/IG.1, 837/71, 834/252, 483 4- 11, 700/169, 700/174, 700/175, 409/187, 409/194
• US Class Current: 83/62.1
• CPC Class Codes: B28D 5/0064 Devices for the automatic drive or the program control of the machines
• CPC Class Codes: B28D 5/029 with a plurality of cutting blades
• CPC Class Codes: Y10T 83/037 Rotary scoring blades
• CPC Class Codes: Y10T 83/089 Responsive to tool characteristic
• CPC Class Codes: Y10T 83/141 With means to monitor and control operation [e.g., self-regulating means]
• CPC Class Codes: Y10T 83/173 Arithmetically determined program
• CPC Class Codes: Y10T 83/6587 Including plural, laterally spaced tools

Abstract

A cutting device having a holding element for holding a workpiece, a pair of cutting blades for cutting the workpiece held by the holding element, the cutting blades being adapted to be rotated, a wear amount detecting element for detecting the amount of wear of each of the pair of cutting blades, and a control element. The control element is arranged to selectively cut the workpiece by both of the pair of cutting blades, or cut the workpiece by one of the pair of cutting blades. When the workpiece is to be cut by one of the pair of cutting blades, the control element compares the amounts of wear of the pair of cutting blades detected by the wear amount detecting element, and allows the cutting blade having a smaller amount of wear to cut the workpiece.

Claims

1. A cutting device comprising:

a holding member for holding a workpiece,

a pair of rotating spindles,

a pair of cutting blades of the same cross-sectional shape such that the cutting blades are interchangeable for cutting the workpiece held by said holding member, said cutting blades being rotated by said spindles,

a wear amount detecting member for detecting an amount of wear of each of said pair of cutting blades,

a control member,

a rotating spindle height detecting member for detecting a height of each spindle of said pair of rotating spindles,

a cutting blade detecting member corresponding to each cutting blade, each cutting blade detecting member including a light emitting element and a light receiving element with one of said cutting blades arranged therebetween, and

a comparing member for detecting a predetermined position of each of said cutting blades by detecting variations in voltage representative of variations in amounts of light received by said light receiving elements at a time that the lowermost portion of said cutting blades obstructs light from said light emitting element to said light receiving element as said cutting blades are lowered, wherein

said cutting blades are movable toward and away from each other, and are movable toward and away from said holding member,

said control member is arranged to selectively cut the workpiece by both of said cutting blades, or by one of said pair of cutting blades,

said wear amount detecting member calculates the amounts of wear of each of said cutting blades based on a difference between the height of their rotating spindles as detected by said rotating spindle height detecting member, and a predetermined position of each of said cutting blades as detected by said comparing member, and

when the workpiece is to be cut by one of said pair of cutting blades, said control member selects whichever cutting blade has a smaller amount of wear as calculated by said wear amount detecting member to cut the workpiece.

2. The cutting device according to claim 1, wherein said workpiece is a semiconductor wafer provided with a plurality of cutting lines, and said control member causes selective and simultaneous cutting of the workpiece by both of the cutting blades along the cutting lines to which the cutting blades are aligned, and causes the workpiece to be cut such that each of the plurality of cutting lines is cut by either but not both of the cutting blades.

3. The cutting device according to claim 2, wherein

said plurality of cutting lines includes a first set of cutting lines consisting of a plurality of cutting lines extending parallel in a first direction, and a second set of cutting lines consisting of a plurality of cutting lines extending perpendicularly to said first direction, and a spacing between the cutting lines of said first set of cutting lines and a spacing between the cutting lines of said second set of cutting lines are each smaller than a minimum spacing between said pair of cutting blades, and

said control member compares the amounts of wear of said pair of cutting blades detected by said wear amount detecting member before the workpiece is cut along each of the cutting lines of said first set of cutting lines, and further compares the amounts of wear of said pair of cutting blades detected by said wear amount detecting member before the workpiece is cut along each of the cutting lines of said second set of cutting lines after cutting of the workpiece along each of the cutting lines of said first set of cutting lines is completed.

4. The cutting device according to claim 3, wherein the first and second cutting lines on said semiconductor wafer are present in odd numbers in said first and second directions, respectively, further wherein each of said first and second cutting lines in said first and second directions, respectively, is cut with the cutting blade having a smaller amount of wear.

5. The cutting device according to claim 1, wherein the wear amount detecting means determines the allowable range of amount of wear of the cutting blades to judge the necessity of changing cutting blades.