Process to edge and polish polycarbonate and CR 39 lenses with diamond wheels

• US 5,711,700 A
• Filed: 02/22/1994
• Issued: 01/27/1998
• Est. Priority Date: 02/22/1994
• Status: Expired due to Term

• Current Assignee: Inland Diamond Products Company
• Original Assignee: Inland Diamond Products Company
• Inventors: Raffaelli, Dennis R.
• Primary Examiner(s): Eley, Timothy V.
• Application Number:
  US08/200,285
• Time in Patent Office: 1,435 Days
• Field of Search: 451/43, 451/53, 451/57, 451/58, 451/240, 451/255, 451/256, 451/541, 451/544, 451/545
• US Class Current: 451/43
• CPC Class Codes: B24B 13/01 Specific tools, e.g. bowl-like; Production, dressing or fastening of these tools
• CPC Class Codes: B24B 9/14 of optical work, e.g. lenses, prisms control of the position of the tool for bevelling optical work B24B47/225
• CPC Class Codes: B24B 9/20 of plastics
• CPC Class Codes: B24D 18/0027 by impregnation
• CPC Class Codes: B24D 3/28 Resins or natural or synthetic macromolecular compounds B24D3/22 takes precedence
• CPC Class Codes: B24D 5/02 Wheels in one piece

Abstract

A process and apparatus for edging and polishing an ophthalmic lens is provided whereby an edge of a polycarbonate ophthalmic lens is polished to a high luster finish substantially equal to the finish on the optical surface of the lens. The process allows the use of one machine for processing of all common ophthalmic lens materials such as polycarbonate, CR 39 or glass, whereby the lens may be edged and polished with one machine. The process of the invention comprises the steps of roughing a polycarbonate lens substantially without coolant and passing a polishing wheel of the present invention over the surface of the lens substantially without coolant and then passing the polishing wheel over the surface of the lens with the use of coolant for at least one pass over the portion of the lens edge to be polished. A single abrasive wheel is used for machine polishing of the lens edge. The wheel is an impregnated wheel of from about 2 to about 60 micron diamond hardness abrasive particles in a concentration of from about 10 to about 200 concentration. The wheel may be used for conventional wet finishing of lens, blank materials other than polycarbonates.

Claims

1. A process for polishing of a polycarbonate lens comprising the steps of:

a) providing an optical lens made of a polycarbonate material having a rough edge surface and a finished optical surface;

b) providing an abrasive finishing apparatus for finishing of the rough edge surface, said step of providing an abrasive finishing apparatus including providing an abrasive finishing apparatus having abrasive particles of a size from about 2 microns to about 60 microns and a concentration of the abrasive particles from about 10 concentration to about 200 concentration;

c) polishing at least a portion of said rough edge surface by causing said finishing apparatus to contact said portion of said edge surface to be polished at least once without the use of a coolant flow or with a coolant flow of about 8 ounces per minute or less; and

d) causing said finishing apparatus to contact said portion of said edge surface to be polished at least once with a coolant flow or an increased coolant flow, wherein a final finish substantially equal to said finished optical surface of the lens is produced.

2. The process of claim 1, wherein said step of providing an abrasive finishing apparatus includes providing a polishing wheel.

3. The process of claim 2, wherein said step of providing a polishing wheel includes providing an impregnated polishing wheel having abrasive grit particles of from about 8 to about 12 microns in size.

4. The process of claim 2, wherein said step of providing a polishing wheel includes providing an impregnated polishing wheel having from 75 to about 125 concentration of diamond particles as said abrasive grit.

5. The process of claim 2, wherein said step of providing a polishing wheel includes providing an impregnated polishing wheel having abrasive grit particles in a size of from about 10 to 30 microns.

6. The process of claim 2, wherein said step providing a polishing wheel includes providing an impregnated bonded polishing wheel having from about 35 to about 150 concentration of diamond particles as said abrasive grit.

7. The process of claim 2, wherein said step providing a polishing wheel includes providing an impregnated polishing wheel having abrasive grit particles of from about 7 to about 30 microns in size.

8. The process of claim 2, wherein said step of providing a polishing wheel includes providing an impregnated polishing wheel having abrasive grit particles of from about 15 to about 20 microns in size.

9. The process of claim 1, wherein the edge of the lens is caused to contact the finishing apparatus a plurality of times without the use of the coolant or the coolant flow.

10. The process of claim 1, wherein roughing and beveling the polycarbonate lens occurs prior to the step of polishing the rough edge surface of the lens.

11. The process of claim 3, wherein the roughing and beveling of the polycarbonate lens is performed with an interrupted cooling cycle.

12. A process for grinding and polishing a polycarbonate lens, said method comprising the steps of:

providing an optical lens made of a polycarbonate material having a rough edge surface and finished optical surface;

providing a rough grinding wheel;

grinding the rough edge surface of the lens with the rough grinding wheel without the use of a coolant;

providing a polishing wheel for polishing the rough edge surface of the lens; and

polishing the rough edge surface with the polishing wheel after the step of grinding with the rough grinding wheel by causing the polishing wheel to contact the rough edge surface at least once with a coolant flow less than about 8 ounces per minute, and at least once with an increased coolant flow.