Differential velocity extrusion

• US 6,645,406 B1
• Filed: 07/03/2000
• Issued: 11/11/2003
• Est. Priority Date: 06/30/2000
• Status: Expired due to Fees

• Current Assignee: Evolution Industries
• Original Assignee: Evolution Industries
• Inventors: Slyne, William J.
• Primary Examiner(s): Eashoo, Mark
• Application Number:
  US09/609,867
• Time in Patent Office: 1,226 Days
• Field of Search: 264/40.7, 264/167, 264/177.1, 264/177.16, 264/178.R, 425/71, 425/145, 425/378.1, 425/465
• US Class Current: 264/40.7
• CPC Class Codes: B29C 2948/92085 Velocity
• CPC Class Codes: B29C 2948/92104 Flow or feed rate
• CPC Class Codes: B29C 2948/92409 Die; Nozzle zone
• CPC Class Codes: B29C 2948/92514 Pressure
• CPC Class Codes: B29C 2948/9258 Velocity
• CPC Class Codes: B29C 2948/926 Flow or feed rate
• CPC Class Codes: B29C 2948/92609 Dimensions
• CPC Class Codes: B29C 2948/92695 Viscosity; Melt flow index [MFI]; Molecular weight
• CPC Class Codes: B29C 2948/92704 Temperature
• CPC Class Codes: B29C 2948/92904 Die; Nozzle zone
• CPC Class Codes: B29C 2948/92961 Auxiliary unit, e.g. for external melt filtering, re-combining or transfer between units
• CPC Class Codes: B29C 48/0017 combined with blow-moulding or thermoforming
• CPC Class Codes: B29C 48/0019 combined with shaping by flattening, folding or bending
• CPC Class Codes: B29C 48/08 flexible, e.g. films
• CPC Class Codes: B29C 48/10 flexible, e.g. blown foils
• CPC Class Codes: B29C 48/131 Curved articles
• CPC Class Codes: B29C 48/325 being adjustable , i.e. having adjustable exit sections
• CPC Class Codes: B29C 48/92 Measuring, controlling or regulating
• CPC Class Codes: B29L 2007/008 Wide strips, e.g. films, webs

Abstract

A method of an extruded membrane of solidified flowable material having a desired curvature comprising extruding flowable material through a die in a curved section; measuring a characteristic of said extruded material at a plurality of positions along said die slot; comparing said plurality of measurements against a desired plurality of measurements respectively at each said position along said die slot and generating a plurality of signals respectively in response thereto; effecting a change in said measured characteristics of said extruded material at said positions along said die slot in response to said signals so as to produce said extruded material having a desired curvature.

Claims

1. A method of producing an extruded membrane of solidified flowable material having a desired curvature comprising:

(a) extruding flowable material through a die slot having a curved section;

(b) measuring a characteristic of the ejection rate of said extruded material at a plurality of positions along said die slot;

(c) comparing said plurality of measurements against a desired plurality of measurements respectively at each said position along said die slot and generating a plurality of signals respectively in response thereto;

(d) effecting a change in said measured characteristic of said extruded material at said positions along said die slot in response to said signals so as to produce said extruded material having a desired curvature.

2. A method as claimed in claim 1 wherein said measured characteristic comprises the velocity of said extruded material at a plurality of positions along said die slot.

3. A method as claimed in claim 2 including cooling said extruded material in a water bath.

4. A method as claimed in claim 3 including winding said cooled extruded material after cooling.

5. A method as claimed in claim 4 wherein said extruding step comprises extruding flowable material through an annular die slot.

6. A method a claimed in claim 4 wherein said extruding step comprises extruding said flowable material through a scrolled die slot.

7. A method of producing an extruded membrane of solidified flowable material having a desired curvature comprising:

(a) extruding flowable material through a die slot having a curved section;

(b) measuring the velocity of said extruded material at a plurality of positions along said die slot.

(c) comparing said plurality of velocity measurements against a desired plurality of target velocity measurements to produce an error signal;

(d) changing the velocity of the flowable materal at each said plurality of positions in response to said error signal so as to produce an extruded membrane having a desired cuvature.

8. A method as claimed in claim 7 wherein said extruded flexible material is extruded through said die in an X direction.

9. A method as claimed in claim 8 wherein said die has a curved section in a Y direction.

10. A method as claimed in claim 9 wherein said extruding step comprises extruding said flowable material through an annular die slot.

11. A method as claimed in claim 9 wherein said extruding step comprises extruding said flowable material through a scrolled die slot.