Hot runner nozzle heater and methods of manufacture thereof
View Patent ↗A hot runner nozzle heater is provided that includes a sleeve defining a slot extending along a length of the sleeve. A first dielectric layer is disposed over an outer surface of the sleeve, and a resistive element layer is disposed over the first dielectric layer, wherein the resistive element layer defines a resistive circuit pattern that is preferably formed by a laser trimming process. A pair of terminal leads are secured to a portion of the resistive element layer thus defining a termination area, and the termination area is positioned proximate the slot and away from the proximal end and the distal end of the sleeve. A second dielectric layer is disposed over the resistive element layer but not over the termination area, a third dielectric layer is disposed over the termination area, and a protective layer disposed over the second dielectric layer and the third dielectric layer.
1. A hot runner nozzle heater comprising:
a sleeve defining a proximal end and a distal end, and a slot extending along a length of the sleeve between the proximal end and the distal end;
a first dielectric layer disposed over an outer surface of the sleeve;
a resistive element layer disposed over the first dielectric layer, the resistive element layer defining a resistive circuit pattern;
a pair of terminal leads secured to a portion of the resistive element layer defining a termination area, the termination area being positioned proximate the slot and away from the proximal end and the distal end;
a second dielectric layer disposed over the resistive element layer but not over the termination area;
a third dielectric layer disposed over the termination area; and
a protective layer disposed over the second dielectric layer and the third dielectric layer.
2. The hot runner nozzle heater according to claim 1 , wherein the slot defines a constant width along the length of the sleeve.
3. The hot runner nozzle heater according to claim 1 , wherein the slot defines a non-constant width along the length of the sleeve.
4. The hot runner nozzle heater according to claim 1 , wherein the layers are positioned a distance away from the proximal end and the distal end.
5. The hot runner nozzle heater according to claim 1 , wherein the resistive circuit pattern is formed using a laser process.
6. The hot runner nozzle heater according to claim 1 further comprising a strain relief secured around the terminal leads and disposed proximate the third dielectric layer.
7. The hot runner nozzle heater according to claim 1 , wherein the sleeve defines a chamfer around the proximal end and around an interior surface of the sleeve.
8. A hot runner nozzle heater comprising:
a split sleeve defining a proximal end, a distal end, and an outer surface;
a first dielectric layer disposed over the outer surface of the split sleeve;
a resistive element layer disposed over the first dielectric layer, the resistive element layer defining a resistive circuit pattern;
a pair of terminal leads secured to a portion of the resistive element layer defining a termination area, the termination area being positioned proximate the split and away from the proximal end and the distal end;
a second dielectric layer disposed over the resistive element layer but not over the termination area;
a third dielectric layer disposed over the termination area; and
a protective layer disposed over the second dielectric layer and the third dielectric layer.
9. The hot runner nozzle heater according to claim 8 , wherein the split sleeve further comprises a slot extending along a length of the split sleeve.
10. The hot runner nozzle heater according to claim 9 , wherein the slot defines a constant width along the length of the split sleeve.
11. The hot runner nozzle heater according to claim 9 , wherein the slot defines a non-constant width along the length of the split sleeve.
12. The hot runner nozzle heater according to claim 8 , wherein the split sleeve further comprises a step-lap interface extending along the length of the split sleeve.
13. The hot runner nozzle heater according to claim 8 , wherein the layers are positioned a distance away from the proximal end and the distal end.
14. The hot runner nozzle heater according to claim 8 , wherein the resistive circuit pattern is formed using a laser process.
15. The hot runner nozzle heater according to claim 8 further comprising a strain relief secured around the terminal leads and disposed proximate the third dielectric layer.
16. The hot runner nozzle heater according to claim 8 , wherein the sleeve defines a chamfer around the proximal end and around an interior surface of the sleeve.
17. A method of manufacturing a hot runner nozzle heater comprising:
creating a split in a sleeve;
applying a first dielectric layer to an outer surface of the sleeve;
applying a resistive element layer over the dielectric layer, the resistive element layer defining a termination area;
creating a resistive circuit pattern in the resistive element layer by laser trimming;
applying a second dielectric layer over the resistive element layer but not over the termination area;
securing the terminal leads to the termination area;
applying a third dielectric layer over the termination area;
applying a protective layer over the second dielectric layer and the third dielectric layer; and
maintaining the split in the sleeve.
18. The method according to claim 17 , further comprising a thermal treatment of the protective layer after the protective layer is applied.
19. The method according to claim 17 , wherein the layers are applied using thermal spraying.
20. The method according to claim 17 , wherein the protective layer is applied using metal wire arc spraying.
21. The method according to claim 17 , wherein the terminal leads are secured to the termination area using thermal spraying.