Valve pin and nozzle configuration and method of control

Patent metadata

Field	Value
Publication number	US-10899055-B2
Application number	US-201615181933-A
Country	US
Kind code	B2
Filing date	Jun 14, 2016
Priority date	Jan 8, 2014
Publication date	Jan 26, 2021
Grant date	Jan 26, 2021

Abstract

An injection molding apparatus comprising: a manifold, a nozzle, A distal tip of the nozzle being comprised of a highly heat conductive insert and an insulation cap that is substantially less heat conductive than the insert, the downstream end portion of the insulation cap being disposed between the gate and the downstream end portion of the highly heat conductive insert forming a fluid seal around the gate, a valve pin, wherein when the valve pin is in a gate closed position, an axially interior surface of a fluid exit aperture of the insulation cap surrounds a gap enabling circumferential surface of the valve pin forming a spatial gap immediately upstream of the gate between the interior surface of the fluid exit aperture of the insulation cap and the gap enabling circumferential surface of the valve pin.

First claim

What is claimed is:

1. An injection molding apparatus comprising:
a manifold having a manifold channel that receives an injection fluid,
a nozzle having a nozzle channel having an axis receiving the injection fluid from the manifold channel, the nozzle having a distal tip in fluid communication with a gate to a mold cavity,
the distal tip of the nozzle being comprised of a heat conductive insert and an insulation cap that is substantially less heat conductive than the insert, mounted coaxially within the nozzle channel in nested contact with each other,
the heat conductive insert and the insulation cap each having a downstream end portion containing a fluid exit aperture that are aligned with each other enabling flow of injection fluid through the nozzle channel downstream into the mold cavity,
the downstream end portion of the insulation cap being disposed between the gate and the downstream end portion of the heat conductive insert forming a fluid seal around the gate,
a valve pin interconnected to an actuator adapted for controllably driven reciprocal movement of the valve pin coaxially through the nozzle flow channel,
the valve pin having a distal end portion having a downstream-most circumferential surface complementary to an axially interior surface of the gate and a downstream surface portion around the circumference of a bulbous portion of the valve pin immediately upstream of the downstream-most circumferential surface that mates with a guide surface of the insert to stop flow of injection fluid upstream of the axially interior surface of the gate, downstream surface portion having a gap enabling circumferential surface around the circumference of the bulbous portion of the valve pin,
the actuator being adapted to controllably drive the distal end portion of the valve pin along a drive path extending between one or more upstream positions where the injection fluid flows through the gate and a downstream gate closed position where the distal end portion of the valve pin mates with the axially interior surface of the gate to stop flow of injection fluid through the gate,
wherein when the valve pin is in the gate closed position, an axially interior surface of the fluid exit aperture of the insulation cap surrounds the gap enabling circumferential surface of the valve pin forming a spatial gap immediately upstream of the gate and downstream of the guide between the interior surface of the fluid exit aperture of the insulation cap and the gap enabling circumferential surface around the circumference of the bulbous portion of the valve pin.

2. The apparatus of claim 1 wherein the actuator is interconnected to a controller that controllably instructs the actuator to drive the distal end portion of the valve pin continuously upstream starting from the gate closed position at one or more intermediate upstream velocities that are less than a predetermined velocity and to subsequently further drive the valve pin upstream at the predetermined velocity.

3. The apparatus of claim 1 wherein the actuator comprises a hydraulically driven or pneumatically driven actuator or an electrically powered motor.

4. The apparatus of claim 2 wherein the actuator comprises a hydraulically driven or pneumatically driven actuator or an electrically powered motor.

5. The apparatus of claim 1 wherein the spatial gap is adapted to receive injection fluid that is forced upstream from the gate when the valve pin is moved downstream toward the gate closed position.

6. The apparatus of claim 1 wherein axially interior surface of the gate comprises a surface of the mold.

7. The apparatus of claim 1 wherein the nozzle channel has an axially interior surface disposed upstream of the fluid exit apertures that is complementary to and slidably engages with the gap enabling circumferential surface of the valve pin to align the axis of the valve pin with the gate during downstream movement of the valve pin toward the gate closed position.

8. The apparatus of claim 1 wherein an axially inner surface of an upstream end portion of the insulation cap is engaged against an axially outer surface of a downstream end of the insert, the upstream end portion of the insulation cap being compressed between the insert and an axially inner surface of the distal tip of the nozzle to seal flow of the injection fluid to within the nozzle channel.

9. The apparatus of claim 1 wherein the distal end portion of the valve pin is configured such that flow of injection fluid through the gate is restricted at one or more positions of the valve pin that are intermediate the gate closed position and a fully upstream gate open position at which flow of the injection fluid is unrestricted.

10. A method of performing an injection molding cycle comprising injecting the injection fluid from an injection molding machine into the manifold channel of the apparatus of claim 4 and using the apparatus of claim 4 to inject the injection fluid into the mold cavity during the course of an injection molding cycle.

Assignees

• Synventive Molding Solutions Inc

Inventors

• Feng Ling
• Liqiao Li
• Henderson William
• Galati Vito

Classifications

• B29C45/27

  Sprue channels {; Runner channels or runner nozzles} · CPC title

• B29C2045/2761

  Seals between nozzle and mould or gate · CPC title

• B29C45/278 Primary

  Nozzle tips (B29C45/2735 takes precedence) · CPC title

• B29C2945/76568

  Position · CPC title

• B29C2045/2767

  the heat insulation being provided with an axial opening being part of the melt flow channel · CPC title