Powder injection molding apparatus

Patent metadata

Field	Value
Publication number	US-12157256-B2
Application number	US-201917262814-A
Country	US
Kind code	B2
Filing date	Jul 22, 2019
Priority date	Jul 24, 2018
Publication date	Dec 3, 2024
Grant date	Dec 3, 2024

Abstract

A powder injection molding apparatus including an injection unit, mold formed of two mold parts with parting surface between first and second mold part, enclosing in assembled state of mold a mold cavity fluidically connected with injection unit via transfer channel, vibrational energy generator and transducer, and clamping unit designed to retain under the effect of clamping force first and second mold parts in contact with each other. Apparatus is characterized in that first and second mold parts include a first and second retaining hole, respectively, each extending essentially perpendicularly to parting surface and arranged opposite to each other respective to parting surface, clamping unit includes first and second pin each extending essentially perpendicularly to parting surface, wherein first and second pins cooperate in assembled state of mold with retaining portion of first and second retaining holes, respectively, to retain first and second mold parts in contact with each other.

First claim

The invention claimed is:

1. A powder injection molding apparatus comprising
A) an injection unit containing a heatable barrel, a nozzle and conveying means arranged in the barrel for conveying feedstock in direction from a feed zone of the barrel towards the nozzle,
B) a mold formed of two mold parts with a parting surface between a first mold part and a second mold part, enclosing in the assembled state of the mold a mold cavity fluidically connected with the injection unit via a transfer channel,
C) a vibrational energy generator and a transducer for transducing the vibrational energy received from the vibrational energy generator to the mold,
D) a clamping unit designed to retain under the effect of a clamping force the first mold part and the second mold part in contact with each other,
wherein:
the first mold part and the second mold part comprise a first retaining hole and a second retaining hole, respectively, each of the first retaining hole and the second retaining hole being centered along a retaining hole axis that is substantially perpendicular to the parting surface and crosses the parting surface, the first retaining hole and the second retaining hole being arranged opposite to each other respective to the parting surface, and
the clamping unit comprises a first pin and a second pin each extending essentially perpendicularly to the parting surface, wherein the first pin and the second pin cooperate in the assembled state of the mold with a retaining portion of the first retaining hole and a retaining portion of the second retaining hole, respectively, to retain the first mold part and the second mold part in contact with each other.

2. The powder injection molding apparatus according to claim 1 , further comprising an amplitude transformer for transforming the wave amplitude of the vibrational energy received from the transducer and transferring the vibrational energy to the mold, the amplitude transformer being positioned between the transducer and the mold.

3. The powder injection molding apparatus according to claim 1 , wherein the transducer or an amplitude transformer is in direct contact with the mold.

4. The powder injection molding apparatus according to claim 1 , wherein the vibrational energy generator and the transducer are arranged such that the vibrational energy is transduced in a longitudinal direction perpendicular to the parting surface.

5. The powder injection molding apparatus according to claim 1 , wherein the application point of the clamping force in the first retaining hole and the application point of the clamping force in the second retaining hole, respectively, lie at a distance from the parting surface of 5 mm to 20 mm.

6. The powder injection molding apparatus according to claim 1 , wherein the application point of the clamping force in the first retaining hole and the application point of the clamping force in the second retaining hole lie at the same distance of the parting surface.

7. The powder injection molding apparatus according to claim 1 , wherein the clamping force ranges from 125 kN to 500 kN.

8. The powder injection molding apparatus according to claim 1 , wherein the mold is designed such that the application point of the clamping force in the first retaining hole and the application point of the clamping force in the second retaining hole lie at least approximately at a node and the parting surface at least approximately at an antinode of a resonant frequency of the mold.

9. The powder injection molding apparatus according to claim 1 , wherein the first retaining hole and the second retaining hole are each formed as a blind hole.

10. The powder injection molding apparatus according to claim 1 , wherein the first mold part and the second mold part comprise a plurality of first retaining holes and a plurality of second retaining holes, respectively, distributed around the mold cavity, and the clamping unit comprises a plurality of first pins and a plurality of second pins, wherein, in the assembled state of the mold, the plurality of first pins and the plurality of second pins cooperate with retaining portions of the plurality of first retaining holes and with retaining portions of the plurality of second retaining holes, respectively, to retain the first mold part and the second mold part in contact with each other.

11. A process for preparing a dental article, the process comprising:
introducing a feedstock into the powder injection molding apparatus according to claim 1 , and
injection molding the feedstock via the powder injection molding apparatus to prepare the dental article.

12. The powder injection molding apparatus according to claim 1 , wherein the transducer is configured to transduce the vibrational energy received from the vibrational energy generator to the mold and to the injection unit and/or to the transfer channel.

13. The powder injection molding apparatus according to claim 1 , wherein the transducer or an amplitude transformer is in direct contact with the mold and the injection unit and/or the transfer channel.

14. The powder injection molding apparatus according to claim 1 , wherein the application point of the clamping force in the first retaining hole and the application point of the clamping force in the second retaining hole, respectively, lie at a distance from the parting surface of 7 mm to 15 mm.

15. The powder injection molding apparatus according to claim 1 , wherein the application point of the clamping force in the first retaining hole and the application point of the clamping force in the second retaining hole, respectively, lie at a distance from the parting surface of 10 mm.

16. The powder injection molding apparatus according to claim 1 , wherein the clamping force ranges from 200 kN to 450 kN.

17. The powder injection molding apparatus according to claim 1 , wherein the clamping force ranges from 300 kN to 450 kN.

18. The process according to claim 11 , wherein the dental article is a dental implant or a dental implant abutment.

Assignees

• Straumann Holding Ag

Inventors

• Bordoli Gabriele
• Buergisser Bruno
• Stephan Marc
• Courvoisier Stephane

Classifications

• B28B1/24 Primary

  by injection moulding {(injection moulding of ceramic slips B28B1/265; of tubular articles B28B21/38)} · CPC title

• B28B1/087

  by means acting on the mould {; Fixation thereof to the mould} · CPC title

• B22F2202/01

  Use of vibrations · CPC title

• B22F3/225

  by injection molding · CPC title

• A61C13/0006

  Production methods · CPC title