Method for determining sintering shrinkage of a pre-sintered body

• US 8,366,978 B2
• Filed: 11/05/2007
• Issued: 02/05/2013
• Est. Priority Date: 11/03/2006
• Status: Expired due to Fees

• Current Assignee: Metoxit AG (AG Ziegelwerke Horw-Gettnau-Muri Holding)
• Original Assignee: Metoxit AG (AG Ziegelwerke Horw-Gettnau-Muri Holding)
• Inventors: Koebel, Stefan, Weber, Wolfram
• Primary Examiner(s): Del Sole, Joseph
• Assistant Examiner(s): Sultana, Nahida
• Application Number:
  US12/513,129
• Publication Number:
  US 20090273108A1
• Time in Patent Office: 1,919 Days
• Field of Search: 264/16, 264/17, 264/19, 264/40.1, 264/DIG.66, 264/603, 264/653, 264/662, 264/666, 264/672
• US Class Current: 264/40.1
• CPC Class Codes: A61C 13/0004 Computer-assisted sizing or machining of dental prostheses
• CPC Class Codes: A61C 13/0022 Blanks or green, unfinished dental restoration parts
• CPC Class Codes: B28B 17/0072 Product control or inspection
• CPC Class Codes: B28B 23/0031 with product identification means, e.g. labels on test products or integrated circuit tags inside products RFID
• CPC Class Codes: C04B 2235/765 Tetragonal symmetry
• CPC Class Codes: C04B 2235/945 Products containing grooves, cuts, recesses or protusions
• CPC Class Codes: C04B 2235/9615 Linear firing shrinkage
• CPC Class Codes: C04B 35/111 Fine ceramics
• CPC Class Codes: C04B 35/486 Fine ceramics
• CPC Class Codes: C04B 35/64 Burning or sintering processes C04B33/32 takes precedence ; powder metallurgy B22F
• CPC Class Codes: G16H 20/40 relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass

Abstract

A method for determining a sintering shrinkage of a pre-sintered body. The method includes providing a green preform with at least one design feature. The green-preform is pre-sintered to form a white body. At least one change in the at least one design feature with the pre-sintering is recorded. An expected sintering shrinkage to a dense-sintered component is determined using the recorded change.

Claims

1. Method for determining a sintering shrinkage of a pre-sintered body, the method comprising:

providing a green preform having a predetermined full sintering shrinkage with at least one design feature;

pre-sintering the green preform to form a white body resulting in at least one changed dimension of the at least one design feature;

measuring the at least one changed dimension of the at least one design feature and recording the at least one changed dimension; and

,

calculating an expected sintering shrinkage from the pre-sintered white body to a dense-sintered component using the recorded at least one changed dimension.

2. The method as recited in claim 1, further comprising measuring a length of the white body.

3. The method as recited in claim 1, further comprising recording a density for the green preform.

4. The method as recited in claim 1, further comprising recording a density of the dense-sintered component.

5. The method as recited in claim 1, further comprising:

recording a distance between two design features to obtain a first recorded result; and

determining the expected sintering shrinkage using the first recorded result.

6. The method as recited in claim 1, wherein compression moulding is used to provide the at least one design feature to the green preform.

7. The method as recited in claim 1, wherein machining is used to provide the at least one design feature to the green preform.

8. The method as recited in claim 1, wherein the recording is performed using a processing machine after the pre-sintering.

9. The method as recited in claim 1, wherein;

the at least one design feature includes at least two design features; and

the determining includes calculating the shrinkage of the white body in various directions.

10. The method as recited in claim 1, wherein:

the at least one design feature includes a plurality of design features;

the recording includes recording the at least one change in the plurality of design features; and

the determining includes determining an average of the expected shrinkage.

11. The method as recited in claim 1, wherein at least one design feature includes aperture.

12. The method as recited in claim 1, wherein the at least one design feature includes an indentation.

13. The method as recited in claim 1, wherein the white body includes a ceramic material.

14. The method as recited in claim 13, wherein the ceramic material includes at least one of zirconium oxide and aluminium oxide.

15. Method for determining a sintering shrinkage of a plurality of pre-sintered white bodies, the method comprising:

measuring a dimension of a design feature of each of a sample of green preforms;

sintering the sample of green preforms to form a corresponding sample of dense-sintered components so as to result in each dense-sintered component having a changed dimension of the respective design feature;

measuring the respective changed dimensions of the sample of dense-sintered components;

calculating an average changed dimension from the respective changed dimensions of the sample of dense-sintered components;

providing a plurality of green preforms, each green preform having a design feature and the plurality of green preforms exceeding the sample of green preforms and corresponding sample of dense-sintered components;

pre-sintering the plurality of green preforms to form a corresponding plurality of white bodies so as to result in each white body having a respective changed dimension of the respective design feature;

measuring the changed dimension of the design feature of each of the plurality of white bodies;

recording the changed dimension of each of the plurality of white bodies; and

calculating an expected sintering shrinkage for each of the plurality of white bodies based on the respective changed dimension of the respective design feature and the average changed dimension of the sample of dense-sintered components.