Control of fired shape by piece orientation

Abstract

A method of making ceramic bodies includes systematically orienting the bodies during firing relative to a temperature gradient in a kiln. The systematic orientation of the bodies relative to the temperature gradient can allow for an average deviation of a measured shape of the ceramic bodies from a predetermined target contour shape to be less than what they would be if the bodies were oriented randomly relative to the temperature gradient.

What is claimed is: 
     
         1 . A ceramic body made by the method of:
 extruding green bodies, said green bodies being extruded to a predetermined target contour shape, wherein a measured shape of at least some of the green bodies at least partially deviates from the predetermined target contour shape;   firing the green bodies in a kiln to make ceramic bodies, wherein, during firing, the green bodies are oriented relative to a temperature gradient in the kiln such that an average deviation of a measured shape of the ceramic bodies from the predetermined target contour shape is less than the average deviation of the measured shape of the green bodies from the predetermined target contour shape.   
     
     
         2 . The ceramic body of  claim 1 , wherein the kiln is a tunnel kiln. 
     
     
         3 . The ceramic body of  claim 2 , wherein the green bodies are moved in a direction in the tunnel kiln and the temperature gradient is parallel to the direction the green bodies are moved. 
     
     
         4 . The ceramic body of  claim 3 , wherein the green bodies comprise an extrusion line, wherein the extrusion line faces the direction the green bodies are moved. 
     
     
         5 . The ceramic body of  claim 2 , wherein the green bodies are moved in a direction in the tunnel kiln and the temperature gradient is normal or oblique relative to the direction the green bodies are moved. 
     
     
         6 . The ceramic body of  claim 1 , wherein the kiln is a periodic kiln. 
     
     
         7 . The ceramic body of  claim 6 , wherein the green bodies comprise an extrusion line, wherein the extrusion line is aligned with the temperature gradient. 
     
     
         8 . The ceramic body of  claim 7 , wherein the green bodies comprise an extrusion line, wherein the extrusion line is normal or oblique relative to the temperature gradient. 
     
     
         9 . A ceramic body made by the method of:
 extruding green bodies, said green bodies being extruded to a predetermined target contour shape, wherein a measured shape of at least some of the green bodies at least partially deviates from the predetermined target contour shape;   firing the green bodies in a kiln to make ceramic bodies, wherein, during firing, at least a majority of the green bodies are oriented in the same direction relative to a temperature gradient in the kiln.   wherein an average deviation of a measured shape of the ceramic bodies from the predetermined target contour shape is less than the average deviation of the measured shape of the green bodies from the predetermined target contour shape.   
     
     
         10 . The ceramic body of  claim 9 , wherein during firing, all of the green bodies are oriented in the same direction relative to a temperature gradient in the kiln. 
     
     
         11 . The ceramic body of  claim 10 , wherein the kiln is a tunnel kiln. 
     
     
         12 . The ceramic body of  claim 11 , wherein the green bodies are moved in a direction in the tunnel kiln and the temperature gradient is parallel to the direction the green bodies are moved. 
     
     
         13 . The ceramic body of  claim 11 , wherein the green bodies comprise an extrusion line, wherein the extrusion line faces the direction the green bodies are moved. 
     
     
         14 . The ceramic body of  claim 11 , wherein the green bodies are moved in a direction in the tunnel kiln and the temperature gradient is normal or oblique relative to the direction the green bodies are moved. 
     
     
         15 . The ceramic body of  claim 10 , wherein the kiln is a periodic kiln. 
     
     
         16 . The ceramic body of  claim 15 , wherein the green bodies comprise an extrusion line, wherein the extrusion line is aligned with the temperature gradient. 
     
     
         17 . The ceramic body of  claim 15 , wherein the green bodies comprise an extrusion line, wherein the extrusion line is normal or oblique relative to the temperature gradient.