Prior art

Analysis of Prior Art for U.S. Patent 11,383,405

An evaluation of the prior art cited during the prosecution of U.S. Patent 11,383,405 reveals several key references that the USPTO examiner considered. These documents are crucial for understanding the landscape of existing technology at the time of the invention and for assessing the patent's novelty and non-obviousness. The following analysis details the most relevant prior art and its potential impact on the claims of the '405 patent.

Key Prior Art and Potential Anticipation

The core of U.S. Patent 11,383,405 lies in its method for controlling the dimensional accuracy of a ceramic molded body by creating a feedback loop. This loop involves measuring the dimensions of the body after it has been cut but before it is dried, and then using a pre-established relationship between those dimensions and the temperature of a control portion of the extrusion machine to adjust the temperature for subsequent production (Claim 1).

Here are the most significant prior art references and their relevance to the claims:

1. JP2017536549A (Corning Incorporated)

• Full Citation: Japanese Patent Application Publication No. 2017-536549 A
• Publication Date: December 7, 2017
• Brief Description: This patent document, cited in the '405 patent itself, discloses a method for controlling extrusion molding by acquiring a shape signal from the outer surface of the ceramic molded body in real-time and comparing it to a reference signal to adjust process parameters.
• Potential Anticipation: This reference is highly relevant as it describes a feedback control system for ceramic extrusion. However, a key distinction from the '405 patent is that JP2017536549A measures the body's shape immediately after extrusion and does not explicitly teach measuring the dimension after cutting to account for any deformation caused by the cutting process. Therefore, while it discloses a similar feedback concept, it likely does not fully anticipate Claim 1 of the '405 patent, which specifies measurement of the cut ceramic molded body.

2. JP6436928B2 (NGK Insulators Ltd.)

• Full Citation: Japanese Patent No. 6436928 B2
• Publication Date: December 12, 2018
• Brief Description: Also cited within the '405 patent, this reference describes a method of measuring the dimension of a ceramic molded body after it has been dried and then adjusting the amount of liquid added to the ceramic material based on this measurement.
• Potential Anticipation: This patent teaches a feedback loop for dimensional control in ceramic manufacturing. However, it differs significantly from the '405 patent in two critical aspects: the measurement is performed after drying, and the adjusted parameter is the liquid content, not the temperature of a control portion. The '405 patent argues that waiting until after the drying step introduces a long delay, making the process less efficient and potentially wasteful. The focus on pre-drying measurement and temperature control distinguishes the '405 patent's claims from this reference.

3. US 2012/0133065 A1 (Caffrey et al.)

• Full Citation: U.S. Patent Application Publication No. 2012/0133065 A1
• Publication Date: May 31, 2012
• Brief Description: This application describes a real-time, closed-loop shape control system for extruded ceramic honeycomb structures. It involves measuring the shape of the extrudate and adjusting process parameters to maintain dimensional accuracy.
• Potential Anticipation: Similar to JP2017536549A, this reference discloses a feedback control system. It teaches monitoring the dimensions of the extruded body and making adjustments. The critical question for anticipation would be whether it discloses measuring the body after a cutting step and specifically adjusting the temperature of a control portion based on a pre-determined relationship. Without these specific elements, it would not fully anticipate Claim 1.

4. US 2011/0278753 A1 (Breuer)

• Full Citation: U.S. Patent Application Publication No. 2011/0278753 A1
• Publication Date: November 17, 2011
• Brief Description: This document details laser scanning systems and methods for measuring extruded ceramic logs. The focus is on obtaining accurate dimensional measurements of the extruded, but not yet fired, ceramic bodies.
• Potential Anticipation: This reference is relevant to the "dimension measuring step" of Claim 1. It provides a detailed method for measuring the dimensions of the unfired ceramic body. However, it does not appear to describe the complete feedback loop claimed in the '405 patent, specifically the pre-established relationship between the measured dimension and a temperature control portion of the extruder, and the subsequent adjustment of that temperature. Therefore, it anticipates a component of the claimed invention but not the entire method.

Summary of Findings

The prior art cited against US patent 11,383,405 establishes that the general concept of using feedback loops to control the dimensions of extruded ceramic bodies was known. However, the inventive step of the '405 patent appears to be the specific combination of elements in its method:

• Timing of Measurement: Measuring the dimension after the cutting step but before the drying step to account for deformation from cutting while still allowing for rapid process adjustments.
• Controlled Parameter: Specifically adjusting the temperature of a control portion of the extrusion machine.
• Control Logic: Utilizing a previously obtained relationship between the temperature and the dimension of the cut body to calculate the necessary adjustment.

While individual elements of this process can be found in the prior art, no single reference appears to disclose the complete combination as claimed in independent claim 1. This unique combination of steps allows for a more responsive and accurate method of dimensional control, addressing the shortcomings of prior art methods that either measure too early (before cutting-induced deformities) or too late (after the lengthy drying process). Consequently, the claims of US patent 11,383,405 were likely found to be novel and non-obvious over this collection of prior art.