Obviousness

An analysis of the obviousness of US patent 11,383,405 under 35 U.S.C. § 103 is provided below, based on the prior art cited in the patent's file.

Person Having Ordinary Skill in the Art (PHOSITA)

A person having ordinary skill in the art (PHOSITA) for this patent would be an engineer or materials scientist with a bachelor's degree or higher in ceramic, chemical, or mechanical engineering, and several years of experience in the field of ceramic manufacturing, specifically with extrusion processes for products like automotive catalysts or particulate filters. This individual would be familiar with process control systems, methods for dimensional measurement, and the effects of process parameters (like temperature and material composition) on the final ceramic product.

Obviousness Analysis of Independent Claim 1

Claim 1 recites a method with the following key elements:

• (a) Extrusion molding a ceramic material using a machine with a temperature control portion.
• (b) Cutting the extruded body to a predetermined length.
• (c) Measuring a dimension of the cut ceramic molded body before drying.
• (d) Using a pre-obtained relationship between the temperature and the dimension of the cut body to calculate and control the temperature in a feedback loop.

A strong case for obviousness can be made by combining the teachings of US 2012/0133065 A1 (hereafter "Caffrey") and US 2014/0151915 A1 (hereafter "Sariego").

Combination of Prior Art

1. Caffrey (US 2012/0133065 A1): This reference discloses the core concept of the feedback loop. It teaches a "real-time, closed-loop shape control of extruded ceramic honeycomb structures." Caffrey describes a system that measures a physical characteristic (i.e., a dimension) of the extrudate and adjusts an "extrusion process parameter" in response to maintain the desired shape. This directly teaches the broad concept of element (d): using a measurement to control a process parameter in a feedback loop to ensure dimensional accuracy.

2. Sariego (US 2014/0151915 A1): This reference explicitly teaches the use of temperature control in extrusion systems. Sariego discloses controlling the temperature of the extrusion die and/or the ceramic material itself to influence the final properties of the extrudate. This directly teaches element (a) of the claim: using an extrusion machine equipped with a temperature control portion.

Motivation to Combine

A PHOSITA would have been motivated to combine the teachings of Caffrey and Sariego for a predictable and improved result. Caffrey provides a general framework for a real-time feedback control system but leaves the specific "extrusion process parameter" open. Sariego identifies temperature as a specific, effective, and well-understood process parameter for controlling the outcome of ceramic extrusion. A PHOSITA, tasked with implementing or improving the dimensional control system taught by Caffrey, would naturally look to known controllable parameters. The use of temperature, as taught by Sariego, would be an obvious choice to implement as the control variable within Caffrey's feedback system. The motivation is straightforward: to use a known control method (temperature adjustment) to achieve the goal of Caffrey's system (improved dimensional accuracy).

Addressing the "After Cutting, Before Drying" Measurement Point

The inventive gist of US 11,383,405 hinges on measuring the ceramic body after it is cut but before it is dried (element c). The patent argues that cutting introduces stress and deformation, so measuring before cutting (as in other prior art) is insufficient, and measuring after drying (as in JP 6436928 B) introduces significant process delays.

However, this specific timing of the measurement would have been an obvious optimization to a PHOSITA.

• The problem identified in the '405 patent—that cutting can deform the extrudate—would be a known phenomenon to a PHOSITA.
• If a PHOSITA implemented the combined Caffrey/Sariego system and found that dimensional errors persisted, a routine step in process optimization would be to analyze the source of the error.
• Upon discovering that the cutting step itself was a significant source of dimensional variation, it would be an obvious and logical modification to move the measurement point of Caffrey's control loop to a position immediately after the cutting step. This allows the feedback loop to account for deformation induced by cutting, thereby providing a more accurate control input.

This is not an inventive leap but rather a predictable step in engineering troubleshooting and process improvement. A PHOSITA understands that for the most effective control, the measurement should capture the state of the object after any step that introduces significant variation. Given the known options of measuring before cutting, after cutting, or after drying, selecting the post-cutting/pre-drying point to gain timely feedback that accounts for cutting deformation would be an obvious choice to try.

Therefore, the combination of Caffrey and Sariego renders the limitations of Claim 1 obvious to a person of ordinary skill in the art.

Obviousness Analysis of Independent Claim 6

Claim 6 recites a method for producing a final ceramic structure by taking the ceramic molded body produced by the method of Claim 1 and adding:

• (e) A drying step.
• (f) A firing step.

The addition of these steps to the process of Claim 1 is obvious. Drying a "green" ceramic body and subsequently firing it in a furnace are fundamental, universally known, and essential steps in nearly all ceramic manufacturing processes. The '405 patent itself acknowledges this in its background section, stating the conventional process is to "obtain a ceramic molded body, and then cutting the ceramic molded body to have a predetermined length, drying and firing it."

There is no unique or synergistic interaction claimed between the feedback control method of Claim 1 and the subsequent, conventional steps of drying and firing. As these are standard, concluding steps in the art, adding them to the otherwise obvious method of Claim 1 does not confer patentability.