This call for prior art is part of the EFF's effort to keep 3D printing open. Read about the initiative here, and check out Google Patents or the USPTO for full details about this particular application.

Process for producing three-dimensionally shaped object and device for producing same "Process for Producing Three-dimensionally Shaped Object and Device for Producing Same"

This application relates to 3D printing using laser sintering, a process capable of better resolution than traditional hobbyist 3D printing using thermoplastic extrusion, where the object is built in a chamber with a localized gas flow to capture fumes generated by the laser melting the powder.


  • App Number: 13/503,217
  • Publication Number: US20120251378 A1
  • Assignee: Panasonic Corporation
  • Prior Art Cutoff Date: Prior Art predating October 21, 2009
  • Availability for Challenge: Open Until at least April 4, 2013

APPLICATION OVERVIEW: This application claims the use of a chamber with a localized gas flow in laser sintering 3D printing. The 3D object is built in the chamber, and the localized gas flow captures the fumes resulting from the laser melting the powder in the process of building each layer of the object. If the fumes are not captured, they may interfere with the laser’s beam.

WHY IT MATTERS: The idea of a localized gas flow is not a new one, and is an obvious solution to the problem of fumes interfering with a laser beam. The open source community has begun to use laser sintering 3D printing methods, which promise of better resolution and a new variety of materials. This type of patent, which covers both the gas capture method and any devices using this method, could block a wide range of inventive activity.

Are you familiar with technology similar to that described in this patent application?

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4 Answers 4


Unfortunately, I can not locate the User Guide or Manual for the DTM Sintersation 2000 which was produced in 1993. In this manual, there will be descriptions of an Atmospeheric Control Unit(ACU) which created airflow away from the part bed through the sides of the machine. This air flow went through particulate filters and then charcoal filters to scrub the vapor / particulate residue from the build chamber as contributed by the laser melting / sintering process.

I personally ran this machine for many years and can attest to its operation. Unfortunately, a User Guide / Manual needs to be located.

http://www.cs.cmu.edu/~rapidproto/students.98/parzick/sintering/process Section 2.2

http://www.google.com/patents/EP0948657A1?cl=en Description Section 1 - Describing ACU for air movement and filtration


  • Question - I would think that an affidavit of a user of a prior art is acceptable evidence, even in the absence of the "User Guide". That is because even if you find the Guide, there is still need to rely on your word that the Guide existed before the cutoff date, and was not created later. Even if the Guide is dated at a prior date, the Examiner needs to accept your word that the Guide was not "back-dated". Therefore, your declaration without the guide is not less good evidence than the guide. Am I wrong? Why?
    – user79308
    Jun 27, 2013 at 4:59

It seems the improve answer function did not work.

this article from 1993 describes the use of a chamber and gasses in the DTM Sinterstation 2000: http://utwired.engr.utexas.edu/lff/symposium/proceedingsArchive/pubs/Manuscripts/1993/1993-11-Forderhase.pdf


For the plastic sintering, one might argue that plastics and metals have similar oxidation issues. The creation of either a vaccuum or inert atmosphere for selective metal sintering is a must and is covered by multiple patents"

(something like: US Patent 4992233).

Sintering metal powder in inert and/or reducing atmosphere has been found to result in a hard porous metal structure without the use of sintering aids. The oxidation resistance of the structure can be enhanced by the firing process comprised of the following steps: oxidation, reduction, and then inert gas sintering.

Patent number: 4992233 Filing date: Jul 15, 1988 Issue date: Feb 12, 1991

  • No laser in that patent
    – George White
    Mar 27, 2013 at 7:14

Laser deposition video from April 22, 2009. http://www.youtube.com/watch?v=Jns8acbluZY

  • Hard to tell at all what is being shown. Specifically, is there a gas flow? The purpose of the gas flow in the patent document is to keep fumes from collecting on a window of a closed-in chamber. In video I do not see chamber or window.
    – George White
    Mar 29, 2013 at 1:51

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