Practice Areas



  • Managing IP, IP Stars, Connecticut, USA, 2013-2017
  • Trustee of the Year, Brightside for Families and Children, West Springfield, MA, 1995
  • Western Mass Pro Bono Referral Certificate of Accommodation for pro bono legal work, 1989
  • Martindale-Hubbell BV(T) Rated
  • "Super Lawyers," Intellectual Property Litigation, Connecticut, 2017
  • "Super Lawyers," Intellectual Property Litigation, Connecticut, 2018


  • State of Connecticut, 1998
  • Commonwealth of Massachusetts, 1988
  • United States District Court, District of Connecticut, 1998
  • United States District Court, District of Massachusetts, 1990
  • United States District Court of Colorado, 2009
  • United States District Court for the Southern District of New York, 2010
  • United States District Court for the Eastern District of Texas, 2011
  • United States Court of Appeals for the Federal Circuit, 1998
  • United States Court of Appeals for the Second Circuit, 2011
  • United States Court of Appeals for the Ninth Circuit, 2001
  • United States Court of Appeals for the Second Circuit, 2011
  • United States Court of Appeals for the Tenth Circuit, 2015
  • United States Tax Court, 1998
  • United States Patent and Trademark Office, 1998


Western New England University School of Law, J.D., cum laude, 1988

Worcester Polytechnic Institute, B.S., Mechanical Engineering, 1985

Certified Flight Instructor

Commercial multi-engine instrument rated pilot

Advanced Ground Instructor (AGI)

Cessna 500 Series Jet (SIC) Type License

Photo of William J. Cass

William J. Cass

Of Counsel

For nearly thirty (30) years, Bill Cass has tried cases in state and federal courts involving technology. As former Co-Chair of Cantor Colburn’s Litigation Department for the fifteen years, he combined his extensive trial experience with his engineering education to present technically complex matters to judges and juries. He has also tried matters before the Patent Trial and Appeal Board. His cases involved complex technology, including medical devices, circuitry, mechanical engineering, material science, chemistry, and computer software. He defended Faro Technologies in a two-week patent infringement jury trial in an action brought by Nikon Metrology N.V. in Federal Court in Boston involving laser scanners. Bill was retained in the Springfield gas explosion case (which destroyed several buildings in 2012). A complete list of his representative matters is set forth below.

Bill holds a mechanical engineering degree from Worcester Polytechnic Institute, where he concentrated in robotics. He is also a certified flight instructor (CFI), holds a commercial multi-engine instrument rating, a Cessna Citation 500 Series Jet SIC rating, and advises clients in aviation-related matters. Bill has spoken on topics concerning intellectual property and products liability internationally at EuroMold, IVA Sweden, Rapid (SME), and also at a White House Symposium on Additive Manufacturing. Bill is also an inventor on a pending patent application involving electronic controls.

Experience Highlights

Of Counsel, Cantor Colburn LLP, May 2017-present

Partner, Cantor Colburn LLP, 2002-April 2017

Associate, Cantor Colburn LLP, 1997-2002

Partner, Ryan, Martin, Costello, Leiter, Steiger & Cass, Springfield, MA, 1990-1997

Associate, Ryan & White P.C., Springfield, MA, 1988-1990

Representative Matters

  • Bill has litigated numerous cases.   Representative examples are listed below.
  • Ciocca Construction Corporation v. Bay State Gas Company d/b/a Columbia Gas of Massachusetts, et al., Case No.: 15-704 (gas explosion) (negligence/property damage/unfair acts and practices in the business of insurance)
  • Pets BKG, LLC d/b/a Petland Kennesaw v. Paul, Case No. 15-1-7596-40 (business disparagement)
  • Stratasys Inc. v. Microboards Technology, LLC d/b/a Afinia, Case No.: 0:13-cv-03228 (DWF/TNL) (patent infringement)
  • Protegrity Corporation v. Epicor Software Corporation (n/k/a Aptos, Inc.), Case No.: 3:13-cv-01781-VAB (patent infringement)
  • Thermolife International LLC v. Better Body Sports, LLC, et al., Case No.: CV-12-09229 GAF (FFMx)) (biochemical supplement relating to D-Aspartic Acid) (patent infringement)
  • Romag Fasteners, Inc. v. Fossil, Inc., et al., Case No.: 3:10-cv-1827(JBA) (patent infringement, trademark infringement, false designation of origin, and unfair competition)
  • Nikon Metrology N.V., et al. v. Faro Technologies, Inc., Case No.: 08-CV-11187 (PBS) (portable coordinate measuring machine - integrated arm and laser scanner) (patent infringement)
  • Protegrity Corporation v. Ingrian Networks, Inc., et al., Case No.: 3:08-cv-00618 (RNC) (data security system/encryption database) (patent infringement)
  • Faro Technologies, Inc. v. Cimcore Corporation, et al., Case No. 6:06-cv-00031-GAP-JGG (EEPROM circuit boards in coordinate measuring machines) (patent infringement)
  • Faro Technologies, Inc. v. Cimcore Corporation, et al., Case No.: 6:05-cv-01702-GAP-JGG (integrated bus for a coordinate measuring machine) (patent infringement)
  • Cimcore Corporation, et al. v. Faro Technologies, Inc., Case No.: 3:03-cv-2355-B-WMC (slip rings in coordinate measuring machines) (patent infringement)
  • Interventional Therapies, LLC, et al. v. Abbott Laboratories, et al., Case No. 6:03-cv-06644-MAT-JWF (vascular suturing device) (patent infringement)
  • Sicurelli, et al. v. Jeneric/Pentron Inc., et al., Case No. 1:03-cv-4934-SLT-KAM (dental composite implant for root canal therapy) (patent infringement)
  • Aearo Company, et al. v. Minnesota Mining and Manufacturing Company, Case No.: IP99-0937-C D/F (hearing protection device) (patent infringement)
  • 3D Ltd. v. Crown Roll Leaf, Inc., Case No. 2:99-cv-00290-WGB (holographic patterns) (copyright infringement)
  • Jeneric/Pentron, Inc. v. Dillon Co. Inc., et al., Case Nos. 3:98-CV-00818-EBB and 3:99-cv-011775 (EBB) (leucite crystalline porcelain for dental restoration) (patent infringement)
  • World Properties, Inc. and Rogers Corporation v. Tonoga Limited d/b/a Taconic Plastics Civil Action No.: 3:98-CV-01218-(JBA) LEAD (microwave circuit board laminate) (patent litigation)
  • Whelihan v. Markowski, et al., 37 Mass. App. Ct. 209 (1994) (negligence/personal injury)




Speaker, White House Symposium
August, 2012
Washington, DC
Additive Manufacturing

Speaker, EuroMold
December, 2011
Frankfurt, Germany
State of the Art Reports and Patent Mapping

Speaker, EuroMold
December, 2010
Frankfurt, Germany
Patent Presentation

Professional Affiliations

National Association of Flight Instructors (NAFI)

Aircraft Owners and Pilots Association

American Bar Association

Intellectual Property Owners Association, Litigation Committee Member

Connecticut IP Inn of Court, Charter Member

Community/Civic Involvement

Member, Mechanical Engineering Advisory Board, Worcester Polytechnic Institute

Member, Bio-Mechanical Engineering Advisory Board, Western New England College