Board Members

Our board members serve to provide guidance to ExOne's organization and vision.

From left to right: Lloyd Semple, Roger Thiltgen, Gregory Pashke, Kent Rockwell, Bonnie Wachtel, John Irvin, William Strome

S. Kent Rockwell


S. Kent Rockwell is currently the Chairman of the Board of Directors. He was the Executive Chairman from August 2016 until June 2018. Mr. Rockwell served as our Chairman and Chief Executive Officer from June 2018 to May 2019, and also from January 1, 2013, when we were formed as a Delaware corporation, to August 2016. 

Prior to that date, Mr. Rockwell served as the Managing Member of Ex One Company, LLP, our predecessor, from 2008-2012. Mr. Rockwell has been the Chairman and Chief Executive Officer of Rockwell Venture Capital, Inc., a private venture capital company, since 1983 and of Appalachian Timber Services, a supplier of timber products for railroads, since 1986. Mr. Rockwell served as Vice Chairman of Argon ST, a public company engaged primarily in defense contracting, from 2004 to 2010. 

Mr. Rockwell served as the Chairman and Chief Executive Officer of Sensytech Inc., which was engaged in the design, development and manufacture of electronics and technology products for the defense and intelligence markets in the United States, from 1998 to 2004. He was Chairman and Chief Executive Officer of Astrotech International Corp., a public company in the oilfield supply business, from 1989 to 1997. From 1987 to 1989, he was Chairman and Chief Executive Officer of Special Metals Corp., a producer of super alloy and special alloy products. From 1978 to 1982, he was Chairman and Chief Executive Officer of McEvoy Oilfield Equipment, a producer of oilfield equipment. Mr. Rockwell served on the Board of Directors of Rockwell International from 1973 until 1982 and served as President of the Energy Products Group of Rockwell International from 1977 to 1982. 

We believe that Mr. Rockwell should serve as a member of our Board because he has intimate knowledge of ExOne, its business and operations and the risks, challenges and opportunities it faces. In addition, Mr. Rockwell brings to our Board nearly forty years of experience with strategic planning, acquisitions and integration, marketing, finance and accounting, operations and risk management, having served in numerous executive and director positions at other public and private companies before joining ExOne.


John Hartner

Director, Chief Executive Officer

John Hartner joined The ExOne Company as Chief Operating Officer in November 2018, and became Chief Executive Officer on May 15, 2019. He was elected to the Board of Directors on May 13, 2020. Mr. Hartner has led technology companies around the world for 30 years in the electronics, cleantech, automation and digital printing industries.  

For almost half of this time, he lived and worked in Asia and Europe.  He founded Digital Industrialist LLC, a company that advises and invests in digital manufacturing businesses.  In the 3D industry, he served as Chief Operating Officer of EnvisionTEC, a healthcare 3D printing leader. Previously he had a 14-year career leading business units of Dover Corporation, most recently as President and CEO of Dover Printing & Identification Segment. Prior to that, he served in various leadership roles with FMC Technologies and Rockwell International. He received an MBA from the University of Chicago and a Bachelors of Mechanical Engineering from Villanova University.


John Irvin


Mr. Irvin, currently Special Advisor to the Chairman, formerly served as our Chief Financial Officer from October 2012 through December 2014 and began serving as a member of our Board of Directors effective January 1, 2013. From 2008 to 2012, Mr. Irvin served as President of PartnersFinancial, a national insurance brokerage company owned by National Financial Partner Corp. (“NFP”), a diversified financial services firm. From 1993 to 2008, he was Chairman and Chief Executive Officer of Innovative Benefits Consulting, Inc., a life insurance consulting firm and wholly-owned subsidiary of NFP. From 1983 to 1993, Mr. Irvin was a partner of Mid Atlantic Capital Group, a financial services company which he co-founded in 1983 and his highest position was vice chairman. 

In 1979, Mr. Irvin formed the certified public accounting firm of John Irvin and Company. From 1976 to 1979, he was an accountant for Arthur Andersen LLP. From 2000 to 2004, Mr. Irvin served on the board of directors of Sensytech Inc., which was engaged in the design, development, and manufacture of electronics and technology products for the defense and intelligence markets in the United States, and also served on its audit committee from 2000 to 2002, and as chairman of the audit committee from 2002 to 2004. Upon the merger of Sensytech Inc. into Argon ST, Inc., a public company engaged primarily in defense contracting, he served as director and chairman of the audit committee from 2004 to 2010. He has served on The American College Foundation Board since 2010.


Gregory F. Pashke

Independent Director

Mr. Pashke has served as President of Pashke Consulting, a strategic, tactical and valuation consulting services company since 1997. Mr. Pashke was a founding and managing partner of Pashke Twargowski & Lee, a northwestern Pennsylvania regional CPA firm from 1974 to 1997. In addition to managing the firm, Mr. Pashke provided managerial and financial consulting and auditing and accounting assurance services primarily to closely held manufacturing and service enterprises. 

Mr. Pashke was Vice-President of Finance for Keystone Aeronautics, a multi-state air charter, aircraft sales and fuel concession enterprise from 1973 to 1974 and was a Senior Accountant with the auditing firm of Ernst & Young from 1971 until 1973. Mr. Pashke has been active in many professional organizations, having served on the National Governing Council of the American Institute of CPAs and as National Vice President of the Society for the Advancement of Management where he chaired the Long-Range Objectives and Nominations Committees. Mr. Pashke also was a member of the Governing Council and the Executive Committee of the Pennsylvania Institute of Certified Public Accountants, where he served on the Ethics and Centennial Committees and as the President of the Erie Chapter of PICPA. 

Mr. Pashke has multiple professional designations in accounting (CPA, CMA – Certified Management Accountant), finance (CFM – Certified Financial Manager), consulting (CMC – Certified Management Consultant) and valuation (CBA – Certified Business Appraiser) and he holds an MBA from the University of Pittsburgh. Mr. Pashke has also authored over thirty articles on a variety of consulting, planning, managerial, auditing, tax and organizational topics. We believe that Mr. Pashke should serve as a member of our Board because he will bring significant financial accounting and reporting, financial planning, tax, internal auditing and ethics expertise to our Board, including through his robust experience in these areas with manufacturing and service enterprises.

Member of the Audit Committee


Lloyd A. Semple

Lead Independent Director

Mr. Semple began serving on our Board on February 5, 2013 and currently serves as our Lead Director. He served as a professor of law at the Detroit Mercy School of Law in Detroit, Michigan from 2004 through his retirement in 2015 (serving as its dean from 2009 to 2013). Prior to 2004, he practiced law at Dykema Gossett, a Detroit-based law firm, where he was Chairman and Chief Executive Officer from 1995 to 2002.

He has served as outside counsel and director for several business enterprises. He was a director of Argon ST from 2004 to 2010. Mr. Semple brings to our Board extensive legal and corporate governance expertise and experience from his nearly forty-year career as an attorney in private practice, where he focused primarily on general corporate matters, mergers and acquisitions, and financial markets and services. His extensive service as counsel and director of several businesses has been extremely beneficial as he serves as the Lead Director of our Board.


William F. Strome

Independent Director

Mr. Strome began serving on our Board of Directors on May 4, 2015. Since August 2015, Mr. Strome has served as an adjunct professor at the John F. Donahue Graduate School of Business, Duquesne University. From October 2014 to July 2017 (when the Company was sold), Mr. Strome served as a director of FBR & Co. (Nasdaq: FBRC), a company providing investment banking, merger and acquisition advisory, institutional brokerage, and research services.  He currently serves as a director of the Merle E. Gilliand & Olive Lee Gilliand Foundation and Aspinwall Riverfront Park. Mr. Strome previously served as Senior Vice President, Finance & Administration of RTI International Metals, Inc. (NYSE:RTI), from November 2007 until his retirement in April 2014. He led the Company’s strategic planning activities, acquisition and divestiture initiatives, and capital procurement as well as investor relations and treasury functions. He was also responsible for RTI’s information technology and insurance functions. 

In 2006 and 2007, prior to joining RTI, Mr. Strome was a principal at Laurel Mountain Partners where he focused on raising acquisition financing for its principal portfolio company – Liberty Waste Services. From 2001 to 2006 Mr. Strome was a Senior Managing Director in FBR’s Investment Banking group. From 1981 to 1997 he served as Deputy General Counsel and Corporate Secretary at PNC Financial Services Group, Inc. (NYSE: PNC) and from 1997 to 2001 he served as a Managing Director of PNC’s capital markets broker-dealer, focusing on mergers and acquisitions as well as strategic advisory services. Mr. Strome holds an undergraduate degree in Economics from Northwestern University and a J.D. and M.B.A. from the University of Pittsburgh.

Chair of the Audit Committee

Member of the Nominating and Governance Committee


Roger W. Thiltgen

Independent Director

Mr. Thiltgen was formerly the managing member of Puris LLC, a firm primarily engaged in the manufacture of titanium powder, and to a lesser extent in printing titanium powder utilizing binder jet 3D printers provided by ExOne. Additionally, Mr. Thiltgen previously served as a board member and Manager of Corporate Development for Astrotech International Corporation, formerly listed on the American Stock Exchange, a company that manufactured, repaired, and serviced above ground storage tanks for the oil and gas industry. He was also Co-Founder and President of HMT Inc., an engineering and consulting company that was acquired by Astrotech. At HMT, he received three U.S. patents for emission control devices manufactured and sold by HMT. 

Mr. Thiltgen has also been a long-time majority owner and President of Tanglewood Resort Properties Inc., a company that operates a resort hotel and conference center, and conducts real estate development in North Texas. Concurrently, he is also President of Champion Resources Inc., a privately held investment company dealing primarily with oil and gas, and real estate investments. Mr. Thiltgen holds a bachelor’s degree in civil engineering from The University of Wisconsin-Platteville.


Bonnie K. Wachtel

Independent Director

Ms. Wachtel began serving on our Board of Directors on February 11, 2013. She is a principal of Wachtel & Co., Inc., an investment firm in Washington, DC involved with the development of growing companies. Since joining Wachtel & Co., Inc., in 1984, Ms. Wachtel has been a director of more than a dozen public and private corporations. She has been a director of VSE Corporation (NASDAQ: VSEC) a provider of engineering services principally to the federal government, since 1991 and of Information Analysis Inc., a provider of IT technical services, since 1992. She was a director of Integral Systems Inc. (NASDAQ: ISYS) a provider of satellite related software and services, from 2010 to 2011. She was also a director of Acies Corporation, a payment systems processor, from 2006 to 2008. Ms. Wachtel serves on the Listing Qualifications Panel for NASDAQ. She practiced law at Weil, Gotshal & Manges in New York from 1980 to 1984. She is a certified financial analyst.

Member of the Audit Committee

Chair of the Compensation Committee