<PAGE>
 
                                                                     Exhibit 3.7


                                                          FEDERAL IDENTIFICATION
                                                          NO.   04-2495703
                                                             -------------------

                       THE COMMONWEALTH OF MASSACHUSETTS
-----------                  William Francis Galvin
Examiner                 Secretary of the Commonwealth
             One Ashburton Place, Boston, Massachusetts 02108-1512


                             ARTICLES OF AMENDMENT
                    (General Laws, Chapter 156B, Section 72)
-----------
Name
Approved       We,         Mitchell G. Tyson             President,
                   -------------------------------------, 
            and          Robert L. Birnbaum              Assistant Clerk,
                ----------------------------------------, 
            of             PRI Automation, Inc.
               ----------------------------------------------------------------,
                          (Exact name of corporation)

            located at       805 Middlesex Turnpike, Billerica, MA 01821
                       --------------------------------------------------------,
                         (Street address of corporation in Massachusetts)

            certify that these Articles of Amendment affecting articles 
            numbered:


                                             3
            --------------------------------------------------------------------
                 (Number those articles 1, 2, 3, 4, 5 and/or 6 being amended)

            of the Articles of Organization were duly adopted at a meeting held
            on January 16, 1998 by vote of:
<TABLE> 
<S>                      <C>                           <C>
            10,541,574   shares of     Common Stock    of  15,298,656  shares outstanding,
            -------------         ---------------------   ------------
                              (type, class & series, if any)

                         shares of                     of              shares outstanding, and
            -------------         ---------------------   ------------
                              (type, class & series, if any)

                         shares of                     of              shares outstanding,
            -------------         ---------------------   ------------
                              (type, class & series, if any)
</TABLE>

C
P           /1/ being at least a majority of each type, class or series
M           outstanding and entitled to vote thereon:
R.A. 
     
 
            /1/ For amendments adopted pursuant to Chapter 156B, Section 70.
            Note: If the space provided under any article or item on this form
            is insufficient, additions shall be set forth on one side only of 
----------- separate 8  1/2 x 11 sheets of paper with a left margin of at least
P.C.        1 inch.  Additions to more than one article may be made on a single
            sheet so long as each article requiring each addition is clearly 
            indicated.
 
<PAGE>
 
To change the number of shares and the par value (if any) of any type, class or
series of stock which the corporation is authorized to issue, fill in the
following:

The total presently authorized is:

<TABLE>
<CAPTION>

--------------------------------------------------------------------------------
       WITHOUT PAR VALUE STOCKS                 WITH PAR VALUE STOCKS
--------------------------------------------------------------------------------
   TYPE         NUMBER OF SHARES         TYPE       NUMBER OF SHARES   PAR VALUE
--------------------------------------------------------------------------------
<S>             <C>                    <C>          <C>                <C> 
Common:                                Common:         24,000,000       $.01
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
Preferred:                             Preferred:         400,000       $.01
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
</TABLE>


Change the total authorized to:


<TABLE>
<CAPTION>

--------------------------------------------------------------------------------
       WITHOUT PAR VALUE STOCKS                 WITH PAR VALUE STOCKS
--------------------------------------------------------------------------------
   TYPE         NUMBER OF SHARES         TYPE       NUMBER OF SHARES   PAR VALUE
--------------------------------------------------------------------------------
<S>             <C>                    <C>          <C>                <C> 
Common:                                Common:         50,000,000       $.01
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
Preferred:                             Preferred:         400,000       $.01
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
</TABLE>
<PAGE>
 
The foregoing amendment(s) will become effective when these Articles of
Amendment are filed in accordance with General Laws, Chapter 156B, Section 6
unless these articles specify, in accordance with the vote adopting the
amendment, a later effective date not more than thirty days after such filing,
in which event the amendment will become effective on such later date.

Later effective date:                           .
                     ---------------------------

SIGNED UNDER THE PENALTIES OF PERJURY, this  30/th/ day of  January   , 1998,
                                           ---------      ------------


              /s/ Mitchell G. Tyson                           , President
--------------------------------------------------------------

              /s/ Robert L. Birnbaum                          , Assistant Clerk.
--------------------------------------------------------------
<PAGE>
 
                       THE COMMONWEALTH OF MASSACHUSETTS


                             ARTICLES OF AMENDMENT
                    (General Laws, Chapter 156B, Section 72)


        ===============================================================

          I hereby approve the within Articles of Amendment and, the 
          filing fee in the amount of $26,000 having been paid, said 
          articles are deemed to have been filed with me this 2nd day of
          February, 1998.



          Effective date: February 2, 1998 
                         


                             WILLIAM FRANCIS GALVIN
                         Secretary of the Commonwealth



                         TO BE FILLED IN BY CORPORATION
                      Photocopy of document to be sent to:


               Robert L. Birnbaum, Esq.
               -----------------------------------------------------------------
               Foley, Hoag & Eliot LLP
               One Post Office Square
               -----------------------------------------------------------------

               Boston, MA 02109-2170
               -----------------------------------------------------------------