<PAGE>   1
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   FORM 10-K-A

[x]      Annual Report pursuant to Section 13 or 15(d) of the Securities
         Exchange Act of 1934

                     For the fiscal year ended July 31, 1998

[ ]      Transition Report pursuant to Section 13 or 15(d) of the Securities
         Exchange Act of 1934
         For the transition period from ____ to ____

                         Commission file number: 0-22974

                              CMC INDUSTRIES, INC.
             (Exact name of registrant as specified in its charter)

DELAWARE                                       62-1434910
(State of incorporation)                       (IRS Employer Identification No.)

4950 PATRICK HENRY DRIVE, SANTA CLARA, CA      95054
(Address of principal executive offices)       (Zip Code)

       Registrant's telephone number, including area code: (408) 982-9999

Securities registered pursuant to Section 12(b) of the Act: None.

Securities registered pursuant to Section 12(g) of the Act: Common Stock, $.01
par value per share

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days.


[X] Yes     [ ] No

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405
of Regulation S-K is not contained herein, and will not be contained, to the
best of registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K [ ]

State the aggregate market value of the voting stock held by non-affiliates of
the registrant: $18,629,507 at October 9, 1998.

Shares of Common Stock, $.01 par value per shares outstanding at September 30,
1998: 7,593,556

                       DOCUMENTS INCORPORATED BY REFERENCE

Documents incorporated by reference and the Part of the Form 10-K into which the
document is incorporated:

Portions of the Proxy Statement relating to the 1998 Annual Meeting of
Shareholders: Part III

Portions of the 1998 Annual Report to Shareholders: Part II , Part IV (2)
<PAGE>   2
PART IV

ITEM 14. EXHIBITS, FINANCIAL STATEMENT SCHEDULES, AND REPORTS ON FORM 8-K.

(1) EXHIBITS

<TABLE>
<CAPTION>
Exhibit     Description 
Number      -----------
<S>         <C>
3.1*        Restated Certificate of Incorporation.
3.2*        Amended and Restated Bylaws.
4.1*        Form of Common Stock Certificate.
4.2***      Securities Purchase Agreement, dated as of May 15, 1996, by and
            between the Company and each of the investors listed therein.
10.1*       Agreement and Plan of Reorganization between CMC Industries, Inc.
            and International Telecommunication Asia PTE, Ltd. dated as of
            October 2, 1993.
10.2*       Lease Agreement between The Board of Supervisors of Alcorn County,
            Mississippi and International Telephone and Telegraph Corp. dated
            August 1, 1961, as amended and supplemented and related documents.
10.3*       Lease Agreement between Corinth Telecommunications Corp. (now known
            as CMC Manufacturing, Inc.) and Douglas Jumper and Truitt Stockton
            d/b/a Jumper-Stockton Warehouses for the Pinecrest Road warehouse
            dated October 20, 1992.
10.4*       Lease Agreement between Corinth Telecommunications Corp. (now known
            as CMC Manufacturing, Inc.) and Douglas Jumper and Truitt Stockton
            d/b/a/ Jumper-Stockton Warehouses for the Sawyers Road warehouse
            dated October 20, 1992.
10.5        Loan and Security Agreement dated September 26, 1996 (and
            Amendments) among CMC Industries, Inc., CMC California, Inc., and
            CMC Mississippi, Inc. and Bank of America Illinois and related
            documents.
10.6*       License Agreement between ITT Corporation and ITT Telecom Products
            Corporation (now known as CMC Manufacturing, Inc.) dated December
            30, 1986.
10.7*       Agreement between Cortelco International, Inc. and CMC
            Manufacturing, Inc. dated as of September 1, 1993.
10.8*       Cortelco USA, Inc. (now known as CMC Manufacturing, Inc.) Profit
            Sharing Savings Plan and Trust for Salaried Employees.
10.9*       Hourly Pension Plan for Employees of ITT Telecom Products
            Corporation (now known as CMC Manufacturing, Inc.) at Corinth.
10.10****   CMC Industries, Inc. 1990 Equity Incentive Plan, amended and
            restated as of November 15, 1996.
10.11*      Form of Indemnification Agreement between CMC Industries, Inc. and
            certain officers and directors.
10.12**     Lease Agreement between Guzik Investments, L.P. and CMC Industries
            dated June 14, 1995.
10.13****   CMC Industries, Inc. 1996 Employee Stock Purchase Plan.
10.14*****  Executive Employment Agreement between CMC Industries, Inc. and Jack
            O'Rear dated August 1, 1997.
13.1******  Excerpts from the 1998 Annual Report to Shareholders.
21.1******  Subsidiaries of the Registrant.
23.1******  Consent of Independent Accountants.
27.1******  Financial Data Schedule (For SEC electronic filing purposes only)
</TABLE>

*        Incorporated by reference to exhibits filed with the Registrant's
         Registration Statement on Form S-1, Registration No. 33-70126.

**       Incorporated by reference to exhibits filed with the Registrant's
         Annual Report on Form 10-K for the year ended July 31, 1995.

***      Incorporated by reference to exhibits filed with the Registrant's
         Current Report on Form 8-K filed the Securities and Exchange Commission
         on May 24, 1996.

****     Incorporated by reference to exhibits filed with the Registrant's Proxy
         Statement on Schedule 14A filed with the Securities and Exchange
         Commission on October 22, 1996.

*****    Incorporated by reference to exhibits filed with the Registrant's
         Annual Report on Form 10-K for the year ended July 31, 1997.

******   Previously filed with the Registrant's Annual Report on Form 10K for
         the Year ended July 31, 1998.
<PAGE>   3
                                   (SIGNATURES


  Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange
Act of 1934, the registrant has duly caused this report to be signed on its
behalf by the undersigned, thereunto duly authorized.


                                          CMC INDUSTRIES, INC.

                                          /s/ Matthew G. Landa
                                          --------------------
Date: October 28, 1998                    Matthew G. Landa, President,
                                          Chief Executive Officer and Director


  Pursuant to the requirements of the Securities Exchange Act of 1934, this 
report has been signed below by the following persons on behalf of the
registrant and in the capacities and on the dates indicated.


<TABLE>
<CAPTION>
           Signature                       Title                                       Date
           ---------                       -----                                       ----
<S>                                 <C>                                          <C>

/s/ David S. Lee                    Chairman of the Board                        October 28, 1998
------------------------------
David S. Lee


/s/ Matthew G. Landa                President, Chief Executive                   October 28, 1998
------------------------------      Officer and Director
Matthew G. Landa


/s/ Andrew J. Moley                 Executive Vice President,                    October 28, 1998
------------------------------      Financial Officer and
Andrew J. Moley Chief               Director


/s/ Ira Coron                       Director                                     October 28, 1998
------------------------------
Ira Coron


/s/ Frederick W. Gibbs              Director                                     October 28, 1998
------------------------------
Frederick W. Gibbs


                                    Director
------------------------------
Charles Holloway


/s/ Richard M. Moley                Director                                     October 28, 1998
------------------------------
Richard M. Moley


/s/ M. Kenneth Oshman               Director                                     October 28, 1998
------------------------------
M. Kenneth Oshman
</TABLE>