Last year's strike against the advertising industry saw the union boycott any commercial work by its members.
SAG warned non-members that if they took part in adverts their future eligibility would be jeopardised.
So far the SAG Hollywood Member Application Review Committee has heard 63 cases, of which 39 have been found to have "wilfully participated" in off limits work.
They have been banned from SAG membership for periods ranging from six months to five years.
Membership of SAG gives pension and sickness benefits as well as representation in pay negotiations.
It is currently in talks with the Alliance of Motion Picture and Television Producers over a new contract.
The deadline for an agreement in 30 July.
Strikes were threatened at the beginning of the negotiations but these fears have since faded.
Pay-per-view
Last summer's strike saw actors demanding to be paid on a pay-per-view basis for all their work.
Advertisers wanted them to agree to flat-rate payments.
The strike was eventually settled after six months - making it the longest strike in acting history.
Advertisers agreed to retain the existing system for network TV - which rewards actors each time their ad is shown - but insisted on an increased flat-rate pay structure for cable and the internet.
The review committee has been sitting almost weekly since February and is expected to continue screening applicants for the rest of the year.
SAG said the work reviews are carried out because of information received during or since the strike or by candidates disclosing the information themselves.
Spokesman Greg Krizman said: "The process of screening applicants for SAG membership against the more than 1,500 records of actors who allegedly performed struck work continues because it is our intention to provide member benefits only to those performers who stood in solidarity with the Guild during last year's work stoppage."