How does Miller present Joe Keller as both a tragic hero and a villain in All My Sons?

In All My Sons, Miller presents Joe
Keller as both a tragic hero and a villain by having Joe force Steve Deever to ship the
faulty machine parts.  On the one hand, Joe may be considered a tragic hero because he
is caught in the dilemma of having to support his family.  Joe believes that the success
of his business is directly related to his caring for his family--he wants the business
to be successful to leave a legacy for his two sons.  He is afraid that his failure to
comply with the demand for machine parts will negatively impact his business.  However,
on the other hand, Joe's actions paint him as a villain.  Joe knows that the machine
parts are damaged, but he does not consider the potential danger that this will cause
the pilots who will later fly the planes containing the faulty parts.  Joe only focuses
on his immediate needs and disregards any concern for others.  After many men die, he
continues to hide his secret and allows Steve to take the fall.  So, Miller paints Joe
as both a tragic hero and a villain.