My dictionary, along with many websites I've checked translates 制作 as
- to make
- to manufacture
What sorts of things may I 制作?
The second definition of "manufacture" leads me to believe that, for example, "I made new flash cards."/「我制作了新的词卡。」, is too small-scale a thing to be 制作'ed. I haven't found any examples at http://www.chinese-tools.com/ or http://www.mandarintools.com/cgi-bin/wordlook.pl or in my dictionary.