Do you need re-entry permits for education visa????

That depends on if you want to travel abroad. Inyour passport you have a prsiion to stamp from Thai immigration. if you leave the country, that permission to stay expires. If you want to travel abroad but keep your permission to stay alive, you can get a re-entry permit.

It keeps your permission to stay alive, when you return to Thailand you will be stamped in untill the date you were originally allowed to stay. If you came back to Thailand on or after that date, your permission to stay will have expired and you will need to get a new ED-visa from abroad.

If you have a valid multiple entry ED-visa you don't need a re-entry permit, as long as you return before the visa expires.