You need to use a different chocolate. Here are some answers in this link.

Here is a link that might be useful: Chocolate melting point.

You could probably get away with the chocolate you're using if you melt it, spread it paper thin on waxed paper, let harden and break up into flakes. Thinner pieces won't be as challenging as actual chunks.

Alternatively, I often put diced brownies in my ice cream. When adding 'extras' like candy, brownie pieces, broken chocolate covered pretzles--I chop them up, and put them in the freezer, then add to the ice cream just the last few minutes of the churning time, when the ice cream is just about done. You only want to mix them in, not take a chance the add-ins will be crushed or broken during the mixing process.

You can put shaved or grated chocolate in your ice cream, and the pieces will be small enough not to break teeth. The only chocolate I usually add to ice cream is Godiva Chocolate liqueur or Mocha Kahlua. You can add these liqueurs to the ice cream as you are making it toward the end, but they will make the ice cream softer.

I like Azzalea's idea of spreading chocolate thin on waxed paper and letting it harden. That seems like a very easy way to get chocolate flakes.

Lars

I use a Trader Joe's bar, chopped into fairly small pieces.

And try this... Your very best vanilla ice cream, add semi-sweet chocolate chopped, and the last couple of turns in the machine, add a couple of spoonfuls of orange marmalade or raspberry jam just long enough to swirl thru, not mix in entirely.