The rough surface casting problem is usually rough surface a cause can occur for several reason.
Please check:

1. Casting temperature too hot.
2. Flask temperature too hot.
3. Melt the metal too long.
4. Rough model, check finish on model.
5. Rough wax, check rubber mold for excess mold release agents.
6. Incorrect water to powder ratio on investment mix, usually too wet.
7. Inadequate set up time before burn out or steam de-waxing.
8. Steam de-waxing for too long, should be 45 minutes to 1 hour.
9. Flasks heated too rapidly, putting cold flask into a hot oven.