Answer : In the past we had test about this surface. We found some problem of roll grinding, cause from coarse grinding and made spiral. And we just processed in few tons for sample only, we need to test for work roll life time.
Also we need to evaluate the effect of
a) operation cost, due to we need to change several time of work roll (2 rolls (1set) / coils (20T)) that estimated cost 125 USD/ton or 4 Baht/kg
b) success ratio due to high quality request that cost approximate 348 USD/ton (as 20% scrap) or 11 Baht/kg. In the past, with NICO requirement, we did the no.519 surface and we found many claim and many block coil (no. 519 produce in APF line) then we lost a lot. Now we change process to do a matted surface by other process and need to test.
Due to above reason, we need to test more coils and marketing needs to accept for failure cost and delay.