Hi,
1. you can the inter operation times like Std. queue time, Min. queue time etc in work Center or Maximum wait time,Std. queue time,Std. move time in the routing these increase the operation timings.
2. In the work center check the capacity utalisation percentage(actual) and check the overlad percentage.
3. Check the work center capacity (actual capacity).
4. Create dummy work center and assign to routing to complete in time frame.
Regards,
Ravi