Dear Vijayan,
Planning strategy for SF would not be required,since the demand for the Finished product would be
generating the dependent requirements for the semi finished product based on the stock/receipt
situation.
Assignment of planning strategy for the semi finished would be required only if there is separate
demand(forecast/sales/production)for the semi finished product level.Planning strategy 70 would be best
suited for the components.
Check help.sap.com to understand more about this planning strategy.
Regards
Mangalraj.S