Unlike DMAIC methodology aimed to improve an existing product, DFSS approach is used during development of new products or services. DFSS model is based on five step DMADV cycle.
Six Sigma DMADV defines, measures, analyzes, designs, and verifies new processes or products that are trying to achieve Six Sigma quality.

Define -defining project goals and customer demands (both external and internal).

Measure - measuring and quantifying the expectations and requirements of customers.

Analyze - analyzing the options of the processes which are required to meet the needs of the customer.
 
Design - detailed designing of processes to meet the needs of the customers.

Verify - verification of the designed performance and the ability to meet the needs of the customer.