There are several threads on this, worth looking around. Your company should do an analysis of its operations and determine where risks can be introduced across all of product realization, and describe what measures you have taken to reduce those risks.
Supplier control (resin purity), equipment control (mold process validation), customer interface (control of customer-initiated change). Those are things that can introduce risks into the system, and which you have direct control over.
Customer knowledge can be a factor her. For medical products, it's a big no-no to use mold release agents, a molding company with no experience in medical devices might not know that.
A risk-based assessment of your process should look at that kind of thing.