I feel your pain - those 6-month lead times on Siemens components are brutal and can really disrupt operations. Here's my practical approach to building redundancy without breaking the bank:

First, I'd start with a tiered redundancy strategy. For your most critical components, implement dual sourcing - but be strategic about it. Don't split 50/50 right away. Start with an 80/20 split where your primary supplier gets most of the business, and your backup gets just enough to keep them engaged and ready to scale up if needed. This keeps costs manageable while building relationships.

For vetting alternative suppliers, I follow a rigorous 5-step process:

1. Technical qualification first - I require sample parts for testing in our actual systems before any serious discussions

2. Factory audits - I personally visit their facilities to see their quality systems, certifications (ISO 9001 is non-negotiable), and production capabilities

3. Financial health check - I use services like Dun & Bradstreet to ensure they're stable enough to be reliable partners

4. Reference checks - I talk to at least 3 of their current customers in similar industries

5. Trial orders - I start with small, non-critical orders to test their delivery reliability and communication

The key is to prioritize based on component criticality and lead time impact. Focus your redundancy efforts on the parts that would cause the most production downtime if delayed. For less critical items, consider building strategic safety stock instead of full redundancy.

What specific Siemens components are giving you the most trouble? I might be able to suggest some proven alternatives that other automation directors have had success with.