How to Evaluate a Contract Manufacturer: 10 Questions to Ask Before Your First Order

Why Evaluation Matters

A manufacturer's website will always say they deliver quality, on time, at competitive prices. Every manufacturer says this. The evaluation process is how you verify which ones actually do it.

The cost of choosing poorly: rejected parts, missed deadlines, rework, air freight to meet deadlines, and ultimately finding a new supplier and starting the entire process again. A few hours of evaluation upfront prevents months of problems downstream.

The 10 Questions

Question 1: "What processes do you perform in house?"

This reveals their actual capability versus what they subcontract. A manufacturer who says they do CNC machining, laser cutting, welding, and galvanizing should be able to name specific machines for each process. If they are vague, they are likely subcontracting. Read more about why this matters: All Under One Roof Manufacturing.

Question 2: "Can you show me your equipment list?"

Ask for specific machine names, models, and quantities. A serious manufacturer is proud of their equipment and will share details willingly. At AMN Engineering, we are happy to share that we run Nakamura CNC lathes, Hardinge Super Precision machines, and Takisawa CNC equipment.

Question 3: "Do you provide material test certificates with every order?"

The answer should be "yes, as standard." Not "yes, if you ask for it." Material test certificates (MTCs) prove the raw material meets the specified grade. A manufacturer who does not provide MTCs by default may not be checking incoming material consistently. Read more: Quality Control in Manufacturing.

Question 4: "Can you send a dimensional inspection report with actual measured values?"

Not just "pass/fail" but the actual numbers measured on each critical dimension compared against your drawing tolerances. This proves they are actually measuring parts, not just eyeballing them.

Question 5: "Will you accept third party inspection?"

Any manufacturer who resists third party inspection (SGS, Bureau Veritas, TÜV) is a red flag. Third party inspection is standard practice in international manufacturing and costs the manufacturer nothing. Resistance usually means they are worried about what the inspector will find.

Question 6: "What happens if parts are out of tolerance?"

The answer should include rework, replacement, or credit. Not "we will try harder next time." You want a clear policy on what happens when things go wrong, not just assurances that they never will.

Question 7: "Can I see examples of similar work you have done?"

Ask for photos of similar parts, reference clients in your industry, or sample inspection reports. A manufacturer who has never made anything similar to your part is a higher risk than one with proven experience.

Question 8: "What is your typical lead time, and how do you handle urgent orders?"

Lead time should be specific: "2 to 3 weeks for this type of work" is a good answer. "Depends" without further detail is a red flag. Also ask about expediting: can they rush an order if needed, and what does it cost?

Question 9: "How do you communicate during production?"

The best manufacturers send progress updates proactively: photos of raw material, in process shots, finished parts before packing. Ask what communication channel they use (WhatsApp, email) and how often you will receive updates.

Question 10: "Can I start with a trial order of 10 to 50 pieces?"

If a manufacturer requires large minimum orders from new clients, they may not be set up for the flexibility you need. A confident manufacturer welcomes trial orders because they know their quality will speak for itself. Read more: Prototype to Production.

Red Flags to Watch For

• Cannot name specific machines or equipment
• Refuses or hesitates about third party inspection
• Does not provide material test certificates as standard
• Vague about lead times ("it depends")
• No photos of their factory or equipment
• Requires large minimum orders from new clients
• Cannot provide references from existing clients
• Quotes without asking detailed technical questions about your part
• Claims to do everything but cannot explain how

Green Flags That Build Confidence

• Names specific machines and their capabilities
• Welcomes third party inspection
• Provides MTCs and inspection reports as standard
• Shares factory photos or offers a video tour
• Responds to inquiries within 24 hours
• Asks technical questions about your part (shows they are thinking about how to make it)
• Offers trial orders at reasonable pricing
• Is transparent about what they subcontract versus do in house
• Has verifiable international clients