Why This List Exists
Most packaging machine buyers walk into supplier meetings with a spec sheet and a budget. They ask about speed, format range, and price. They forget to ask about changeover time, training depth, parts availability, and what happens when the machine breaks at 2am on a Saturday. Six months later, they are running at 60% of rated speed, paying premium freight on emergency parts, and trying to find a service engineer who can fly in next week.
The buyers who avoid this outcome ask better questions. They treat the supplier evaluation as a structured interview, not a sales conversation. They ask the same questions of every supplier so they can compare answers directly. They ask follow-up questions when the supplier is vague. They take notes and they hold suppliers to their answers during contract negotiation.
This list is the 20 questions that matter. We split them into four groups: technical, operational, commercial, and reference. Ask all 20 of each shortlisted supplier. Compare the answers. The supplier that gives specific, numerical answers and willingly provides references is almost always the safer choice. The supplier that hedges, qualifies, or deflects is telling you something important.
For the broader framework on how to evaluate suppliers against your specific application, start at the Machine Selector pillar.
Technical Questions (1-7): Specs, Materials, Changeover
Technical questions reveal whether the supplier actually understands your application or is configured to sell you whatever they have on the shelf.
1. What is the realistic throughput on my specific product and format? Do not accept the rated speed from the brochure. Rated speed is on ideal product under ideal conditions. Ask the supplier to quote realistic sustained throughput on your product, your film or carton, and your target bag or case weight. The gap between rated and realistic is usually 15-25%. A supplier that will not commit to a realistic number is a supplier that does not know.
2. What is the changeover time between my two most common formats, end to end? Changeover time matters more than peak speed on most lines. The supplier should quote changeover in minutes, including format parts swap, HMI recipe load, and first-good-pack validation. Get the quote in writing. Ask whether the quote assumes a trained changeover team or a single operator. The realistic number for a format change on a VFFS is 20-45 minutes. Anything under 15 minutes on a multi-format line is suspicious.
3. What format parts are required for each of my SKUs and what do they cost? Format parts (forming tubes, seal jaws, guide rails, magazine plates) are an upcharge and they are not cheap. A forming tube for a VFFS runs $1,500 to $4,500. Seal jaws run $800 to $2,500 per set. For 8 SKUs across two bag sizes, you may need $15,000 to $30,000 in format parts. Get the full list and the price before signing the PO.
4. What film or material specifications does the machine require? Machines are calibrated to specific material ranges. A VFFS that runs 50 micron PE will not run 25 micron compostable film without re-engineering. Ask for the material specification sheet and verify your current or planned film falls within it. If you plan to switch to mono-material structures for sustainability, confirm the machine can run them today.
5. What is the machine's tolerance for product weight variation? Powder filling, liquid filling, and counted-piece products all have weight variation. A machine sized for nominal weight may struggle at the high end of the tolerance. Ask the supplier how the machine handles product weight variation and what happens at the extremes. The wrong answer is "the operator adjusts." The right answer involves automatic feedback and statistical process control.
6. What is the electrical and pneumatic consumption at sustained throughput? Energy cost is 1-3% of total cost of ownership but adds up over 10 years. Ask for consumption at idle, at 50% throughput, and at sustained throughput. Compare across suppliers. A machine that draws 30% more power than a competitor will cost you $5,000 to $15,000 more per year in electricity.
7. What is the machine's compatibility with my existing upstream and downstream equipment? Infeed conveyors, product dosers, checkweighers, metal detectors, case packers, and palletizers all need to integrate. Ask the supplier about their experience integrating with your specific upstream and downstream equipment brands. The supplier should provide a timing diagram and handshake protocol as part of the proposal.
Operational Questions (8-13): OEE, Maintenance, Training
Operational questions reveal what running the machine will actually be like after the installers leave.
8. What OEE (overall equipment effectiveness) should I expect at 3 months, 6 months, and 12 months post-install? A new machine does not hit target OEE on day one. The ramp curve matters. Ask the supplier to commit to OEE targets at 3, 6, and 12 months and to explain what support they provide during ramp. Realistic targets for a well-installed VFFS: 55-65% at 3 months, 70-75% at 6 months, 75-82% at 12 months. A supplier quoting 85% OEE at 3 months is either lying or has a very narrow definition of OEE.
9. What is the recommended preventive maintenance schedule, in hours and dollars? Preventive maintenance consumes 3-8% of machine purchase price annually. Ask for the full PM schedule: daily, weekly, monthly, quarterly, annual. Ask for the parts cost for each PM event and the labor hours required. Compare across suppliers. A machine that is cheaper to buy but requires 50% more PM hours may be more expensive to own over 10 years.
10. What is the typical mean time between failures (MTBF) on this model? MTBF is the average hours of run time between unplanned stoppages lasting more than 15 minutes. For mid-market VFFS machines, MTBF should be 200-400 hours. For premium machines, 400-800 hours. A supplier that does not track MTBF or will not share it is a supplier that does not measure their own quality.
11. What training is included in the purchase price, and what costs extra? Standard training is usually 3-5 days on-site for operators and 2-3 days for maintenance. That is not enough. Ask what extended training costs, what off-site training at the supplier's facility costs, and whether training materials (videos, manuals, e-learning) are included. Budget $8,000 to $20,000 for additional training on top of the included package.
12. What is the HMI language support and documentation quality? If your operators speak a language other than English, verify the HMI supports it. More importantly, ask to see the actual operator manual and maintenance manual, not a sample chapter. Manuals that are 30 pages of bullet points are useless. Manuals that are 200+ pages with photographic procedures, troubleshooting trees, and parts diagrams are useful for the next 15 years.
13. What remote diagnostics capabilities does the machine have? Modern machines should support secure remote access for supplier service engineers to diagnose faults without flying on-site. Ask whether remote access is included, what the annual fee is, and what the typical response time is for a remote session. A supplier with strong remote diagnostics can resolve 60-70% of issues without an on-site visit.
Commercial Questions (14-17): Warranty, Payment, Lead Time
Commercial questions determine what happens when something goes wrong and who pays for it.
14. What does the warranty cover, for how long, and what is excluded? Standard warranty is 12 months parts-only from shipment. That means you pay for the technician to install the replacement part. Push for 18-24 months parts-only at no extra cost, or 12 months parts-and-labor including technician travel. Exclusions matter: wear parts (seal jaws, belts, blades) are almost always excluded. Get the exclusion list in writing.
15. What is the payment schedule and what leverage do I have on terms? Standard is 30% on order, 60% on shipment, 10% on acceptance. Push for 20% on order, 70% on acceptance, 10% at 90 days post-acceptance. The 70% on acceptance gives you leverage through commissioning. Withholding payment until after a successful factory acceptance test is your strongest protection against a machine that does not perform.
16. What is the lead time from signed order to ready-to-ship, and what protections exist if the supplier slips? Lead time for standard mid-market machines runs 14-20 weeks. For custom configurations, 24-36 weeks. Ask what protections exist if the supplier slips. A liquidated damages clause (typically 0.5-1% of machine price per week of delay, capped at 10-15%) is standard and reasonable. Suppliers that refuse liquidated damages on lead time are telling you they expect to slip.
17. What is the total cost of ownership over 10 years, broken out by category? A supplier that wants your long-term business will provide a TCO estimate. The estimate should break out purchase price, installation, training, energy, spare parts, software licensing, and projected major overhauls. Compare TCO across suppliers, not just purchase price. A $120,000 machine with $180,000 of TCO add-ons over 10 years is more expensive than a $150,000 machine with $100,000 of TCO add-ons.
Reference Questions (18-20): Sites to Visit, Customers to Call
References are the most important questions and the ones suppliers fear most.
18. Can you provide three references in my region running this exact model for over 18 months? The exact model matters. A reference running a different model tells you little. Over 18 months matters: that is when the honeymoon period ends and wear-related issues surface. In my region matters: support quality varies by region and a reference 3,000 miles away tells you nothing about your local service team. If the supplier cannot provide three references meeting all three criteria, the installed base is smaller than they claim or the customers are unhappy.
19. When was the last service call each reference required, and how was it resolved? Call the references and ask this directly. The answer tells you about real-world reliability and service quality. A reference that has not needed service in 18 months either has an unusually good machine or is not running it hard. A reference that needed service and got a same-day resolution is gold. A reference that waited 11 days for parts and 5 days for a technician is warning you.
20. What would each reference do differently if they were buying again? This open-ended question surfaces everything else. Common answers: "We would have bought the next size up," "We would have specified the dual-lane option," "We would have negotiated harder on training," "We would have visited the factory during build." Patterns across multiple references reveal the model's characteristic weaknesses.
Red Flags in Supplier Answers
Watch for these signals during supplier meetings:
- Vague answers on realistic throughput: a supplier that will not commit to a sustained throughput number on your specific product is hiding something.
- Refusal to provide references in your region: the installed base is either small or unhappy.
- Response time quoted in days instead of hours: the supplier does not have a service network in your region.
- Parts fill rate below 80%: you will wait for parts regularly.
- No documented PM schedule: the supplier does not know how their own machine ages.
- HMI screenshots that look 15 years old: the control system has not been updated.
- Warranty exclusions that include major components: the supplier does not trust their own engineering.
- Pushback on factory acceptance test: the supplier is not confident the machine will pass.
Any one red flag deserves follow-up. Two or more red flags from the same supplier should remove them from the shortlist.
Building a Supplier Scorecard
Turn these 20 questions into a scorecard. Score each shortlisted supplier on a 1-5 scale across the four categories: technical fit, operational readiness, commercial terms, and reference quality. Weight reference quality highest: a supplier with strong references covers for many other weaknesses.
A typical scorecard will surface one clear leader and one clear loser across three or four shortlisted suppliers. The leader is your primary supplier. The second-place supplier is your fallback and your leverage during negotiation. Never tell the leader they won until the contract is signed.
This process takes time: 4-6 weeks for a serious evaluation. That time pays back many times over. The factories that skip this work are the ones buying machines they regret within 18 months. For the next step in the buying process, see our breakdown of 10 costly buying mistakes that this evaluation process is designed to prevent.