Practical Due-Diligence Framework for Plastic Film Machinery Projects

When sourcing blown film lines, cast film lines, slitter rewinders, laminators, or Printing/converting modules, “supplier expertise” is not a slogan. It shows up in how the supplier defines technical risk, manages engineering changes, controls quality, and supports commissioning.

Below is a field-ready framework to evaluate the difference between factory technical teams and trading sales agents—using questions, evidence requests, and scoring criteria that can be applied to real quotations and factory visits.

Quick Comparison

1. Engineering Depth Test

What to ask and what “real” looks like

Ask these technical questions and watch for structured answers:

1. What screw L/D, compression ratio, and mixing section do you recommend for my resin system and output target

• Factory team: explains resin MFI range, filler level, recycle ratio impact on torque and melt temperature

• Sales agent: repeats a standard spec sheet or avoids details

2. How do you control gauge variation and edge thickening at high line speed

• Factory team: discusses die lip control, air ring stability, haul-off calibration, cooling uniformity

• Sales agent: focuses on “high precision” wording

3. What are your tension zones and control logic for Slitting/rewinding stability

• Factory team: outlines unwind–infeed–rewind tension map and sensor strategy

• Sales agent: gives general “auto tension” claims

Evidence to request

• Process flow diagram or technical proposal with control logic description

• Resin/material requirement sheet they provide to confirm selection basis

• Reference configuration for similar materials and thickness range

2. OEM/ODM Customization Authority Test

Determine whether customization is structural or superficial

Ask about changes that require engineering ownership:

• Can you redesign screw geometry for high CaCO₃ masterbatch or recycled blends

• Can you modify die internal flow to improve layer distribution in multilayer film

• Can you upgrade automation from manual to servo-driven tension and closed-loop control

• Can you adapt electrical systems for destination country standards and cabinet layout compliance

Factory team indicators

• Provides drawings, revision control, engineering change approval workflow

• Offers options with defined trade-offs and lead times

• Confirms what is feasible and what requires redesign

Trader-limited indicators

• Only offers cosmetic changes, interface language change, or “add a sensor” style upgrades

• Needs long back-and-forth for engineering answers

3. Quality Control Traceability Test

Verify whether QC is real or marketing

Request these documents (sample pages acceptable):

• Material certificates for key wear parts (screw/barrel alloy, roller material)

• Heat treatment or surface treatment records (nitriding depth, hardness results)

• Runout/concentricity inspection for rollers

• Electrical inspection checklist for cabinet wiring and safety interlocks

• Factory Acceptance Test outline and typical report format

Factory team capability

• Can explain inspection points and tolerances, not just “pass/fail”

• Provides traceability by serial number or batch

Sales agent limitation

• Only provides a generic “QC report” without measured values or traceability

4. Commissioning and Troubleshooting Capability Test

The real test is what happens after installation

Scenario questions to ask

• If bubble instability occurs, what parameters do you check first and why

• If slitting has telescoping or wrinkling, how do you rebalance tension and nip pressure

• If melt pressure fluctuates, what checks do you do on resin, heating zones, screw wear

Factory team response

• Offers diagnostic tree logic and likely root causes

• Proposes measurable checks and corrective actions

Trading agent response

• Requests video/photos and forwards to factory

• Has no structured troubleshooting workflow

5. Spare Parts and Lifecycle Support Test

Long-term support separates real suppliers from resellers

Ask for

• Standard spare parts list and recommended first-year spare kit

• Lead time commitment for critical wear parts (screws, heaters, sensors, bearings)

• Whether they keep engineering archives per serial number

• Remote support capability and response time process

Factory team advantages

• Parts compatibility is guaranteed because design archive is internal

• Upgrades and retrofits are feasible without reverse engineering

6. Export Compliance and Documentation Readiness Test

Compliance is proof of technical maturity

Ask whether they can provide

• Risk assessment and safety guarding documentation for CE markets

• Electrical schematics and component lists aligned to destination requirements

• Operation manual set structure and language support

• Pre-shipment inspection and documentation workflow

Factory technical teams typically own the compliance file generation process. Traders often depend on upstream factories and may have gaps.

7. On-Site Evaluation: What to Observe in a Factory Visit

Strong factory indicators

• Engineering team present in meetings, not only sales

• Measured inspection instruments in use and visible records

• Assembly and wiring standards (labeling, routing discipline)

• Test run area with defined FAT procedure

• Clear parts storage and traceability system

Red flags

• No engineering staff available for direct discussion

• Vague answers on tolerances and inspection criteria

• “We can do everything” without constraints or drawings

8. Scoring Checklist You Can Use Immediately

Score each item from 0–5:

1. Engineering answers are measurable and structured

2. Can provide drawing revisions and change control process

3. QC reports include measured values and traceability

4. FAT procedure is documented and repeatable

5. Spare parts and lifecycle support plan is clear

6. Export compliance file readiness is demonstrated

7. Troubleshooting logic is systematic, not reactive

A supplier scoring high across these areas is typically factory-led and technically reliable.