| 1 | Verify the Complete Process Route | The line should provide a clearly defined route covering: Precursor handling Oxidation or stabilization Carbonization Optional graphitization Surface treatment Sizing Winding | Request a process flow diagram, equipment list, utility balance, material-flow diagram, and a description of how each section is connected. Confirm whether surface treatment and sizing are integrated or supplied as separate modules. | A factory may offer only furnaces while omitting downstream treatment and winding. Ask for a complete line boundary and identify every item required to produce saleable carbon fiber. |
| 2 | Check Equipment Quality and Temperature Control | Typical reference temperatures include approximately 200–300°C for stabilization, 1,000–1,600°C for carbonization, and up to approximately 2,500–3,000°C for high-temperature graphitization, depending on the product. | Review furnace temperature uniformity data, heating-zone layout, insulation design, atmosphere-control method, pressure or flow monitoring, thermocouple calibration records, and maintenance procedures. | Poor temperature uniformity can cause inconsistent tensile properties, shrinkage, surface quality, and conversion yield. Require measured uniformity data rather than relying only on the rated furnace temperature. |
| 3 | Match Capacity to Actual Demand | Compare capacity using the same basis: kg/day tonnes/year tow count line speed operating hours Capacity must include realistic uptime, planned maintenance, yield loss, and changeover time. | Request a capacity calculation showing line speed, number of running hours, loading width, tow size, expected yield, annual operating days, and the assumed utilization rate. Check whether the figure is design capacity or demonstrated output. | A quoted annual capacity may represent ideal conditions and may exclude downtime or off-specification material. Compare guaranteed capacity with demonstrated production records from a comparable process. |
| 4 | Evaluate Production Flexibility | A flexible line should support relevant tow sizes and product grades, with practical adjustment of: Line speed Tension Residence time Furnace atmosphere Sizing level | Ask for the supported tow-count range, recipe-management functions, changeover procedure, minimum stable operating speed, typical changeover time, and trial results for at least two product specifications. | A line designed for one fixed product may be difficult to adapt. Confirm that mechanical guides, rollers, tension controls, software recipes, and treatment systems can accommodate the planned product portfolio. |
| 5 | Inspect Process Control and Quality Monitoring | The control system should monitor and record critical parameters such as: Temperature Atmosphere Line speed Tow tension Pressure Sizing application | Review the PLC or SCADA architecture, alarm history, data-logging capability, recipe control, calibration schedule, traceability method, and quality-test plan for tensile strength, modulus, elongation, sizing content, and filament appearance. | Limited data capture makes it difficult to identify the cause of property variation. Require batch-level traceability from precursor lot through furnace conditions, surface treatment, sizing, and final package. |
| 6 | Assess Energy Efficiency, Safety, and Environmental Controls | The factory should address: Inert-gas management Off-gas handling Exhaust ventilation Fire protection Emergency shutdown Thermal insulation | Request energy consumption estimates per kilogram of fiber, gas-consumption data, off-gas treatment design, safety risk assessments, interlock lists, emergency procedures, and applicable inspection or compliance documentation. | High energy use, uncontrolled flammable gases, and inadequate exhaust systems can increase operating cost and safety exposure. Include safety validation and utility consumption in the technical acceptance criteria. |
| 7 | Confirm After-Sales Support and Scale-Up Capability | The supplier should provide: Installation support Operator training Spare-parts planning Remote diagnostics Process commissioning Performance acceptance testing | Review the commissioning schedule, training syllabus, recommended spare-parts list, response-time commitment, software-support policy, warranty terms, acceptance-test protocol, and upgrade options for additional capacity or automation. | Inadequate technical support can extend commissioning and downtime. Make payment milestones dependent on installation, stable operation, product trials, documented output, and agreed quality results. |