Polyurethane Post Cure Oven for Automated Polyurethane Forklift Wheel Manufacturing

The process requirement was to complete the final post-cure cycle for demolded polyurethane wheels after the upstream molding-related stages had been completed. This stage required a long-duration thermal hold capable of processing a high number of parts simultaneously while maintaining continuous production-line throughput.

APPLICATION REQUIREMENT

• The equipment serves as the final post-cure stage for demolded polyurethane forklift wheels in an automated manufacturing line.
• The oven accepts product at an elevated entry condition (approximately 150°F) after earlier thermal processing and sustains the required final cure exposure over an extended residence time of approximately 24.47 hours.
• The process demands a machine optimized around capacity, dwell time, product density, and controlled line movement rather than short-cycle indexed heat-up.

CAPACITY / THROUGHPUT REQUIREMENT

• The machine processes a high number of parts simultaneously to support continuous production-line throughput of approximately 17.65 parts per hour.
• Maximum part size basis: approximately 17.7 in. diameter × 11 in. high; maximum part weight approximately 121 lb per part (approximately 111 lb steel, 10 lb polyurethane).
• The three-level conveyor arrangement was required to maximize in-oven part count within a manageable floor footprint.

THERMAL CONSISTENCY REQUIREMENT

• The oven maintains zone-to-zone thermal consistency over the full length of the heated body and across all three conveyor levels.
• Stable multi-zone thermal conditions are required throughout the long residence time to ensure consistent final cure across the part population.

LINE INTEGRATION REQUIREMENT

• The machine fits within an automated manufacturing environment with dependable conveyor handling and controls architecture compatible with the broader Allen-Bradley production-line platform.
• Zone-level monitoring, multi-conveyor coordination, and machine-to-machine communication were required for proper integration with the rest of the line.

SAFETY / CLASSIFICATION REQUIREMENT

• The oven was classified as NFPA 86 Class B, consistent with its post-cure thermal duty.

UTILITY REQUIREMENT

• Required electrical service: 480V / 3PH / 60Hz.

The thermal process requirements were established from the need to complete the long-duration final post-cure cycle for demolded polyurethane forklift wheels at the end of an automated manufacturing line.

TEMPERATURE CAPABILITY

• Operating temperature: 270°F to 295°F.
• Maximum design temperature: 325°F.
• Product entry temperature: approximately 150°F.

PROCESS BASIS

• The thermal process basis is final long-duration post-cure of demolded polyurethane forklift wheels, positioned as the last major thermal stage in the manufacturing sequence.
• Cure time: approximately 24.47 hours. Throughput: approximately 17.65 parts per hour.
• The machine's thermal role is long-duration final stabilization and cure completion, not short-cycle transition processing.

HEAT INPUT REQUIREMENT

• Heat source: electric resistance heat.
• Total installed heat input: 288 kW across four zones.
• Zone heat distribution: Zone 1 — 108 kW; Zone 2 — 36 kW; Zone 3 — 36 kW; Zone 4 — 108 kW.
• The front- and back-loaded heat distribution supports the way product progresses through the long thermal cycle.

AIRFLOW DELIVERY REQUIREMENTS

• Recirculation fans: four New York Blower 27 PLR recirculation fans, one per zone.
• Recirculation airflow: approximately 16,000 CFM per zone.

EXHAUST / VENTILATION BASIS

• Entrance-end exhaust: PQ-1 exhauster at approximately 550 CFM.
• Exit-end exhaust: New York Blower GP-18 exhauster rated to approximately 3,000 CFM maximum.
• Oven classification: NFPA 86 Class B.

To deliver the process requirements for the final long-duration post-cure stage, the following equipment concept and architecture was developed.

OVERALL CONCEPT

• One large four-zone electric-heated post-cure oven serving as the final thermal module in an automated polyurethane forklift wheel manufacturing line.
• The machine is built on structural steel reinforced pan-style construction and uses a three-level flat-wire conveyor arrangement within a four-zone heated body to achieve high in-oven part density and extended dwell time without excessive floor space.

HEATING ARCHITECTURE

• Heat source: electric resistance heating. Total installed heat input: 288 kW across four zones.
• Zone heat distribution: Zone 1 — 108 kW; Zone 2 — 36 kW; Zone 3 — 36 kW; Zone 4 — 108 kW.
• The front- and back-loaded heat configuration supports the machine's long-duration post-cure duty and the thermal progression of product through the system.

AIRFLOW / RECIRCULATION ARCHITECTURE

• Recirculation fans: four New York Blower 27 PLR recirculation fans, one per zone, each delivering approximately 16,000 CFM.
• Entrance-end exhaust: PQ-1 exhauster at approximately 550 CFM.
• Exit-end exhaust: New York Blower GP-18 exhauster rated to approximately 3,000 CFM maximum.

CONVEYOR / HANDLING ARCHITECTURE

• Conveyor type: three-level flat-wire conveyor arrangement.
• Conveyor drives: three gearmotors total.
• Part positions: 144 parts per level × 3 levels = 432 parts total simultaneously in the oven.
• The three-level arrangement allows very long dwell time and high part density within a more compact floor footprint than a comparable single-level machine would require.

SHELL / CONSTRUCTION ARCHITECTURE

• Shell construction: structural steel reinforced pan-style oven construction.
• Heated zone arrangement: four heated zones of approximately 171 in. each, followed by an exit vestibule.
• Total overall length: approximately 759.8 in.

CONTROLS ARCHITECTURE

• Control platform: Allen-Bradley line-integrated multi-zone controls architecture consistent with the broader production line.
• Control enclosure: remote-mounted NEMA 12 enclosure.
• The controls package manages multiple zones, multiple conveyor levels, encoder-based handling feedback, and a larger distributed-I/O structure than the earlier-stage modules in the line.
• Zone-level monitoring thermocouples and conveyor feedback devices support stable long-duration operation and line-level coordination.