Conveyorized Electric Heat Shrink Oven for Wiring Harness Heat Shrink Processing

The process requirement was to heat shrink components on wiring harnesses using a compact continuous conveyorized process. The application centered on connectors and related harness components passing through the oven on a belt conveyor rather than being manually loaded into a batch chamber.

APPLICATION REQUIREMENT

• The equipment was required to heat shrink components on wiring harnesses in a continuous pass-through conveyor process.
• The application centered on connectors and related harness components moving steadily through the heated work area rather than being loaded into a batch chamber.
• The overall need was for a practical continuous oven capable of delivering repeatable thermal exposure to wiring-harness components within a compact production setup.

CONVEYOR / PROCESS REQUIREMENT

• A simple, repeatable conveyor process was required to move product continuously through the heated work area at an adjustable speed.
• The oven had to provide a compact conveyor path, stable product presentation through the heated zone, and a straightforward operator interface for starting the recirculation fan, running the conveyor, and adjusting line speed.

FOOTPRINT / INTEGRATION REQUIREMENT

• The system needed to fit within a relatively small footprint while maintaining adequate access for installation, operation, and maintenance.
• Shipping and receiving access basis: 12 ft W × 16 ft H dock door.

SAFETY / CLASSIFICATION REQUIREMENT

• The oven was configured as NFPA 86 Class B with no VOCs allowed, making it well suited for controlled heat-shrink processing without the added complexity of a Class A volatile-handling architecture.

UTILITY REQUIREMENT

• Required electrical service: 208V / 3PH / 60Hz. Full load amperage: 78.5 A.

The thermal process requirements were established from the need to heat shrink components on wiring harnesses in a controlled continuous-conveyor environment.

TEMPERATURE CAPABILITY

• Operating temperature: 426°F.
• Maximum temperature: 450°F.
• Required work-area uniformity: ±10°F, referenced at multiple locations on the supply-duct face.

PROCESS BASIS

• The thermal process basis is continuous heat shrinking of components on wiring harnesses.
• The process was built around a compact heated zone with controlled vertical airflow, adjustable conveyor speed, and repeatable electric heat delivery appropriate for continuous heat-shrink processing.
• No VOCs allowed. Oven classification: NFPA 86 Class B.

HEAT INPUT REQUIREMENT

• Heat source: electric resistance heat. Heating elements: 1 kW Inconel elements. Total installed heat: 24 kW.
• Heater configuration: two heater banks of 12 kW each with solid-state relay power control.

AIRFLOW DELIVERY REQUIREMENTS

• Airflow pattern: vertical down.
• Total circulated air volume: approximately 1,500 CFM at 3 in. w.c.
• Recirculation fan: New York Blower 128 PLR plug fan; 2 HP TEFC motor.
• Supply discharge: adjustable slots at 2,500 FPM through 18 gauge aluminized steel supply duct.
• Return concept: open return through sides of chamber.

EXHAUST / VENTILATION BASIS

• Exhaust type: non-powered exhaust, consistent with Class B electric process.
• Exhaust opening: 7 in. × 4 in. Fresh air inlet provided on oven body.

To deliver the process requirements for this wiring harness heat-shrink application, the following equipment concept and architecture was developed.

OVERALL CONCEPT

• One compact conveyorized electric Class B oven for continuous heat shrinking of wiring harness components.
• Single heated zone with vertical-down airflow, continuous belt conveyor motion, and a straightforward controls architecture matched to the heat-shrink duty.

HEATING ARCHITECTURE

• Heat source: electric resistance. Total heat: 24 kW across two 12 kW heater banks.
• Heating elements: 1 kW Inconel elements. Heat control: solid-state relay control per bank.

AIRFLOW / RECIRCULATION ARCHITECTURE

• Airflow pattern: vertical down. Top-mounted recirculation system directing heated air downward through the work area; open return through sides.
• Recirculation fan: New York Blower 128 PLR plug fan — approximately 1,500 CFM at 3 in. w.c.; 2 HP TEFC motor.
• Supply discharge: adjustable slots at 2,500 FPM through 18 gauge aluminized steel duct.
• Exhaust: non-powered, 7 in. × 4 in. opening with fresh air inlet on oven body.

CONVEYOR / HANDLING ARCHITECTURE

• Conveyor type: Teflon-coated fiberglass belt conveyor, 30 in. wide, 86 in. total length.
• Conveyor drive: Nord right-angle helical-bevel gearmotor, 1/3 HP, through Allen-Bradley PowerFlex 525 VFD; speed range approximately 2–6 ft/min.
• Speed adjustment: manual 10 kohm potentiometer. Take-up: spring-loaded. Head/tail pulleys: crown type.
• Load area: 18 in. Unload area: 22.625 in. Conveyor height: 36 in. above finished floor.
• E-stop stations at load left, load right, unload left, and unload right — each disables the conveyor only.

SHELL / CONSTRUCTION ARCHITECTURE

• Work area: 30 in. wide × 36 in. deep × 6 in. clear height above conveyor belt.
• Overall dimensions: 95.68 in. L × 68.50 in. W × 103.30 in. H. Approximate weight: 4,500 lb.
• Wall construction: 4 in. thick walls with 4 in. of 6 lb mineral wool insulation.
• Interior: aluminized steel. Exterior: carbon steel, PQ Blue finish. Control panel finish: gray / PQ White.

CONTROLS ARCHITECTURE

• Control enclosure: oven-mounted NEMA 1, 36 in. × 36 in. × 12 in., listed to UL 508A Open Industrial Control Panel.
• Temperature controller: SSI 804, 1/4 DIN. Work-area overtemperature protection: Gefran 650L.
• Manual operator controls for recirculation fan start and conveyor run; conveyor speed via potentiometer.
• Motor starters: IEC type. Non-fused 100A disconnect switch included. Recirculation fan airflow switch included.
• Applicable standards basis: NFPA 79, NFPA 86, UL 508A.