LEWCO, Inc. was recently chosen to design and manufacture an 800°F electrically heated walk-in oven that is used primarily for curing honeycomb composite structures, but also has the capability for vacuum assisted composite curing. The enhanced duty batch oven features a top mounted heater-box with 180 kW of heat capacity. The oven is equipped with a 24,000 CFM high-efficiency circulation fan delivering horizontal airflow and providing uniform heat throughout the workspace. A variable speed drive is included on the exhaust fan for controlled cooling cycles and shorter purge time. The airflow volume of the oven is designed to meet strict temperature uniformity requirements. A 9-point temperature uniformity survey was conducted at 500°F and 750°F to ensure that customer requirements for their specific process have been met. The temperature uniformity survey exceeded customer specifications of +/-10°F, by achieving better than +/-5°F.
Oven controls include a Programmable Logic Controller (PLC) with a touchscreen Human Machine Interface (HMI) that includes LEWCO’s composite curing program. A Eurotherm Nanodac temperature controller and redundant high-limit controller provide precise temperature control and over-temperature protection. This control system has a multitude of capabilities, such as serial communication port, ramp/ soak programming and data logging for up to 24 channels. All the data can be downloaded via Ethernet or local USB.
Included with the oven are (4) ½” NPT vacuum ports located on the interior with (4) electro pneumatic vacuum valves installed on the exterior. Also, (4) vacuum transducer ports are located adjacent to each vacuum port. All vacuum ports are connected to a common 1” NPT header pipe for a single point connection to the customer’s vacuum source. Each vacuum valve and transducer is hard wired back to the control panel for monitoring, control and data logging.