ÂÌñÏ×ÆÞ

Delta Air Lines recently purchased a LEWCO Inc. (Sandusky, Ohio) 500°F vacuum-assisted composite curing oven to manufacture parts for its airplane cabins.

The vacuum-assisted composite curing (VACC) process involves drawing a vacuum on composite lay ups in vacuum bags while cured in an oven. LEWCO supports this process by equipping its composite curing ovens with a vacuum pump, thermocouple jacks and vacuum ports. This oven has 22 vacuum ports in the workspace that are connected to control valves on the exterior of the oven. Thermocouples are attached to the lay ups to monitor and record the temperature of the parts being manufactured.

Oven controls include a Eurotherm Nanodac temperature controller and redundant high-limit controller. This controller has a multitude of capabilities, such as a serial communication port, ramp/soak programming, and a 24-channel data logger. A programmable logic controller (PLC) interfaced with a human machine interface (HMI) and temperature controller communicate over Ethernet IP, allowing remote monitoring. The oven is designed to meet current AMS2750 standards.

The enhanced duty walk-in oven features a top mounted heater-box with a 1,000,000 BTU direct fired natural gas burner and 35,000 CFM high-efficiency circulation fans. A variable speed drive is included on an exhaust fan for a cooling cycle, thus allowing the fan to operate between 500 and 1,500 CFM. The airflow volume of the oven is designed to provide strict temperature uniformity requirements. The air supply duct size and placement are also vital in providing proper airflow and heat transfer.

Due to flammable volatiles present in the workspace, the oven was designed to NFPA 86 Class A standards. Many features are involved in meeting this standard including safety ventilation, a purge cycle, and explosion relief. LEWCO Industrial Ovens meet these standards.