LEWCO recently designed and built a custom rotisserie curing oven for a government funded, aerospace material Research facility. The oven featured an electric heater box that delivered dual airflow uniformly to the workspace. This application required a custom rotisserie cart and spline drive to rotate the composite workpiece. Due to the nature of the manufacturing process, a variable speed drive was required to allow the work to spin at various speeds while being cured. The speed/rotation was determined by the viscosity of the composite material being cured in order to form a uniform thickness on a cylindrical shaped part. Many government specifications, tolerances and procedures had to be followed for this critical process. With our engineering and manufacturing capabilities, LEWCO was the preferred vendor for this project.
Key oven features include:
• With the complex requirements of curing filament wound composites, the air temperature uniformity requirements were +/- 10°F from setpoint. The actual outcome was +/- 5.5°F.
• Part rotator: Custom spline drive mounted to back wall of oven, accepted machined shaft of 2,000 lb part and rotated at 1-30 RPM
• Manually loaded cart weighing in excess of 2,500 lbs, complying with OSHA and requiring less than 50 lbs of force to move. Cart was designed with adjustable fixtures and custom graphite bearings to hold customer supplied parts while rotating in a 650°F atmosphere.
• Silicon-Controlled Rectifier controls a massive 108 kW heater bank with 0-100% output control while monitoring voltage and amperage consumption.
• Custom Operator Interface Terminal with easy to use operations, recipe control and data trending screen communicating with Eurotherm controllers for precise and accurate temperature data logging.
• Additional thermocouple inputs included to monitor part/air temperatures as needed in future process requirements.
• Ethernet/FTP and USB communications included to allow for fast and simple data extraction.
• Nitrogen atmosphere capable, through wall fittings for nitrogen supply and a fresh air blocking plate were included with this oven for applications that were not curing a solvent based resin.
• The oven was designed as a single piece construction for ease of rigging and installation thereby reducing cost.
BASIC DESIGN DETAILS
• Utility: Electric, 480/3/60; 200 AMP Disconnect
• NFPA 86 Class A Oven, max solvent load: 0.04 Gallons/batch
• Maximum Temp: 650°F.
• Heat Capacity: 108 kW
• Workspace dimensions 61” wide X 120” deep and 61” tall
• Airflow Style: Dual
• Circulating Blower: 12,000 CFM
• Exhaust Blower: 62 CFM