Continuous curing ovens are more complex, require a higher initial investment, and call for more maintenance than (batched) box ovens. In cae of high-volume manufacturing of products that need systematic and consistent thermal processing, continuous ovens offer significant benefits that can deliver high ROIs over time.
Autonational Composites applies continuous oven systems in its automated production lines. Continuous ovens are developed for processing wound mandrels (composite product) on conveyors, so it’s understandable that they are ideally suited for such operations. A continuous oven transports the products with an controllable speed through a controllable temperature zone(s) and is provided with a mandrel rotation system to prevent sagging of the resin during curing. The length of temperature zones coincides with the cuing time needed at the designated temperature.
Some of the features and options commonly found in our continuous ovens include:
- Electrical or natural gass heating
- Accurate and consistent temperature control in the different sections
- Variable temperature zones
- Separate heating and cooling chambers
- Transport and mandrel rotation control
- Early detection of obstructions in the oven
- Excellent isolation to prevent loss of heat
- Mandrel rotation system
- Automatic doors at entry and output side of the oven.
- At the end of the oven transport a cooling zone is provided.
Because continuous ovens don’t require repeated loading and unloading, or heating up and cooling down between each batch, labor and energy demands often are much lower than with batch ovens. The consistent and even distribution of heated air — and cooled air, where required — reduces processing time and typically results in greater consistency in quality across parts and throughout production runs.
A semi-continuous oven is equal to a continuous oven, but intake of the products takes place in batches. In front of the oven inlet, a partial or full oven load is allocated to a buffer position. Next, this entire batch is fed into the oven at once, with the previous batch being placed on an output buffer (behind the oven outlet) at the same time.
Box oven Batch box ovens are closed-process machines; when the door is closed, the heated chamber is sealed. Batch ovens are best utilized for smaller production quantities, large parts that are difficult to run on conveyors, and for items with different sizes, shapes, weights, and thermal requirements.
Batch ovens typically require lower capital investment than continuous ovens, but they also demand greater manpower to operate because they must be manually loaded and unloaded.
In semi-automated installations Autonational Composites usually fits box oven systems. A box-type curing oven is a static curing system, heated by electrical heating elements or natural gas. These ovens are generally equipped with insulation to prevent the outside of the oven to reach temperatures above 150°C.
Loading a batch oven normally involves racks or baskets for transferring the products for thermal processing into and out of the unit. Products to be cured can be placed on a special support system inside the oven can be adjusted to different mandrel diameters & lengths. In addition, a rotating mandrel system prevents sagging of the resin during curing.
In front of the oven, an input buffer stores or buffers wound mandrels. Behind the oven a cooldown station makes cooling easier. Both buffers are actually stationary rotation tables.
When cooling is required inside the oven, it adds time to the manufacturing process, since the same chamber must be cooled, then reheated for the next batch.
Infrared heating systems
Infrared heating systems are often used for gelling & curing of composites based on for example polyester resins directly towards the mandrel after winding on the winder or on a separation rotation unit.In combination with other curing systems, a well controlled curing of the product can be guaranteed.
Autonational Composites applies induction technology for the curing of composite products from the mandrel outwards. In combination with other curing systems, a well-controlled curing of the product can be guaranteed.