Annealing generally means heating the material to relieve stress, which may be generated during the previous manufacturing process. When a material is annealed, the stress is reduced to prevent cracking and premature failure of the part.
Annealing Oven Applications for Plastic Parts
Plastic parts are used extensively in automobile manufacturing to reduce cost, as well as to reduce the weight of cars for better fuel efficiency. Many appliances also use plastic parts to lower cost and weight. These are a few examples of common plastic parts and how an annealing oven is used to improve the performance and durability of the end product.
The five gallon water bottle you see in a water cooler is blow-molded from Polycarbonate resin. The bottle has a complex shape with variations in wall thickness and reinforcement for making the bottle strong. When the bottle comes out of the mold, it cools at different rates causing stresses in the material. The resin suppliers recommend annealing to extend the life of the bottle manifold.
The process involves heating the bottle to 260 degrees F in an annealing oven, then letting it cool gradually. An annealing oven can use infrared or hot air convection heating. The advantage of an IR annealing oven is that it requires only 4 minutes to heat, whereas a hot air annealing oven requires upwards of 12 minutes. The advantage of a hot air annealing oven is the ability to run multiple lanes, whereas in an IR oven you can run only a single lane.
The back reflector on an automotive headlight is sonically welded to the front lens. This process seals the headlight and protects the electrical components from water and wind. However, the welding process causes stress at the joint. Annealing the material removes the stress and extends the life of the headlight.
Electrical connectors for solar panels
Like headlights, the electrical components used in solar panels must be protected from the elements, including UV rays. Properly relieving stress in an annealing oven results in increased performance of the solar cells.
Many plastic films, such as those used in television screens, are extruded in multiple layers simultaneously. The layers consist of different polymers and have varying thicknesses, causing stresses during the cooling process. An annealing oven is used to heat the film to a specific temperature and cool slowly to relieve the stress in the film layers.
Radiant Energy’s Annealing Oven Designs
An annealing oven requires multiple zones to make sure each surface is heated uniformly and all the stresses are removed. At the same time, it’s critical to ensure that nothing exceeds the annealing temperature as this will damage or distort the shape of the part. An annealing oven is a complex system, and it needs to be tailored to the precise needs of your material and your process.
Radiant Energy offers both IR and hot air annealing oven designs to meet your production requirements. We can help you understand the advantages and limitations of the different heating technologies and designs, and work with you to make the best decision for your needs.