August 2020 MARIETTA, GA ~ Despatch ovens feature a variety of chamber sizes and temperature capabilities, as well as exceptional temperature uniformity, flexibility and tight process control and monitoring. The LBB model is available in five sizes from the small benchtop 2.3 cu ft. to 27.7 cu ft. The LAC model is available in four sizes from 3.7 to 18 cu ft. and the TAD/TFD walk in two sizes the 52.6 cu ft. and 216 cu ft.

These high performance annealing ovens are used around the globe within a variety of industries, including technology, transportation, healthcare and industrial manufacturing.

Annealing is the most commonly used for treating metals, but other materials, including glass and plastics. Depending on the material, annealing temperatures range from less than 100 degrees C to more than 1000°C., a process that can take hours or several days.

During the annealing process, a metal, plastic or glass is heated to a specific temperature or color and then the metal is cooled at a controlled, specified rate. This process changes the physical and chemical properties of the material to make it more malleable, or improve ductility; provide stress relief and create a new microstructure.

A specialized annealing oven gives users the ability to tightly control and monitor the heating and cooling process, allowing for proper recrystallization to occur within the material. The materials are annealed at the eutectic point and then allowed to cool. Annealing often softens the materials so they can be shaped or cut more easily, but can also increase its strength and ductility. Metals are often annealed to prepare them for further heat treatments.

The environment; temperature maintained, both during and after the annealing process; and cooling rate are critical. Typical temperatures used in heat-treating the most common materials include:

• Steel – 150°C to 1232°C

• Stainless Steel – 345°C to 400°C

• Aluminum – 90°C to 775°C

• Copper – 120°C and up to 800°C

• Plastics – 77°C and up to 260°C

Annealing plastics is recommended based on the following conditions:

• If the end-use conditions are demanding enough to require stress relief beyond what can be achieved through the product design, process and materials.

• If stress relief after machining is necessary.

• If during the post polishing process the material would likely crack due to surfaces stresses caused by the polishing itself.

Advantages of Annealing Plastics that have been stress relieved offer tighter tolerance, improved chemical resistance, improved wear resistance, improved flatness control, and better able to handle machined stress.

Plastics require different annealing conditions and temperatures:

• Polycarbonate: 250°F(121°C) for as short a time as possible determined through experimenting with test data

• Ultem: slowly brought up to 400°F(204°C) and then held for two hours

• ABS materials: heat deflection temperature at 264 psi (170°F to 240°F) and held for 1-2 hours.

• Supec resins: Annealed at 400°F(204°C) for 4 hours