Plastic annealing is a heat-treatment process that alleviates residual or internal stresses in thermoplastic parts and materials. This process improves the plastic’s dimensional stability and reduces its risk of cracking, wearing, and degrading. In high-precision or structural applications, plastic annealing is often critical for meeting specific dimensional and performance requirements. At COMCO Plastics, Inc., annealing is a value-added service we offer as part of our commitment to quality products.

What Is the Process of Annealing Plastic?

Machining or manipulating plastics can create residual stresses that may compromise the material’s fatigue life, impact strength, and chemical resistance. In certain applications, these stresses can significantly diminish part performance, eventually leading to premature failure. Plastic annealing uses controlled heating and cooling to relieve these stresses and improve structural integrity. 

So, what is the annealing process? Manufacturers can perform annealing as a standalone treatment or as a secondary treatment following procedures like injection molding, extrusion, and other plastic manufacturing methods. Typically, annealing is a three-stage process:

  • Recovery. First, the thermoplastic part or material is placed in an oven or heating chamber that gradually increases its temperature. This relieves any internal stress.
  • Recrystallization. During the recrystallization stage, the heat level rises above the material’s recrystallization temperature without surpassing its melting point. This allows for the formation of new grains that are free of any preexisting stress.
  • Grain growth. Using various techniques, the material cools to room temperature at a slow, controlled rate. Engineers optimize the cooling process to ensure the full development of the new grains.

Industries Served

Plastic annealing is optimal for applications that require high dimensional stability or very specific mechanical and chemical properties. Examples of industries that use annealed plastic parts include:

  • Aerospace. Plastic annealing is critical for ensuring defect-free, tight-tolerance thermoplastic parts that meet the aerospace industry’s strict quality and safety standards.
  • Healthcare. Capable of holding tight tolerances and less likely to warp at elevated temperatures, annealed parts are ideal for precision medical components that must withstand heat sterilization.
  • Military and defense. In the military and defense industries, plastic annealing can create military-grade plastic components for aircraft, satellites, missiles, and other mission-critical applications.
  • Semiconductors. In semiconductor manufacturing, annealed plastic components can help minimize or eliminate issues such as warpage and deformation.

Advantages of Plastic Annealing

Plastic annealing provides several advantages for its end products, including:

  • Increased integrity and dimensional stability. The annealing process provides defect-free plastic parts or materials with improved structural integrity and a higher durability rating. It also helps prevent warpage when parts are exposed to prolonged high temperatures. These are especially important traits for plastics in structural applications like PVC piping.
  • Enhanced resistance properties. Annealing minimizes the occurrence of cracking, providing the material with improved resistance to a range of harsh chemicals and solvents. Also, annealed plastics exhibit improved grain structure, allowing them to better withstand abrasion, wear, impact, and other mechanical stresses.
  • Decreased expansion and shrinkage. By modifying the microstructure of the plastic, annealing can significantly reduce shrinkage and expansion. This allows the material or part to maintain tighter tolerances and the desired dimensions during operations.
  • Diminished creep and hoop stress. Annealing heat treatment addresses the risk of plastic deformation from creep and hoop stress in components.
  • Improved machinability. Annealing changes the plastic’s properties and increases the ductility of the material while reducing its brittleness, rendering it easier to machine.

Plastic Annealing Services From COMCO Plastics

Plastic annealing plays an important role in improving the machinability of plastics and creating higher-quality parts that are less susceptible to mechanical and chemical stresses. For optimal results, it is important to work with an experienced provider who can correctly adjust each annealing variable according to the material’s specific properties.

COMCO Plastics is a one-stop-shop plastics manufacturer specializing in the production of precision-machined high-performance plastics and components. As a value-added service, our plastic annealing capabilities allow us to optimize the plastic parts we produce for a range of harsh, high-stress environments. With our goal of continuous improvement and innovation, we work hard to ensure on-time, affordable, high-quality products that we manufacture to your exact specifications to best fulfill the needs of your application.

To learn more about our plastic annealing capabilities, contact us today or request a quote to begin your project.