Introduction

PET, or polyethylene terephthalate, is a type of thermoplastic polymer that belongs to the polyester family. It is a widely used material known for its clarity, strength, and versatility. PET plastic has a range of applications across various industries.

Here are some key features and applications of PET plastic:

• Properties: PET plastic is a lightweight, transparent, and durable material with excellent mechanical properties. It has high tensile strength, impact resistance, and dimensional stability. PET is also known for its resistance to moisture, chemicals, and UV radiation.
• Packaging: PET plastic is commonly used in packaging applications, particularly for beverage bottles, food containers, and personal care product containers. Its transparency allows for product visibility, while its barrier properties help in preserving the freshness and integrity of the packaged goods.
• Textiles: PET is used to produce polyester fibers, which are widely utilized in the textile industry. These fibers are commonly used in clothing, upholstery, carpets, and other textile applications. PET fibers offer good strength, wrinkle resistance, and colorfastness.
• Films and sheets: PET is manufactured into thin films and sheets that are utilized in various applications such as packaging films, labels, graphic overlays, and protective coatings. PET films have excellent optical properties, thermal stability, and resistance to chemicals.
• Engineering applications: PET plastic can be reinforced with glass fibers or other additives to enhance its mechanical properties. This makes it suitable for engineering applications such as automotive parts, electrical components, and industrial equipment.
• Recycling: PET is highly recyclable. It can be reprocessed into new PET products or other products like textiles, carpets, and insulation materials. The recycling of PET helps in reducing waste and conserving resources.

Overall, PET plastic is valued for its clarity, strength, recyclability, and versatility. Its usage spans across packaging, textiles, films, engineering applications, and more, making it a popular choice in numerous industries.

CNC Machining PET

CNC machining of PET (polyethylene terephthalate) involves using computer-controlled machines to precisely cut and shape PET plastic into desired components. Here is a general overview of the CNC machining process for PET plastics:

• Design: Create a detailed design of the PET component using computer-aided design (CAD) software. This design will serve as a blueprint for the CNC machine.
• Material selection: Choose the appropriate grade and size of PET stock material. PET is available in various forms such as sheets, rods, and blocks. Select the form that best suits your project requirements.
• CNC programming: Generate a CNC program based on the CAD design. This program will provide instructions for the CNC machine to accurately cut and shape the PET material.
• Machine setup: Set up the CNC machine by securing the PET stock material onto the machine’s worktable or chuck. Ensure that it is properly aligned and clamped to prevent movement during machining.
• Tool selection: Select the appropriate cutting tools for machining PET. Carbide or high-speed steel (HSS) tools with sharp edges are commonly used for PET machining. It is essential to use sharp tools to achieve clean cuts and minimize heat generation.
• Machining process: The CNC machine will follow the programmed instructions to cut and shape the PET material. The specific machining operations will depend on the desired component, such as milling, drilling, turning, or threading.
• Cooling and chip evacuation: PET has a relatively low melting point, so it is important to use coolants during machining to dissipate heat and prevent material deformation. Air or water-based coolants can be used to keep the tool and workpiece cool. Proper chip evacuation methods, such as using compressed air or chip brushes, should be employed to prevent chip buildup and ensure smooth machining operations.
• Quality control: Regularly inspect the machined PET component to ensure it meets the desired specifications. Use measurement tools such as calipers or micrometers to verify dimensions and tolerances.

It is important to note that PET has a relatively low melting point compared to some other engineering plastics. Therefore, it is essential to carefully monitor and control the machining parameters such as cutting speed, feed rate, and coolant usage to prevent overheating and material deformation.

Following proper machining techniques and guidelines for PET will help achieve accurate and high-quality results. It is also recommended to consult with experienced machinists or CNC service providers who have expertise in machining PET for best practices and advice specific to your project.

PET Burrs

When machining PET (polyethylene terephthalate) using conventional methods, the formation of burrs is generally minimal compared to some other materials. PET has good chip formation characteristics, which can help reduce burr formation. However, it is still possible to encounter some burrs during the machining process.

Here are a few factors that can influence the formation of burrs when machining PET plastics:

• Cutting tool selection: Choosing the appropriate cutting tool geometry and sharpness is important to minimize burr formation. Using tools with a high rake angle and sharp edges can help produce cleaner cuts and reduce burring.
• Cutting speed and feed rate: Optimal cutting parameters, including the cutting speed and feed rate, need to be determined for PET machining. Using the right speeds and feeds can help control chip formation and reduce the likelihood of burr formation.
• Tool wear: Dull or worn-out cutting tools can contribute to increased burring. Regularly inspecting and replacing tools when necessary is important to maintain machining quality and minimize burr formation.
• Machining technique: The machining technique employed can also affect burr formation. Techniques like climb milling, where the tool cuts against the direction of workpiece movement, tend to produce fewer burrs compared to conventional milling.

While PET typically produces fewer burrs compared to many other materials, it is still important to inspect machined parts for burrs and perform any necessary deburring operations to achieve the desired surface finish and functionality.

Deburring can be accomplished using various methods such as manual deburring with files or deburring tools, tumbling, abrasive blasting, or chemical deburring processes. The specific deburring method will depend on the size, complexity, and tolerance requirements of the machined PET component.

Overall, PET’s good chip formation characteristics and machinability contribute to reduced burr formation. However, it is essential to consider the machining parameters, tool selection, and deburring processes to achieve the desired surface finish and dimensional accuracy while minimizing burrs.

Cryogenic Deburring

Cryogenic deburring is a process that involves exposing components to extremely low temperatures to make burrs brittle and easily removable. Cryogenic plastic deburring is suitable for PET (polyethylene terephthalate) due to its specific characteristics and low melting point.

Cryogenic deburring is an effective method for removing burrs from PET components as it can be easily frozen and the burrs made brittle. The parts are loaded into a cryogenic deburring machine and are blasted with a fine polycarbonate media while being tumbled against one another. This process removes the burrs from the CNC machined PET parts.

If you are interested in sending in PET plastic samples for a cryogenic deburring evaluation, please contact us at (508) 459-7447 or email us at info@nitrofreeze.com.