Polycarbonate is one of the most popular plastics when it comes to machined parts. Specifically, many manufacturers use it in medical equipment and in vitro equipment. Known for its clarity and toughness, polycarbonate machined parts offer a myriad of uses for designers.
Polycarbonate is available in many shapes and forms (such as rod and plate), and experts create it using multiple polycarbonate machining manufacturing processes.
For polycarbonate machining applications below 0.375-inches thick, glazing-grade polycarbonate (or window grade) is often the best option. Glazing-grade is a low-cost extruded product that ships with protective masking. It is available in several tints since manufacturers often use the plastic as part of a protective cover for devices where looks matter.
At 0.375 inches and up in thickness, polycarbonate is sold as a machined plate for polycarbonate machining. If compressed, the product is clear and has protective masking. On the other hand, if it has been extruded, it has a rough, translucent look. Both types have either a purple or gray tint. However, polycarbonate machining for optical parts is also available without color by using transparent polycarbonate.
Both rod and tube polycarbonate are extruded products used in polycarbonate machining. Rods are ground to size, leaving a non-clear finish. Manufacturers deliver tubes in protective sleeves and are window glass clear.
Cost of Polycarbonate
In sizes greater than 0.375 inches thick, polycarbonate is about 15 percent more expensive than acrylic and three times less expensive than Ultem (polyetherimide). Polycarbonate machining for resulting machined parts that need thinner stock, a glazing grade is an inexpensive option.
Machine-grade polycarbonate plates, rods, and tubes used in polycarbonate machining are naturally clear, with either a purple or grey tint depending on the resin. Black is also readily available for polycarbonate machining. Glazing-grade polycarbonate is a clear product and tinted product; the tints include bronze, grey, and smoke.
Polycarbonate is known for its toughness and impact resistance, so it is often used in polycarbonate machining for bullet-proof glass applications. However, this does not mean that the plastic resists stress cracking or crazing. Since it is an amorphous material, it suffers from steady-state stress; mechanical stress or certain chemicals will cause cracking or crazing. A common example of this is with fasteners which may stress crack when overly tightened.
This plastic has a higher continuous use temperature than acrylic. For polycarbonate, that temperature is 225 degrees Fahrenheit, whereas acrylic is 150 degrees Fahrenheit.
In addition to a higher continuous use temperature than acrylic, polycarbonate has better chemical resistance. It tolerates methanol, ethanol, and bleach. As a result, machined polycarbonate manifolds are perfect for liquid biopharma applications where alcohols are part of the rinsing process.
Polycarbonate machining material is also available as a USP Class VI material, which means it is suitable for blood and skin contact. This is one reason the medical device industry favors it for use in instrumentation.
Polycarbonate Machining Tips
- Since polycarbonate machined parts wear poorly, do not use these parts in bearing or sliding applications.
- Avoid stress risers. Corner radii reduce the risk of stress cracking and strengthen parts.
- Polycarbonate machined layers are readily bondable, so consider a bonded multilayer manifold to improve performance.
- Heat-staked inserts are important for small threads under #2 or 2 mm--for those applications that require repeated disassembly.
- Consider straight threads over pipe threads, as pipe threads create steady-state stress.
- Machined parts with this type of plastic require annealing after machining, so look for shops that can provide this service.
- Carefully torque threads to avoid stress cracks.
- Do not accept whitish burn marks.
- Polycarbonate machining often forms a tough burr. Therefore, deburring is often necessary, but a smooth, burr-free machined part is possible.
Benefits of Polycarbonate
- There are many benefits of polycarbonate as a material choice, including:
- Polycarbonate machined parts are translucent in appearance but can easily return to clear via a vapor-polishing process.
- This plastic is quite dimensionally stable; close tolerances are possible.
- It has a higher continuous use temperature than acrylic.
- It is available as a USP Class VI material.
Disadvantages of Polycarbonate
There are also some disadvantages to using polycarbonate as a material choice, including:
- One of the biggest disadvantages to using polycarbonate is that it scratches easily. This can be overcome by using an anti-scratch coating.
- Polycarbonate can expand under heat. Therefore, companies that provide plastic machining services need to fully understand and accommodate for this property.
How Polycarbonate and Acrylic Differ
Designers may find themselves comparing polycarbonate to acrylic due to their similarities. However, they are different in a number of key ways, including:
- Polycarbonate is much stronger than acrylic.
- Acrylic is not nearly as resilient as polycarbonate.
- Acrylic can be heated and reshaped, while polycarbonate cannot.
- Polycarbonate is more expensive than acrylic.
Polycarbonate is a material choice that has a multitude of uses and applications, including:
- Clear windows
- Bullet-proof enclosures and windows
- Agricultural applications such as greenhouses
- Parts for a wide variety of industry applications
- Electronic components
- Protective eyewear
- And much more
About Controlled Fluidics
Controlled Fluidics works exclusively in top-quality plastic bonding and custom plastic assembly expertise and products. Our precision plastic machining experience dates back to 1980, and expert engineers lead our highly experienced staff. Our commitment to producing the finest precision manifolds and plastic components, as well as our responsiveness and delivery speed, sets industry standards.
Established in 2011, Controlled Fluidics collaborates with customers to solve plastic machining and manifold fabrication challenges.
We thrive on developing ground-breaking technologies, and our experts are ready to assist you with your complex designs. Contact us today!