Purple gloves holding up an unpolished plastic part and a polished plastic part for comparison

At Controlled Fluidics, our polishing technology is second to none. Regardless of the process used, we ensure that each precision plastic part with an optical finish is made to specifications and beyond expectation.

Let Your Project Shine

The Controlled Fluidics proprietary fast plastic machining technologies render plastics extremely optically clear. As a result, manifolds or regular machined plastic components turn out equally dazzling and optically functional!

Plastic has significant advantages over other materials, such as glass and quartz, for optical finishing. Plastics weigh less, are durable and heat-resistant, and can take a polish just as brilliantly as traditional materials do. So when optimal clarity and a smooth, clean finish are part of your production goals, we can deliver precision plastic polishing fast!

A Polished Finish, Every Time

Our methodologies achieve exceptional optical clarity. No single plastic polishing technique fits every application. We are skilled at choosing the best polishing solution for your part. Polishing, especially on amorphous plastics, increases surface stress on plastic products. Surface stress management is a critically important part of the plastic polishing process. Our polishing processes mitigate polishing-induced surface stress, providing high-quality plastic components that meet customer requirements. Plastic polishing methods used at Controlled Fluidics are:


Buffing is a traditional polishing method that works on all types of plastics, smoothing the surface. However, actual clarity is limited by the approach (cotton cloth abrading the surface, with thousands of multi-directional scratches). Suitable for large flat pieces with limited holes and projections.

Flame Polishing

Flame polishing utilizes a hot flame to treat plastic surfaces, providing a visually clear surface for some plastics. Operator-dependent, some surface waviness is to be expected. The ability to internally polish is limited to larger features at or near the surface for this method.

Optical Machining

Optical machining is a plastic machining method utilizing special tooling and equipment for true optical results. Finishes are measured for form and roughness. This method produces the finest finish on most plastics (100 angstroms roughness is typical).

Vapor Polishing

We reserve this plastic polish method for clear plastics only (polycarbonate, Ultem®, polysulfone, and acrylic). It produces a good result for see-through applications and can polish internal features (such as threads and bores). Not effective on semi-crystalline materials.

Plastic Polish Materials

Going through the plastic polishing process transforms common materials into extremely optically clear building blocks optimized for any project that relies on transparency. When selecting materials for a project that will require polishing, you can use the list below to narrow your options. Any of these materials will be excellent options for polishing projects.

Polished Acrylic

Although general-purpose grade cast acrylic polished parts will block UV wavelengths up to 360 NM, consider UVT grade for any application requiring transmittance of 280 NM and above. Polishing of acrylic allows for many novel edge lighting approaches, including the possibility of total internal reflection.

Polished Acrylic components are the most common clear parts. In addition to being relatively scratch-resistant compared to other amorphous plastics, Acrylic is also one of the least expensive materials for clear parts with the finish tint-free. As a result, it is the closest plastic substitute for window glass and can be utilized in light pipe applications. Acrylic can be polished via buffing, flame polishing, and optical machining, although polished acrylic lenses are often produced by optical machining. Drilled holes can be straight and clear with a skilled machinist, and light transmittance is near 92%.

Polished Polycarbonate

Presenting a blue or gray tint, polycarbonate polished components are softer than acrylic, resulting in lower scratch resistance. Conversely, polycarbonate parts have greater toughness than acrylic parts. Unlike acrylic, polycarbonate is available as a USP class VI medical grade material, commonly used in medical devices with blood flow or skin contact. Polycarbonate has a max service temperature of 225F, good resistance to chemicals used in cleaning instruments, and is polished via vapor polishing or optical machining.

Polycarbonate is available in colors and a window grade (no tint) resin. Car headlights covers, in particular, benefit from polycarbonate’s combination of clarity, high impact resistance, and low cost. It's important to note that polycarbonate is not UV resistant and requires an addition of a UV stabilizer to avoid yellowing. Any polished polycarbonate medical components that require FDA or USP Class VI certification use a non-UV stabilized material. Although polycarbonate costs more than acrylic, it costs considerably less than higher performance materials like Ultem, making it an excellent choice for many projects.

Polished Ultem

Dark amber in color, Ultem components are polished via vapor polishing or optical machining. Due to their best-in-class continuous service temperature of 330F and high resistivity, Ultem finds uses as insulators and other electrical devices. Ultem is UV resistant and will not degrade under exposure. It is tolerant of steam sterilization and is available as an FDA or USP Class VI material in colors. Optical machining will provide finishes below one microinch for optical applications, while vapor polishing will produce a surface finish of fewer than twelve microinches.

Our team can reduce Ultem’s light transmittance based on thickness. As a result, polishing of thicker blocks (>2’’) takes on a black-like appearance. Note that clear surfaces can be degraded by handling scratches.

Polished Polysulfone

Light amber in color, polished polysulfone parts are often used in hot water applications due to the material’s higher continuous service temperature of 300F. In addition, polysulfone is resistant to water absorption and can tolerate steam sterilization to 285F. Biocompatible grades are available in colors. Polysulfone parts are particularly resistant to radiation sterilization, and clear polysulfone components can be used in FDA-compliant devices.

Both vapor polishing and optical machining are effective approaches to increase clarity. Clear polysulfone components can be used in FDA-compliant devices and are commonly used in sterilization trays as their clarity allows for easy inspection.

Polished Radel

Like Ultem, polished Radel (PPSU) is dark amber in its natural color, and standard stock colors for polishing are white and black. Radel allows for unlimited steam sterilization, but other methods, including radiation, dry heat, and cold sterilization, are acceptable. As a result, polished Radel components are frequently used in medical devices.

Radel responds well to vapor polishing and optical machining, and polished Radel components offer better impact and chemical resistance than Ultem and polysulfone parts. However, clear Radel components do absorb light in the UV range and are unsuitable for those applications. Light transmittance for a 2mm thick clear sample is 80% with 3% haze.

Polished Polyethersulfone (PES)

Like Ultem and PPSU, polished PES is dark amber in its natural color. Vapor polishing and optical machining can achieve excellent results with a very smooth surface finish. In addition, PES has an excellent flame resistance of UL 94 V-O, and polished PES parts have a continuous service temperature of 350F. These properties, along with the material’s good dielectric constant, low loss factor, and high resistivity at temperatures above 200C, make PES an excellent high-temperature electrical insulating material.

Expert Selection

Ready to let our experts select the most effective method for polishing your machined plastic parts? Contact us today to get started.


Ready to let our experts select the most effective method for polishing your machined plastic parts?