Polycarbonate is a remarkable material that's incredibly strong yet beautifully clear. It's 250 times tougher than glass but weighs only half as much. When you machine it right, you get parts that can handle tough conditions very well. The material works fine at temperatures between -40°C and 120°C.
We carefully and precisely machine polycarbonate for you at ApexRapid. To avoid problems, this material needs the right speeds and cooling when cutting. If you cut it wrong, the edges will melt or crack very quickly. We now know how to make clean parts that stay clear and look great.
We completely understand that your polycarbonate parts need to be perfect. Every time, our CNC machining gets tolerances down to ±0.05mm. We can help you whether you're trying out an idea or making hundreds of parts. Let's look at how CNC machining makes polycarbonate work perfectly for you.
Polycarbonate Machining
CNC machining polycarbonate means cutting and shaping it with computer-controlled machines. The machines follow precise instructions to make your parts just right. This way, every piece is of the same quality. You can now make shapes that are too hard to make manually.
Different cutting tools, like end mills and drills, carefully take away the material. When polycarbonate gets hot while being cut, it becomes soft, so speed is important. The right tools and settings keep it from melting or breaking. With sharp carbide tools, you can get the clean cuts and smooth finishes you want.
When you use the right settings all the time, the material cuts well. With the right setup, you can get things right to within ±0.025mm. The process keeps polycarbonate's well-known strength and clarity.
| Property | Value | Unit |
| Density | 1.20 | g/cm³ |
| Tensile Strength | 60 - 70 | MPa |
| Tensile Modulus | 2.0 - 2.4 | GPa |
| Elongation at Break | 80 - 150 | % |
| Flexural Strength | 90 - 100 | MPa |
| Impact Strength (Notched Izod) | 600 - 900 | J/m |
| Glass Transition Temperature | 145 - 150 | °C |
| Heat Deflection Temperature (1.8 MPa) | 128 - 138 | °C |
| Continuous Service Temperature | -40 to 115 | °C |
| Light Transmission | 86 - 89 | % |
| Refractive Index | 1.586 | - |
| Water Absorption (24hr) | 0.15 - 0.20 | % |
| Coefficient of Linear Thermal Expansion | 65 - 70 | ×10⁻⁶/°C |
| Dielectric Strength | 16 - 18 | kV/mm |
Polycarbonate Sheets
Following the right steps carefully is the best way to machine polycarbonate. Each step helps keep things from cracking or melting, which are common problems. We'll explain the steps to you so you know what to expect. These steps will make sure that your parts always come out well.
Glass-Filled Polycarbonate Rod
Polycarbonate takes in water from the air, so it's important to dry it first. Before machining, put your material in an oven at 120°C for 2 to 4 hours. This gets rid of moisture that can cause bubbles when cutting. Please check your stock for any scratches or other problems before you use it. If you catch these early, you won't have any problems later on.
How you hold polycarbonate together is very important for keeping it from cracking. Instead of tight spots, apply even pressure across the surface. Soft jaw inserts help spread the clamping forces evenly and safely. Don't tighten it too much, because that can make the material crack right away. The clamp should hold the material firmly but not too tightly.
When working with polycarbonate, having sharp cutting tools is very important. When tools are dull, they make heat that melts the material instead of cutting it cleanly. This material works best with carbide end mills that have positive rake angles. Two-flute designs help cut chips away more easily. Before you start, please check your tools to make sure they are in good shape.
For your first cuts, use moderate spindle speeds of about 2,000 RPM. A good balance is 0.15mm per tooth. To keep the heat down, keep your cut depth between 1 and 2 mm. When you see small, clean chips forming, you'll know the settings are right. Make small changes as needed based on how the material reacts.
Check your first few cuts to make sure everything is working right. The material should cut cleanly, without smoking or making stringy chips. To keep the temperatures under control while cutting, use a constant air blast or coolant. Please stop and slow down if you smell smoke. The part should feel a little warm after machining, but not too hot.
For the best surface quality, use lighter cuts for finishing passes. When you make your last passes over surfaces, use shallow depths of about 0.05mm. If you need to, for safety, use fine sandpaper to carefully remove sharp edges. With careful polishing, you can bring back optical clarity to clear parts. Take your time finishing to keep the best qualities of the material.
Please check your parts soon after machining, while they're still warm. Check for small stress cracks, especially around corners and holes. To see if there are any problems inside, hold clear parts up to the light. To make sure everything meets your requirements exactly, measure the important dimensions. This careful checking makes sure you get parts that work perfectly.
Some parts benefit from a stress-relieving treatment after machining finishes. Placing parts in an oven at 130°C for 90 minutes helps relax internal stresses. Allow them to cool slowly inside the oven for the best results.
Polycarbonate Machining Process
Different machining methods work better for different polycarbonate parts depending on their shape and needs. Your choice has a big effect on both the quality of the part and how quickly it can be made. Knowing what each method is good at will help you choose the best one with confidence. Let's take a look at the main ways that polycarbonate parts are machined.
CNC milling shapes polycarbonate by using rotating cutters that take off material in controlled passes. Carbide end mills that spin at 2,000 to 3,500 RPM make pockets, slots, and complicated shapes very well. The method can make precision housings and instrument panels with tolerances of ±0.05mm. Milling is good for electronic enclosures because it works well with complicated mounting features and ventilation slots. When you use sharp tools and get rid of chips properly, you get great surface finishes.
CNC turning makes cylindrical polycarbonate parts like bushings, sleeves, and optical barrels on lathes. The cutting tool shapes the diameter while the workpiece spins at 800 to 1,500 RPM. You get smooth, concentric surfaces that are perfect for guide rollers and bearing housings. This method of machining lens barrels keeps the wall thickness even, which is important for how well they work optically. The cutting action that happens all the time makes surfaces that are free of stress and won't change shape over time.
Drilling makes clean holes in polycarbonate that are dependable for assembly and functional purposes. When you use a Brad-point drill at 1,000 to 2,000 RPM, the material won't grab or crack. Peck drilling every 3–5 mm removes chips and lowers the temperature in deeper holes. The holes for mounting in panels and clearance in brackets are always exact and clean. Using sharp carbide drills keeps the quality high across hundreds of holes before they need to be replaced.
Routing quickly and accurately cuts polycarbonate sheets into certain shapes and profiles. CNC routers that run at 18,000 to 24,000 RPM make clean edges on display panels and guards. You can cut sheets that are 2mm to 25mm thick into both straight lines and complicated curves. Routing's ability to follow complex patterns is useful for machine guards and safety shields. Compared to slower sawing methods, the high-speed cutting puts less stress on the edges.
Laser cutting uses focused light to melt and vaporize polycarbonate along the cut line. CO2 lasers with a beam width of 0.1 to 0.3 mm and a power of 100 to 150 W can make very detailed patterns. You can get very fine details in decorative panels and stencils that machines can't match. The cut edges are slightly frosted from the heat, which actually helps the glue stick. This method is used by light diffusers and architectural panels to make complex shapes inside.
Waterjet cutting uses water that is under pressure and mixed with an abrasive to cut through polycarbonate cleanly. The process stays cold, so there is no melting, discoloration, or thermal stress. You can cut thick pieces up to 100mm thick while keeping the edge clear. This way of cutting is good for large protective shields and custom panels. The kerf width of 0.8 to 1.2 mm lets you get good detail without any heat-affected areas.
Polycarbonate CNC-Machined Parts In Different Industries
Sawing makes straight cuts that are cheap and easy to do before detailed machining starts on polycarbonate stock. Blades with carbide tips and 80–100 teeth that spin at 3,000–4,000 RPM stop chipping and melting. Band saws can make curved cuts in thicker pieces when they need to make custom shapes. With this method, you can quickly cut rectangular blanks and trim sheets to size. Choosing the right blade and using moderate speeds will keep the edges clean for the next step.
Threading makes strong screw threads in polycarbonate that can be put together without breaking. Using helical interpolation to thread mill at 1,500 to 2,500 RPM greatly lowers the stress on the material. A single-point cutter can make threads from M3 to M12 in bosses and mounting points. When metal inserts aren't right, threaded polycarbonate is used for camera mounts and adjustable fixtures. The method lets one tool make threads of different sizes, from 6mm to 30mm in diameter.
Finishing makes polycarbonate parts look and work better after they have been machined. Different finishes are better for different uses and looks. Picking the right method makes your part work better and look better. Let's look at the main finishing choices we have.
Deburring gets rid of sharp edges and burrs on polycarbonate parts that have been machined. Hand filing or tumbling in plastic media is a safe way to smooth edges. This stops cuts from happening while handling and makes the overall look better. It also gets rid of stress points that could lead to cracking later.
Sanding with paper with a grit of 320 to 1200 makes machined surfaces smoother over time. Plastic polish compounds do a good job of bringing back the original glossy finish. This method works great for optical parts and display panels. With careful, patient work, you can get glass-like clarity.
Flame Polishing
A torch is used in flame polishing to melt the surface down to a very thin layer. Quick passes at a distance of 5 to 10 cm make the edges look clear and shiny. This makes cut or machined surfaces clear again in a beautiful way. This finish is often used on architectural panels to make them look professional.
Vapour polishing puts parts in contact with solvent vapours that slightly dissolve the surface. The material flows back into a smooth, even finish without touching anything. This method can reach shapes that are too complicated for hand polishing. This is what medical housings use to keep their optical clarity.
When necessary, painting polycarbonate surfaces gives them color and protection. Two-part polyurethane paints make coatings that are long-lasting and resistant to chemicals. Light surface preparation makes sure that things stick well and last a long time. A lot of the time, painted finishes are used on car parts to brand them.
Protective coatings make surfaces much more resistant to scratches and UV rays. Hard coats make surfaces harder, from 2H to 4H. Coatings that don't reflect light make displays and panels less shiny. Versions that are UV-resistant stop things from turning yellow when used outside.
Printing permanently adds graphics, text, and other decorative elements. Pad printing works well on surfaces that are not flat or have curves. Screen printing makes long-lasting images on flat surfaces. Printing is used on equipment panels for branding and instructions.
Annealing polycarbonate
Annealing relieves stress inside by heating parts to 130–135°C for one to two hours. Cooling down slowly stops new stresses from forming later. This treatment stops parts from cracking later on. Parts that have been stress-relieved stay stable in size better over time.
Polycarbonate Electronic Enclosures
We're ready to help you create precision polycarbonate parts for your projects. Our team understands polycarbonate's unique properties and machines it with care. You'll receive parts with excellent clarity, tight tolerances, and reliable performance.
Whether you need prototypes or production quantities, we're here to support you. Our CNC equipment handles polycarbonate machining with the precision your applications demand. Get started today with a quick quote for your polycarbonate components.
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