Polycarbonate Machining Ultimate Guide: Benefits, Guidelines, and Applications
In the manufacturing and engineering landscape, polycarbonate material has gained popularity overtime due to its many advantageous properties such as its transparency, high heat and impact resistance, optical clarity, and durability.
Polycarbonate machining requires proper tool selection and optimized parameters to help achieve smooth finishes while maintaining polycarbonate’s strength and optical clarity in fabricated components. This article explores polycarbonate CNC cutting, its benefits, important tips for machining, and its limitations.
What Is Polycarbonate Machining
Polycarbonate, sometimes termed Lexan or Makrolon, are amorphous thermoplastic polymers that are used to manufacture structural units in various industries due to their mechanical and chemical properties.
They are handy to work with, easily molded, have a very high impact strength, excellent dimensional stability and a high elastic modulus. Also, polycarbonate sheets can sometimes be used to alternate glass.
CNC polycarbonate machining is a process that involves the cutting and shaping of a polycarbonate plate or rod into parts for specific applications in industries using either the CNC milling, routing, laser, or turning cutting process.
Benefits of CNC Polycarbonate Machining
Versatility
Polycarbonate block is an extremely versatile and amorphous material that can be efficiently molded into smaller bits. CNC polycarbonate machining offers the avenue of forming both intricate and simple shapes with varying sizes.
Precision
Leveraging CNC technology in polycarbonate sheet machining allows the manufacture of components with complex geometries and tight tolerance. Programmed CNC machines are known to achieve identical parts consistently with high precision while maintaining high-quality for large production.
Surface Finish
CNC polycarbonate machining produces excellent, polished, and smooth surface finish on polycarbonate parts which help enhance its aesthetic appeal and also increase its resistivity to corrosion and wear.
Rapid Prototyping
As a subtractive manufacturing process, CNC machines are efficient for automatically producing prototypes or product models accurately based on the design specifications inputted into the machine.
Material Efficiency
CNC machining processes are a lot easier and more efficient to carry out on polycarbonate sheets because of its lightweight, resistance to heat, and transmittance. This helps reduce waste production while maximizing output during machining.
Guidelines for Machining Polycarbonate
If you are a manufacturer, student, engineer, or DIY enthusiast who would love to carry out the polycarbonate machining process, the following tips are essential for you to know in order to achieve optimal results.
Proper Tool Selection
When selecting tools for CNC polycarbonate machining, ensure you go for the tools that are designed specifically for plastics. Experts recommend milling polycarbonate with High-speed steel (HSS) or carbide tools for sharp edges and polished surfaces.
Also, because polycarbonate sheets are prone to chipping and stress cracking, it is very important that you make use of sharp CNC cutters when machining to avoid a rough finish on the machined parts and prevent wearing of tools.
Choose Cutting Tools With Compatible Diameter
Having a vast understanding of the different diameters of cutting tools and when to use them is very crucial as the thickness of the polycarbonate sheet you are working with determines the diameter of the tool to use.
For instance, a 4 mm cutter is used for a sheet that is 5 mm or less thick, a 6 mm is applicable for panels that are 5 mm-10 mm thick, while a cutter between 8 mm-10 mm diameter is used for panels that are thicker than 10 mm.
Use of Coolants and Lubricants
When carrying out CNC polycarbonate machining, the use of coolants and lubricants is very essential as it helps reduce heat buildup and remove chips, while extending tool life. Importantly, not all coolants are acceptable when machining polycarbonates.
Non-aromatic, water-soluble coolants are the best for polycarbonate machining as they prevent material melting when machining. This will also help you achieve better polycarbonate edges.
Set Proper Cutting Speed
The cutting speed refers to how much of the polycarbonate the cutter cuts per time. Several factors contribute to this, including the power of the machine, the diameter of the cutter, and the thickness of the polycarbonate.
Even if the machine has a high operating power, if you use a very small diameter cutter on an incredibly thick polycarbonate sheet, it will get clogged and you will waste useful time.
However, most CNC machines have features that allow you to alter the speed of the machine, thereby helping you get better results. The right speed for your workpiece depends on the depth of cut you want to achieve.
Post-Processing Techniques
Polycarbonate machining parts are usually prone to stress cracking due to the heat and tensile load during machining. The annealing process which involves heating your machined polycarbonate part to a specific temperature and allowing it to cool is very essential in improving its mechanical properties, and achieving quality precision.
Surface Finishing for Polycarbonate Machining
Surface finishing is required because scratches can be formed during polycarbonate machining, so it is done to remove these scratches and ensure a smooth surface finish. Polycarbonate machining surface finish can be achieved through the following methods:
Buffing
It is a mechanical method of finishing that involves the use of a fast rotating cotton polishing wheel to remove tool marks on polycarbonate machined parts improving its surface.
Buffing is highly efficient for large parts with simple outer surfaces. However, one major downside of buffing is that the final surface finish usually has a less clear polishing effect compared to vapor polishing.
Vapour polishing
Vapour polishing removes tool marks and scratches by the application of a solvent on the surface of the machined polycarbonate which reacts, melting the surface and allowing it to flow forming a more smooth coverage of the scratch.
It is one of the most preferred surface finish processes during polycarbonate machining because it gives a uniform glossy and optically clear look to the part.
Scratch-Resistant Coating
One of the many limitations of CNC polycarbonate machining is that polycarbonates are easily scratched and form marks on the surface. So another method of achieving a smooth surface finish is by applying scratch resistant coatings such as diamond-like carbon (DLC), CR39, polysiloxane, and NANOMYTE SR-100.
Applications of Polycarbonate Machining
Polycarbonate machining parts and components can be applicable in various industries as listed below:
Automotive
Polycarbonate is used in making automotive parts, especially heat resistant plastic in vehicles. Also due to its high strength impact, lightweight, and toughness, it is employed in making bulletproof windows, headlights, signal lenses, and sunroofs.
Healthcare
Because of its transparency, durability, and dimensional stability, machined polycarbonate parts can withstand FDA-approved sterilization methods such as radiation and autoclaving. They are used for making medical equipment like blood filters, incubators, and oxygenators. PC’s transparent quality makes it easier for doctors to monitor and record blood infusions..
Household Appliances
It is used in making household electrical equipment such as water bottles, television enclosures, food containers, green houses and many more. Polycarbonate machined parts are used as insulators for electrical components.
Limitations of Machining Polycarbonate
Regardless of its many benefits, polycarbonate machining is not without its limitations and considerations. Polycarbonate has a high heat sensitivity which makes it melt easily during machining if proper supervision is not carried out.
Another limitation is its ability to get scratched and obtain marks leaving the surface rough, so much care is needed especially during the buffing and sanding processes.
Lastly, polycarbonate is susceptible to warping and deforming, putting large PC components together can make it collapse and deform under its weight and make it develop voids.
Conclusion
Polycarbonate machining is a popular CNC milling process that offers precise, versatile, clarity, strength, and a wide range of applications in various industrial sectors. We have provided you with tips on how to achieve optimal final products with minimal defects in this article.
However, would you be looking for expert polycarbonate machining solutions? Contact us, let’s get you precise-crafted components tailored to your needs.