1. Characteristics and Applications of Acrylic Materials

Acrylic (PMMA) is a transparent, strong thermoplastic with high light transmittance, widely used in billboards, light boxes, transparent shields, etc.

Acrylic is resistant to UV rays and chemical corrosion, and has optical transparency similar to glass, making it a good substitute for glass. At the same time, its surface hardness is moderate, and it is easy to polish during processing, but it is also easy to scratch, so it has high requirements for tools and processing conditions. 

2. Key Settings for CNC Processing Acrylic

1. Feed rate and cutting depth: It is recommended to set the feed rate between 75 and 300 IPM (inches per minute) to prevent overheating or material fragmentation during cutting. The cutting depth is recommended to be controlled at half the tool diameter to maintain cutting stability. 

2. Spindle speed: Usually the spindle speed is set at around 18,000 RPM to obtain a clean cutting effect without overheating. 

3. Cooling system: Acrylic is easy to melt due to friction, so cooling is particularly important. A spray cooling system or air cooling system can be used to keep the tool and the material surface at a low temperature to prevent the edge from melting.

3. Acrylic CNC Processing Tips

1. Choose the right tool: It is recommended to use an O-flute tool or a 1/4-inch diameter solid carbide tool. This type of tool has a large chip removal space, which can effectively reduce material debris and reduce friction on the edge. 

2. Multiple shallow cuts: Multiple shallow cuts can remove material layer by layer, reduce heat accumulation, and help improve cutting accuracy and finished surface quality. 

3. Avoid melting and re-bonding: By using a large-diameter tool with a higher cutting speed, the acrylic material can be cooled to a low temperature before cutting to reduce the material from re-bonding due to frictional heating.

4. Surface treatment and fixing tips

1. Prevent vibration: Acrylic is relatively fragile, and it is easy to cause surface scratches or uneven cutting due to vibration during processing. Use a vacuum adsorption table or fixture to firmly fix the acrylic to reduce workpiece vibration and help obtain a smooth surface effect. 

2. Grinding and polishing: After processing, polishing paste or UV light can be used for secondary treatment to further improve the surface finish. This treatment not only improves the visual effect, but also reduces the tiny scratches caused by processing.

5. Common problems and solutions for acrylic CNC processing 

1. Cutting edge cracking: Choose the right tool, such as an O-groove tool or a carving tool with an inclination of 60°. This type of tool is suitable for acrylic cutting and can reduce the chance of cracking. 

2. Melting phenomenon: Increase the feed rate and use spray cooling to ensure that the tool stays on the material as short as possible to avoid material melting caused by excessive friction. 

By mastering these meticulous processing techniques and setting methods, operators can significantly improve the quality of acrylic CNC processed products, reduce scrap rates and optimize processing time.