INTRODUCTION
Milling plastics is a subtractive process, which means that if an error is made, the part is scrapped. This requires precision and accuracy when Machining to achieve the desired results. Plastic milling involves using a machine to remove material from a plastic workpiece to form a finished product with specific dimensions and tolerances. This guide provides an overview of plastics machining, plastics CNC milling techniques, plastics milling, considerations for plastics milling, and common plastics machining processes.
What is plastic Machining?
Plastics Machining refers to using CNC machines to machine plastics into the desired product. The plastics processing industry has a variety of technologies used to produce plastic parts, including Machining, injection molding, extrusion, blow molding, and thermoforming. CNC milling of plastics is a cutting process performed on engineering plastic materials with a milling cutter on a milling machine. In the production of single products or small batches, metal milling machines or wood milling machines can be used; in the case of large batches, there are now corresponding machine tools for specialized processing.
CNC milling technology for plastics
CNC milling technology uses computer-controlled machines to create precise cuts in plastic workpieces. CNC milling machines use cutting tools, including end mills, face mills, and ball mills, to remove material from the workpiece. These machines are programmed using CAD/CAM software to generate toolpaths to control the movement of the cutting tools. This allows for high accuracy and repeatability in plastic milling.
Plastic Milling
Plastic milling involves using a machine to remove material from a plastic workpiece to achieve the desired shape and size. The process begins with a CAD/CAM file uploaded to a CNC machine, which generates toolpaths for the cutting tool. The workpiece is clamped to the machine’s table, and the cutting tool moves along the programmed path to remove material from the workpiece. This process is repeated until the desired shape and size are achieved.
Milling is the processing of multiple small turning tools combined, but milling also has its special characteristics, mainly for the following aspects of several issues.
1. The hardness of these plastic materials is very low (9.2-17.4HB), and the tensile strength is low (14 a 60MPa). Thermal conductivity is very low [ 0.0418~0.193w/(m-K)] (1/175-1/458 of the general thermal conductivity of steel), and the modulus of elasticity is very small.
2. Under the same cutting conditions, its cutting force is only 1/14 of that of cutting 45 steel. However, its thermal conductivity is extremely low, and its hardness is also very low, so its cutting temperature does not exceed 120℃ at the highest.
3. Because of the low melting point of thermoplastics, when the cutting temperature does not reach the melting point, it begins to soften, resulting in the phenomenon of smearing and affecting the smoothness of the surface of the workpiece, the softening point of nylon 1010 is 180 a 220 ℃, polystyrene is 95 ℃, organic glass is 60 ℃.
(1)Tool material. Use high-speed steel or carbide.
(2) tool geometry parameters. 7. = 15 ° a 25 °. As the modulus of elasticity of such materials is very small, elastic recovery is large; to reduce the friction of the rear tool surface, take a. = 15 ° an 18 °. To control the direction of chip discharge, the spiral angle of the end mill = 20° a 25°. The main deflection angle of the face milling cutter Kr = 45 °. The chip tank of the milling cutter should be as large as possible.
(3) Milling dosage. As long as the cutting temperature does not exceed the material’s softening temperature and produces the phenomenon of smearing, VC should be higher to improve processing efficiency.
4. CNC lathe processing plastic parts to avoid thermal expansion and contraction and open cooling during processing, the starting machining amount is not easy to be too large Machining as much as possible against the upper tolerance
5. CNC machining center in the processing of plastic and metal materials is the difference between the processing of plastic need to pay attention to the use of end mills tool edge to be sharp, the need for water cooling, spindle speed to be faster (machining center speed in 3000-5000) cutting volume (rough Machining each knife dry 1-5MM, finishing with a ball end mill) speed of 2500mm-3500mm per minute, in addition to plastic clamping to be firm ( prevent loosening the fixture plastic product deformation).
6. Plastic milling cutter and metal milling cutter should be the following differences: milling cutter in sharpening into a large front angle, rear angle, vice rear foot and the main angle of deviation to be easy and feasible; processing plastic cutting forces generated by small so that you can choose a larger diameter; milling thermoplastic plastic, usually produce puffy chip, so there should be a larger chip space; milling glass fiber as the substrate of the thermosetting, tool wear is very When milling glass fiber-based thermoset, the tool wear is very serious, so the tool with better wear resistance should be used.
Considerations for plastic milling
When milling plastics, several factors must be taken into account. One of the main considerations is the type of plastic to be milled. Different plastics have different characteristics, such as melting point, flexibility, and hardness, which can affect milling. For example, thermoplastics can melt and deform if the cutting tool generates too much heat, while thermosets can become brittle if the milling process generates too much stress.
Another consideration is the cutting tool used in the milling process. The cutting tool must be selected based on the type of plastic being milled and the desired shape and size of the finished product. The cutting tool must also be kept sharp to prevent material distortion and to ensure a high-quality cut.
Milling speed and feed rate are also important considerations. The milling speed must be optimized to prevent melting or distortion of the plastic, while the feed rate must be set to ensure effective material removal without damaging the workpiece. The coolant used in the milling process can also affect milling speed and feed rate.
Common Plastic Machining Processes
There are several common plastic machining processes used in the plastics processing industry. These processes include milling, drilling, turning, and threading. Milling is used to removing material from a plastic workpiece to achieve the desired shape and size. Drilling is used to create holes in the workpiece while turning is used to create cylindrical shapes. Threading is used to create threads on the workpiece.
Conclusion
Milling plastics is a complex process that requires precision, accuracy, and careful consideration of the milled plastic. CNC milling technology is an effective and accurate method for milling plastics, but several factors must be considered to achieve high-quality results. Cutting tool selection, milling speed, feed rate, and coolant all affect the milling process and the quality of the finished product. With proper consideration and care, milling plastics can produce a high-quality product that meets the desired specifications. If the CNC milling process is needed for machining plastic parts, contact ANPLLO for your service.