Machined fine pen: C Angle

C Angle is the chamfering, is the cutting edge of a part into a certain Angle of slope, usually used at the end or steps of the part. The chamfer Angle is generally 60,45,30,20,15, etc., set according to the actual needs. The chamfer is also divided into the inner chamfer and the outer chamfer, see the figure below, the left side is the inner chamfer, and the right side is the outer chamfer.

Inverse Angle annotation. The annotation format of mechanical drawing is: C chamfer length x chamfer angle, as in the figure above, marked as C1.6x30; if the chamfer angle is 45, that is, the default Angle of the chamfer, can be abbreviated: C chamfer length, such as C2.

The function of chamfering mainly has the following four aspects:

Prevent stress concentration: the edges and corners of the parts are easy to produce stress concentration, resulting in fatigue cracks, fracture and other defects in the process of use. Chamfer can reduce the stress concentration at the edges and corners, and improve the strength and service life of the parts.② Easy assembly: chamfering can make the end or shoulder of the shaft has a guiding role, both to facilitate the initial positioning, but also reduce assembly resistance, so that the parts are easier to assemble in place. For example, in the thread connection, the chamfer can make the thread easier to enter, improve the assembly efficiency. Perplus with the guide chamfer, the chamfer Angle is generally small, such as 20 or 15; the chamfer Angle is too large, the chamfer root edge is easy to press the cut meat. The larger the surplus, the smaller the inversion Angle, and the better the guiding effect. At the same time, there should be sufficient preguide section for the initial assembly.

③ Remove burrs and sharp edges: in the process of machining, the edges of the parts are easy to produce burrs and sharp edges, these burrs and sharp edges will not only affect the appearance quality of the parts, but also may lead to parts in the assembly, use of scratch personnel or damage other parts. Chamfer can effectively remove burrs and sharp edges, make the edge of parts smooth, improve the safety and reliability of parts.④ Easy to follow-up processing: in some follow-up processing process, such as welding, painting, etc., the chamfer can make the back channel processing more smoothly. For example, in welding, the chamfering can make the weld more uniform, beautiful, improve the welding quality; in painting, the chamfer can make the coating more evenly over the surface of parts, improve the coating quality of edges.

Chamfer processing, there are mainly the following five methods: ① turning chamfering: in the lathe, the use of a knife on the parts of the end of the outer circle or the inner hole end surface chamfer processing. Turning chamfer is suitable for processing the chamfering of rotary parts such as shaft and disc. During processing, the tip Angle of the knife should match the required chamfer Angle, and the size of the chamfer should be controlled by adjusting the feed amount and cutting depth of the knife.② Milling chamfer: using a milling machine and a milling cutter to chamfer the parts. Milling chamfer is suitable for the machining plane, slot and other parts. For plane chamfer, a vertical cutter or three-sided blade cutter can be used to process the required chamfer by adjusting the speed, feed and cutting depth of the cutter.③ Drilling chamfer: after drilling, use a special chamfer drill or drill to chamfer the hole. This method is often used to process the inner chamfer of the hole parts. The blade angle and size of the chamfer drill shall be selected according to the required chamfer angle and size.④ The grinding chamfer: grind off the edges and corners of the workpiece through the grinding process, so that it can form a smooth slope with a specific Angle. This process can not only remove the burrs and sharp corners from the edge of the workpiece, but also improve the safety and assembly performance of the workpiece. Grinding chamfering is usually used to process parts with high precision and high surface quality requirements, such as monocrystalline silicon wafers, optical components, etc.⑤ Manual chamfer: in the case of no machining equipment or the chamfer accuracy requirement is not high, manual chamfer can be used. Manual chamfering usually uses tools such as a file, sandpaper, etc. During operation, fix the parts in the appropriate position, file along the edges of the parts at the required chamfer angle, and then polish the filed chamfer face with sandpaper to make it more smooth. The accuracy of manual chamfer is relatively low, but it has the advantages of strong flexibility and simple operation.

After introducing the role of R Angle and C Angle, you may ask: in the actual design process, when to use R Angle, when to use C Angle? We compare from the dimension of action: from reducing stress concentration, R Angle is better than C Angle; surplus assembly, C Angle is better than R Angle; deburr and sharp edge; R Angle is better than C Angle; appearance, R Angle is better than C Angle; processing cost, C Angle is lower than R Angle, which is more suitable for mass production. Therefore, the design should correctly choose the R angle or the C angle according to the actual application scenario.