Turning is a method of cutting a workpiece on a lathe using a workpiece relative to the tool rotation. Turning is the most basic and common cutting method. Most workpieces with a rotating surface can machine by cnc turning. Such as the cylindrical surface in the table. The conical surface in the surface, as well as the end face, groove, thread and rotary forming surface. Common lathes can divide into horizontal lathes. And a floor lathe. Vertical lathes and turret lathes, as well as profiling lathes. Most of them are horizontal lathes.
Due to the development of modern scientific skills. A variety of high-strength, high-hardness engineering materials are being used. Traditional turning skills are difficult or impossible to do for some high intensity. Even the processing of high hardness data. Modern hard turning skills make this possible. And achieved significant benefits in production.
First, the characteristics of turning processing
Turning has a higher power than grinding. Turning often requires large cutting depths and high workpiece speeds. The metal removal rate is generally several times that of the grinding process. A variety of surface finishes can complete in one setup during turning. Grinding requires repeated installations. Thus the auxiliary time is short. And the positional accuracy between the machined surfaces is high.
(2) Low equipment input cost. When the yield is the same, the lathe investment is better than the grinding machine. The cost of its support system is also low. For small batch production, no special equipment is must for turning. Large-scale machining of high-precision parts requires rigidity. CNC machine tools with high positioning accuracy and repeatability.
(3) Suitable small-volume flexible production requires. That the lathe itself is a flexible processing method with a wide processing scale. The lathe is easy to handle and the turning clamp is fast. Hard turning with grinding is better suited to flexible production requirements.
(4) Hard turning can achieve excellent machining accuracy of parts
Most of the heat produced in hard turning is take away by the cutting oil. Surface burns and cracks like grinding do not occur. Excellent surface quality. Accurate roundness. It ensures high positional accuracy between machined surfaces.
Second, the cutting tool information and its selection
(1) Coated carbide tool
Coated cemented carbide tools are coated with one or more layers of good wear resistance on cemented carbide tools with good resistance. The coating generally has the following effects:
On the one hand: it has a much lower heat transfer coefficient than the tool base and workpiece data. The thermal effect of the tool base is weakened.
So: it can improve the friction and adhesion of the cutting process. Drop the generation of cutting heat. Coated carbide tools are compared to carbide tools. Great progress has been made in terms of strength, hardness and wear resistance.
(2) Ceramic data cutter
Ceramic tools have high hardness and high strength. Good wear resistance and good chemical stability. Outstanding anti-adhesive function, low friction coefficient and low price. When used , the durability is high, and the speed can be several times higher than that of cemented carbide. Particularly suitable for high hardness data processing. Finishing and high speed machining.
(3) Cubic boron nitride cutter
The hardness and wear resistance of cubic boron nitride is second only to diamond. Has excellent high temperature hardness. Compared with ceramic tools. Its heat resistance and chemical stability are poor. But, the impact strength and the anti-crushing function are better.
Third, the choice of cutting oil
(1) Tool steel cutters have poor heat resistance. The hardness is lost at high temperatures. Thus, the cooling function is required to be selected. Cutting oil with low viscosity and good fluidity.
(2) When high speed steel tools are used for high speed rough cutting. The amount of cutting is large and a lot of cutting heat occurs. A cooling oil with good cooling properties should be used. If using high speed steel cutters. Low speed finishing. Generally, low viscosity cutting oil can reduce the friction bond between the tool and the workpiece. According to the cutting tumor formation, improve the processing accuracy.
(3) Cemented carbide tools have higher melting point and hardness. Good chemical and thermal stability, cutting and wear resistance is much better than high speed steel tools. Active sulfur cutting oil can be used in general processing. If it is heavy cutting. The cutting temperature is very high. Simple and fast wear tool. At this point, inactive vulcanized cutting oil should be used and the flow rate of cutting oil should be increased. Make sure that the cooling is smooth enough.
(4) Ceramic tools, diamond tools and cubic boron nitride tools have high hardness and wear resistance. Low-viscosity inactive vulcanized cutting oil is generally used for cutting. To ensure the surface finish of the machined workpiece.
The above is the precautions for the characteristics of the turning process. Reasonable selection of tools. And cutting oil products can improve the quality of the workpiece.
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