Turning uses a stationary and non-rotating tool because during turning it is the workpiece that rotates, not the tool. Turning tools typically consist of replaceable inserts inside the body of the turning tool. The blades are unique in many ways, including shape, material, coating and geometry. The shape can be round to maximize edge strength, diamond shaped so the sharp tip can cut delicate parts, or square or even octagonal to increase the number of individual edges that can be applied as the edge wears. The material is usually carbide, but ceramic, sintered metal or diamond inserts are also available for more demanding applications. Various protective coatings also help these blade materials cut faster and last longer.
Turning uses a lathe to remove material from the outside of a rotating workpiece, while boring removes material from the inside of a rotating workpiece.
As finishing requirements become increasingly demanding, new cubic boron nitride formulations may provide a more reliable alternative to carbide.
These features help improve cutting tool stability, standardize cutting performance, and extend tool life, allowing shops to run unattended with confidence.
UNCC researchers introduce modulation into tool paths. The goal is chip breaking, but higher metal removal rates are an interesting side effect.
Different chipbreakers are designed for different parameters. Processing videos show the difference in performance between chipbreakers used for the right and wrong applications.
Machining clamps with different coatings during roughing and finishing shows how choosing the right coating can have a huge impact on process performance.
Turning is the process of removing material from the outside diameter of a rotating workpiece using a lathe. Single-point tools cut metal from the workpiece into (ideally) short, crisp, easily removable chips.
Early turning tools were solid rectangular pieces of high-speed steel with a rake and clearance angle at one end. When a tool becomes dull, mechanics sharpen it on a grinding machine for reuse. High-speed steel tools are still common on older lathes, but carbide tools have become more popular, especially in the brazed single-point form. Carbide has better wear resistance and hardness, which increases productivity and tool life, but is more expensive and requires experience to sharpen.
Turning is a combination of linear (tool) and rotary (workpiece) motions. Therefore, cutting speed is defined as the rotation distance (written as sfm – surface feet per minute – or smm – square meters per minute – the movement of a point on the surface of a part in one minute). Feed rate (written in inches per revolution or millimeters) is the linear distance the tool travels along or across the surface of the workpiece. Feed is also sometimes expressed as the linear distance traveled by the tool in one minute (inches per minute or millimeters per minute).
Feed rate requirements vary depending on the purpose of the operation. For example, in roughing, high feeds are often more suitable for maximizing metal removal rates, but require high part rigidity and machine power. At the same time, finishing can slow down the feed rate to achieve the surface finish specified in the part drawing.
Boring is primarily used to machine large hollow holes in castings or punch holes in forgings. Most tools are similar to traditional turning tools, but the cutting angle is especially important due to chip flow issues.
The spindle on a turning center is either belt driven or direct driven. Generally speaking, belt driven spindles are an older technology. They accelerate and decelerate faster than direct drive spindles, meaning cycle times can be longer. If you are turning a small diameter part, the time required to turn the spindle from 0 to 6000 rpm is very long. In fact, the time required to reach this speed can be twice as long as a direct drive spindle.
Belt driven spindles may have slight positioning errors due to belt lag between the drive and the encoder. This does not apply to direct drive solid spindles. High up and down speeds and high positioning accuracy when using a direct drive spindle are significant advantages when using C-axis motion on live tool machines.
The integrated CNC tailstock is a valuable feature for automated processes. Fully programmable tailstock provides increased rigidity and thermal stability. However, the cast tailstock adds weight to the machine.
There are two main types of programmable tailstocks—servo-driven and hydraulic. Servo tailstocks are convenient, but their weight can be limited. Typically, a hydraulic tailstock has a telescopic bushing with 6 inches of travel. The spindle can also extend to support heavy workpieces and exert more force than a servo tailstock.
Power tools are often seen as a niche solution, but their implementation can improve many different processes. #base
Kennametal KYHK15B grade is reported to provide greater depth of cut than PcBN inserts when machining hardened steels, superalloys and cast irons.
Walter offers three Tiger·tec Gold grades, specially developed for turning steel and cast iron.
Lathes are one of the oldest machining technologies, but it’s still good to remember the basics when considering purchasing a new lathe. #base
Walter’s cermet turning inserts are designed for dimensional accuracy, excellent surface quality and reduced vibration.
Since there are no international standards defining carbide grades or application ranges, users must rely on judgment and basic knowledge to achieve success. #base
Ceratizit’s three new ISO-P carbide inserts with standard coating are optimized for specific production conditions.
Post time: Sep-18-2023