题目：More about Precision Machining
More about Precision Machining
Precision machining is what produces a huge number of both large and small objects that we use in daily life. Each intricate piece that makes up an object requires one level or another of a machinist's skills. Likewise, a tool or machine that has been worn down will often require machine tool calibration, welding, or grooving by a precision machinist. From the production of aircraft aluminum alloys to surgical bone drilling devices and custom automotive tools, precision machining reaches into every technology and industry, including oil and gas. In other words, if an object contains parts, it required precision machining.
Quality precision machining requires the ability to follow extremely specific blueprints made by CAD (computer-aided design) or CAM (computer-aided manufacturing) programs like AutoCAD and TurboCAD. The software can help produce the complex, 3-dimensional diagrams or outlines needed in order to manufacture a tool, machine, or object. These blueprints must be adhered to with great detail to ensure that a product retains its integrity. While most precision machining companies work with some form of CAD/CAM programs, they still work often with hand-drawn sketches in the initial phases of a design.
Precision machining is used on a number of materials including steel, bronze, graphite, glass, and plastics to name a few. Depending on the size of the project and the materials to be used, various precision machining tools will be used. Any combination of lathes, milling machines, drill presses, saws and grinders, and even high-speed robotics may be used.The aerospace industry may use high-velocity machining, while a woodwork tool-making industry might use photo-chemical etching and milling processes. The churning out of a run, or a specific quantity of any particular item, can number in the thousands, or be just a few. Precision machining often requires the programming of CNC devices which means they are computer numerically controlled. The CNC device allows for exact dimensions to be followed throughout the run of a product.
Cemented carbides have been widely applied in cutting tools and wear-resistant components due to their ultrahigh hardness and good wear resistance. However, the disadvantages of limited impact toughness and high cost have restricted their further application. Consequently, cemented carbides are usually joining with ductile steels to combine the advantages of both. Among various materials joining technologies, brazing have been an effective method to achieve high quality dissimilar cemented carbide joints. In this paper, the research status of cemented carbide brazing is reviewed. The materials utilized as brazing filler metal in cemented carbide brazing joints are summarized in detail. Researchers have done lots of works utilizing Cu based and Ag based brazing filler metals which are the most commonly used interlayers in brazed joints of cemented carbide and ductile steel. The effects of different filler metal on wettability, microstructure, phase constitution and mechanical properties of brazed cemented carbides joints are analysed. Besides, a series of newly developed brazing filler material such as nickel-based high temperature brazing filler metal, amorphous brazing filler metal and high entropy alloy brazing filler materials are also involved. These newly developed brazing filler metals have shown great potential in fabricating high quality joints. Finally, the current issues of cemented carbide brazing are reviewed and the develop trend is predicted.
Historically, hardened parts were often ground as many cutting tools could not stand up to the rigorous demands of materials with high hardness. Today, many companies are switching from grinding operations to hard turning, as the benefits are numerous.
Hard turning is typically defined as turning of materials harder than 45 Rockwell C (Rc) although, typically hard turning is considered 58 to 68 Rc. As with any machining application the cutting tool must be harder than the material being machined. With this definition, in theory, a carbide insert could machine 60 Rc material, since most carbide is over 85 Rc. However, the reality is carbide inserts would not be able to endure the heat generated in hard turning.
Cubic Boron Nitride (CBN) is the number one choice for hard turning applications. CBN is a man-made very hard material, second in hardness to Polycrystalline Diamond. CBN offers extreme hardness, toughness, chemical and thermal stability.
The sintered CBN blank is cut into desired shapes which are brazed onto cemented carbide blanks in the form of ISO standard geometries; these are final CBN, single or multiple corner inserts.
A common failure mode with CBN in hard turning applications is flaking of the CBN blank. The cause is often the braze. The CBN tip is relatively small so the brazing area is too, then, the braze softens due to heat and causes the CBN to move, causing the flaking. End-users often lose productivity by moving to a softer CBN grade, that runs slower and does not last as long. However, the root cause is often the braze between the CBN and the carbide insert softened and caused the premature flaking. Another common failure mode is the tip comes off while machine. This is an obvious symptom of the braze softening.
This is the reason Tungaloy has introduced its “CBN WavyJoint”. The WavyJoint is a connection surface between the CBN segment and the carbide insert that is an irregular curving surface, alternating in opposite directions, similar to that of waves. This increases the contact surface between the CBN and the carbide insert by 160%. This feature alone decreases the probability of braze softening significantly.
The CBN WavyJoint insert is available in Tungaloy’s new BXA20 grade.
BXA20 is a new substrate, with a lower CBN content, coupled with a new coating that has excellent adhesion strength, making this grade ideal for resisting both crater and flank wear.
The BXA20 coating is a multi-layered titanium aluminum nitride that is 2 times thicker than conventional grades, which enhances flank wear resistance.
The binder in BXA20 has special chemical composition in titanium carbo-nitride base that is well balanced between hardness and toughness. Because of this, BXA20 has very high fracture resistance. This gives BXA20 a wide range of applications from continuous to heavy interrupted cuts.
BXA20 can run at speeds of up to 180 m/min (590 SFM)
WavyJoint is available with an “H” (heavy) edge prep which strengthens the cutting edge, making this ideal for interrupted applications.
This insert is also available with the new HM chip breaker. This breaker enables smooth and reliable chip control, while reducing crater wear on the rake surface. The chip breaker also works to reduce any chatter.
The CBN Wavy inserts are available in CNG*, DNG*, TNG*, VNG* and WNG* geometries.
How precision machining is affecting the future state of medical devices
Precision machining is found in a variety of sectors, including electronics, aircraft, and healthcare. CNC machines are used to make a lot of medical components and devices. The medical equipment industry consists of various medical parts, such as implants for spine reconstruction, knee, and hip replacements, etc.
In an industry where mistakes lead to serious injuries or even death, the machining process of medical parts must be extremely precise. In addition to manufacturing complying with ISO 9001 quality management obligations, medical components and devices must comply with other higher standards.
Medical tools are built with care to ensure that each patient treated is handled with precision. Precision machining is used to manufacture surgical tools, lasers, and even robotics which are now being used in surgeries. CNC Machining provides the know-how, processes, and machinery needed to manufacture these incredibly small parts.
Among all machining techniques, CNC machining has shown to be the best suitable for developing precise medical equipment and instruments. Over time, advancements in CNC processing technology have humanised the manufacture of medical equipment.
CNC Machining in medical device manufacturing
Because of its strong compatibility with the health industry, machinists have begun to tap the potential of CNC medical machining in producing medical precision components. Here are some types of medical equipment that are manufactured using CNC machining:
CNC machining can produce high-quality surgical tools needed by medical professionals during procedures, such as:
Such CNC manufactured surgical equipment and instruments necessitate meticulousness and precision and additional safety criteria.
CNC machining is a finely detailed and precise process for crafting equipment such as medical instruments. Because certain tools need to be customised for individual patients, they typically are not made using mass production machines. Making custom items by hand can be time-consuming and expensive, but CNC machining allows companies to streamline the process without sacrificing quality and speed of delivery.
Micromachining deals with the manufacturing of remarkably small medical parts utilised in implantable devices and others. Micromachining can produce very small tools or parts, including:
Drug delivery systems.
Miniature screws for implants and devices.
These machines are extremely sophisticated despite their small size, necessitating extreme accuracy and ability.
For medical professionals, proper durable and effective equipment is important to ensure that their patients are comfortable and get the best treatment possible. Machinists also require the same; therefore, it is beneficial to make repeated use of strong tools. One strong tool used by both groups is CNC machining. Those who engage in the medical profession commonly perform surgery on patients' bodies where implants are required. These implants can be manufactured through processes performed by machinists using 3D printing or other methods to produce higher-quality gadgets.
Essential medical equipment
CNC machines manufacture the essential equipment needed for today's world, such as heart rate monitors, x-ray machines, and MRI scanners, among a long list of other important items. All these devices are comprised of thousands of individual pieces that can be manufactured using a CNC machine.
The advantages of precision machining in the medical industry
Thanks to precision engineering, we can experience many medical breakthroughs today that would not be possible if not for the new and improved technology and products brought about by the developments and innovations of this field. Take a look at some ways precision machining affects your health and how it will continue to advance the state of medicine in the future.
Machining meets the most stringent tolerances
In the medical industry, accuracy is of the utmost importance. One aspect that contributes to surgical success is a tool that fits perfectly into a surgeon's hand. However, precision machining is not limited to surgical instruments. It helps construct robotic arms and other devices used in surgeries to perform complex operations which were unthinkable even ten years ago - such as breast augmentations or microsurgeries on embryos without harming the mother.
- Creado: 21-02-22
- Última sesión: 21-02-22