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CNC Machining Titanium
More than 15 years of CNC machining titanium and prototyping experience, high precision, powerful quality inspection system, faster project feedback and delivery to you. Titanium has been neglected for a long time because of its properties. But in the 20th century, with the development of metallurgy and CNC manufacturing technology, people have a new view on this material. At present, titanium is favored by medical equipment for its excellent weight / strength ratio (3 times higher than steel), corrosion resistance, human tissue compatibility and excellent performance at high temperature. In the field of aerospace, titanium parts are particularly popular because of their light weight and strong strength. However, there are many difficulties in CNC machining titanium.
titanium alloy
In order to enhance its properties, titanium often adds many other metal elements to make up alloy. The allotrope transformation of titanium occurs at temperatures above 800 ℃. The elements that reduce the use temperature of titanium are called β stabilizers, while the elements that improve the availability of titanium are called α stabilizers. According to the content of stabilizer, titanium alloy is divided into 4 groups.
1. Non alloy titanium. It’s basically pure titanium. Non alloy titanium has the best corrosion resistance, but its strength is low.
2. Alpha titanium alloy. Alpha alloy has better creep resistance, so it can be used in high temperature performance.
3. α – β titanium alloy. Because of its excellent properties, titanium alloy is the most widely used. α stabilizers increase the heat resistance of the material and β stabilizers increase the strength of the alloy. The most common α – β alloy Ti-6Al-4V accounts for nearly 50% of the total titanium alloy market.
4. Beta titanium alloy. This titanium alloy is harder than his, but they are also more dense.
Seven reasons why titanium is difficult to macined
Titanium can maintain high strength even at high temperature. Even with high-speed cutting, its plastic deformation resistance remains unchanged. This requires much more cutting force than any steel.
When chips are finally formed, they are very thin, and the contact area between chips and tools is three times smaller than that of steel. Therefore, the tip of the tool must bear more cutting force.
Titanium alloy has high friction coefficient for cutting tool material. This increases the cutting temperature and force, and requires higher cutting tools.
At a temperature of more than 500 ℃, titanium reacts with most tool materials. If the heat accumulates too much, titanium will self ignite when cutting, so the coolant must be used when cutting titanium alloy.
Due to the small contact area and thin chips, all the heat in the cutting process flows to the tool, greatly reducing the service life of the tool. Only high-pressure coolant can keep up with the heat and neutralize each other.
The elasticity of titanium alloy is very low. This causes additional vibration, tool chatter and deflection.
At low cutting speed, the material will stick to the cutting edge, which is very adverse to the surface finish.
Choose the right cutting tool
Manufacturing engineers around the world have put forward many strategies to improve titanium processing speed. The first step of successful CNC titanium machining is to select CNC cutting tools. Over the years, many Hardmetals have proved to be good at cutting titanium. In order to better CNC machining titanium parts, cutting tools must have many properties.
Tools must be hard under high temperature.
Tools must have higher resistance to shaking.
The tool must have anti fatigue performance.
The tool must not react with high temperature titanium.
Tools must have high strength.
The tool must have good thermal conductivity.
The most suitable range of tool materials with all of the above characteristics is WC / Co alloy. Another possible solution is high-speed steel because they are very resistant to cracking. Diamond tools also show good wear resistance to titanium.
CNC machining titanium technology
Titanium machining strategy
Another feasible way to improve titanium machining performance is to apply special titanium processing strategy. Our titanium machining service has been very skilled in selecting the right cutting parameters to minimize titanium processing time. However, in addition to parameter optimization, there are some unconventional machining strategies that can greatly improve the cutting speed of titanium.
Ledge tool
These tools were developed by General Electric. The protruding lugs of the tools they use are thin. Instead of the whole tool, only this thin-walled frame can cut titanium. As the chip is also very thin, so there is no difference, but the wear of the wall frame is slower and easier to sharpen. The side wear of the wall frame is very fast, and then the wear process of the rest of the wall frame is constant, while the side wear is slow.
Rotary blade
The rotating blade is used for turning titanium alloy. Due to the lack of accuracy in machine tool design, it was impossible to achieve this before. However, the level of manufacturing technology now makes their use possible. The main principle is that the cutter blade is round and rotates around the fixture when the cutter cuts the blank. In this way, the heat transfer will be faster and the tool will not heat too much. Therefore, the cutting speed can be increased.
Ultrasonic assisted metal removal
In fact, adding ultrasonic vibration to the cutting tool will make chip formation easier. The elasticity of titanium chips is very poor. When the cutting edge begins to cut the material, the deformation hardening will make it worse. Ultrasonic promotes chip fracture rather than deformation, which has a positive impact on tool life, surface finish and tool characteristics. It prevents material from accumulating on the cutting edge and allows the machinist to increase the cutting speed.
Titanium anodizing
Titanium anodizing is a completely biocompatible process, which is usually used for orthopedic implants, dental implants, medical equipment components and medical prototypes. Anodizing of titanium can produce a variety of colors without the application of organic dyes or artificial coatings on the metal surface.
DDPROTOTYPE improves titanium anodizing process to produce reliable, consistent, reproducible colors. Our anodizing process produces the brightest colors. We have found that many customers can benefit from this process, which is a cost-effective way to ensure that their parts are completely free of the small burrs that may remain after machining, while maintaining critical tolerances. It also provides a clean, bright surface, so your parts can show the most dynamic anodizing surface treatment.
Want to know more?
When you’re preparing for the next project, it’s really important to choose the right processing techniques and raw materials for the rapid prototyping. At DDPROTOTYPE, we will be happy to provide you with more professional advice. Please feel free to contact us at info@ddprototype.com or upload your CAD file here.