The various properties of titanium make it an attractive material for parts, but many of its properties also affect its machinability. What are the attributes of titanium alloys, what are the characteristics of titanium alloy processing, what problems should be paid attention to when processing titanium alloys, what methods are there when processing titanium alloys, and how to choose a good titanium alloy processing manufacturer? The details are described below.
Properties of titanium alloy
Titanium has an excellent strength-to-weight ratio, and its density is usually only 60% of steel. Titanium has a lower coefficient of elasticity than steel, so it has a harder texture and better deflection. The corrosion resistance of titanium is also better than that of stainless steel, and its thermal conductivity is low. These properties mean that titanium will produce higher and more concentrated cutting forces during processing. Titanium alloys are prone to vibrations that can cause chattering during cutting, and they are also prone to react with cutting tool materials during cutting, thereby exacerbating crater wear. In addition, titanium alloys have poor thermal conductivity. Since the heat is mainly concentrated in the cutting area, the tools used for titanium alloy parts processing must be high hardness and high heat resistance.
The characteristics of titanium alloy processing
In actual processing, it is not easy to meet all the conditions required for processing titanium alloy parts, because ideal stable conditions are not always available. In addition, many titanium alloy parts have complex shapes and may contain many fine or deep cavities, thin walls, bevels, and thin brackets. If you want to successfully process such parts, you need to use large overhang and small diameter tools, which will affect the stability of the tool. When processing titanium alloys, potential stability problems are often more likely to occur.
When milling titanium alloys, the tool is required to work with at least the minimum feed-usually 0.1mm per tooth. If there is a tendency to vibrate, damage to the blade or shortened tool life will be inevitable. A possible solution is to accurately calculate the feed per tooth and make sure it is at least 0.1mm.
What problems should be paid attention to when processing titanium alloys
- A smaller rake angle and a larger clearance angle are used to increase the contact length between the chip and the rake surface, reduce the friction between the workpiece and the flank surface, and the tooltip adopts an arc transition edge to improve strength and avoid sharp corners burning and chipping. Keep the blade sharp to ensure smooth chip evacuation and avoid chip sticking and chipping. The cutting speed should be low to avoid excessive cutting temperature. The feed rate should be moderate to avoid excessive burning. If the cutting speed is too small, the cutting edge will wear too fast due to working in the hardened layer. The cutting depth can be larger so that the tip of the tool can work below the hardened layer, which is beneficial to improve the durability of the tool.
- Use cemented carbide tools as much as possible, such as tungsten-cobalt cemented carbide and titanium alloy because these alloy tools have a low affinity, good thermal conductivity, and high strength. Impact-resistant ultra-fine-grain cemented carbide can be selected for intermittent cutting at low speeds, and high-speed steel with good high-temperature performance can be used for forming and complex tools.
Titanium alloy material processing method
- Use positive-angle geometry blades to reduce the cutting force, cutting heat, and workpiece deformation.
- Maintain a constant feed to avoid the hardening of the workpiece. The tool must always be in the feed state during the cutting process. The radial tool engagement ae during milling should be 30% of the radius.
- Use high-pressure and large-flow cutting fluid to ensure the thermal stability of the machining process and prevent surface degeneration and tool damage caused by excessive temperature.
- Keep the cutting edge of the blade sharp. Blunt tools are the cause of heat build-up and wear, which can easily lead to tool failure.
- Work in the softest state of the titanium alloy as much as possible, because the material becomes more difficult to work after hardening. Heat treatment improves the strength of the material and increases the wear of the blade.
- Use a large arc radius or chamfer to cut in and put as many cutting edges as possible into the cutting. This can reduce the cutting force and heat at every point and prevent local damage. When milling titanium alloys, among the cutting parameters, the cutting speed has the greatest influence on the tool life vc, followed by the radial tool engagement (milling depth) ae.
How to choose a good titanium alloy processing manufacturer
With the development of processing technology, in recent years, titanium alloys have been widely used in aircraft engine parts, drone parts, auto parts, motorcycle parts, bicycle parts, medical parts, etc. From the above analysis, it can be seen that CNC machining of titanium alloy is a highly demanding and difficult job, and it is especially important to choose the right supplier. 3QMACHINING company has a wealth of experience in titanium alloy processing, from drawing confirmation, prototype design to perfect processing, on-time delivery, 3QMACHINING company can meet your requirements.