Importance of Titanium CNC Machining
Due to the complexity of titanium CNC machining, many machine shops are reluctant to use this cutting-edge material. However, many manufacturers are using titanium to create high-quality parts due to its excellent properties. Fortunately, capable CNC machinists and tool manufacturers have provided useful titanium CNC machining tips.
1.Tips for Titanium CNC Machining
1) Choose the Right Cutting Tool
Due to the growing demand for titanium, tool manufacturers are developing unique ways to improve the machinability of titanium. Cutting tools with titanium carbonitride (TiCN) or heat-resistant titanium aluminum nitride (TiAlN) coatings can last longer.
Overall, machinists should choose the highest quality titanium-specific tools and regularly inspect and replace worn equipment. In addition, try to use tools with smaller diameters and more cutting inserts to help maintain a consistent workpiece removal rate while limiting heat buildup. A good rapid prototyping company will ensure this.
2) Secure the Part
Since titanium is prone to tool chatter, machining titanium will be easier if you can reduce vibration. Hold the workpiece tight to prevent workpiece deflection. Also, use a high-quality CNC machine with an extremely rigid tool configuration. You can also consider using shorter cutting tools to reduce tool deflection.
3) Use a high-pressure coolant system
Titanium CNC machining requires contact at a small fraction of the tool radius, as well as sharp and extremely low feed rates per tooth. However, this will result in heat that is difficult to remove from the work area. If we leave it alone, it will eventually damage our cutting equipment and make it difficult to maintain tolerances. Therefore, use the best coolant configuration when cutting titanium alloys.
High-pressure coolant systems are an effective aid. Depending on the application, the spindle may also be required. Increasing the coolant concentration may also be useful when working with titanium alloys.
4) Consider cutting parameters
When titanium CNC machining, temperature control must be carefully controlled. One of the simplest ways to keep the workpiece and tool cool is to use a constant stream of high-pressure coolant directed at the cutting area. If you blow the chips away from the cutting area, they will not stick to the machining equipment.
When titanium CNC machining, feed rate, spindle speed, and chip load must also be considered. This includes limiting the stress on tools and equipment and avoiding staying in one position for too long. To improve cutting efficiency and minimize machining temperatures, it may be worth investigating an alternative cutting method, such as increasing the axial depth of cut while reducing radial engagement.
2.Different Titanium Grades for Titanium CNC Machining
There are many types of titanium alloys and grades, each with its own uses, advantages, and disadvantages. Let’s take a closer look at these grades:
1) Grade 1
This is pure titanium with a low oxygen content. It is the softest and most ductile of the most commonly used titanium alloys. Grade 1 titanium is extremely easy to machine, impact-resistant, corrosion-resistant, and formable. On the downside, it is less strong than other types of titanium. This grade is used for titanium CNC machining parts in the medical, automotive, and aerospace industries.
2) Grade 2
This is pure titanium with a standard oxygen content. It is often referred to as workhorse titanium. It is very corrosion-resistant, strong, formable, weldable, and ductile, but has low strength. Grade 2 titanium is used in the medical and aerospace industries to make titanium CNC machining parts for aircraft engines.
3) Grade 3
This is pure titanium with a moderate oxygen content. Although used less frequently than Grades 1 and 2, this titanium has excellent mechanical properties. It has excellent corrosion resistance, machinability, and strength. It is used for titanium CNC machining parts in the medical, maritime, and aerospace industries.
4) Grade 4
This is pure titanium with a high oxygen content. This titanium alloy is strong and corrosion resistant. However, it is not easy to manufacture and requires large amounts of coolant and high feed rates. Grade 4 titanium alloys are used in cryogenic vessels, CPI equipment, aircraft components, heat exchangers, and other applications.
5) Grade 5
This is also known as Ti6Al4V. Grade 5 titanium alloy contains 4% vanadium and 6% aluminum. It is not as strong as other alloys, but has great corrosion resistance and formability. It is ideal for power generation, offshore and marine applications, and critical airframe structures.
6) Grade 6
This is also known as Ti 5 Al-2.5Sn. This titanium alloy has good weldability, stability, and strength, especially at high temperatures, so it is used in manufacturing titanium CNC machining parts for airframes and jet engines.
7) Grade 7
This is also known as Ti-0.15Pd. This titanium alloy grade is comparable to Grade 2, with the only difference being the addition of palladium for improved corrosion resistance. Grade 7 titanium alloy has excellent formability and weldability. It is suitable for manufacturing chemical processing equipment.
8) Grade 11
This is also known as Ti-0.15Pd. Grade 11 titanium is comparable to Grade 7. However, it is more ductile and less tolerant to other impurities. It has less strength than Grade 7 and is used in the marine and chlorate production industries.
9) Grade 12
This is also known as Ti0.3Mo0.8Ni. Grade 12 titanium is expensive and contains 0.3% molybdenum and 0.8% nickel, with good weldability, high temperature strength, and corrosion resistance. It is used in housings and heat exchangers, marine and aerospace components, etc.
10) Grade 23
This is also known as T6Al4V-ELI or extra low clearance. Grade 23 titanium has similar qualities to grade 5 titanium, but with higher purity. It has high fracture toughness, biocompatibility, and relatively low machinability. It is used to make orthopedic pins, screws, surgical nails, and orthodontic appliances.
3.How to Choose the Right Titanium CNC Machining Tool?
When it comes to titanium CNC machining, it is usually a bad idea to use just any cutting tool. Here is how to choose the best cutting tool for milling titanium or other custom titanium CNC machining techniques such as titanium lathe turning:
1) Consider the number of cutting edges of the cutting tool
To reduce product cycle time, you must increase the number of teeth on the end mill. For titanium alloys, more teeth equals less chatter. For example, a 10-flute end mill, while tight for the chip load required for most materials, is ideal for titanium alloys. This is primarily because titanium CNC machining requires limited radial engagement.
2) Consider high-feed milling cutters
When using 5-axis CNC machining and radially oriented titanium alloys, high-feed milling cutters are ideal for reducing interaction. These tools are designed specifically for the purpose of titanium CNC machining.
3) Consider cutting tool coatings
Coatings can significantly improve a tool’s ability to withstand the heat generated by titanium. TiAlN (titanium aluminum nitride) is an excellent coating to consider. It has lubricity and resists built-up edge, galling, and chip welding, making it particularly well suited to the temperatures encountered when CNC milling titanium.
4) Keep cutting edges sharp and avoid interrupted cuts
Titanium metal has strength and elasticity due to its low Young’s modulus. This means that sharp tools are required to effectively and frictionlessly remove chips from the surface.
Interrupted cuts should be avoided whenever possible as they can hammer chips into a sharp tool, potentially causing premature tool failure.
4.Surface treatment after titanium CNC machining
Whether for functional or aesthetic reasons, CNC machined titanium CNC parts can benefit from a range of surface treatments.
Titanium surface treatments include:
- Smoothing
- Electrophoresis
- Sandblasting
- Brushing
- Polishing
- Chrome plating
- Painting
- Metallization
- PVD coating
- Powder coating
5.Application of titanium CNC machining parts
Titanium CNC machining products are durable, corrosion resistant and beautiful. These properties enable them to be widely used in various industries. Here are some of their applications in various industries:
1) Medical and dental
Titanium metal has a wide range of applications in the medical industry due to its high strength, low conductivity, corrosion resistance and physiological pH. Titanium medical parts include tapered, self-tapping or straight bone screws, dental implant screws, skull screws for skull fixation systems, spinal fixation rods, orthopedic pins, connectors and plates, etc.
2) Marine/Navy Industry
Titanium is more corrosion resistant than most natural metals. Due to its corrosion resistance, titanium is ideal for manufacturing propeller shafts, underwater robots, ball valves, rigging equipment, marine heat exchangers, pumps, exhaust liners, fire protection system piping, and onboard cooling systems.
3) Automotive
Titanium vs. aluminum is a hot topic in the automotive industry, with aluminum having the upper hand due to its availability and cost-effectiveness. Despite this, titanium is still used to manufacture automotive parts. Titanium and its alloys are mainly used to manufacture valves, valve springs, retainers, automotive block brackets, lug nuts, engine piston pins, suspension springs, brake caliper pistons, engine rocker arms, and connecting rods for internal combustion engines.
4) Aerospace
Titanium is a popular material in the aerospace industry due to its many desirable properties. These properties include high strength-to-weight ratio, excellent corrosion resistance, and performance in high-temperature environments. In the aerospace industry, seat components, housings, shafts, valves, turbine components and filter parts, and components of oxygen generation systems are all made of titanium.
6.Conclusion
As you may know, the best titanium for your product depends on the function and application you require. If you are developing a titanium CNC machined product for medical use, you should consider titanium grade 23. Alternatively, if you want a titanium CNC machined product that performs well at high temperatures, you should consider titanium grade 6.