Application of Several Tools in Milling Precision Parts of Titanium Alloy
Key words: Titanium alloy milling process, Titanium alloy milling tools, finishing Titanium alloy, China Titanium alloy processors, Titanium alloy cavity, Titanium alloy slot, Titanium alloy milling parts
There are many factors that must be considered in the actual titanium alloy processing. Based on this, the milling process of titanium alloys is different from the main processing methods that have been used for a long time. The development of two new milling tool solutions and applications has opened up new possibilities for titanium milling. Compared to many other materials, the potential for successful processing of titanium alloys is much smaller and the processing properties are different. Titanium alloys vary greatly in processability, which affects the choice of processing methods and tools as well as the processing. But like any other alloy, you need to plan more carefully – from choosing the machine for the job to programming the cutting details. Although the characteristics of the parts in the aerospace manufacturing industry are quite similar, they vary in size and shape. Therefore, the choice of machine tools, fixtures, coolants, tools, machining methods, and cutting parameters is not the same. Due to the limited space in the tool magazine, the flexibility of the process is a prerequisite. In terms of production efficiency and capability, the type of tool holder and the adjustment of the tool installation are key factors.
Just as roughing and finishing operations must be planned according to different parameters. For indexable cutters and overall cemented carbide cutters, titanium alloy milling, which is related to different application fields, also appears. The size and shape to be machined and the appropriate tool type are the first determining factors. Indexable tools are the most efficient in removing materials and are now considered the first choice for roughing, and they are unmatched in large, flat surface finishing. Solid carbide tools are widely used in semi-finishing and finishing operations. When the radius of indexable blade tool and the size of cavity and groove are too small, the whole cemented carbide tool is also an ideal solution.
The programming data of the parameters of the parts to be processed is the basis for selecting special milling cutters. Since the maximum metal removal rate should be balanced with the economic tool life, based on this, other tool variables can be determined. For titanium alloys, the basic factors of the tool include the use of cemented carbide materials, sharp and strong cutting edges, and a relatively large positive rake angle. These elements can meet the special heat resistance and chemical requirements of titanium alloys. In terms of geometry and tool materials, indexable insert technology has undergone a long process of development. It is becoming a more cost-effective solution, replacing a large number of existing carbide tools and even for medium and large size tools.
1. Radial milling of titanium alloy materials
Radial milling is ideal for titanium machining. However, large radial depths of cut can greatly shorten tool life. The large axial depth of cut has little effect on the cutting temperature, so it does not affect the tool life in the same way. Therefore, using long-edge milling cutter with close pitch, 30% radial cutting depth and maximum axial cutting depth allowed by specific application are the best methods to remove titanium alloy materials efficiently.
As a result, the long edge milling cutter is suitable for rough milling and finishing of many titanium alloy parts. The long spiral edge of the long-edge milling cutter is very suitable for large number of radial milling in titanium alloy processing. The indexable blade long-edged tool consists of multi-row blades, which are the same as the cutting edges of the continuous grinding whole carbide tool. At present, the indexable inserts that are raised from the bottom of the tool along the outer circumference have reached the limit of achieving good processability and safety in the titanium alloy. Large size flutes for efficient chip evacuation are required. Combined with an efficient positive rake angle and sharp blades, it combines into an indexable long-edge tool for excellent machining performance.
For titanium milling, stable clamping of the cutting insert is critical. Even in roughing, any movement of the cutting insert can result in uneven wear and put the cutting edge at risk. Slight signs of wear can blunt the cutting edge during titanium machining, which can accelerate wear and cause tool breakage. For a row of tightly fixed continuous blades, the axial support of blades is particularly difficult, which leads to excessive dependence on blade screw. Therefore, when using long-edged milling cutters, the best way to achieve outstanding performance is to have a solid interface between the blade and the cutter body. The blade holder must have a defined support and locking device, with special consideration for axial and rotational forces.
Second, the coolant is vital
Titanium milling depends on the coolant used – the higher the quality, the better the machining. It has been proven that high pressure cooling applications (pressure ranges from standard 70 x 105 to 100 x 105 Pa depending on the system used) have shown significant advantages. Because high pressure cooling is standard on many modern machine tools, it is a potential resource for optimizing titanium milling. High pressure cooling affects heat distribution, chip formation, cutting edge bonding tendency, tool wear and surface integrity, which has a very significant effect on titanium alloy processing results.
Because titanium alloys are prone to chemical reactions, it is easy to weld the workpiece material to the cutting edge during processing, which can affect tool life and lead to secondary cutting of the chips and blockage of hard chips. The coolant ejected from the nozzle under high pressure plays a key role in temperature control and thus affects the processing results and reliability. The tool nozzle is directly aligned with the portion of the blade that is in contact with the finished surface to form a so-called "hydraulic wedge" between the chip and the rake face of the blade. Because these nozzle holes are part of the tool's non-adjustable part, they have been optimized during assembly and eliminated instability, resulting in a more consistent and safer process. For practical reasons, the indexable milling cutter has a lower diameter of 12 mm, while the cemented carbide tool has an upper diameter limit of 25 mm based on cost performance. The choice of intermediate and overlapping ranges depends on the specific application. For finished, fine-ground solid carbide end mills are usually the best solution, and for roughing, the best solution is indexable tools. However, tools suitable for this intermediate range continue to evolve as the tool modular provides a completely different viewing angle through this interchangeable head milling cutter.
Deep and narrow cavities require longer tool accessibility. To make these cavities not a bottleneck in processing, a solution that provides good performance is combined with small tooling capabilities and processing flexibility. The use of lengthened chucks to clamp the whole carbide end milling cutter in order to penetrate into the cavity can not achieve the best stability, because this will limit the cutting parameters and bring risks to the quality of the parts. However, the interchangeable knife has the dual advantages of the indexable and finishing capabilities of the solid carbide tool.
From the perspective of performance and machining results, tool cost and flexibility requirements, the interchangeable tool system has an obvious advantage in the tool diameter range of 10~25mm. Not only does it provide a high degree of flexibility, but it also reduces tool inventory. Its finishing ability is superior to that of indexable insert tools, and the cost of the tool is greatly reduced compared to the solid carbide tool. In addition, there is no need to worry about the smaller size of the blade due to regrind. The ability to select different cutter heads in combination with the shank provides a high degree of flexibility and more possibilities for optimization. The interface between the tool tip and the tool holder is a key factor in such tools. Its performance depends on strength, stability, accuracy, repeatability and ease of grip. The large enough axial support surface, tapered radial support surface, specially developed thread profile and screw support together create the unique interface required between the cutter head and the shank. This interface is the basis for ensuring good machining performance under large tool overhang conditions.
Fourth, successful titanium milling
In roughing milling, in order to obtain the best metal removal rate, axial cutting depth is the main factor to consider; In finishing milling, the optimum feed rate must be considered. In titanium alloy processing, whether it is a roughing or finishing process, although the cutting speed can be different, it is always limited. Knowing the basic principles of these titanium alloys, you can do a lot of work to optimize the process, making titanium machining more competitive and achieving a reliable process. The four key factors to consider are machine tool capabilities, coolant supply, cutting tools and machining methods.
In radial milling with low cutting speeds, the machine needs to have sufficient power and torque, and a suitable spindle is required to achieve a satisfactory metal removal rate. If the machine also uses small diameter tools, the spindle speed range needs to be high enough for excellent machining results. In general, the spindle interface needs to be evaluated and its connection stability should not be too weak. In order to obtain sufficient bending rigidity of the tool, good end face and taper contact are basic requirements; In order to eliminate the tension on the tool produced by the spiral or radial milling tool, sufficient clamping pressure is critical.
Titanium alloys have become an increasingly popular material in machine shops. Whether the corresponding processing technology can be further developed makes the performance and processing results of this material reach a new level is a crucial factor. Milling plays a dominant role in the processing of titanium alloys, in part because the processing of cavity, shape, groove and edge in aircraft fuselage parts is a challenging process. Most of the machining is two-dimensional, and the machining requirements are becoming more stringent due to cavity depth and radius requirements and other challenging factors. As for the machine tools used, they are very outdated for titanium machining. This requires the selection of the best tooling systems and machining methods for excellent machining and maximum machine utilization. Compared with ordinary machining, titanium alloy milling methods and programming techniques are even better. The rounded corners and contours are machined in the recommended way to achieve exceptional results in the machine's production cycle and minimizing waste. In general, to ensure that the correct tool path is machined from the start, it takes more time to optimize the programming before machining, which is more effective than choosing an off-the-shelf process. The performance improvements brought about by the new development of milling tools directly enhance the performance of titanium alloy materials. In overcoming the machining challenges of titanium alloy materials, special tools play a major role, and in the optimization part, it plays an important role in the process selection and application of the correct tool.
There are many factors that must be considered in the actual titanium alloy processing. Based on this, the milling process of titanium alloys is different from the main processing methods that have been used for a long time. The development of two new milling tool solutions and applications has opened up new possibilities for titanium milling. Compared to many other materials, the potential for successful processing of titanium alloys is much smaller and the processing properties are different. Titanium alloys vary greatly in processability, which affects the choice of processing methods and tools as well as the processing. But like any other alloy, you need to plan more carefully – from choosing the machine for the job to programming the cutting details. Although the characteristics of the parts in the aerospace manufacturing industry are quite similar, they vary in size and shape. Therefore, the choice of machine tools, fixtures, coolants, tools, machining methods, and cutting parameters is not the same. Due to the limited space in the tool magazine, the flexibility of the process is a prerequisite. In terms of production efficiency and capability, the type of tool holder and the adjustment of the tool installation are key factors.
Just as roughing and finishing operations must be planned according to different parameters. For indexable cutters and overall cemented carbide cutters, titanium alloy milling, which is related to different application fields, also appears. The size and shape to be machined and the appropriate tool type are the first determining factors. Indexable tools are the most efficient in removing materials and are now considered the first choice for roughing, and they are unmatched in large, flat surface finishing. Solid carbide tools are widely used in semi-finishing and finishing operations. When the radius of indexable blade tool and the size of cavity and groove are too small, the whole cemented carbide tool is also an ideal solution.
The programming data of the parameters of the parts to be processed is the basis for selecting special milling cutters. Since the maximum metal removal rate should be balanced with the economic tool life, based on this, other tool variables can be determined. For titanium alloys, the basic factors of the tool include the use of cemented carbide materials, sharp and strong cutting edges, and a relatively large positive rake angle. These elements can meet the special heat resistance and chemical requirements of titanium alloys. In terms of geometry and tool materials, indexable insert technology has undergone a long process of development. It is becoming a more cost-effective solution, replacing a large number of existing carbide tools and even for medium and large size tools.
1. Radial milling of titanium alloy materials
Radial milling is ideal for titanium machining. However, large radial depths of cut can greatly shorten tool life. The large axial depth of cut has little effect on the cutting temperature, so it does not affect the tool life in the same way. Therefore, using long-edge milling cutter with close pitch, 30% radial cutting depth and maximum axial cutting depth allowed by specific application are the best methods to remove titanium alloy materials efficiently.
As a result, the long edge milling cutter is suitable for rough milling and finishing of many titanium alloy parts. The long spiral edge of the long-edge milling cutter is very suitable for large number of radial milling in titanium alloy processing. The indexable blade long-edged tool consists of multi-row blades, which are the same as the cutting edges of the continuous grinding whole carbide tool. At present, the indexable inserts that are raised from the bottom of the tool along the outer circumference have reached the limit of achieving good processability and safety in the titanium alloy. Large size flutes for efficient chip evacuation are required. Combined with an efficient positive rake angle and sharp blades, it combines into an indexable long-edge tool for excellent machining performance.
For titanium milling, stable clamping of the cutting insert is critical. Even in roughing, any movement of the cutting insert can result in uneven wear and put the cutting edge at risk. Slight signs of wear can blunt the cutting edge during titanium machining, which can accelerate wear and cause tool breakage. For a row of tightly fixed continuous blades, the axial support of blades is particularly difficult, which leads to excessive dependence on blade screw. Therefore, when using long-edged milling cutters, the best way to achieve outstanding performance is to have a solid interface between the blade and the cutter body. The blade holder must have a defined support and locking device, with special consideration for axial and rotational forces.
Second, the coolant is vital
Titanium milling depends on the coolant used – the higher the quality, the better the machining. It has been proven that high pressure cooling applications (pressure ranges from standard 70 x 105 to 100 x 105 Pa depending on the system used) have shown significant advantages. Because high pressure cooling is standard on many modern machine tools, it is a potential resource for optimizing titanium milling. High pressure cooling affects heat distribution, chip formation, cutting edge bonding tendency, tool wear and surface integrity, which has a very significant effect on titanium alloy processing results.
Because titanium alloys are prone to chemical reactions, it is easy to weld the workpiece material to the cutting edge during processing, which can affect tool life and lead to secondary cutting of the chips and blockage of hard chips. The coolant ejected from the nozzle under high pressure plays a key role in temperature control and thus affects the processing results and reliability. The tool nozzle is directly aligned with the portion of the blade that is in contact with the finished surface to form a so-called "hydraulic wedge" between the chip and the rake face of the blade. Because these nozzle holes are part of the tool's non-adjustable part, they have been optimized during assembly and eliminated instability, resulting in a more consistent and safer process. For practical reasons, the indexable milling cutter has a lower diameter of 12 mm, while the cemented carbide tool has an upper diameter limit of 25 mm based on cost performance. The choice of intermediate and overlapping ranges depends on the specific application. For finished, fine-ground solid carbide end mills are usually the best solution, and for roughing, the best solution is indexable tools. However, tools suitable for this intermediate range continue to evolve as the tool modular provides a completely different viewing angle through this interchangeable head milling cutter.
From the perspective of performance and machining results, tool cost and flexibility requirements, the interchangeable tool system has an obvious advantage in the tool diameter range of 10~25mm. Not only does it provide a high degree of flexibility, but it also reduces tool inventory. Its finishing ability is superior to that of indexable insert tools, and the cost of the tool is greatly reduced compared to the solid carbide tool. In addition, there is no need to worry about the smaller size of the blade due to regrind. The ability to select different cutter heads in combination with the shank provides a high degree of flexibility and more possibilities for optimization. The interface between the tool tip and the tool holder is a key factor in such tools. Its performance depends on strength, stability, accuracy, repeatability and ease of grip. The large enough axial support surface, tapered radial support surface, specially developed thread profile and screw support together create the unique interface required between the cutter head and the shank. This interface is the basis for ensuring good machining performance under large tool overhang conditions.
Fourth, successful titanium milling
In roughing milling, in order to obtain the best metal removal rate, axial cutting depth is the main factor to consider; In finishing milling, the optimum feed rate must be considered. In titanium alloy processing, whether it is a roughing or finishing process, although the cutting speed can be different, it is always limited. Knowing the basic principles of these titanium alloys, you can do a lot of work to optimize the process, making titanium machining more competitive and achieving a reliable process. The four key factors to consider are machine tool capabilities, coolant supply, cutting tools and machining methods.
In radial milling with low cutting speeds, the machine needs to have sufficient power and torque, and a suitable spindle is required to achieve a satisfactory metal removal rate. If the machine also uses small diameter tools, the spindle speed range needs to be high enough for excellent machining results. In general, the spindle interface needs to be evaluated and its connection stability should not be too weak. In order to obtain sufficient bending rigidity of the tool, good end face and taper contact are basic requirements; In order to eliminate the tension on the tool produced by the spiral or radial milling tool, sufficient clamping pressure is critical.
Titanium alloys have become an increasingly popular material in machine shops. Whether the corresponding processing technology can be further developed makes the performance and processing results of this material reach a new level is a crucial factor. Milling plays a dominant role in the processing of titanium alloys, in part because the processing of cavity, shape, groove and edge in aircraft fuselage parts is a challenging process. Most of the machining is two-dimensional, and the machining requirements are becoming more stringent due to cavity depth and radius requirements and other challenging factors. As for the machine tools used, they are very outdated for titanium machining. This requires the selection of the best tooling systems and machining methods for excellent machining and maximum machine utilization. Compared with ordinary machining, titanium alloy milling methods and programming techniques are even better. The rounded corners and contours are machined in the recommended way to achieve exceptional results in the machine's production cycle and minimizing waste. In general, to ensure that the correct tool path is machined from the start, it takes more time to optimize the programming before machining, which is more effective than choosing an off-the-shelf process. The performance improvements brought about by the new development of milling tools directly enhance the performance of titanium alloy materials. In overcoming the machining challenges of titanium alloy materials, special tools play a major role, and in the optimization part, it plays an important role in the process selection and application of the correct tool.
