In complete machining, there are special requirements for the machine and machining processes. If you are dealing with a difficult-to-machine material such as titanium, special know-how is required to master these requirements. With a machining solution for aircraft landing gear parts, WFL MILLTURN Technologies GmbH & Co. KG can convince with expert know-how in this area.
The aerospace industry is an important market segment for WFL. In this branch of industry, more and more materials that are difficult to machine are gaining ground. Titanium processing in particular is a field in which WFL can score points with its accumulated know-how.
Material with special properties
Titanium has always made special demands on tools and machines when it comes to machining. In recent years, titanium 3.7165 has established itself as a lightweight material with excellent properties, especially in the aerospace industry, but also in the medical field. It is one of the most widely used titanium alloys, containing 6% aluminum and 4% vanadium. This alloy, commonly referred to as Ti6Al4V, has a very good combination of toughness, corrosion resistance and toughness. Although good empirical values and cutting data are now available for this material, machining is still one of the supreme disciplines in machining.
The titan among titans
New titanium alloys are constantly being developed for special applications, often due to special customer requirements. Titan 5553 (Ti5Al-5V5Mo3Cr) is considered by several WFL customers to be the desired material for landing gear production in the aviation industry. This material is characterized by improved properties in terms of strength and toughness. It is also less sensitive to structural changes when heated. This material is one of the real titans when it comes to machining and takes its name from Greek mythology. Ti 5553 is arguably one of the most difficult-to-machine materials on the market today. When processing it, a cutting speed of 45 m/min should not be exceeded,
Titanium machining challenges
Problems such as spot heat due to poor heat conduction and the associated chemical change in the material (brittleness at higher temperatures) and the formation of built-up edges occur to a much greater extent with this material than with other titanium alloys. Therefore, with Ti 5553, special care must be taken to ensure that the cutting speed, feed and depth of cut are precisely matched. The use of suitable cooling lubricants is just as important as the right cooling strategy. Fast and continuous chip removal must be guaranteed. Another challenge with this material is removing the forging skin, which experts call "elephant skin". Due to the upstream forging process and the resulting thermal and metallurgical influences, this skin has a very high edge hardness. Due to the low modulus of elasticity, titanium tends to evade the pressure of the tool and to fuse with the cutting edge. As already mentioned, the machining should therefore take place at a low cutting speed, but with a relatively large infeed depth and an adjusted feed rate. In any case, ensure that the tools are clamped in a vibration-free, sharp manner and that the workpiece is securely clamped. but relatively large infeed depth and adjusted feed. In any case, ensure that the tools are clamped in a vibration-free, sharp manner and that the workpiece is securely clamped. but relatively large infeed depth and adjusted feed. In any case, ensure that the tools are clamped in a vibration-free, sharp manner and that the workpiece is securely clamped.
Experience is key
All of this shows that machining titanium requires a great deal of experience in selecting and using the tools used and in the machining strategies. As early as the concept phase, it must be shown that critical aspects of processing can be addressed in production. For example, it must be taken into account that different material thicknesses in the workpiece blank require adapted processing strategies. Heat-affected zones must also be taken into account, as must the cutting forces that occur. Materials that are difficult to machine, such as titanium, have helped shape the development of the WFL machines. It is precisely for these demanding applications that WFL supplies individual solutions which, in addition to the actual machine, also include topics such as cooling and production strategy.
"In order to be able to offer WFL customers a process-reliable solution, WFL develops modules that allow the design of the machine to be precisely tailored to the respective application." Reinhard Koll, Head of Application Engineering WFL