The new grade CTP5240 has been adapted specifically for this task.
Weight reduction is the central requirement in the modern aerospace industry for both civil and military aviation. The industry sector responds to this requisite with new materials such as carbon fibre. In this context titanium is also gaining ever more importance in aircraft construction. In fact structural components which hold the carbon fibre components together are made of titanium, which is why they can be considered the framework of modern aircraft construction. Due to this tendency, structural components made of aluminium are reducing in importance. Consequently a considerably higher number of component subcontractors will have to deal with this difficult to machine material.
The CERATIZIT specialists have therefore made it their goal to offer the industry a tooling solution which allows high productivity and relatively low production costs for components made from such challenging materials. This is only possible by developing tools and inserts with excellent performance in terms of tool life, cutting parameters and process security. It is not sufficient to upgrade existing carbide grades and geometries to reach this goal. This is why our development team have been concentrating on developing a completely new combination of cutting material, coating and geometry, adapted exactly to the special challenges of titanium alloys right from the start:
New carbide substrate with excellent heat resistance properties. New coating with sufficient toughness, high wear resistance and small coefficient of friction. New geometries for improved chip formation when machining titanium.
The advantages of titanium alloys compared to other materials are obvious. Titanium alloys are mainly characterized by low density which is only a little more than that of aluminium. Simultaneously they show twice as high a strength so that structural components can be designed slimmer and with lower weight. A disadvantage is their bad machinability which has a negative impact on manufacturing costs due to low cutting speeds and short tool life. The most important reason for this bad machinability is the extremely low thermal conductivity of titanium alloys. Titanium conducts heat about ten times worse than steel. Contrary to the machining of steel the heat produced during the cutting process is therefore not evacuated with the swarf, but the major part of the heat is concentrated inside the tool or the cutting edge.
This is where CERATIZIT gets things moving. A carbide grade with substantially increased heat resistance was developed. The main advantage of the new CERATIZIT grade is really its heat resistance, which allows cutting speeds up to -20% higher than comparable products from competitors.
The recently developed grade which is to protect the carbide substrate against abrasion also serves as a heat barrier. This means the coating itself must have low thermal conduction properties to prevent the heat from reaching the carbide. In order to minimise the heat generation, it is essential that the coating has the smoothest possible surface and the swarf can glide over the rake face without substantial resistance. The recently developed TiB2 coating by CVD from CERATIZIT totally fulfils these specifications.
The inserts for titanium machining are customarily provided with protective chamfers in order to stabilise them at high temperatures, but this results in the disadvantage of increased cutting pressure. Now CERATIZIT offers the decisive competitive edge. Only the extremely heat resistant substrate of the new CERATIZIT grade CTC5240 enables the application of inserts with very positive geometries, without protective chamfer and with a light edge hone to be used for the machining of titanium. In this way cutting pressure is reduced which also limits heat generation, and chip formation is greatly improved through these extremely positive geometries. Additionally compressed and lamellar chips are avoided, i.e. the cutting pressure and subsequently wear is reduced. All in all these effects result in a 20% increase in tool life compared to other suppliers.