Getting the maximum out of the machines

As a supplier of aircraft components to OEMs and major aircraft suppliers, Abu Dhabi-based aerostructures component manufacturer, Tawazun Precision Industries (TPI) relies on 5-axis machining centres from machine tool builder, Handtmann A-Punkt Automation to cover its diversity of applications.
In total, seven Handtmann machines are being used for high-speed aluminium machining, in addition to dedicated titanium machines from other manufacturers. TPI currently faces an increasing order book as Airbus, Boeing and other aerospace customers have signed multi-year contracts. “A decrease in production volumes is not of any concern at all,” states Kyle Wagner, operations manager, Aero-Structures at TPI, referring to official forecasts of Airbus and Boeing, which are absolutely positive. Along with the development of the international aerospace industry, TPI has been growing constantly for years. And so did its output. TPI is currently forecasting to increase their production volumes by 50% year on year for the next three years. Within its production it tries to keep a reasonable balance between aluminium and titanium machining to always being able to offer what the OEMs need. In correspondence to its usage in aircraft, the material ratio is about 80:20. Among other brands, TPI uses seven 5-axis machining centres from Handtmann for high-speed milling of aluminium. Covering more than 50 unique part numbers in total, TPI is machining a notable variety of aircraft parts. The seven Handtmann machining centres are varying too in terms of machine type. The profile machining centre PBZ HD 600 is primarily machining fuselage frames and cockpit frames, centre wing boxes and various beams with a total length of up to 6,000mm. With a maximum travel speed of 70/40/40m/min in XYZ high performance in aluminium machining and appropriate cutting parameters are guaranteed. With the two HBZ Compact Cell 200/100 horizontal machining centres equipped with a 2,000 x 1,000mm table and additional set-up stations for main-time parallel set-up TPI is producing a mixture of different structural parts, wing sections and fuselage frames with a 30,000rpm high power spindle and 60/40/60m/min travel speed. The four HBZ AeroCell 500/200 machines with 5,000 x 2,000mm pallet size are used for high speed machining of fuselage frames and a lot of various parts between cockpit and wings. The four machines allow the machining of any HBZ AC dedicated part on each of the four machines which allows a lot of flexibility. The big pallet size allows getting several identical parts out of one aluminium plate. A powerful high speed spindle with 125kW and 30,000rpm ensures high material removal rates and thus short machining times. The integrated pallet automation of the HBZ AeroCell machines increases productivity additionally as non-productive times are kept to a minimum. “These machines are brilliant for high speed milling,” a TPI NC-programmer states, referring to the HBZ AeroCell as well as the HBZ CompactCell horizontal machining centres. He also highlights the extreme power of the machines. This is one of the advantages resulting from the horizontal concept combined with high spindle power: high cutting rates and advantageous chip removal favour really good cycle times. Wagner is satisfied with the Handtmann machines' performance. Cycle times are even better than estimated by TPI before buying the HBZ AeroCell machines. Very fast rapid feeds; very good cutting rates; very powerful machines and efficiency - all resulting in satisfying productivity. In terms of user-friendliness, machine operator Vivek seems to be proud about the fact that he was the first person at TPI who ever touched a Handtmann machine. He rates the Handtmann machining centres positively and highlights the easy set-up due to horizontally positioned pallets on the HBZ AC and HBZ CC, good chip removal system, good operation in general and good visibility of the machining environment. The HBZ AC being a rather large machine has a video camera for improving the visibility while machining.  Although the current degree of capacity utilisation on the TPI shopfloor is around 100% TPI plans to significantly increase the output. The planned 50% increase of total output is only possible with powerful machines and improved milling strategies, especially as TPI doesn't necessarily plan to invest in a lot of new machinery until the current programs have been fully optimised. “We want to get the absolute maximum out of the machines,” states Wagner. “They are so powerful that there is still some potential by modifying and optimising milling strategies, optimising programs and modifying tool selection to reach the best results possible. The machines are not the limitation. There's still a lot of room for improvement.” Besides process optimisation, TPI will also set an even higher priority on machine maintenance and service support to keep the machines running smoothly. As TPI produces 24/7, machine reliability is most important. Therefore also service support is crucial. In this respect, TPI is satisfied with Handtmann. According to Wagner, spare part deliveries, reaction times, remote diagnostics, problem solving, training – all of these major service quality features are considered as very positive. In case of a machine stop the complexity of the Handtmann machining centres with detailed PLC programs and remote diagnosis capabilities allow an immediate detection of faults and to diagnose them easily due to various internal sensors for example. Ordering seven machines in total in a very short time starting from 2010 there have been some challenges on both TPI and Handtmann side in the beginning. But in the meantime most of them could be overcome so that the degree of capacity utilisation of the Handtmann machines is now as good as expected. Even though being a rather small and young company, the UAE based company considers themselves as a “key player in the international aerospace industry”, who plays a significant role in the international aero structures supply chain. Not necessarily in terms of volumes, but especially due to excellent reputation for on-time delivery, on-time quality and cost competitiveness, according to Wagner. When it comes to high speed aluminium cutting, TPI's seven Handtmann machining centres are a fundamental base for its plan of significantly increasing its output and for staying one of the key players in the international aerospace supply chain. www.handtmann.de/bearbeitungszentren