A very wide variety of materials are used in the aerospace industry, from aluminium through to composites. Low weight is the central criterion, but the demands on the CNC machining vary widely as CNC machining specialist MAKA points out.

Abrasive, thin components call for excellent part handling. Honeycomb structures such as those used in engine cowlings and cabin interiors need the highest precision tool control. The CNC machines must be able to handle dimensions from small to large with the same precision. And, of course, the productivity of the machines must not suffer as a result. That means perfect automation with high throughput rates.

When the drill produces a hole in a CFRP panel with a cycle time of 0.6 seconds, a great deal is demanded of the machine technology. When the finished part is then installed in the cowling of an aircraft engine, absolute precision is the order of the day. Here, too, MAKA has developed a solution that satisfies the customer. The machine, with its 12 synchronised drilling spindles, has been in operation with a renowned European manufacturer of aircraft parts since 2014.

It is used to drill 50,000 holes per square metre with a hole spacing of 4.2 mm in thin acoustic elements of CFRP; reliably and at an incredible speed. The MAKA technicians developed floating bell and air cushion especially for the hold-down devices of the spindles to avoid scratches on the abrasive surface.

Honeycomb structures with their benefits for stability account for over 50 per cent of the structural weight in aircraft construction. Apart from the outer shells and partition walls inside the aircraft, honeycomb structures are also used in engine cowlings. Extreme differences in temperature prevail here, leading to the formation of condensation.

Here, a groove is milled in the honeycomb chambers through which the condensate can drain off. For this, the tool has to mill a large number of defined grooves at intervals of just a few centimetres in the ridges of the honeycombs that are only a few tenths of a millimetre thick. One challenge for MAKA was the exact control of the individual honeycomb segments. A camera-based recognition process was therefore selected that first scans the honeycombs and transmits the exact co-ordinates to the machine. The exact machining positions are then transmitted to the milling spindle.