Theme building

Occupying a floorspace of 5,770mm by 9,055mm, Mori Seiki has extended its NH series of high speed, high precision horizontal machining centres with the announcement of the large scale NH10000 DCG. The company started taking orders for the new model at the beginning of March 2010. 

In recent years, the need for machine tools that achieve higher levels of efficiency and precision has been increasing as demand for the machining of large parts and difficult-to-cut materials used in the construction machinery, aircraft and printing equipment industries has been growing. In response to this need, Mori Seiki has developed the NH10000 DCG – the latest model in its NH series of high speed, high precision horizontal machining centres.

The NH series has a long pedigree of success in metalcutting applications. Mori Seiki reports orders of approximately 6,000 units since the release of the NH5000 in August, 2002. A year later, the NH4000 DCG – equipped with the company's original technologies, DCG (Driven at the Centre of Gravity) and DDM (Direct Drive Motor), was released.

The robust, stable and reliable NH10000 DCG can handle a maximum workpiece size of 2,000mm diameter by 1,600mm and a maximum loading capacity of 3,000kg (5,000kg as an option). For operability, the NH10000 DCG is designed to facilitate set-up operations, including the centre alignment of a workpiece and the height difference between inside and outside of the machine has been eliminated by installing work platforms. In the case of large machines, the setup operations are usually conducted inside the machine. In addition, by using the set-up station with large working area and wide door opening, the machine offers improved operability and accessibility.

A number of options are available including long tool capacity and automatic indexing set-up station specifications for the machining of large workpieces.

Box clever

In line with other models in the series, the NH10000 DCG features ‘box-in-box' construction which supports the saddle at both sides. Despite the machine's large structure, the centre of gravity of moving parts is guided and driven with excellent balance characteristics, achieving roundness values of 2.12μm (when the scale is provided) by minimising residual tool tip vibration during positioning and by improving machined surface quality.

The DCG drive system on the X and Z features two ballscrews which help to control vibration – a major factor in enhancing greater machining accuracy, prolonging tool life and reducing cycle times. Moreover, it achieves rapid traverse rates of 50m/minute.

For the B rotary axis, Mori Seiki offers a full indexing table using DDM as option. DDM is said to facilitate improved transmission efficiency, high speed and zero backlash by transmitting the drive power directly to the rotary axis. The 90° indexing time (with a workpiece weight of 5,000kg) is reduced to 1.9 seconds.

New functionality

The Draw-back system, available for through spindle coolant specifications, is a function in which coolant left in the spindle is sucked back into the tank when coolant stops flowing. This prevents the residual coolant from adhering to the spindle taper and being carried into the tool magazine during tool change with ATC. With this function, long term problems caused by coolant can be avoided, ensuring stable machining accuracy.

An additional function that automatically changes the Z axis stroke according to the rotation angle of the B axis makes it possible to extend the Z axis stroke by up to 40mm – enabling machining with a shorter tool overhang, which leads to improved machining conditions.

Designed to provide even better accessibility and operability, internal and external work platforms have been installed and the height difference between the inside and outside of the machine has been eliminated. These ensure much easier operations inside the machine such as centring of workpieces and checking of machined workpieces. With a wide door opening for the setup station (2,350mm), the NH10000 allows easy loading and unloading of workpieces up to a diameter of 2,000mm. Additionally, the machine is equipped with three spiral conveyors to offer excellent chip disposal. These conveyors, two of which extend to the setup station, collect chips and coolant not only from the machining area but also from the setup station and transfer them to the external conveyor. 

Big league

A long tool magazine option, capable of storing tools up to a length of 1,000mm – the same size as the pallet – is also available. The use of long tools enables users to perform deep hole boring and gundrilling of large workpieces that require accurate coaxiality without a 180° turn on the B axis. With an optional maximum loading capacity of 5,000kg, which is the largest among Mori Seiki horizontal machining centres, the NH10000 has the optional automatic indexing set-up station that allows automatic rotation of heavy workpieces. Users can choose from a number of specification options to suit individual needs.

The NH10000 has axis travels of 1,700mm x 1,400mm x 1,510mm (XYZ) and a pallet working surface of 1,000mm by 1,000mm. Maximum pallet loading capacity is 3,000kg (optional 5,000kg) and maximum workpiece swing diameter by maximum workpiece height is 2,000mm by 1,600 mm.

Mori Seiki
www.moriseiki.co.uk