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Following two weeks of extensive acceptance trials and in-depth deep hole drilling process training, a team of Chinese engineers are to take delivery of a £500,000 Mollart Prismabore combination two spindle milling and gundrilling cell for producing a range of four different rocker arms for use in large marine diesel engines.

The trials carried out at the Chessington, Surrey plant of Mollart
Engineering involved the milling of a series of boss and face features on
the heavy alloy steel forgings and the gundrilling of various oil feed
holes, some at compound angles, 6.8 mm and 8 mm diameter and up to
220 mm deep.

The Prismabore PRB-40 twin spindle machine has a drilling capacity
between 3 mm and 40 mm dia by up to 1,500 mm deep. Controlled by
Fanuc 31i-Model B, it has an X-axis of 2,000 mm, a Y-axis of 1,000 mm,
an independent ram with a stroke of 850 mm to form the Z-axis and a U
-axis for drilling depths up to 1,500 mm. The B-axis driven rotary table is
1,200 mm square with a 10 tonne loading and each axis is fitted with the
high accuracy linear scale option for the Chinese customer.

Both the drilling and milling spindles sited side by side, are
independently driven for maximum flexibility. The ISO 50 taper milling
spindle is powered by an 11 kW drive and the drilling spindle by a 15 kW
motor. Through and around the tool is high pressure coolant feeds
which can be set at up to 110 bar. Renishaw tool probing and tool
length measurement is also fitted.