Broadbent Stanley has revealed how Balfour Beatty Rail Track Systems has taken advantage of its machine tool rebuild and retrofitting service.

The quest was to locate a large capacity planomill, rebuild it and retrofit a CNC control system Within a short period of time, a 1970s Waldrich model SLP 220 manual planomill was sourced, given a full inspection with a detailed report prepared on the work required to strip the machine, rebuild modifying the slideway systems and adding a milling head and convert to CNC The machine, a twin column elevating rail configuration with 800mm of vertical travel, came complete with twin independent spindles and a 9 x 2.2m table with a travel of 9.5m and 2.5m between columns.

Once the machine was stripped into component parts the detailed modifications began.

The two heads were re-engineered and converted to AC drive utilising 60kW GE Fanuc motors and while Balfour Beatty wanted to retain the 60 ISO taper vertical spindle drive, it also needed the flexibility of universal heads.

Two new fully universal heads were sourced, modified and adapted for ease of removal and replacing by the machine operator.

New slideway systems were provided for the heads along with the elevating rail, which was redesigned utilising synchronised recirculating ball screws and hydraulic counterbalance, retaining the full 800mm of vertical travel required.

Heidenhain linear scales were also fitted to the crossrail making it a fully closed-loop system.

The table top was remachined and fitted with hydrostatic slideways driven by a twin pinion anti-backlash system.

The machine required six axes under CNC control and the GE Fanuc model 31i controller was selected, also utilising its latest high torque digital drives.

Within a few months the machine was completed, passed off by the customer and subsequently installed and commissioned by Broadbent Stanley personnel in Balfour Beatty's South Queensferry machine shop.

As with all of Broadbent Stanley's rebuilt machines it comes complete with a 'no quibble' unconditional 12-month warranty. 

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