Ramping up the torque

Part of the Howco Group, claimed to be the largest independent supplier and processor of material solutions for equipment used in downhole, subsea and surface systems, Stockport-based Howco Bredbury has an established reputation for delivering quality precision engineered components to the oil and gas, aerospace, energy and transport industries.

Due to essential component production, Howco Bredbury’s managing director Ian Booth needed to improve the drilling cycle time on a new product line used in subsea applications. As a result, efficiencies were made which allowed for the machining of internal features and contours in the same set-up as drilling.

“The production of a single 170mm diameter hole through steel billets, which can vary in size up to 1m by 800mm square, requires a machine with appropriate torque and Ward CNC seemed to be the only machine supplier that was willing and able to provide a suitable solution,” Mr Booth explains.

A Hartford PBM 115A CNC horizontal boring and milling machine, with X-, Y- and Z-axis travels of 2,000mm to 2,500mm x 1,600mm to 2,000mm x 1,500mm respectively, was selected jointly by both parties as the solution.

“The first requirement was for a relatively small spindle of 110mm diameter to enable easy access – which the PBM has,” says Mr Booth. “And while the machine’s spindle speed of 2,500 to 3,000rpm was fine, what was really crucial was an increase in torque to enable the machine to consistently ‘push’ the 170mm holes through the billets. Based on this, Ward CNC’s answer was to uprate the Z-axis motor from 30Nm to 55Nm.”

In addition, Ward CNC increased the W-axis drive ratio by changing the ballscrew pitch from 12mm to 8mm pitch to eliminate the potential that the additional Z-axis torque would result in ‘pushing back’ the W-axis (quill axis).

Finally, Ward CNC engineers also interfaced a Cogsdill facing head and four line bars for the final contouring and feature machining of the workpieces.

Modifications on the initial machine – which were also fully endorsed by Hartford – were undertaken by Ward CNC at its Sheffield headquarters. The second, identical machine was supplied to a similar specification direct from Hartford in Taiwan.

With the first of the Hartford PBM duo already installed, Mr Booth has nothing but praise for its performance: “It’s doing everything we asked of it and most importantly, it’s reducing our hole drilling time.

“The second machine will be installed alongside the first to create a cost-effective and highly productive machining cell for Howco’s business moving forward.”

HOWCO BREDBURY www.howcogroup.com

WARD CNC www.wardcnc.com