A leading European producer of helical and spur tooth pinion gears has selected a GTG2 gear-grinding centre from Holroyd Precision to test-grind a range of specialised gears and tooth forms.

Developed purposely for grinding precision spur and helical gears, worms, screws and rotors of up to 350 mm diameter and 160 mm gear face width, Holroyd GTG2 grinding centres use what is described as a unique machining system to achieve accuracy to DIN 2 levels and beyond.
Steven Benn, Holroyd’s regional sales director, says: “The customer required a machine capable of grinding a variety of gears to exacting tolerances. Products to be manufactured include spur and helical gears; gears with end tip relief and root fillet radius; worm tooth forms such as ZA, ZI, ZK and ZN; worms with sunken tooth forms; and dual lead forms with both cylindrical and tapered roots. The GTG2 was selected for its versatility, reliability and accuracy – the latter achieved through high levels of on-board machine intelligence and a machining process developed to compensate for helical twist.”
Helical Twist occurs when helical gears are ‘lead crowned’ to improve meshing and reduce noise and wear. Lead crowning varies the amount of material removed from the flank of a tooth, across the face width, by causing the tool motion
to deviate from a true helix.
The problem is that ‘in-form’ grinding has the undesirable effect of causing the profile of the tooth flank to vary across the face. Particularly in high precision and low noise applications, this variation affects gear wheel performance by concentrating loads on particular areas of teeth during meshing.
GTG2 machines correct this problem by calculating and controlling additional motions of the wheel during the grinding operation using dedicated software written by Holroyd engineers.
For further information www.holroyd.com

To meet growing demand for ever more precise surface finishing in aerospace, Fintek has invested in a latest generation stream finishing machine from OTEC Präzisionsfinish GmbH.

“The new SF is particularly important for our aerospace work to ensure the precise profile tolerances now demanded for turbine blades are met,” explains operations manager Jamie Phillips. “For example, the control provided by the new step motor technology allows us to repeatedly change and lock the angle of the blades as they pass through the process media to carefully manage the finishing effect on vital leading and trailing edges.”
With six other stream finishing machines, along with drag finishing and centrifugal finishing systems, the AS9100 and ISO9001 accredited company says it has the capacity, depth of knowledge and expertise to provide a comprehensive range of surface finishing services. These range from deburring and mirror-finish polishing to smoothing and polishing, as well as important edge rounding. For aerospace, this offer covers not just turbine blades but complete blisks, gear wheels, cutting tools, fasteners and extremely thin parts.
“Problem solving is integral to our service,” says Phillips. “We work closely with aerospace customer engineers, including in research and development, to create better parts by applying surface finishing techniques that meet their commercial objectives. Often we’re able to achieve a quality of surface finish in minutes [sometimes seconds] that can’t be matched by hand or other traditional methods. Furthermore, processes are precisely repeatable to ensure total quality consistency and confidence to achieve surfaces with values down to Ra 0.01.”
For aerospace companies requiring on-site processing, Fintek is the exclusive UK agent for OTEC, and can supply and install machines.
For further information www.fintek.co.uk