CNC surface grinding machine exceeded all requirements for grinding a diverse range of cylindrical mould tooling from 292mm) to 711mm diameter to be used in timing belt system manufacture.

The Gates Corporation of Denver, Colorado in the USA was established in 1911. Formally known as the Gates Rubber Company, they are now one of the largest high precision automotive timing belt manufacturers in the World. Recently when needing to ramp up their production facilities in support of new business growth, they contacted Jones and Shipman and asked them to review a project they had on the table.

It consisted of a very specific and demanding set of criteria that had to be met in support of a new range of Gates high precision timing belts.

The challenge was to grind a diverse range of cylindrical mould tooling from 11in (292mm) to 28in (711mm) diameter.

Soon after an initial contact Jones and Shipman's application engineers provided an in depth application assessment report confirming that a model in their ProGrind range was capable of not only achieving their requirements, but also exceeding them in all departments, accuracy and process time, plus giving them the requested larger capacity.

Jones and Shipman is not traditionally known as a manufacturer of large capacity production surface grinders.

However with the introduction of their award winning Dominator range, with its three dimensional grinding capabilities and more recently a high accuracy ProGrind range, most applications can now be fulfilled.

The Jones and Shipman (J and S) ProGrind is designed to marry physical size with high precision, high productivity and incredible flatness.

Incorporating Jones and Shipman's simple to use and quick to set 'Easy' software via a GE-Fanuc Touchscreen control and A.C.

Digital Servos with Heidenhain 'Absolute' linear scale feedback, it proved to be the ideal machine for the Gates Corporation.

Having established from the initial feasibility study that a ProGrind 1267 was the grinder of choice, design and process optimisation commenced.

A Nikken CNC Rotary indexer and heavy-duty hydraulic tailstock was chosen to support and drive the mould tools, each of which would be held between centres.

With all mould blanks being produced from alloy steel and of a fixed length of 17in (450mm), J and S recommended twin high precision diamond discs as the optimum wheel dressing option.

The discs, accurately lapped with 0.004-5in (0.1-0.125mm) radii, where chosen to complement the mould tooth profile accuracy and mounted on a J and S custom disc dressing unit for easy of use.

After machine build in the UK, grinding trials commenced on sample mould blanks to prove out the form and optimal wheel dress frequency.

The wheel form profile and the mould tooth profile being initially optically checked against master overlays.

Further verification of the form being obtained via a ground tooth form test piece on a CMM.

Having established the initial wheel dress frequency and grinding parameters, the machine was accepted following a 'lights out' run of a Gates mould and shipped to Gates Corporation's, Denver, facility for on-site commissioning and final grinding acceptance trials.

Operator familiarisation and training with the Easy software quickly progressed through dressing and grinding flat forms on a test mould.

From this point training moved on a pace and the first test blank a 115-tooth profile mould, was set and run with a roughing cut.

As the ProGrind is a 24/7-production grinder the machine ran unmanned for the next day.

After inspection the wheel was redressed for a four-hour finishing cycle.

A full inspection by CMM of all geometry including size and profile angularity confirmed that all features where well within tolerance.

The ProGrind was then set to grind a 100-tooth mould; this took a day to rough grind.

Their existing machine, an Okamoto, which had started an 80-tooth mould one-hour after the ProGrind, was still grinding with three teeth left after a day and a half.

In fact the CEO of the mould customer who was visiting at the time remarked on how efficiently the ProGrind was operating.

Final acceptance was signed and the ProGrind passed over to the Gates Corporation in Mid July 2006.