CNC upgrades high-volume centerless grinding

Aspecialty machine builder that emphasises grinding technology has launched a re-engineered, centerless grinder based on one of the world’s most widely used machines. The builder, RefreshEng, had a boost on the project from software development support from CNC vendor NUM. Controlled by NUM’s Flexium CNC kernel, this upgrade will convert any of the Cincinnati 2-OM family of centerless grinder machines to the same kind of automated and precision machining available on state-of-the-art grinders - but at about 60% less investment cost that a new machine represents.

Initially, the new NUM CNC-based machine is targeted at centerless grinding applications in the aerospace industry, and comes with application-specific software to automate the production of the specialty countersink, button-head, and relief style fasteners used in aviation fuselage and engine production.

RefreshEng’s CNC upgrade package is offered in four variants, with a choice of three auto-loading options. The NUM-based upgrades transform the Cincinnati 2-OM’s original hydraulic- and mechanical-dressing architecture (with fixed cam-and-stylus control) to an advanced CNC software-based system with up to seven axes of servomotor-based motion depending on customer choices.

To complete the automation upgrade to the highest standards, RefreshEng incorporates several advanced features that optimise productivity, precision and operator safety. These include acoustic sensors that automatically monitor and compensate for grinding wheel wear.

The machine also uses the sensing system to dynamically adjust grinding wheel feedrate to provide gap elimination. According to NUM, this feature can reduce grinding cycle times by almost 20% across a batch of raw material parts with varying dimensions.

Higher-resolution control of movement, and the ability to interpolate movement of motion axes, improves both grinding accuracy and extends the range of shapes that can be ground.

The grinding wheel is fitted with a Schmitt Balancing System,which dynamically eliminates vibration.Wheel speed can be varied to suit differcent component materials.

Another noteworthy feature is a choice of drop-,finger-or front-loading loaders to automate the broad range of common centerless grinding applications. The finger loader accepts a very large variation in part size,from 10 mm long x 3mm diameter,up to 200 x 25mm.

Refreshing opportunity
The idea for the project grew form RefreshEng's particular expertise with centerless grinding,derived from its well-established tooling services in the U.K.and Europe. Many of its clients wanted to re-control their old machines to an advanced level, to increase throughput and eliminate manual operations, but had found it difficult to source the technical support for such work. RefreshEng recognised the opportunity, especially for the popular Cincinnati 2-OM, as it estimates there are still some 2000 of these machines in the UK alone.

RefreshEng - whose staff has grinding-machine design experience - had clear ideas of how to update the mechanical architecture. This involved the complete replacement of hydraulics in favour of servomotor-controlled motion, with numerous modifications to the underlying framework including new castings to mount the electro-mechanics. The key hurdle for RefreshEng’s CEO Damian Clements was finding a CNC supplier that would be prepared to complement his company’s know-how with high-level control system software skills. In order to make the project financially viable, RefreshEng also wanted the CNC supplier to defer the return on their development efforts until sales of the machine started to build.Girls Air Jordan 1