With more than 50 years’ experience of providing custom-built precision instruments, the specialist engineering company Reliance Precision Ltd has established a global reputation supplying to a range of industry sectors, including medical, scientific, laboratory automation, defence, aerospace and space.
In addition to offering standard motion control components and electro-mechanical assemblies (many are available ex-stock and are featured in the company’s catalogue), it also provides custom-designed sub-systems — and even complete instruments. In-house engineering capabilities include design, development, prototyping, manufacturing, assembly and test.
Reliance’s manufacturing capability is backed up by a comprehensive range of CNC machinery that allows the company to undertake high-speed machining, five-axis machining, jig boring, sliding-head one-hit machining and gear cutting.
It also undertakes centreless grinding, rack grinding and the grinding of exceptionally hard materials. Sustained investment in cutting-edge equipment has allowed Reliance to continuously improve its capabilities, with one of its recent purchases being a Studer S11 CNC cylindrical grinder from Mold-based Micronz Ltd (
www.micronz.co.uk).
Alex Greenhalgh, Reliance’s estimating manager, said: “The nature of the sectors that we serve, and the type of demanding high-precision work that we undertake, dictates that we only invest in technically advanced machine tools.
“A growing workload, especially for small parts with challenging accuracy specifications, prompted our recent search for an additional CNC cylindrical grinding machine.
To ensure that we purchased the optimum machine for our needs, we did an analysis of factors such as the size, shape and accuracy requirements of the grinding work that we had completed over the past five years.
The results of this study allowed us to prepare a specification for our ideal machine. As we already have a 40-year-old Studer grinder that is still working perfectly, this manufacturer was naturally on our shortlist.
We also looked at machines from other leading manufacturers; and while a couple of the options we were considering had some of the features we were looking for, the Studer S11 was the only compact CNC cylindrical grinding machine that met — and in some areas exceeded — our technical wish-list.
“To verify the machine’s suitability, we sent two of our grinding team to Studer’s Swiss headquarters to witness in-depth machining trials. We subsequently placed an order for an S11, which is now fully operational and producing very accurate small parts that feature excellent surface finish characteristics.
Although this machine takes up very little floor space, it is highly productive; and in addition to significant cycle-time reductions, the rapid wheel changes offered by the S11 provide further efficiencies.”
Machine details
The S11 features a Granitan S103 mineral-casting machine base that provides excellent damping characteristics and ensures high levels of surface finish and excellent grinding wheel life.
This thermally stable material also accommodates short-term fluctuations in temperature, thereby ensuring high levels of dimensional accuracy, while the high-speed grinding option contributes to increased productivity with peripheral wheel speeds of up to 140m/sec. Moreover, the S11 requires a floor space of less than 1.8sq m — and it does not use any hydraulic power.
The machine’s X and Z axes are designed as a self-contained cross-slide unit, with the workpiece table bolted directly to the machine structure — an arrangement that has been used for many years on production cylindrical-grinding machines.
Both axes have linear guideways mounted on roller bearings, while the glass scales on these axes have a resolution of 0.00001mm. The machine’s wheel-head is available with a plunge angle of 0 or 20deg, while the motor spindle features a hollow shaft, integrated contact detection and a balancing unit.
Furthermore, the S11’s work-head accommodates grinding between fixed centres, as well as live-spindle grinding; it also features an ‘airlift’ that simplifies adjustment when undertaking setting up or resetting, while fine adjustment allows taper corrections in the micron range to be made.
Studer provides a large selection of dressing units, and grinding-wheel profile and dressing parameters are readily defined via macros. A software package is available for further fine-tuning of the dressing process.
Control is via a Siemens Sinumerik 840D SL CNC system, and there is a separate manual control unit that allows the operator to get close to the grinding process when setting the machine. Fully integrated in-process gauging can also be specified.
Meanwhile, the StuderWINfocus operator interface has been designed to provide an efficient and stable programming environment.
It features: Studer Pictogramming, which allows the operator to string the individual grinding functions together, leaving the control unit to generate the ISO code; and Microfunctions for the programming of grinding and dressing sequences.
Being designed as a production grinding system, the S11 offers a variety of loading and unloading systems, and several machines can be linked together.
Comprehensive quality control is possible during the grinding process. This control comprises in-process and and post-process measuring, recording, evaluation and correction.