Mikrosa 125 Siemens 5 axis CNC Rebuild

A 70 year old, original Mikrosa SASL 125 Centreless Grinding Machine rebuilt with a 5 axis Siemens S7-1500 control retrofit package and an integrated bowl feeder and parts conveyor to automatically load the machine with a continual feed of parts.

The customer had an original Mikrosa 125 already in production, but it had become unreliable due to mechanical wear, and increasingly difficult to maintain with original electrical components becoming obsolete and impossible to source. An old donor machine was taken from our stocks, and rebuilt to the required specification. This avoided the customer having to lose their machine from production during rebuild, as the completed machine was part exchanged with their original on delivery.

The machine carried the first S7-1500 controller to be delivered to the UK by Siemens, which again demonstrated how we continue to place ourselves at the cutting edge of available technology. The machine was delivered in throughfeed configuration, with 0.1 micron fine adjustment/compensation to the infeed slide. Along with our bespoke centreless grinding software and 12" touchscreen interface, the highly automated machine was easy to use, even for an operator more accustomed to a manual machine.

The machine was fitted with a rear operator control as well as the main touchscreen HMI. This enabled the operator to set the machine at the front as per usual, but then to station themselves at the rear of the machine to inspect machine output, and adjust infeed slide position and control wheel spindle speed from the rear of the machine, to control size and roundness. This manual inspection and adjustment could be upgraded to a post process gauge with closed-loop feedback, for automated machine adjustment.

The improvements in mechanical condition, electrical reliability and automation helped the customer in improving throughput and accuracy, and reducing scrap to an almost non-existent level. The machine is also far easier to set and adjust for those operators who aren't as experienced on centreless grinders directly, but can use the touchscreen.

At 75 this year, we're convinced this machine will still be in production by the time it's 100 years old. It should be just about ready for another rebuild by that stage as well; I wonder what the available technology we'll be integrating will look like by then?

More information can be found at www.ctmachinetools.com/retrofit.