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Gray Floor Type Boring Machine CNC Retrofit

On this project we were contracted by a Machine Tool Rebuilder for a CNC Retrofit on a Gray floor type boring machine. The rebuilder did a complete mechanical rebuild on the machine, but needed an integrator to do the control replacement.


The floor type boring machine was purchased and rebuilt for a major machinery re-manufacturer in the mining industry. It had been converted from a manual machine to CNC in the 70s. The first recontrol had been done using a GE550, which at the time was state-of-the-art. Upon rebuilding the machine it was determined that the GE550 system was not a viable control option.


The GE 550 CNC system consisted of:

  • Incremental feedback

  • Inductosyn scales

  • DC servo motors

  • Multiple control panels

  • Single rack drive on X axis

  • Limited CNC functionality

  • No networkability

  • Memory size limitations


Based on the original systems limitations we set out to provide the customer with a solution that would address the short comings of the original CNC System. Additionally, the customer had specific control requirements that needed to be met for the application. Our solution consisted of a turnkey CNC retrofit using a NUM CNC System.


The NUM CNC System allowed us to provide a high-end CNC Retrofit Solution that boasted the following machine enhancements to the floor type boring machine:

  • Low maintenance costs

  • Onboard user help files

  • Ease of system use

  • Short setup times

  • Variable spindle speed control

  • Selectable CNC or manual machine functionality

  • The addition of a portable handpulse generator pendant for manual positioning and machining

  • RS274 programming standard (G-Code) allowing increased programming flexibility

  • Unlimited program storage and drip feed capabilities

  • Anti-backlash system on main axis (X – tandem function)

  • Smooth operation of main axis bearing total machine weight (over 100,000 lbs)

  • High resolution digital servo system with absolute feedback

  • Axis pitch error compensation for axis accuracy

  • Axis backlash compensation

  • Probing Functionality


All of the control engineering and panel build was done off site. When the retrofit package was complete, a time convenient for the installation was set.The retrofit package was delivered to the customer’s rebuild site and the installation started. Installation of the new control system took about three days. When this work was completed we began powering up the machine and checked it for functionality. We worked with customer’s personnel during this phase of the project so they would become familiar with the new control. This portion of the project was just the first phase as the whole machine had to be disassembled and shipped to the end user.Gray Floor Type Boring Machine CNC Retrofit

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