OES designed a 4 axis stepper driver and controller for a customer that manufactures metal cutting machines. The objective was to reduce the over all cost of the machine control, improve the reliability and serviceability of the control, use parallel or USB communications, and improve the operating speed and performance of the machine.

The situation:

One of OES’s customers manufactures and sells small metal cutting machines to metal fabrication shops. Theirs is a very unique product that enables even small shops to have a fully automated computer controlled cutting device capable of cutting complex parts and shapes. The control unit consists of a standard PC and a custom built stepper motor control and machine interface.

The problem:

The original control device consisted of a combination of off-the-shelf and custom built components,  including 4 individual stepper motor drives, a custom made interface board, various switches, relays and indicators, connected together with a complex wiring harness that has to be manually assembled and terminated as each machine was built. Since the units are intended for use in harsh industrial environments, problems occasionally arise due to the presence of metal chips or dust, fluids, and vibration. When a problem does occur, the customer has to troubleshoot to identify the specific component failure (stepper drive or control board), then disconnect and remove the failed device and install the appropriate replacement. The following is a summary of the initial control unit characteristics that OES’s customer sought to improve on:

• High cost of individual components and parts.
• Complex and time consuming (costly) wiring harness.
• Required multiple voltage DC power supply
• Required the HMI to be equipped with a parallel port
• Reliability problems.
• Difficult to service.

The solution:

OES designed and developed a 4 axis stepper motor driver and controller for this specific application. All of the individual components (such as switches, LEDs, relays etc) were included in the single board design, completely eliminating the interconnection wiring harness. The design eliminated the need for multiple DC voltages, and increased the working voltage to the stepper motors. Quick-disconnect terminal blocks were used for all connections, simplifying installation and removal (if necessary). OES also chose to use .093” circuit board material (instead of the standard .060” material), and conformal coated the final assembly. Because the power supply could now be optimized for the stepper motor control, the torque and speed of the motors was also improved.The result:

• Reduced component cost.
• Eliminated interconnection wiring harness (saving cost and assembly time).
• Improved power supply (and reduced the cost of the power supply)
• Improved communications and connectability through USB 
• Significantly improved reliability.
• Significantly improved serviceability.
• And, improved the machine’s performance!

Summary:

The OES 4 axis stepper driver and controller significantly reduces the over all cost of the machine control, greatly improves the reliability and serviceability, and improves the operating speed and performance of the machine.