EHA Electro-Hydraulic Automation

EHA has the capability and the resources to refurbish valuable but outdated equipment with updated automation controls and safety devices.

Project: Refurbish customer’s numerous industrial press machines to achieve increased productivity, better mechanical performance and safety.


  1. To cost-effectively refurbish several pieces of similar equipmentHuman Interface technology on Industrial Press
  2. Keep components similar and interchangeable
  3. Decrease spare parts inventory
  4. Improve machine automation architecture
  5. Install equipment and verify with test pieces

Increased Productivity

A human-machine interface (HMI) is typically local to one machine or piece of equipment, and is the interface method between the human and the equipment/machine. An operator interface is the interface method by which multiple equipment that are linked by a host control system is accessed or controlled.

Each press was updated with a HMI (Human Machine Interface) which stores a recipe of data for each die change. Each die has a part number punched into the HMI and parameters are loaded specific to that die to control the position and tonnage for each part. Waste is virtually eliminated and setup time was greatly reduced to minimize change-over labor cost.

  • The press has the capability to pass on information for recording cycle times and number of cycles over Ethernet network.

Better Mechanical Performance

The existing hydraulic system was loud and inaccurate requiring the use of multiple directional control valves, flow controls, and manually adjusted limits for positioning. In addition:

  • The set-up procedure was labor intensive
  • Had lots of part variance
  • Created wasteful man-hour costs
  • Was full of system shock and leaked

The old system was eliminated and simplified with one proportional valve for motion control, a pressure transducer for tonnage control, and a linear transducer for position control. The new, simplified combination has increased speed, accuracy, force, position control, and is quieter.  Additional cooling and filtering were added for heat and contamination control for less down time.


The old system was associated with operational safety hazards. Improvements included:

  • Guarding & light curtains
  • Safety switches
  • Safety controllers
  • Hydraulic lock valves (to reduce the possibility of an unsafe condition during operation.

The guarding was installed to provide safety for operator and non-operators by incorporating physical barriers around the press using doors for accessibility with locking safety switches.  An area scanner was added to simplify accessibility during production for the operator eliminating opening and closing safety guarding creating operator fatigue.  The cycle start was done with a no-touch, two hand no tie down optical switches to help contribution to safety and help eliminate operator fatigue.