Hydraulic power units show their environmental side


green hydraulic power unitMJC Engineering is a custom machine tool builder in Huntington Beach, Calif. that specializes in metal-spinning machines for applications such as sheet spinning, flow forming, wheel spinning and rotary forging. The company’s machines produce end products such as car wheels, aircraft engine housings, spacecraft fuel tanks, and welding gas cylinders. They typically use very large volumes of hydraulic power in operation.

About three years ago, the company’s president, Carl Lorentzen, began investigating the configuration of the hydraulic units used on his company’s machinery. He had a great interest in servo-pump technology, having read about its application in other industrial uses such as injection molding machines, extruders, stamping presses, offshore oil rig assemblies, cranes, and lifts.

“We had looked at a variety of ways to improve the energy efficiency of our machines. Being a California company, there are substantial incentives offered here for documented energy savings in machine building and operations. Plus, I felt it was simply the right course of action to do our part in protecting natural resources,” Lorentzen said.

Another thing that motivated Lorentzen was a recent company safety audit conducted by its insurance company. Sound levels were tested, and the hydraulic power units were a concern.

MJC began serious investigation into the application of servo-pump technology to replace the constant motor operation on the main hydraulic unit of the machines, in a concerted effort to reduce energy consumption, noise and, owing to the smaller hydraulic reservoirs needed, the machine footprint.

“We are fortunate to have on our staff an amazing group of electrical, hydraulic, controls and mechanical engineering talents,” Lorentzen said. “All these engineers had the same reaction I did, and we began to rethink our hydraulic power units from the ground up.”

The company turned to his longtime supplier of CNC, PLC and drives technology, Siemens, for further assistance. A team led by Chris Britton, the sales manager for the region, assisted with various application engineering studies, energy and controls testing to affect the optimum design, all while working in concert with the MJC team.

“They use a wide variety of our motion controls and components on their machine builds, including CNC, PLC, motors, spindles, power modules and our drive control chart (DCC) technology that allows configuring of all the control loop structures,” said Britton. “As it happens, [we] have been frequent project partners for some time, so this marriage of technologies was even easier to accomplish. We offer our Sinamics servo-pump technology to customers, utilizing various pumps with our motors and drives.”

A further advantage quickly emerged, as the Green Hydraulic Power unit (GHP) began to take shape. Little or no external cooling was required to dissipate the ambient heat of the unit.

GKN Aerospace in Orangeburg, South Carolina was the first customer for whom an entirely new spinforming machine was built, using a complete Green Hydraulic Power unit. MJC’s VP Per Carlson and his hydraulic engineer Jerry Wang designed the unit. An already documented result of the GHP unit onboard its machine, GKN has experienced nearly a 70% energy consumption savings, plus the quieter operation and smaller footprint.

Following this development, Lorentzen had another, more profound revelatory moment. He realized the unit could easily be adapted onto any type of heavy hydraulic piece of equipment. Subsequently, he established Green Hydraulic Power Inc., which today functions as a free-standing enterprise.

green hydraulic power unit controls“The GHP is a complete turnkey system with I/O options to run with any PLC, to control the power utilization on virtually any type of hydraulically-powered machine. We researched the variable speed drive hydraulics for over two years to devise the optimum solution on our current standard models, which comprise 15, 30, 55 and 80 kW units,” said MJC electrical engineer and robotics manager Jose Machuca.

More than a dozen MJC machines with GHP units have been built and installed as of late 2017, with no issues reported. Lorentzen cites the extended warranty on the Siemens components, which constitute the majority of those used on the GHP, as a further upside.

“We had a very dynamic interaction with the Siemens engineering team to make this unit come alive. We frankly didn’t know what to expect at the outset, but the results have been very pleasing, so far. And we’ve only just begun,” said Machuca.

Further options under development for GHP include Siemens Scalance wireless control, kW torque setpoint on pressure, fail-safe compatibility, custom touchscreen and other monitoring and maintenance tools for operation and unit data transmission in an Industry 4.0 environment, over a Profinet industrial Ethernet protocol.

When equipped with the high-level Safety Integrated PLC and other required components, the GHP is suitable for severe environments such as oil rigs, chemical processing equipment and other challenging work environment applications.

Currently, machines with this green hydraulic unit are in operation at such industry giants as Meritor, SpaceX, Worthington and multiple plants of GKN Aerospace. Most have been in use for six months to a year without performance issues. Owing to the widely varying duty cycles involved, Lorentzen explained, “We can say with high certainty our customers are experiencing up to 90% energy savings, plus the quieter operation and reduced carbon footprint as additional positives. I’m certainly glad I read what others were doing with servo-pump technology, as it’s made a big and very positive impact on our company.”

MJC Engineering & Technology Inc.

Green Hydraulic Power Inc.

Siemens Industry Inc.



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