Posted to News on 10th Apr 2024, 15:45
Apex Designs Hydraulic Power Unit for Giant Steel Plate Cutting Machine
Apex Hydraulics was approached by a client that had been partnering for many years with a local steel rolling mill. As machine designers, they had been commissioned to redesign, manufacture and install a new steel plate shear press with cutting plate.
They contracted Apex Hydraulics for the supply of all the hydraulic cylinders along with the Hydraulic Power Unit and full electrical control system.
As part of the initial planning process, Apex agreed to a site visit to see the old shear press working in action and take some initial site parameters. Apex engineers went through the requirements of the cylinders with the machine builder and designed the hydraulic power unit along with a Siemens PLC electrical control system, which would integrate with the rolling mills electrical control systems.
There were five different cylinder designs; shears, clamps, table drop, scrap arm and scrap eject, with multiples of each cylinder required.
An automated system
This project was particularly involved, as Apex was commissioned to provide every part of the hydraulic system including the cylinders, the hydraulic power unit, all of the electrical cabinets, control system, and the programming.
The Hydraulic Power Unit (HPU) is large, with a 1500 litre tank capacity, and measuring 4m long x 2m wide x 2.6m high. It weighs in at around 4 tonne dry weight and has a large heat exchanger due to the extreme working environment. The HPU in general had a total of 150kW, providing a 173 litre / min flowrate at 210 bar working pressure.
The HPU was built with a complete electrical cabinet and enclosure including onsite wiring and integration to existing production systems. Full electrical, hydraulic and HPU user manuals, part lists and calculation sheets were all provided.
Apex also manufactured the main shear cylinders, which have a 360mm bore x 180mm rod x 600mm stroke, and an internal linear transducer for PLC and proportional control.
The cylinders have proportional valves that are controlled by the PLC. The entire system links into the customers existing production line systems, so they can be controlled from either the local HMI screen or via JEB Rxi profibus communications and can be used in either manual control or automated sequences. The HMI screen can be used for fault finding and adjusting the setpoints.
It shows a 3D model of the HPU system and highlights areas with errors for easy fault finding and servicing. Easy-to-use navigation screens and prompts ensure that operation and servicing is easy to follow. Live particle count for oil cleanliness can also be monitored along with pressure, oil levels, temperatures, flows and electrical consumption. The HMI can also show the live position and pressure information for the main shear cylinders and the maintained cutting angle during use, as well as being capable of controlling the operating speed to increase and slow down the production rate.
A number of safety features have been incorporated, including Pilz safety relays, E-Stops, guard safety and power contractor monitors.
The signal from the plate rollers is designed to indicate the thickness of the plate coming though, to allow the system to adjust the angle of the cut accordingly, as the wrong angle could warp the plate.
A laser monitor measuring system cross checks plate thickness with input and then a different cutting angle can be set for each 5mm thickness of plate. The system is entirely automated to do the preliminary check, establish the thickness of steel, set up for the correct cutting angle, clamp and then cut.
An ancillary pump and motor set system works six smaller cylinders on the system, such as table positioning, material clamping, material ejecting and table clearing.
A new foundation for a giant machine
The new machine is 70 tonnes in weight and capable of cutting 400 tonnes; much more powerful than the old machine which could cut 80 tonnes. The new machine also cuts far more quickly.
While Apex were manufacturing the system, the machine designer and end user had to prepare foundations for the new machine, whilst carrying on with full production. Although the new machine is now working, the old machine remains in situ, due to its size and the complexity of removing it.
Pressure and sequence testing was carried out, with the client present, before it left the Apex factory. Due to the 190kW power of the equipment, a diesel power generator had to be set up to do the testing. Apex provided onsite commissioning and integration to replace the old system with the new.
