FPES (Excel Hydraulics) was contracted by Sydney company Carlton Sheet Metal to improve the reliability on their pivotal Roll Forming machine.
The Roll Former machine prepares the base building block materials for their air conditioning ducting manufacturing business. Without the continual production of these base sheet blanks, Carlton’s ability to keep operating would be severely jeopardised. The machine is operated by a hydraulic system that controls the feeding of sheet steel, punching and guillotining operations.
The heavy two ton rolls of galvanized steel sheeting are loaded into the Roll Former with a forklift. The steel is manually feed into the machine ready for operation. With the hydraulics and electrical control system turned on, and, using the pendant control in manual mode, the operator feeds the sheeting in. A program is inputted into the control system with variables such as the desired length of the finished sheet, the type of holes and notches to be punched in the sheet and the position of these holes in relation to the sheet’s length. Once all the data is in, the automatic cycle is activated and away the machine “chunders” producing the base sheet blanks.
Up until recently the previous hydraulic system was so unreliable Carlton could only use the machine until 10:00AM after which time the machine become inoperable. The hydraulics would overheat making the oil so thin which, in turn, caused a loss of pressure. Once the pressure was lost, there was not enough force for the punching and guillotining operations to function. A complete hydraulic system redesign was required.
The original system was complex and cumbersome utilising two variable displacement pumps and an array of leaky valves. Looking at the desired final machine specifications and Carlton’s requirements of a more reliable and, therefore, increased productivity outcome, we came up with a better solution.
Using new technology, one single pump and some good ingenuity the new design was completed. A single Parker Hannifin variable load sense pump delivered oil to an open loop proportional valve and a two position unloading valve. Load sense back-to-back checks sandwiched under these valves sensed any movement of the two valves to bring the pump on stroke. The proportional valve metered flow to the main sheet feed drive motor. This was controlled by Parker’s latest PWD electronic control module easily programmed from a notebook computer. The unloading valve supplied flow to a remote manifold, accumulator and pressure switch. Located on the remote manifold were the three directional control valves that operated the two punching and guillotining operations. The pressure switch energised the unloading valve once any pressure drop was sensed.
The whole new hydraulic assembly was mounted on a steel frame and attached to the floor adjacent to the Roll Former. The previous hydraulics were mounted overhead which, not only made servicing difficult, but probably added to the overheating problems.
The new hydraulics have been in operation for three weeks and, apart from some small commissioning adjustments to the electronic control module, the machine has not missed a beat. Carlton can run the Roll Former all day and into their afternoon shift if they so desire without any loss of productivity.
With the use of better design techniques and new products from Parker Hannifin, an old machine can be brought back to life with an increase in productivity.