Coil Handling System

Coil Handling & Compacting Machine Required Redesign & Reconfiguration

The Hope Group engineers assessed and addressed issues at a Chinese wire drawing mill for a US machine manufacturer experiencing difficulties with their coil compacting system. They successfully redesigned and reconfigured the equipment to meet its original specifications.

The machine that handles and compresses wire coils, securing them with wire or steel strapping, had problems. The force it used to compact and the positioning of the coils were not consistent. The chief engineer at The Hope Group compared it to hands squeezing the coil, but one hand pushing the other out of place.

Working together with client engineers, The Hope Group’s engineering team revamped the hydraulic control system. The old system intermittently shifted one side of the compactor, causing inconsistent force control and affecting coil compression, which could damage the coils.

Inconsistent Positioning

After looking at the circuit and power unit, we found that the problem of inconsistent positioning was because of using big DIN cartridge valves. They often have issues with dirt and debris in the system. To match the hydraulic power unit’s filtration level, we decided to use low-leakage poppet-style pilot-operated check valves instead. We installed two of these valves for each DIN valve to make sure we met the needed flow rate.

Inconsistent Pressure Control

The problem with pressure control came from the system being over-pressurized when the cylinders first moved. At the beginning, the cylinders worked in regeneration mode and then switched to final compaction. But the system had resistance, so the pressure needed for regeneration became higher than for final compaction. Using a proportional pressure relief valve to control pressure made things worse when lowering the pressure for compaction, which messed up the compaction force.

Solution Achieved

The solution was to swap out the old valves with faster, larger Parker valves that control direction and relief. We also redesigned the manifold and simplified the hydraulic system, making the pipes and hoses bigger. This dropped the pressure in the regeneration system way below the compaction pressure, making compacting much more reliable. Once we finished the redesign, we put together, tested, and packed up the hydraulic control system for shipping to Shanghai, China.