Abstract
This paper analyzes the long-term flatness deviation and local magnetic attenuation problems of ordinary rectangular electromagnetic chucks when clamping ultra-thin steel sheets under high-speed grinding. Taking the dense fine-pole Huaigong electromagnetic chuck as the research object, this paper optimizes the internal coil layout and magnetic pole spacing structure, and verifies the actual clamping stability through continuous bench grinding test. The test results prove that the optimized Huaigong dense pole chuck effectively solves thin workpiece warpage and processing vibration, and is widely used in surface grinder finishing scenes.

Research Background
In precision machinery processing, thin steel plates below 2mm are prone to bending deformation under uneven clamping force of traditional single-row pole electromagnetic chucks, and local magnetic field gaps will lead to obvious ripples on the workpiece surface after grinding. In the past two years, many mold processing factories have put forward higher requirements for chuck magnetic uniformity, and Huaigong magnetic industry has launched dense fine-pole customized electromagnetic chucks aiming at this pain point. Traditional chucks generally adopt 5mm pole spacing, while the standard dense pole product of Huaigong electromagnetic chuck narrows the pole distance to less than 4mm, and uses small independent copper coils for segmented winding instead of integral large coils.

Practical Test & Analysis
We selected the 300×600mm standard Huaigong dense fine-pole electromagnetic chuck for 20-hour continuous grinding test. The test workpiece is 1.2mm cold-rolled steel plate, grinding linear speed 32m/s. After continuous operation, the surface flatness error of the workpiece controlled by Huaigong chuck is stabilized within 0.006mm/m, while the flatness error of ordinary chucks of the same specification exceeds 0.022mm/m. The internal structure adopts laminated H35 silicon steel sheet magnetic core, which reduces eddy current heat generation; the average surface magnetic force reaches 145N/cm², and the magnetic difference between different areas of the panel is controlled below 3.2%. During the test, we also found that the closed epoxy insulation layer of Huaigong coil can resist coolant erosion, and the coil short-circuit failure probability is reduced by more than 60% compared with open coil structure.

Conclusion
The dense fine-pole Huaigong electromagnetic chuck realizes uniform magnetic force coverage through micro-pole layout and segmented copper coil design. It is especially suitable for thin parts, small precision parts grinding processing, stable continuous work for more than 20 hours, greatly reducing workpiece deformation and reject rate, which has high popularization value in precision machining industry.