Hydraulic support is used in coal mines to uphold the roof. It will prevent the roof from falling and keep good space for operation, ensure the safety of miners, and ensure good working conditions. It's reliable and strong in protection, easy and fast to be mobilized. Its installation would increase coal production, lower costs, reduce labor intensity, and ensure safety.
Shandong Mining Machinery Group Co., Ltd. was established in 1955 and at present has 13 subsidiaries and 2000 employees. As a listed company since 2010, it's one of the most important machinery manufacturers in China, taking a leading position in the industry for both market share and technical capability. Their main products are fully-mechanic equipment for coal mining, coal washing, mine safety, brick-making, post-press packaging, and unmanned aviation.
The Technical Challenge
The hydraulic support is made of thick plates of Q235 with thicknesses from 6mm~30mm. GMAW process has been used but the welding spatter was too much and made the surface of workpieces covered with metal particulates. It has brought many difficulties to the painting process. Manual grinding was vastly demanded to reach the quality criteria. Time and manhours have been costly. The end-user has tried to use pulse GMAW. Although the spatter has been reduced, the following problems came up.
1）Arc length is too long for conventional pulse MIG/MAG. Welding speed has obviously decreased and therefore lowered production efficiency.
2）Welding arc energy was not centralized. Penetration depth was lowered. After trials with higher welding amperage, defectives like cracks have come up more frequently.
3）Arc ignition and crater arc were not good enough. Quality issues like incomplete fusion happened more often and affected quality negatively.
Hydraulic support welding workpiece
MEGMEET Equipment and Solutions
Artsen Plus500 PR with a short-arc pulse process was recommended as per the welding challenge on site. As a fully digital-control inverter MIG/MAG equipment, Artsen Plus500 PR is able to weld with a super-lower spatter for DC MAG/C02 and short-arc pulse for various welding positions.
1） The inverter frequency reaches as high as 100K HZ. A feedback mechanism with almost zero delays enables precise reaction and control of the transfer of every droplet.
2） Precise control at the milliseconds level for arc ignition and crater arc, which greatly improves the overall welding finishing.
3） The featured Thunder Fusion shortens arc length by about 1/3 that of a normal pulse and increases the stiffness and directivity. Penetration depth and welding speed are significantly increased while welding spatter is greatly lowered.
Normal Pulse MIG/MAG Welding
Comparison of Welding Result
By working with a robotic welding system, Artsen Plus500 PR increased the welding speed by 30% along with satisfactory results. The fusion result was as fine as 2mm and meets the QC criteria of the end user. Spatter was limited to an extremely low level with no particles on the surface of the workpiece. Polishing and grinding were therefore not requested. The overall production efficiency has increased by 27%. The reliability of Artsen Plus500 PR also has enabled long-time operation with multiple shifts but very stabilized performance.
Megmeet Artsen Plus Welding Machine Application