显赫的人
发表于 2025-3-28 14:58:58
http://reply.papertrans.cn/39/3834/383325/383325_41.png
高脚酒杯
发表于 2025-3-28 19:52:28
Rotary Percussion and Auger Drilling,percussion or hammer action in conjunction with a chisel bit can be used to penetrate hard material. High-pressure air pumped to the face of the bit down the centre of the rods serves to lubricate the cutting surfaces and to remove the broken rock (cuttings) by blowing it to the surface. The cutting
GENRE
发表于 2025-3-29 00:08:01
http://reply.papertrans.cn/39/3834/383325/383325_43.png