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我厂一九八二年以前使用进口板牙加工细牙铜螺丝,质量较好,板牙的使用寿命长。后改用国产板牙加工,螺纹外径负值超差,废品率高,板牙的使用寿命短(5～30分钟),造成板牙的消耗量大。为此,我厂对国产板牙进行调查分析,寻求对策。首先对不能使用和可短时间使用的板牙进行检验测量,其前角约20°,硬度约HRC60,没有什么明显的差别。但当测量切屑孔与外径处最小壁厚时,其值变化较大,且通过计算发现;当e=(0.118～0.121)D时,这种板牙
I plant before 1982 the use of imported dental processing fine teeth brass screws, better quality, long life of the teeth. After the switch to the use of domestic machining, thread diameter negative tolerance, rejection rate is high, the short life of the teeth (5 to 30 minutes), resulting in a large consumption of teeth. To this end, I plant on the domestic Dies for investigation and analysis, to seek solutions. First of all, can not be used and can be used for a short time to test and measure the teeth, the front angle of about 20 °, the hardness of about HRC60, there is no significant difference. However, when measuring the minimum wall thickness of the hole and the outer diameter of the chip, the value changes a lot, and is found by calculation. When e = (0.118-0.121) D,