LAPPING some general info(螺纹折叠形成原理)

LAPPING 折叠See following pictures as examples for lapping看下述折叠图片.Not OKNot OKLapping in threadLapping螺纹折叠 折叠Not OKNot OKLapping in threadMaterialfolds or cracks in the thread profileLapping under microsocope after grinding在螺纹轮廓上有材料折叠及裂纹 金相显微镜下剖开后的螺纹折叠Reasons for lapping:折叠原因1. Pitch is not adjusted correctly = matching between moving (long) and stationary (short) threading die (see picture 1)螺纹线未正确调整=动静搓丝板未匹配(见图片一)2. To much pressure on bolt when placed between the threading dies (at the beginning of the threading station). When the pressure on the bolt between the two threading dies is to HIGH, the bolt will start to slip instead of rotate. When the bolt begins to slip you will have lapping. (threading dies are positioned to close to each other)将工件置于两搓丝板间时压力过大(开始加工螺纹时).当压力过大时螺栓开始滑移而非旋转.当螺栓开始滑移时就产生了折叠.(两搓丝板间距离太近)3. 1and 2 can also be caused if there is variation in the shank diameter between different lots/containers with the same part = when the bolt is headed in one machine and rolled in a separated thread roller. It is better to roll thread in a boltmaker so you are certain that the blank diameter does not vary.如果不同批的零件同一部分螺纹坯径不均匀也会引起序号1及2描述中所产生的折叠=尽可能在同一台设备上镦制并且在一个单独的螺纹设备上加工.由一台设备加工成形(带螺纹)会更好些.这样会确保螺纹坯径不会有变差. 4. Not enough pressure on the bolt when placed between the threading dies, when the pressure on the bolt between the two threading dies is to LOW the bolt can be introduced to far between the threading dies (threading dies are positioned to far from each other)加工螺纹时压力不足.其产生原因是两搓丝板距离过远时.5. Incorrect introduction (to late or to early) because the introduction finger is not correct (to long or to short, wrong profile). 不正确的引入(过迟或过早)是因为送料板过长,过短,错误的形状.6. Timing of the introduction finger in relation to the movement of the threading dies is not correct (to late or to early)送料时间与搓丝板的运动时间(过早过晚)不匹配.7. The blank is conical and therefore not introduced straight between the threading dies螺纹坯径是锥形时引起工件不能直接引入到搓丝板间.8. The blank is not straight and therefore not introduced straight between the threading dies毛坯杆弯会引起工件不能直接引入到搓丝板间.Inspection for lapping折叠检测For inspection for lapping we take 3 bolts, degrease them and place them for 1 minute in HCL (acid) with 16 % concentration and temp of 80 C. Then rinse with water and dry with compressed air. Check the thread on each bolt under a microscope for lapping and cracks.检测螺纹时,我们拿3个螺栓,脱脂除油后将它们在浓度为16%,温