外国公司做的焊接培训.ppt

Weld Quality Awareness Induction Training,Mike Bell,Aims of the session,To understand the importance of weld quality,Learn to recognize basic weld defects,Understand how the most common defects are caused,Appreciate the contribution operators can make to preventing defects getting into cars.,Introduction,Together with press-forming, welding is our main business.,Almost all welding is done by robots,Robots are consistent and tireless, but,At the moment robots do not have eyes and ears That is why we depend on YOU,Why defects are important,Bad welds = poor durability,Durability is how long the parts are expected to last before failure,Target durability is 150,000 miles or 10 years,Chassis part failure can lead to :-,Serious injury or death,Warranty costs / recall,Loss of contracts and jobs,Fatigue failure,Fatigue occurs when loads are applied backwards and forwards many times,Eventually a crack will appear and grow. Usually the crack will start at a weld toe,The higher the stress, the faster the growth. Defects increase the stress and make parts fail sooner,MIG / MAG Process,Parent material,Fillet weld terms,To obtain a good weld the parts must be in the right place,The main cause of defects is poorly placed parts or weld,Part position incorrect gives a poor weld,Here the weld is biased giving a small leg length and poor penetration,Effect of poor position,OK weld,Biased weld not OK,This time the part is incorrectly located the other way giving either,Poor fusion and small leg to lower, or,Burnthrough,Effect of poor position,WHAT IS WRONG WITH THIS?,Reasons for position fault may be:,or,Part not placed against fixture,Loose fixture,Reasons for position fault may be:,Spatter on fixture,Lap welds,Good weld,Top sheet mispositioned,Results in weld being too small,Edge of sheet visible,Fit up gap gives same effect,Small weld,Top sheet mispositioned towards weld,Small weld this side,Weld is high,Undercut reduces the thickness of the material and concentrates stress,The worst defects of all,Omitted,Complete misweld,Mispositioned weld causes:-,Weak, undersize welds,Poor fusion,Early failure,Burnthrough,High scrap and rework costs,Gas shroud,Porosity,Porosity,Makes welds weak,Might be worse than you think,Can only be repaired by grinding out,Leads to expensive rework and scrap,How can you help,Remember why defects are important,Report defects and equipment faults,Always work to your standard operation instruction,Do all clean and check activities thoroughly,Learn to recognize defects,