The operation factors lead to the blockage of the die, and how to reduce or avoid the blockage of the die in the operation to obtain the correct specific die profile information and material head (tail) and samples as soon as possible, for the correction of qualified samples timely delivery is very important.
A. Blocked die caused by excessive pressure
When the profile is extruded, there is no radial traction force, and the wall thickness on the section (flow rate reasons) is not consistent with the time of the extrusion working belt. When part of the wall thickness of the extrusion working belt disappears due to resistance and the flow capacity is accelerated, so that the wall thickness of the extrusion working belt is not completely siphoned away.
The wall thickness is accelerated when the bearing already in flow phrase , and did not work out with slows down, the cantilever length, irregular shape, wall thickness difference, flat chamber and the coexistence of the more common in the mould, once all such mould wall thickness are out of work, with the things will get better, not easy also die blocked, but there are bent or wave, A twist is possible.
If the extrusion speed is accelerated, according to the principle of liquid pressure flow, the liquid naturally flows to the place where the resistance is small! Make fast faster, slow fast not much, increase the flow rate difference, resulting in a greater flow difference! Forming drag force. The wall thickness at the junction of different working belts is folded and compressed, and the blank cutter wall is rubbed, and finally the blank cutter space is blocked and the die is blocked.
Therefore, especially the hollow die first pressure must be slow, and pay attention to the export situation, available iron (aluminum) bar (lever principle) spade has been out of the fast side, do not let it to the slow place of oppression. Can also grasp the unloading die, the surface of all the fast side of the shovel, and on the slow side from the outside to the inside of the lubricating oil, and then on the machine extrusion will be significantly improved.
If the extrusion ratio is small, the temperature allows as much repetition as possible. This method can effectively reduce the blocking die, get the sample, but the head is not complete, it is best to have a die repair worker in the field!
Similarly: too much pressure change or frequent change will also cause blocking die.
B. Blocking mould caused by improper oil coating or oil pollution pressing
Oil pollution pressing is absolutely taboo in hot extrusion of aluminum profiles, must be avoided. Its direct consequence is to affect the surface quality and easily cause the extrusion continuity of the profile foot and side, and then break the blocked die, but also affect the quality of the profile structure, performance.
Oil pressure into the plane die can be said to be fierce to go fast, and once pressed into the cylinder or shunt die chamber, less than a rod, more than ten root eight can not be eliminated.
Sometimes, large oil is pressed into the flow of the dead corner, will be small feet, thin edge from head to tail hair cracking phenomenon.
Sometimes large oil is pressed out of an instant, will cause teeth, feet, male head members around the filling of aluminum imbalance, there is part of the point or surface of the hollowing, flow rate change so that the male head four weeks static pressure balance is broken. Under the extrusion force, the teeth, feet, male head deviate, twist, crack, break, break and even collapse!
Therefore, the shape of the complex small feet small teeth of the thin wall profile should pay special attention to oil pressure, prevent blocking die.