What is the root cause of the warpage of foamed equipt concrete
? In the production of foamed concrete equipment, problems of warpage of the equipment sometimes occur. So, why should we start?
1. The warping deformation of equipt concrete
depends largely on the difference between the radial and tangential shrinkage of the equipment. This difference may be caused by a different degree of molecular orientation. Since the melt molecules generate molecular chain orientation under the action of external force during filling of the device, the molecular orientation along the flow direction of the melt is greater than the molecular orientation in the vertical flow direction. After the filling is completed, the oriented molecules always try to restore the original coiling state, resulting in a shortened length of the device in this direction. Therefore, the shrinkage in the two mutually perpendicular directions is unbalanced, and warping deformation is inevitably caused.
2. The equipt concrete
mold is not properly cooled. If the cooling system design of the mold is not reasonable or the mold temperature is improperly controlled, insufficient cooling will cause the equipment to warp and deform. Especially when the difference in wall thickness of the device is large, the device is particularly prone to warpage due to inconsistent cooling shrinkage of various parts of the device. Therefore, when designing the shape structure of the equipment, the section thickness of each part should be as uniform as possible. In addition, the equipment must maintain sufficient cooling set time within the mold. In addition, when designing the casting system of the mold, the flow characteristics of the melt should be kept as parallel as possible during the filling process. Thus, although the formed devices have different shrinkage in the mutually perpendicular directions, they do not cause a large warp deformation.
3. The mold release and exhaust system design of equipt concrete
is unreasonable. If it is subjected to a large unbalanced external force during the demolding process, it will cause a large warp deformation of its body structure. In this regard, in the mold design, the draft angle, the position and number of the ejector pins should be reasonably determined, and the mold strength and positioning accuracy should be improved. For small and medium-sized molds, the anti-warping mold can be designed and fabricated according to the warpage rule, and the cavity is made into a curved surface opposite to the warping direction in advance to offset the orientation deformation. However, this method is difficult to master and requires repeated trials and revisions.