The methods to solve casting parts sticking molds trouble--(2)
1.2 Draft Angle
Too small draft angle(or no draft angle, or have opposite draft angle)、the mold side is uneven (erosion, crush, defects, etc.), rough surface etc., casting parts will get blocked in the direction of mold releasing. When the casting part is releasing, the part surface is hurt by the mold, If the condition is bad, the whole surface will be hurt.
(1) mold design and manufacturing is not correct, The draft angle is too small on the forming surface of mold cavity or core , will cause releasing resistance very large. For the casting part which is not allowed to have draft angle, it is best to leave the processing allowance to the casting part. So the area without draft angle can shaped by secondary machining.
(2) The crush deformation on mold core or core wall, protrude in the cavity side will affect releasing casting part. If the bumps or mold cracks on forming surface, will also affect the casting mold release.
The cavity surface is too rough, or has process mark, or process, polish texture is not the same direction as releasing direction, or bad flatness in releasing direction, those will increase releasing resistance and hinder the casting mold release, resulting in casting surface scratches. This scratches in the direction of releasing shows like straight line groove, the shallow ones less than 0.1 mm, the deeper ones about 0.3 mm.