1.pipe type ejection mechanism characteristics. Pipe jacking, also called a hollow push rod or tube, especially suitable for circular, cylindrical center hole of the plastic parts ejection. It is pushing is stable and reliable, high coaxiality, it uses the entire surrounding push the plastic parts, plastic parts of uniform stress, deformation is small, no launch marks. But for the wall thickness is less than 1.5mm due to the processing of plastic parts, difficult and easy deformation, pipe jacking with unfavorable.
  2.pipe type ejection mechanism structure. Pipe jacking type ejector used form mechanism. Among them, the core so as to shoulder is fixed on a movable mould seat plate, core is longer, so that the thickness of mold closing increase, but the structure is reliable, used for ejecting distance is not the occasion; another, core fixed round pin or cotter, pipe jacking in the middle of a long slot, the long slot should be larger than the top the distance in the round pin length of the following, the core of this structure is relatively short, the mould is compact in structure, but the fastening force is small, high precision requirements with the pipe and the core and cavity of the mould core, suitable for larger diameter. There is a pipe in the cavity sliding, can shorten the length of pipe jacking and cores, but the cavity thickness will increase. The last one is the fan pipe, the pipe is difficult to manufacture, easy to damage.
  3.design considerations. Push tube to heat treatment, hardness is 50-55HRC, the minimum Cui hard length is greater than the matched with the cavity length and launch distance; for some soft plastic, such as PE, soft PVC, pipe jacking type ejector mechanism used to be, used in combination with other elements; the release speed, plastic parts easy to be pipe jacking thrust deformation, so the release speed should be selected carefully.