Nanjing Cowin screw is designed according to the building block principle, and the combination can be changed according to the operation needs. When disassembling the screw, try to drain all the materials of the main machine before stopping the main machine and all auxiliary machines. Turn off the power switch of the head electric heating. The electric heating of each section of the fuselage can still work normally. Then disassemble the screw in the following steps. Remove the die cast aluminum heater of the head temperature and pressure measuring element, wear thickened asbestos gloves, remove the head assembly (pay attention to prevent scalding), and clean the materials in the head hole and the end of the head screw while it is hot.
Steps to disassemble the screw from an extruder：
1. loosen the fastening screws or nuts at both ends of the shaft ends of the two sleeve spline couplings, and mark the corresponding positions of the spline at the tail of the two screws and the sleeve coupling, facing the two output shafts of the transmission case, the left is shaft A, and the right is shaft B.
2. Pry the two screws from the coupling to pull out a section synchronously and slowly, then turn the two screws tightly with soft iron wire, pull them out one after another, and put them on the ground with two sleepers. Immediately, use steel wire brush, copper shovel and other tools to quickly clean the materials on the screw surface while it is hot. If it cannot be cleaned, it can be sent to the barrel for heating before cleaning. After cleaning, the screw head can be removed (note that the screw head is left-hand thread) and then the screw element can be removed. Wood hammer and copper rod can be used to gently tap along the axial direction around the screw element. If materials penetrate into the surface of the mandrel, which makes it difficult to disassemble, they can be put back into the cylinder for heating. After the materials in the gap are softened, they can be removed while hot.
3. The removed screw element section and inner hole keyway shall also be cleaned in time and placed on the spare parts rack orderly. It is strictly prohibited to collide with each other (the screw elements that are not used temporarily shall be coated with anti rust grease). The residual materials on the mandrel surface shall also be thoroughly cleaned. If it is not assembled temporarily, it shall be hung vertically to prevent deformation.
4. The holes in the barrel can be cleaned with a wooden stick wrapped with a cloth.
5. The assembly configuration of the two screws must be identical (except when the toothed disc is used). During assembly, the inner hole of each element and the sleeve on the mandrel shall be fully closed, and the joint shall be smooth without dislocation. Finally, tighten the rod head screw (the screw thread should be greased).
6. After the two screws are placed side by side according to the working position, check that the two screw shafts are uniform in radial direction, and then push the two screws into the cylinder at the same time according to the corresponding marked position of the spline at the screw tail and the sleeve coupling, so that the screw tail is closely close to the gear shaft surface of the transmission case, tighten the screws or screw caps at both ends of the spline, and re tighten the tail sealing gland. Apply a thin and uniform layer of lubricant on the tail spline before installing the screw.
7. After the screw is installed, manually turn the screw to rotate it for more than 2 weeks. After confirming that there are no abnormal phenomena such as interference, scraping and grinding, the machine head can be installed. During installation, molybdenum disulfide lubricant shall be evenly applied on the screw thread surface.
8. After the machine head is heated to the predetermined temperature, it can be started according to the normal procedure.