Why do we use graphite manufacturing bearing?
1).Considering from the perspective of the friction loss, the graphite has excellent friction coefficient because the friction coefficient of bearing material is as small as possible.
2).For the structure, graphite is a solid material, it is oil-free lubrication , it reduce the oil lubrication system so as to reduce the failure rate;
3).The graphite has high chemical stability;
4).The cheap price and strong versatility,the ordinary metal material for bearing is undesirable apparently if it is operated at high temperatures, the graphite material which has the high temperature resistance and more cheap price than the custom-made high temperature strength materials is available.
The manufacturing method of general graphite bearing can be achieved by the following technical scheme:
1).Model making: the mold material select polystyrene foam plastic slab or expandable polystyrene resin beads which density in 10-22g/dm3; drilling a hole which the diameter less 0.2mm than the graphite rod on the disappear die shape and then put the graphite rod which is long 1-2mm than the wall thickness of pattern into it .
2).Brushing the expendable pattern casting coating which special uesd in copper alloy on patterns for mold which has installed the graphite rod on it .the coating thickness should in 0.5-1.0mm , and then put it into the drying room and drying at below 50 degrees.
3).Connect the drying model with EPS foam plastics runner;;
4). Put the assembly model into the lost foam sand box and then add dry sand equably and shock it slightly to make it compaction; during this process , the amplitude is less than 2.0mm, the vibration frequency is 50Hz and covering the upper part of sand box with plastic cloth to seal it , vacuum negative pressure, high temperature alloy liquid is poured; negative pressure control in the 0.02-0.05MPa;
5). Discharging the negative pressure after pressure maintenance for 10 minutes ;
6). We can obtain the required graphite bearing after excising the sprue and machining.
