Have following aspects cause main shaft shaky:

1. The end of main shaft is not tight or can't be tightened.                                  
2. 350 and above models main shaft spline and spline fitting has large matching gap,32 and below models key way in main shaft tail and drive shaft,drive shaft and key way of safety pin holder has a large matching clearance.                                   
3. Safety pin and safety pin cover, safety pin cover and safety pin holder hole has a large clearance.                                                                   
4. Main shaft bearing deformation or worn bearing.                              
5. The lose of ring die inner bore roundness is over large ≥0.30.                   
6. The clearance between two pressure rollers is adjusted unequally.

Solutions:

Firstly,check main shaft is tight or not,remove the back adding oil system in advance, remove gland from main shaft,check butterfly spring deformation or not. If the butterfly springs are flat, change new ones, keep the amount of butterfly spring and assembled position same as before disassembling.Then tighten the screw of main shaft gland,start pellet mill to check if main shaft is shaky.

If main shaft is still shaky, the gland should be taken down,use brass stick to chock up main shaft, use a sledgehammer to hit the main shaft out toward ring die direction,then take down sealing cover of main shaft to check if main shaft bearing is good.If the clearance is too large, take down the bearing to change a new bearing, then install the main shaft in order and tighten it up. During the process of main shaft installation, pay attention to put the inner ring of main shaft bearing straight, so the main shaft can be assembled in right position. In normal condition, afer assembly in place,the difference between the end face of both sides of main shaft and the end face of driving wheel is about 10mm. If check out the fit clearance of spline is large，the fit clearance of key groove is large,the fit clearance of safety pin is large and the inner wall of ring die is with the lose of roundness,etc, the above components must be replaced. After the main shaft installation, start the empty pellet mill to check the shaky situation.

After the main shaft is normal, adjust the clearance between pressure roller and pressure die correctly, the clearance of one side is large, the clearance of the other side is small, such may cause the main shaft shaking, unsmooth discharging and unstable current,etc.
 

If you use new ring die,check if the compression ratio of ring die matches processing material,the compression ratio is over large,the resistance of powder through the die hole is big,the pressed out pellets are too hard, the output is also low. The compression ratio of ring die is too small,the pressed out pellets are out of shape. Must select compression ratio again and check if the inner bore of ring die is smooth and ring die is with the lose of roundness, inferior ring die because of the inner bore is coarse, ring die is with the lose of roundness cause big resistance  of discharging, pellets are not smooth, hard discharging and output is lower, so you must use high-quality ring die.

If the ring die have been used for a period of time, must check if taper bore in inner wall of ring die is worn , if the pressure roller is worn, if they are badly worn, process and repair ring die, ream the taper bore again ,change pressure roller, the worn taper bore has a great influence on the output.                                          
 
The clearance between ring die and pressure roller should be adjusted properly, when the livestock and poultry feed is produced, the appropriate distance is about 0.5mm. If the distance is too small,the pressure roller would rub ring die and the useful life of ring die is shortened. If the distance is too large, pressure roller would skid and the output is reduced.                                                             

Note that the conditioning time and quality of raw materials, especially control the moisture of raw material before entering the pellet mill, the moisture of raw material is usually 13% before conditioning. If the moisture is higher, the moisture of raw materials is too high ≥１６％ after conditioning,causing skid in the die and hard discharging.                                                                    

Pay attention to the grinding fineness of raw materials should match the diameter of die bore,the grinding fineness of raw materials of small pellet feed should be more finer. Meanwhile,ensure the quality and temperature of steam, if the steam quality is poor and the conditioning temperature is low, both can affect the curing effect of powder materials and reduce the output.                                          

Check the distribution of raw materials in ring die,don't allow material to run one side, if similar situation happens, the position of the big and small feeding scraper must be adjusted, let raw materials distribute evenly in the ring die. Not only extend the useful life of ring die, but also the discharging is more smooth.