Question: Issues with polypropylene extrusion granulation equipment
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Our workshop just replaced the pelletizing knives, but within two days, a large amount of powder was generated, along with material with tails. As a result, the S80320 machine had to be cleaned every 20 minutes; otherwise, the qualified material would flow down from the larger pieces, making it quite troublesome to collect it. The workshop decided to replace the template, but things remained the same after that. Today, the pelletizing knife was replaced as well, along with the cutter disc; yet even after starting up the machine again, material with tails could still be seen, although in much smaller quantities. May I ask what methods we can use to identify the real cause? (Pelletizing water temperature: 63°C, cutter wear: 7.46) I would appreciate it if someone who knows this well could provide a detailed answer. Thank you in advance :L
Is the resin high MI? If so, the water temperature for granulation can be reduced. Adjust the cylinder temperature to reduce the mixing effect
It is recommended that you check whether there is any sinking in the tracks of the pelletizer
Several aspects are mainly checked: 1. The levelness of the cutting blade; the smaller the horizontal error of the cutting blade, the better； 2. The gap between the cutting tool and the template should not be too large or too small ； 3. The horizontal alignment of the pelletizer must be accurate ； 4. The opening ratio of the template must be maintained during operation ；
I don’t know what happened, but yesterday the cutting tool in the workshop was changed again. I was the one who sharpened it, and the result didn’t seem very good – there were many scratches on it; the area around the mold holes could be sharpened, but the sides couldn’t. The technician said it needed to be sharpened again, but the manager insisted that work should go on. So I started using it, and the granulation quality improved. Ugh, why is it so difficult to get things done? :L Could that senior recommend any materials for me on extrusion granulation? The key issue is that the operating procedures in our workshop were formulated based on those from other factories; they’re not useful at all. We have to rely on experience when operating. Thank you for your understanding
Pelletizing and drawing, knife pressure, the smoothness of the die template, as well as the die holes, all play a role.
Could LZ tell us about the types of granulators you use? It seems similar to the underwater granulation system I used before; we used JSW’s machines
If there are no issues with the process, it might be related to the alignment and balancing of the trolley. Check the balance of the trolley, as well as the alignment of the cutter head, and also the operating condition of the sliding bearings when the trolley moves.