US recycler shares his experience using Polystar
Managing director of the Tennessee-based recycler, Mr. Irvin Payne, shares his own experience with Polystar recycling extruder :
Can you give me your opinion of your Polystar?
My experience includes installing and operating American extruders and German extruders for over 30 years. My opinion of Polystar is they do a very good job of designing and building extruders and for the price, cannot be matched. I looked at buying a German machine at three times the cost before I decided on the Polystar.
Which Model is it?
I have the two stage extrusion pelletizing system with a cutter compactor. I have added a separate shredder as the PP material we now process is much more difficult to shred and slowed the rate down. When we were processing LDPE, LLDPE, and HDPE film (post-industrial, post-commercial, and post-consumer) we did not have any problem with the compactor maintaining rate.
We have ran BOPP film with just the shred drum at over 1500 lbs/hr. We also have a melt filter on the line to remove labels, etc. and it works well with the Polystar. You will likely be processing your own film so you would not need the melt filter unless you were to use recycled content from post-consumer or post commercial film back into your film.
Output in reality compared to nameplate output kg/h?
We cannot operate the line at nameplate which is 1700 lbs/hr but can operate the line at over 1600 lbs/hr with some materials based upon bulk density. Bulk density often depends upon screen size with a regular shredder and with a shred drum the toughness of the material partly determines how finely it is shredded along with the condition of the blades and how tightly the shredded material is packed into the screw. You will likely find the LLDPE film runs at a slightly slower rate than the LDPE film for this reason. BOPP film will run at 1500 lbs/hr on my line with the shred drum with sharp blades.
Part of the rate determination is the learning curve with the cutter compactor. We have found with ours (I do not know if this will apply to yours) that we can run the shred drum at elevated temperatures to increase the rate and use the water injection system to keep the plastic in the shred drum from melting completely. After the operators have experience doing this they become very adept at maintaining rate. The double vacuum system removes the water from the melt very effectively and we ran wet material all the time when we were running post-consumer LDPE. In fact, we ran wet PP today and it runs fine with the double degassing system. I would definitely recommend the double degassing unit if you will run printed film.
With a compactor the rate at which you feed it is everything. If you overfeed the compactor you will have problems and if the feeding rate varies much you will have problems. The line operators first learn to feed the line at a steady rate and then they learn their other tasks. We currently run PP bags at 1400 lbs/hr and the extruder is rated at 1500 lbs/hr for PP. Again, this is a learning experience to achieve rate and the average rate is probably 20% lower than the instantaneous rate due to operational issues such as screen changes and other operational issues. Our average rate for PP bags is about 1200 lbs/hr.
As you probably know, an extrusion process is managed through First Pass Yield (Good product processed/Total product processed), Utilization (Uptime as a percent of scheduled hours), and Rate (% of achievable nameplate based upon material). The product of these three metrics is the Efficiency. We strive for 95% First Pass Yield, 95% Utilization and 95% rate. The product of the three metrics is 86% Efficiency. This is challenging but very profitable if you can achieve it.
Are you pleased with the performance?
Very pleased. I am quoting another line with Polystar with a few modifications so I can compound with recycled materials.
Quality of the produced pellets?
The pellets we produce are of the highest quality and our customers love them. The double de-gassing (vacuum) system really makes a difference in the quality of the pellet.
Quality of the machine?
I had concerns when I purchased the machine but I was told Taiwan quality is much higher than Chinese quality. I was really amazed at how well the line performed when we started the line and started producing pellets. Polystar has done a great job in designing and producing an extruder that performs consistently. I operate my extruder 24 hours per day for five days every week and we usually work 12 hours on Saturday and Sunday days to keep up with demand. This is pushing the extruder and equipment and we push to run at the top rate all of the time. We ship three to four trucks per week every week from this line.
You should install the best water cooling system you can (we use a cooling tower but you may need a chiller) and a very good filtration system for the water to remove pellets and fines. With the right design, the extruder will operate without problems but without proper cooling and filtration, the extrusion system will become contaminated and this will affect the operation of the extruder.
I do not think anyone will regret buying a Polystar line. I am available to talk to potential customers and welcome a visit from any potential customer that would like to see a line in operation or would like to perform a trial. We are happy to show it off.