Barrel jackets

[Safehands34]

Can anyone give me any info on fitting barrel jackets to the barrel?

Is it worth it long term? will sheer heat become a problem? Running mainly pp and abs with some nylon.

I know it will help with initial start ups but was wondering if having them on all the time will just create problems.

[joeprocess]

I think barrel insulators are a good investment. With PP, ABS, and Nylon I would not think shear heat would be an issue unless you are over processing the material anyway with high screw speeds. My experience has been that the best approach to this is to blanket the back half to 2/3rds of the barrel. The feed zone heaters work the hardest and you can get much better life out of them by insulating. Keeping the front of the barrel un-insulated prevents issues with plastic sticking to the blanket during purging. A downfall of insulator blankets are that the barrel takes a LOT longer to cool off between changeovers. Going from a Nylon to PP temp. could take a lot longer then you like. This is another reason though to leave the front zone un-insulated. In this way you can apply a box fan to the front of the barrel and wick heat from the whole barrel during a changeover.

[rickbatey]

The tough but true answer: it depends! If you run resin(s) in the same temperature range then you'll love them. They will save you power and cool the plant. But if you must drop temperature to run POM after PA, then you have to purchase version with removable top part or use a fan and wait for temps to drop. Better scheduling or again running in the same temp range cancels that point. While I ran natural abc/pc and never changed resins, we had no issues with over heating and didn't even change any settings. Also if you're prone to nozzle leaks, you may miss the leak until it's huge!!
Rick.

[Safehands34]

Thanks guys, it's not often we go from nylon to pp so think it will be an option to take up. My main concern was the sheer heat issue, but that's been put to bed.
I was only thinking about the feed zone too, we have a few issues with build ups from time to time

Thanks again

[Squirter]

One thing to consider, if there is a possibility of running heat sensitive materials in the future e.g.POM, I would recommend having a removeable jacket section at the front of the barrel over the metering zone. When lowering or switching off heaters at the end of a run, the temperature lowers very slowly when the barrel has a jacket on. When running POM for example, I have found it better to run without the jacket over the metering zone as it gives a less troublesome start up. With the jacket left on, the slow cool down time can create a longer start up due to discoloration in the resin which needs to be cleared.