I recently had to replace our dishwasher. So of course I had to take the old one apart. It contained many goodies, including a blower fan that will be perfect for my fume extraction system. The dishwasher (Maytag) parts are actually well labeled for plastic type. The large tub and door liner are Polypropylene at about 2.5 mm thick, this is over 7 kg of good material.
I tried an angle grinder and an abrasive wheel to cut it into sections. The abrasive wheel melts the plastic instead of generating a lot of chips like a saw blade. It worked reasonably well so some optimization will be worthwhile. For the flatter pieces I also used my manual metal shear since it does not generate any micro-plastic.
I had wanted to try one of the geared, low speed garden chippers so this was a good excuse to get one. There are a number of brands but in the US, this one was the easiest to get. It is rated 15A at 115V and is geared down to about 60 RPM. The picture below also shows the blade configuration.
The results came out pretty well. The chipper easily chewed up the long strips in the picture and generated medium sized chips. These will fit into my injection machine. I did run the chips through a second time but it mostly just reduced some of the odd shaped ones from the first pass.
I am encouraged with the results. I originally thought I would use the geared motor for something but the chipper is useful as is. I’m not sure how else I would have dealt with the 2.5 mm PP without using a saw and generating a lot of micro-plastic.