Extruder flaw and solution

Hello all, below is an email I have sent out to our customers regarding the extruders in current form. I am not sure if anyone else has had this issue but as we managed to replicate it twice (not deliberately) I figure it is an actual flaw not just a weird, one-off issue. I hope this info is useful to someone else and might save you the work we have had to do to come up with a solution.


I still LOVE PP machines!


Good afternoon,


After testing at Darwin Plastic Makers Space we have discovered a pretty major flaw in the extruder design and have decide that it is not ethical for us to send them out knowing they have an issue.


Below are pictures of a bent cradle and a snapped auger (the second one!) from DPMS. We believe this is due to the extra torque from the slightly larger motor and tortion between the cradle and gearbox. (shown is the basic cradle before we dissassembled to repair) The auger shown is a quality Promac auger bit, snapped completley at the shank – this was turned on after cooling completely with a tube full of solidified plastic. (human error but easy to do) This is fixable and we have come up with a solution that will work around human error.


Rather than install a safety cutout stopping the auger turning if it is not heated first, we have decided to remodel the shredder to eliminate the problem all together and we are remaking all of the frames and rebuilding new cradles to reduce tortion and we are also introducing a chuck style fitting to the bearing so this creates a weak point that will give before snapping an auger.


The chuck fittings have been ordered but are on back order for 2 weeks. Our welder is also taking a well deserved break and wont be back until midweek, next week so this slows production for 2-3 weeks on current orders (we need to be sure the chuck fittings fit within the cradle or design a new cradle as well)

If you are waiting on a multiple order that includes the extruder, please expect a delay.

The new frames are modelled on our redesigned shredder frames which reduce loss of torque between the gearbox by using heavier steel and fitting the gearbox above the motor and the same will apply to the extruders once complete. ( pictured is our shredder frame to illustrate)

I am incredibly proud of how strong our machines are and in spite of this set back to the extruder production, I am really pleased with the new design and believe this will ensure a more robust machine and the failsafe (chuck) will protect your auger. (particularly in the case of upgrade screws costing so much more)


If you would like more information or to ask any questions, feel free to call or email.


Kind Regards

Melodie M





Hello  @morethantencents

I know this problem has been a while ago, but I faced the same exact problem with the bent bearing support (Craddle) after a few runs of my machine

Appreciate if you can share how your improvements fared, specially that I already did some modifications to the auger / coupling and afraid to start it again
The torsion forces and rotational pressure from the screw seem to be causing the problem so your help will be greatly appreciated