Damage extruder

Hi @davehakkens
I have an issue with my extruder, which bend the bearing support in the first run.
I start the heaters as 230° for 3 heaters and 250°  for the last one and wait for 15 min after it reach the temp, but the machine jamed and after adding a small quantity from PET.
After I opened the nozzle I found non melted plastic which create a jam and push the extruder to back which bend the bearing support.
So what is your analysis of the situation and how can we fix this problem?

I suppose you did not wait enough time to heat the barrel. Or maybe your motor turns too fast. Difficult to say without more information.
Btw, did you verify your temperatures with an external thermometre? People in the french community had some bad experience with PID’s.

I only use 300w band heaters, anything less than that won’t produce enough heat or will take forever to reach the desired heat

If I had a motor as strong as yours, I would just install an arduino with a relay and a thermocouple. Arduino would switch on or off the relay to connect or disconnect power to the motor only if the thermocouple detects a temperature of at least 120 celsius. That would ensure you would never power on the motor while the extruder is cold.

I’m not a electronic professional but to secure the motor just a bit I think you can add a transistor, if the band heater aren’t switched on, the motor can’t be switched on. I don’t know if you know what is it but you’ll find a lot things about it on the internet.
Otherwise, if you know use a bit an arduino, I think, you can do a PID controller with it an do some thing like this: until the bands aren’t at X °C the motor can’t be switched on. I don’t know if this is possible with your (or an other) PID controller.

Sure just after 4 days I will upload the full design. @anne-barbier

I just checked your video again: it’s actually a cool coupling, it easily breaks, before it creates bigger damage, lol. Do you have more pictures or details about this ?

you have such a nice extrusion screw but your barrel seems too thin, and quite crap; not sure but I would replace it too.

1. i had once 3x 200W & 1x 250W heaters and i noticed it’s not enough to run 250 deg-c stable; so i think 3x 300W & 1x 350W is the safe config.
2. not me, but sounds interesting despite it’s a little overkill but cool when being drunk with precious plastic 🙂

Dear All,

When I run today I found strange issues as below:

1- I notice that the heat was going down from 300 to 250 and it continue to go down when I add the plastic and I was afraid from having a new breakdown, so I shut down the machine down to secure the parts, and I think that means that the heaters power is not enough ( I have one 180W in the front and 3 pieces 110W). Am I right or there is another element which I didn’t figure out? And how can we improve that? Also, in the BOM sheet that point is not covered well so how can we improve it to secure extruder V4.0?
2- I made a stupid mistake I switch on the motor without switching on the heaters and the coupling has been broken, which mean that I must add an interlock between the motor and the heaters to protect the motor from running before it reaches a set point, did any one did something like that?






one thing i noticed during the tests was that the v3 extrusion needs different filter hole diameters and a better arrangement of the holes (star), hdpe was working best with 5mm, others with 4, 3mm was creating just way much too pressure 🙂 but of course, all the other factors have to play nice as well, force, speed, temp. there is a nice %$^$%^#% article about this, i will post the link if i find it back. one thing is for sure, each tiny part plays an important role: surface finish of the filter, thickness of the filter, you could write an entire book about 🙂

same here, my client managed to rip the whole extrusion section apart. i knew my welding was bad – like always – but it survived all my tests against different plastics…
my research however in regard of filament extrusion told me that there a quite a number of sensors along the extrusion; ie: if there is no sufficient output  it triggers the emergency stop… not sure how to tackle the problem in it self for newbies but i’d be delighted to have more guidance/faq in our upcoming manuals…again, v3 is lacking way too much details/warnings, kudoz on v4 though

Just try adding more plastic on the hopper. If you dont add enough then the barrel will get full of plastic but there won’t be enough to generate pressure and push the plastic through the nozzle

Hi All,
I run the machine today with HDPE and it melted well but there is no filement has came from the nozzle ( 4mm ) but I think the quantity which I add it in the hopper was small. So what do you think about that?

72rpm is pretty fast, just make sure the output of the nozzle is not too narrow to allow the extruder to release pressure quickly

Nice  ! So I don’t think that the motor is too fast but I’m not an expert.
Yes, send us pictures of your realisations ! And try to use the PET again to tell us the result 😉

Hi everybody,
I fix the machine adding a new strong support and flexible link between the motor and the bearing.
The motor is 1.5 HP with output 72 rpm
And I changed thermocable sensor location.
After 1 hour I will try to use the machine with new setting
HDPE plastic
Front heater is 300°
Back heater 280°
And I will inform you about the result

Hello !
PLease send pictures, it very help to find problems ! I don’t really know extuders but you could check the temperature, else I think you should increase the temperautre, I saw that PET melt at ~260°C – 270°C