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I'm still fighting this bump noise coming from the EZextruder stepper motor slipping. I thought my hot end temp was too low not allowing the ABS to melt and squeeze through the hot end fast enough thus cause a pressure buildup on the EZextruder stepper, but I've since set my hotend at 241 Celcius constant and the bump noise hasn't stopped.

I find that if I slide my Feedrate slider in Repetier Host down to 65 or 70 it seems to do it less, but prints take much longer. And any time the printer needs to lay down more plastic it begins to slip again almost every 7 seconds. What could this be? Can I achieve higher speeds and not "bump"?

http://www.youtube.com/watch?v=N2Zi7toq ... e=youtu.be

note: another symptom I have is that my outer perimeters don't seem to meet unless the speed(Feedrate slider) is down around 70 or 80.

can you get it to reproduce without feeding plastic?

Oh good call. Ill try that tomorrow.

I had a slipping issues that turned out to be bad filament. It would slip on retracts and end up shaving little bits of the plastic off causing it to leave gaps in the prints.

MDMD can you give me a link to the filament you bought that solved the issue? Thanks!

Jay, if I remember correctly the issue you're having is that the stepper is actually skipping, right? I'm referring to the "thunk" sound coming from the EZStruder. If that's still the case, it's really not related to how well the EZStruder grips the filament. What's happening is the stepper is trying to feed filament and what's happening is the back-pressure in the hot end builds to the point where the stepper can't move any more and it "hops back" when the compression is released by the skipped step. You might even notice that the bowden tube will jerk a little bit as the compression is released.

Have you had a chance to verify your thermistor reading against a thermocouple yet?

Another possibility is you've got a partial jam in the nozzle caused by burnt filament or debris. Since you're running ABS, you might want to give the nozzle a soak in Acetone overnight and get it all cleaned out.

g.

When I had a problem like this ... I had to put a fan on the Rambo to keep the driver cool.
I tried every speed and setting , the faster I ask it to go the more clunking noise it made.
The fan made it work like it should.
YMMV

geneb wrote:Jay, if I remember correctly the issue you're having is that the stepper is actually skipping, right? I'm referring to the "thunk" sound coming from the EZStruder. If that's still the case, it's really not related to how well the EZStruder grips the filament. What's happening is the stepper is trying to feed filament and what's happening is the back-pressure in the hot end builds to the point where the stepper can't move any more and it "hops back" when the compression is released by the skipped step. You might even notice that the bowden tube will jerk a little bit as the compression is released.

Have you had a chance to verify your thermistor reading against a thermocouple yet?

Another possibility is you've got a partial jam in the nozzle caused by burnt filament or debris. Since you're running ABS, you might want to give the nozzle a soak in Acetone overnight and get it all cleaned out.

g.

Interesting -- my extruder makes that same noise. I didn't realize it was a problem I thought it happened specifically on retractions (i'm thinking that it usually occurs on a layer change) and was just the speed at which the retraction happened. But if that's not the case, then I'm having a problem too My prints have been coming out fairly good, so I'll have to do some more testing to see if I can determine specifically when it happens.

Edit: Oh, and I'm using PLA with the hot-end at 185C (thermocouple inside says it's actually about 182C). I have tried some prints at 190C but don't recall if the sound was there or not.

Geneb thanks, I've connected a thermistor and let everything get hot and saturated and it reads 5 degrees C higher than what repeteir host is showing so I have increased my temp set at 241C, it doesn't seem to make a difference.

I currently have two .50 brass tips and a .35 brass tip and it bumps on all. I will soak them though.

I've tried an origianl Xbox dual fan blowing right on the Rambo. It was loud and overkill and didn't make a difference.

Geneb yes the pressure building through the filament and inhibiting the stepper to push anymore and then the thonk/slip is what makes sense to me as well. I'm not sure what else to try other than keeping the federate slider almost all the way to the left. Is anyone else experiencing this? I'm getting proper heat for abs at 236 Celsius (remember my repetier host shows 5C lower than what it really is). I could increase hot end temp to 245C in repetier but don't want to melt the PEEK.

Does the skip happen only on the first layer or two, or does it happen throughout the print? How fast are you printing?

g.

geneb wrote:Does the skip happen only on the first layer or two, or does it happen throughout the print? How fast are you printing?

g.

For me, the skip happens throughout the print. I'm printing with PLA and have been bumping up the temperature to see if it's changes anything (I'm now at 195C -- probably actually around 192 based on prior thermocouple testing). Still getting the skips. I had my speed set at 30 mm/s. Just dialed it down to 18.6 mm/s (62% in RH) and I haven't heard a thump since I did that.

dpmacri wrote:

geneb wrote:Does the skip happen only on the first layer or two, or does it happen throughout the print? How fast are you printing?

g.

For me, the skip happens throughout the print. I'm printing with PLA and have been bumping up the temperature to see if it's changes anything (I'm now at 195C -- probably actually around 192 based on prior thermocouple testing). Still getting the skips. I had my speed set at 30 mm/s. Just dialed it down to 18.6 mm/s (62% in RH) and I haven't heard a thump since I did that.

I spoke too soon Just started getting more thumping

The skip happens throughout the whole print. It occured so often in my latest print that it cut the ABS plastic where the teeth of the stepper motor comes in contact with the filament. I took my hot end apart and pulled out the transparent tubing inside. It looks like this:
Is that buldge normal?

Well I couldn't wait, I went ahead and replaced the smaller transparent high heat resistant tube with some other of the exact same type I had and it looks to have solved the problem.
1. Feedrate slider is at 140
2. Flowrate is at 89, which I've had to keep at 115 or higher

No bumping and the plastic is flowing fat! I'll have to recalibrate my flow. Finally.

That's VERY un-normal.

When the PTFE gets over heated, it shrinks - I didn't think you'd over heated your hot end so I didn't suggest checking that. I'm amazed that you didn't burn the PEEK in half.

g.

Geneb, another good call on your part!

The story goes: during my prelimenary x, y, and z calibrations for each tower, as I sent the script "G0 Z0 X-77.94 Y-45 F3500" to my rostock max. The wiring I had for my hot end thermistor had stretched and pulled the thermistor out of the hot end, still wrapped in the hightemp RTV, just enough to NOT to make contact with the hot end but not enough for the naked eye to see.

I did melt the PEEK and Steve mailed me a new one. This was before our Google hangout. So me never seeing the high temp tubing before the melt down, I didn't know what it was supposed to look like. I never knew it was consticting the filament flow.

Thanks again for your time! Everything is good now, I think.

Ok. I'd totally forgotten that you'd cooked the PEEK section. I didn't even think to ask if you'd replaced the liner. It should be noted somewhere that if you over temp the hot end to the point that the PEEK section fails, the liner should be replaced at the same time.

Do you have a photo of your cooked PEEK section? If so, can I have unresized copies of it and the one of the liner photo above so I can put it in the manual?
tnx.

g.

Well I have both pictures but I'm not sure how big they are. Ill check tomorrow.

I never had any tu humping with either PLA or ABS until I got T-Glase from SeeMeCnc now it sounds like a machine gun. Threading the T-Glase the extruder was also more difficult than usual and was very tight and the filament is not consistently round.

Jmick