Please Help

[Lazerjock]

Hello,
I bought the Rostock Max last month and really enjoyed putting it together. I followed the manual and calibrated it using the recommended settings except for the nozzle size. Where I work we have calibrated gage pins and I was able to measure to opening very accurately. As it turns out the .5 mm nozzle is really .457 mm. So I adjusted the settings in the software accordingly.

I am printing using White ABS with a PEEK cooling fan and the recommended printable shroud. (After 4 attempts I got one that would work.)

I experimented with several different hot end temperatures ranging from 225C to 235C and a bed temperature ranging from 98C to 105C.

I've searched the forum looking for a similar problem with no luck, but I'm not sure exactly what this would be called. Sorry if it has already been answered.

I've attached 2 pics. The test cube and an EZ struder indicator. The EZ struder indicator attaches to the motor shaft allowing me to see when to motor is turning.
The indicator printed perfect in my opinion, but the test cube only printed the first third before having problems. You might be inclined to say it has something to do with the square hole going through the center of the cube since that is where it seems to start having problems, but I have tried other prints without hollow areas and it did the same thing.

My printer also makes a "thunking" noise after 5 - 10 minutes of printing. I'm not sure if this is related or not to the other problem. I did find some answers in the forum for this, like verifying the nozzle size, and increasing the hot end temperature, but I'm nervous to go much higher than 235C. Neither have made any difference.

Thank you in advance for your help.

Chris

[Eaglezsoar]

The thunking you are hearing could be caused by an out of tolerance spool of filament, it could be too wide in places causing it to get "stuck" and the thunk is the Ezstruder pushing the
wide part then releasing thus making the noise. You do not indicate which slicer you are using but I would try a different slicer just too see if it makes a difference.
I would measure that filament you are using a several different areas and see what the tolerances are. It is not unknown to get a bad spool even from the expensive name brands
of filament.

[Batteau62]

Did you verify your hot end temp with a thermocouple meter? This will tell you if that 235C is accurate, or it's lower, causing your extruder stepper to miss steps(thunking noise)because the filament is not reaching temp.
http://www.amazon.com/BestDealUSA-Chann ... uple+meter

[Lazerjock]

The thunking you are hearing could be caused by an out of tolerance spool of filament, it could be too wide in places causing it to get "stuck" and the thunk is the Ezstruder pushing the
wide part then releasing thus making the noise. You do not indicate which slicer you are using but I would try a different slicer just too see if it makes a difference.
I would measure that filament you are using a several different areas and see what the tolerances are. It is not unknown to get a bad spool even from the expensive name brands
of filament.

I measured the filament during the initial setup and got an average of 1.75mm. I just re-measured taking a much large sample. I measured 16 times over a 2 foot span and got an average of 1.74mm. The widest measurement was 1.82mm and the narrowest 1.66mm. I'm guessing the 1.82mm width could cause problems. So there is nothing that can really be done about this other than replace the spool?

The slicer I'm using is the one recommended in the manual called Slic3r. I stuck to the manual as close as possible. I will try another slicer though.

Thank you for the quick response.

[Lazerjock]

Did you verify your hot end temp with a thermocouple meter? This will tell you if that 235C is accurate, or it's lower, causing your extruder stepper to miss steps(thunking noise)because the filament is not reaching temp.
http://www.amazon.com/BestDealUSA-Chann ... uple+meter

I have a thermocouple for my Fluke 87 and measured the hot end at 176C on the brass nozzle. The set point was 230C. I would think there would be a slight deviation from the displayed temperature but not that much. How do I adjust for this deviation so the temperature is displayed correctly?

Thank you too for the quick response.

[Batteau62]

The most popular way is to shove it as far into the filament hole as possible. Wires allowing, and don't get it stuck:) I've also read that people back the nozzle out just enough to sneak it in the gap. Then wrap some kapton tape over it to lessen the error. It's an important number to know.

[Captain Starfish]

Looks exactly like the symptoms mine had.

First, I had way too cold thermistor readings. If you unwind the brass nozzle a little and sneak the thermocouple in there before gently tightening up you get a pretty solid read.

Next, do a bit of a search on creating your own parameters for the thermistor - you'll need to get a temperature and resistance into the thermistor both at room temperature and at operating temperature, feed 'em into a formulae and then grab the numbers and update your firmware accordingly. It's a pain but makes a huge difference.

I still had the thunking issue after that (although everything got a lot better). It turned out to be the controller board overheating and the thermal cutout on the extruder driver cutting power to it. The filament would spring back, nozzle would lose pressure and the extrusion would lose material. Fixed by a fan pointed at the controller board.

[Lazerjock]

Thanks for the ideas. I will re-measure the temp by unscrewing the nozzle and research recalibrating the thermistor.
Hope that takes care of it.

[Lazerjock]

Eaglezsoar,
I see that you are in NE Ohio. I grew up in a little (really little) town on the Ohio/PA line called Hubbard. Ever heard of it?

[dpmacri]

Eaglezsoar,
I see that you are in NE Ohio. I grew up in a little (really little) town on the Ohio/PA line called Hubbard. Ever heard of it?

I know of Hubbard. I grew up across the state line (PA side) in an even smaller place called Frizzleburg. Pulaski is where the post office is there

[Lazerjock]

Small world isn't it? My grandparents took me to the flea market in Pulaski when I will little. All of my family is still in Ohio. My wife is from Iowa and all of her family is there. We live in Orlando Fl. Never have to worry about the fam popping in unexpectedly.

[Eaglezsoar]

Eaglezsoar,
I see that you are in NE Ohio. I grew up in a little (really little) town on the Ohio/PA line called Hubbard. Ever heard of it?

I live about 30 miles south of Hubbard in a small city called Columbiana. Great area actually except the winters really suck.

[Eaglezsoar]

Chris, try opening the door on the printer and putting a small fan blowing on the Rambo board. The stepper drivers getting too hot and cutting out will also produce those thunking noises.

[Lazerjock]

Chris, try opening the door on the printer and putting a small fan blowing on the Rambo board. The stepper drivers getting too hot and cutting out will also produce those thunking noises.

I measured the hot end temp by pinching the thermocouple for my meter between the brass nozzle and aluminum that houses the resistors. It measured 4 degrees lower than displayed when set at 230C. I'm doing another print now. I increased the hot end temp to 240C which should be 236C in reality. So far the print looks good and no thunking, but I just started it.

Thank you for the feed back.


I really need to get back to Ohio to visit, but I think I'll wait till it warms up a little. LoL
you guys are getting pummeled.

[Lazerjock]

The print finished and looks great. There are no globs all the layers look smooth and even and there was no thunking. The edges of the cube where it touches the glass warped a little, but that is a different issue. I will research it on the forum. I have stumbled across a couple threads before so I should be able to resolve this easily.

I consider this SOLVED....

Thank you everyone.
I will be posting more as I get more experience and try to help others as you helped me.