Welcome to the SeeMeCNC Community

Hi,
I completed my Rostock Max a couple of days ago and was able to print several little objects. The engineering on this kit is absolutely awesome and I have no complains... Apart from the Extruder setup. What a piece of $@#$@#. When I installed the resistors and the thermistor I was surprised to see that silicone was used as a structural attachment. What about duct tape or chicken wire? Not mentioning that it is impossible to find this Kapton tape. It looks that two distinct engineering teams worked on this project; The guy who came out with the idea of using silicone and tape on one side and the marvellous team that designed all the rest. Dont tell me it is the same guy.

Anyway. I struggled to weld the thermistor, struggled to install the assembly through the mounting plate without twisting the wiring and started the test. During the autotune process on calibrating the PID loop I noticed that it gave me some results even if the temp was around 150C. I played a bit with the wiring and restarted the process and it gave me different result around 200C. I kept these results, calibrated the end switches, and was able to print several objects. Until now. The temperature went crazy. I dismantled the thermistor, scratched out the silicone, re-installed in its cavity it and re-siliconed it. I waited for it to dry, restarted the autotune process, and found out that Abs is dripping from the hot end like crazy while the temperature havent reached 130C. I am not fooling with this thing anymore.

Any suggestions? I see that some people are using the E3D V6. Any good results? Any drawback? Any spare parts that I should get when I order?
Any other devices?

many thanks for your help.

Regards,

Serge

ps: Otherwise I am very very pleased with this machine, with the instruction manual, and with this forum.

You can also change the Thermistor to an M3 Screw-in unit sourced from eBay and do away with the RTV sillyness. A wrap with silicone tape can also work wonders.


While you at it, you can also change the resistors to a 6X20mm 40W cartridge heater. Heats faster, lasts longer, cures measles, etc. Again eBay is your friend.

Gene has a very good video showing how this is done.

Well, im not the biggest fan of the hot end either, but i printed with it for quite some time before upgrading. I am very happy with the e3dv6 and i use threaded thermistors they are a blessing. So i would suggest the e3dv6, threaded thermistor (a spare or two wouldnt hurt) and spare nozzles, bowden tube and fittings, and a spare heater cartridge.
Make sure you print the mount before tossing the stock hot end into "The Box".

If you haven't got the patience to work through your wobbly thermistor issues then my suggestion is to pick up the printer, take it out the front of the house, open the wheelie bin and drop the printer in it.

Because this isn't the last time you will need perseverance, a logical approach to problem solving and a little lateral thinking to get your printer to do what you want it to do. Not by a long shot.

If your thermistor is consistently at the wrong spot, it's firmware calibration adjustment time using a thermocouple on an appropriate multimeter. But sounds like that's not your grief, sounds like your temps are just all over the place.

1. Get some spare 100K thermistors of the appropriate type (perhaps best just buy them from SeeMe).
2. Get a thermocouple on a multimeter - only twenty bucks and you'll use it again.
3. Start at one end of the thermistor signal path and work to the other. Something is shonky. Either the thermistor is stuffed (easy to crack), it's wiggling in the bog and making/breaking mechanical contact with the hot end, one or more connections are intermittent or high impedance, or you've got too much noise being picked up on the thermistor signal lines back to the controller.

I wouldn't upgrade to an E3D head until you get this sorted out and have a bit of time on the standard head. But maybe that's just me.

Just in case it wasn't mentioned above, you'll need a working hotend to print a new mount platform to hold the E3Dv6 hotend.

edit: it was, unless you can buy those somewhere?

Captain Starfish: I have been doing electronic projects for many decades and I know about perseverance and testing methods. But today, in 2015, It is not conceivable to assemble parts using silicone and to install this thermistor that seems to be designed for a circuit board application. Especially when you are paying over $ 1,250.00 for a kit including freight and duty. I believe I have the right to be a little bit annoyed. As I said, as a whole this kit was perfect apart from the extruder setup. Take it as a constructive criticism if you wish. This printer is beautiful and when I have the right part installed I will be more than happy.

Kas and DavidF: Thanks for the input on the new mount platform. I didn't realize and after reading you I found a dealer in the states who can provide the E3D and the mount platform.

Nitewatchman: Thanks for the tip

I'm just gonna leave this here:

That concept of bogging in the thermistor is one of a whole bunch of cost optimisations made to get a large capacity 3D printer of reasonable quality output built down to a price bracket.

Many, many other people have looked at it, thought "ooh, a bit rough", but have gotten over themselves and realised you get what you pay for and gone on to do some spectacular printing with a perfectly functional hot end.

Whilst you may have an aesthetic issue with the design, the design is not causing your wandering temperatures. Call it a constructive criticism if you like, but if you have that much experience with debugging your builds then you might want to try dissociating your dislike for the design from the issue in your own mind because it looks like that's blocking you from solving your wandering temperature problem.

I have an E3D head, purchased not to fix temperature stability issues but to print higher temperature filament. I have had far more issues with the "better" design of the E3D thermistor mount than I ever did with the bog-in-hole standard SeeMe one.

If you cannot see the distinction between your dislike of the design and the problem you're having, then go buy an E3D head by all means. Hopefully it's not an issue caused by running thermistor wires to close to the stepper drive cables or something like that, though, because the E3D head will then suffer from exactly the same problem.

Good luck!

That cross talk and radio interference is why all my wires are twisted pairs. For the steppers I twisted each coil as a pair. All my control, power, and thermistor lines are CAT-5 wire which even has a different twist ratio for each pair. The designers of CAT-5 did that to reduce crosstalk even more.

Well Captain Starfish, you made me realize that I might have been a bit harsh in my original comment and I am sorry about it.
However, i see your point, i don't disagree, but it my case I prefer a sturdier assembly. No steppers motors were working during my last attempt, It was just at the preheating mode when I noticed the difference in temperature. Also, when I took out the thermistor, the insulation was completely carbonized, which is logical due to its location, and which is another potential source of problems. I know that after fooling around a bit more I could get it to a satisfactory level, for a while. But what's the point? Why not getting the sturdier part right away? i might be wrong but the E3D V6 seems sturdier. With regards to the interference, that is why twisted pair shielded Belden cables are often specified in industrial or commercial application for thermistor wiring. But are you sure that at a such low voltage and frequency interference is such an issue? if its the case shielded Belden cable might help. By the way, which issues did you have with the E3D? if I may ask?