Hotend broke need replacement ideas

[deadpool66]

While replacing the arms on my rostock the thermistor wire popped off.

I would prefer not use a hot end that is glued together.

What would you guys reccommend?

[Xenocrates]

What do you print most often? ABS? PLA? are you working on functional, structural parts, or good looking ones? It makes rather a lot of difference.

If you work mostly in PLA, I suggest getting a screw in thermistor and heater cartridge for the stock hotend (Eliminating the RTV entirely), and modifying it to take that. It's also good for ABS, although Nylons and polycarbonate won't work well if at all with it.

If you're a functional parts person, I'm partial to the E3D. No fiddly thermistor bulb, nice solid set screws, high temperature, a variety of nozzle sizes, and other nice features.

There are lots of guides for selecting hotends, and also for upgrading the stock one.


Stock upgrade video
Hotend choice guide

There are more if you go looking. I'm just not going to write another full guide from scratch, or search them out. But there's been an update to the E3D, which allows all of them to use a cartridge thermistor stock, or add a PT100 on easily, which makes it even more resilient, easy to assemble, and convenient.

[deadpool66]

Im printng mostly fantasy models for painting swords and helmets and things. I prefer pla but want to try wood fill and the like.

I didnt realize I could use a cartridge on the stock end.

[Xenocrates]

Wow you are fast on the response. Which model scale/line are you doing? That use case is both detailed enough, and close enough to mine that I have a lot more to say on that subject.

[deadpool66]

Ive been doing full size replicas latley working on the antman helmet but I also like to smaller character models.

Detail is important the stock head does a good job. If it hadn't been cemented together I could have fixed it right away now I have to wait.

[Tincho85]

This one is also a very good tutorial.

[youtube]http://www.youtube.com/watch?v=Fdb3nyu29ko[/youtube]
https://www.youtube.com/watch?v=Fdb3nyu29ko


Stay with the stock hotend, for PLA and ABS is great. But if one day you decide to buy another one, the threaded thermistor and the heater cartridge could still be used.

[deadpool66]

Stock it is I thought about stealing the e3d off my prusa but figured that would be more irritating in the end. Already wired a screw in thermistor now I have to wait for the hot end to come.

Thanks for the advice.

[deadpool66]

Installed the new arms upgraded firmware bought the parts to modify hotend... and the wait is killing me.

[deadpool66]

Hotend modified [img]http://i11.photobucket.com/albums/a182/deadpool2099/rostock/20160811_104925_zpsjzwdohlk.jpg[/img]

[deadpool66]

Just cant catch a break installed new hotend and now having multiple issues. Cant break 200c and if the fan kicks in lose temp dramatically.

Extrusion is poor as well not enough filament coming out and the nozzle clogged I think.

I'm going to break it down again tomorrow what a pain.

I idea why I cant hit 200? I did do the pid tuning

[Xenocrates]

A few things to check:

Thermistor profile. Have you updated it to the correct one for the screw in thermistor?

Heater element resistance. It's been known to happen that even E3D has managed to accidentally ship a 24V cartridge instead of a 12V one. If your heater block is supposed to be 40W (a usual standard), the resistance should be ~4 ohms. If it's around 14, then it's a 24V cartridge that was accidentally shipped, and you'll need to contact the seller. If it's somewhere in the middle, it may be a dud, or some other wattage.

Power supply voltage at the hotend. Sometimes, especially with the original Viotek power supply of earlier V2s and V1s, the power supply can supply too little voltage (Especially if the bed is also running)

PID tuning. If you did it before you changed the heater cartridge/thermistor, then the tuning is off. The power available is rather different.

Airflow direction. If the fans can somehow hit the heater block, be they layer or PEEK fans, that can cool the heater block off, especially if it's not insulated.

I suspect that the PTFE liner is damaged, and that the low temperatures are contributing to the issues that would cause. I personally find that most filaments won't even start to flow well until 205~210, including PLA (My measurements likely don't reflect yours, and are not representative of a large variety of filaments, hotends, or sensors, so add salt to taste)

[deadpool66]

I did not update thermistor profile. How would I go about doing this?

Power supply is the old atx style.

And it was working great b4 ugghhhh.

[deadpool66]

Im using this thermistor same as on my rep rap.

https://www.amazon.com/gp/aw/d/B00THZJI ... UTF8&psc=1

I did pid tuning after I installed hotend.

I was printing pla at 190 perfectly b4 same on my rep rap.

[deadpool66]

Would I adjust the firmware for the thermistor using the e3d settings as its the same kind?

[Mac The Knife]

The thermistor you posted a link to has the same resistance as the one that SeeMeCNC sells, so you shouldn't have to change anything in the firmware. Do you have a link for the cartridge you bought? Even with that old powersupply, it should heat up over 200C easily. Either you have a bad connection at the cartridge, or at the RamBo, (check the connections at the RamBo,,, the screws can come loose from heat cycles,,) or they shipped you the wrong cartridge,,,, assuming you ordered a 12 volt, 40 watt.

[deadpool66]

https://www.amazon.com/gp/aw/d/B014YB9M ... UTF8&psc=1

Ill check the commections when I get home.

[deadpool66]

I took the hot end apart replaced the liner reassambled wrapped it in kapton and.... I got it going.

Still working on the pid tuning I get it to hold temp during test with fan on but am still getting fluctuations during print.

I ran through the autotune and got the averages but still not perfect.

Thanks to everyone for their advice.

[deadpool66]

Hey guys Im so close but still have issue. My hotend will not retain temp with fan on unless its at like 5 percent during print which is not helpful. I have ran pid auto tune 3 times with fan at 100% and it holds temp fine during the tuning.

I wrapped the block in kapton and thermal tape and this helped a little but its still dropping about 10 degrees with the fan on 30%.

Should I manually adjust the pid settings?

[Tincho85]

Is it because of the fan cooling the heater block or because of your PSU not being able to keep up with the load?
Remove the fan so it blows to another direction and check.

Also, check if your cartridge/resistor is not chewed or has a bad connection. The wiring Is it thick enough?

[deadpool66]

Its only when the fan is blowing on the heater block.

[TwoTone]

I'm a little late to this, but what I think I see in the picture is you didn't wrap the element in foil to get a snug fit.
Not sure if that's the heat problem, but I made the same mod following a different guide and wrapped ours in foil and haven't had an issue.

[deadpool66]

Suppose I could try tinfoil but the grub screw holds it snug. I double wrapped the hotend with kapton and thermal tape and it holds temp much better however I'm still get fluctuations but I can stay within 5 degrees now and 75% fan. If I don't have the fan cranked up the supports are welded to the part.


Which pid value could I tweak a bit? Its was holding temping perfectly prior to updating firmware.