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Tevo Little Monster Hotend replacement

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I recently bought an E3d Volcano from filastruder to replace the stock hotend on my LM. I do not know what all I need to change to make the hotend work or even if I bought the right one. I bought the standard E3D Volcano but I purchased 12V I don't know if this is right or not... It also came with a cartridge thermistor and I have no idea what to change to make this work with the stock firmware. Any help would be appreciated. I'm getting tired of having to rebuild this printer after every 2 or 3 successful prints. The bowden tube pulls loose and fouls the tube, then I have to take it apart and rebuild the hotend, but now the height has changed so I have to re-calibrate the whole printer.... just getting tired of it all.

Hey champ,

You need a 24V heater for the Tevo LM, just jump on to aliexpress and order a 40W one.
https://www.aliexpress.com/store/product/3PCS-Trianglelab-3D-Printer-12V-40W-6-20MM-Cartridge-Heater-Reprap-12V-40W-With-100CM-cable/1654223_32815934251.html

The thermistor will go into the new heatblock without issue, you will just have to change the coefficient in the config file to get it set right, if you are keen on a better thermistor that will work over 230*C then grab the one below when getting the heater.
https://www.aliexpress.com/item/1PCS-trianglelab-Thermistor-Cartridge-350-for-E3D-hotend-v6-heater-block-Maximum-support-to-350-degrees/32843785247.html

Seeing you have had some issues I would personally suggest you just buy the below part, it will give you the high temp thermistor, a heatblock, titanium heatbreak (super good to prevent sticking) and hardened nozzle. I know it hurts after spending a bunch on E3D genuine parts but you will have the E3D parts as a spare, the aliexpress ones from this company surprisingly work much better than genuine E3D ones.
https://www.aliexpress.com/store/product/High-temperature-3D-printing-Upgrade-Kit-Volcano-hotend-A2-Hardened-Steel-Volcano-Nozzles-for-peer-peek/1654223_32879568140.html

Also remember to use thermal paste on the heatbreak where it goes into the heatsink, do not add it to thermistor or heatblock.

I would also suggest printing my Mk2 fan duct and PTFE support to improve the heatsink cooling and take the force off the hotend PTFE connector preventing it wearing and slowly backing back out.

I figured something was wrong, when I plugged in the 12v heater it disabled the stepper motors and the hot end dropped... I’ll have to google the settings for the thermistor cartridge, and you’re totally correct about E3D being over-rated, I’ve seen better quality in some of the things I’ve ordered off amazon and AliExpress. I’ve already changed out the heartbreak to be all metal and I’m running a stainless .6 volcano nozzle. I’ve been contemplating the “pro-build” you suggest on the Tevo forum, with the duet and the whole kit and kaboodle, but so far I’m just trying to get the LM to be reliable.

My main issue seems to be getting the machine to actually use the bed leveling feature. It seems to only work half of the time and when it doesn’t the nozzle winds up too close to the bed causing the filament to jam the nozzle and push out the PTFE tube jamming the hotend. This usually happens if the BLtouch is flashing when the print starts, I have to remember to manually reset it. I’ve followed all the postings about using Pronterface to set the initial height, but as I stated earlier I keep having to rebuild the hotend so I usually wind up tweaking this value in gcode. I was hoping the “new” hotend would fix that, but as you can see I bought the wrong parts.

Well thanks for the links and the advice! I’ll keep banging away at it and it’ll work. After all the point of the hobby is tinkering and learning!

Thanks for the tip. Your comment made me think. I went to config file. I found "temperature_control.hotend.max_pwm 255 # Max pwm, 64 is a good value if driving a 12v resistor with 24v." Answer found. Printer uses pwm singular with max value of 255. I switched to value 64. Now the voltage is about 5.8v. Littlemonster is alive again

Edit:
I downloaded the latest Firmware "https://github.com/tevo3d/Tevo-Little-Monster". I changed the config file "temperature_control.hotend.max_pwm 255" to "temperature_control.hotend.max_pwm 64". Save files. I installed the Firmware and recalibrated the printer.

Hey mate,

Yeah, the BLTouch is a complete waste of time, the probe relies on some heatshrink to hold it together and provide the accuracy of measurement. With it positioned in the heat stream from the hotend it very quickly stops being anywhere near accurate.
What I suggest you do is go and grab some 60mm M5 bolts (suggest hex head to make it easier to turn when adjusting), large diameter washers (sometimes called exhaust washers) and locknuts from the hardware store and make your bed adjustable. You replace the 6 bolts and spacer holding the bed in place with the new bolts, a washer on either side and locknut under the bed to hold the bolt in place. Do the nut up tight enough to prevent the bolt moving/wiggling but still loose enough to allow you to turn it from above, some dry lube like Silicon spray is recommend between washers and bed. I also added some thread locker to the locknuts to ensure they don’t come loose over time. Now you can drop the bed back in, align the bolts with the holes and slowly work your way round the bolts, a turn or two at a time, screwing in the bolts until the nuts hit the base of the printer. Now just screw each bolt out about 4 full turns to give yourself some room to adjust them up or down.

Next step is to remove any config adjustments to endstops and tower corrections. Then take/make something (will refer to it as a chock) to fit snug between top of the arm carriages and the top of the printer on one of the arms (some timber block or 3d print something). Now go around and adjust the bolts, that goes up into the endstop, on the remaining 2 carriages until they fit perfect with the chock between them and top of printer. This will get everything mechanically near perfectly square with the top of the printer which will allow us to do the same to the bed. Also worth checking how square the towers are to each other while you are there, you can loosen the bolts on the towers and tweak them as needed (only way to do this is a LOT of manual measurements with an accurate ruler and square). We have everything carriage wise squared up you can now it is time to square the bed to the frame. Start by stepping the print head down till it touches the middle of the bed and set this height as the new Z height (you should lose a little total print height but we are talking a few mm).

Now you have set the height you can either manually or with a set of Macros move the heat to about 50mm from the edge at each “bed adjustment” point and manually adjust the bed up or down (with your feeler gauge under nozzle, aka paper) at each of these points. Work in triangles when adjusting (so 3 points in a triangle shape first, then next three then back to first 3 etc). Every time you adjust one point it will put every other point out of level so this process will take some time (I normally take about 3 hours to do this with some breaks). I can put my macros up if you like, I start 5mm off the bed with hotend to ensure no crash then slowly step the head down and adjust the bed at same time to prevent a crash. Don’t bother to heat the bed up of go near the middle of the bed at this stage, we just want the bed to be square on the adjustment points.

Now things get a little more complicated, once you have everything perfect (painful I know) you then need to set the delta radius in order to remove and dishing of the bed surface. Bring the hotend down till it touches the centre of the bed (use your feeler gauge), have a look and see if you are at Z0 or if you are a little high/low. If you are high then you need to reduce the delta radius a little, if it is a little low then reduce the delta radius a little, do this in 0.1mm increments at a time. Each time you adjust the delta radius you will probably have to adjust the Z height a fraction. So make the adjustment to delta radius, then bring hotend down and check it at one outer point and one middle point and repeat making changes until the outer and inner points are perfect (remember you will probably have to change the Z heigh when you change delta length). I can’t stress enough that at this stage DO NOT MANUALLY ADJUST THE BED BOLTS. Once you are real close, start adjusting delta radius by 0.01mm at a time.

Once the above is completed you can now run a decent bed level print to test you level, you will pretty much always make some super fine adjustments while it prints (print in 0.15mm layer height), but once completed you will have a perfectly square and level bed, which should mean you don’t need to go anywhere near the auto level again. Doing it this way ensure a far better level than an auto one and also means you are not making micro motor adjustments (does not really work for 1.8* motors on 20 tooth pulleys) for bed level which causes distortion in your prints. Now make sure delta radius and Z height is recoded in your config file and you should not have to do any bed levelling again.

Great write up and good advice. I will definitely have to give this a go! I would very much appreciate it if you would share your macros, and I feel that many people besides myself will benefit from this! I’ll have to give this a try when I get back home next week, I’ll make sure to let you know how it goes! I really do like the little monster, and I’m excited to finally be able to dial it in.

So here are the macros, make sure you put each one in their own macro, don't copy the bits after => into the macro. Point 0 is the centre.

Point 0
=>
G28
G1 X0 Y0 Z5 F5000 ;bed level point 0

Point 1
=>
G28
G1 X70 Y100 Z5 F5000 ;bed level point 1

Point 2
=>
G28
G1 X120 Y0 Z5 F5000 ;bed level point 2

Point 3
=>
G28
G1 X70 Y-100 Z5 F5000 ;bed level point 3

Point 4
=>
G28
G1 X-70 Y-100 Z5 F5000 ;bed level point 4

Point 5
=>
G28
G1 X-120 Y0 Z5 F5000 ;bed level point 5

Point 6
=>
G28
G1 X-70 Y110 Z5 F5000 ;bed level point 6

No probs, will put them up tonight and hopefully get the chance to do the write up in Thingiverse tomorrow with clear instructions