The post is still under construcion
look also 3 post below for the rest of the description !!!

This will take some time to explain with photos (i must still produce some of them) and descriptions... So for now I open the 3d.
I'll use this post as reminder for me, to do not forget all the steps I made and , maybe , it will be useful for other adventurer decide to puts ends on a such big delta printer.

1st and important... The Tevo company is terrible. I mean the back office for sure. In particular Kelly Zheng took 3 month for NOT send what she promised (and I paid). Paypal cover the funny joke.

2nd... the printer for became something close an accurate tool need lots of work and money to put in.

Inspirational :
https://www.akeric.com/blog/?p=4325#Upgrades

List of upgrade and modifications....

Hardware:

1. DuetWiFi + Duet LCD 7" (last firmware stable) + heat sink (with thermal pad T412) on parts could became hot.
2. Nema motors 0.9 (for 3 motors + extruder) + dumpers + 4 12v noctua 6cm for cooling with lamptron fan hub (with resistance for lower the fan speed)
3. Extruder (Bondtech)
4. Original D3D Hotend + Volcano extension + copper nozzle (Nickel coated) + silicon cover.
5. Original BLTouch v2
6. Belts with iron core
7. Full enclosure
8. End filament guide/sensor
9. Custom Borosilicate glass (41,5cm X 5mm) + adapters block (i'll provide the STL)
10. Cartridge modified for better precision and less torque.
11. Starting for the hot chamber solution... Double plexiglass (aluminum + double plexiglass + pvc + .... ) .

Software:
Slicer used ... Firmware Settings and so on...
For now I'm using Ultimacker Cura and Matterhacker doing tons of test for the better result. The Firmware I'm using the last stable 2.02. And I'll try to explain why I used those settings.

Filament used :
At today I have used 3 filament.
1)Formfutura Easyfill ABS
2)Patona ABS
3)Formfutura ApolloX (ASA)

I can say the Easyfill ABS was pretty good but suffer as all the ABS of retraction and therefore warping.
The Patona was pretty bad. Pop any time at any temp. Warping like hell. Cost half the Formfutura. But a shiny finish.
The ApolloX is a ASA material that have less problem of warping of ABS at the cost of a little less beautiful finish (small percentage against the Easyfill).
Less warping not mean none. So for object that have a big amount of layers ,placed as a corner , and a little surface of contact with the bed , you can experience some warping at the extreme corner. Any way very less than the other two ABS.

1. The pouring of all the cable was not so fast as I imagined. I little scared of cook everything at the end i succeeded.
   I putted the two mobo close each other and with a laptop on the side started slowly to move all the cables using white plastic scotch to sign what i was moving.

The two schema:

With lots of patience I toke a very small screwdriver and moved the cables from the old connectors to the new duet ones. Some one have catted come plastic on the old ones and plugged on the new board but instead of this I preferred to use the connectors that can stay blocked when inserted.
Other tricky stuff...the optical sensor have strange color wire. All different. So I looked at the schema and the polarity of the endstop (as in picture) and considered one endstop at ones as per se cabled.

2)The nema motors 0.9 . I soldered all the cables and covered it with thermo sheath . Some hot glue for blcok the cables that enter in the motor.
Applied a heat sink on each one with under a 3M thermal pad.
Recovered from old back covers of some computer case , 3 metal plate. Of course drilled.
Then I linked all the fans (also the mobo one , changed with a 12v one) to a 12v fan hub. And between of them I putted a potentiomenter for regulate the fan speed as i like. (the noctua at half speed are really silent).
Between the motor and the support I applied the classical nema dumpers.
I had to smooth the metal pivot (was full rounded) for a better block of the gears.

1. The Bondtech extruer. I have to say the bowden connection is a little lose, so make sure you insert the teflon hose well to the end.
   I just added on the top a little piece of hose for a better guide and for a convenient calibration. (using the digital caliper im far enough to do not touch anywhere during the operation)

1. Also if the chinese copy of the volcano D3D hotend was not that bad , I decided of put the original one. The TLM already have a volcano copy inside but with a small metal core and an old thermal sensor. All tensions are 12v.
   
   
   

2. The original BLTouch v2 is slightly different. It have a sturdy shell despite the copy is a little more thin. The original trigger is in plastic and not in metal. The copy writing are a little more faded. The original one should be more accurate.

3. Because of this article:
   https://www.reddit.com/r/3Dprinting/comments/61j9et/i_tested_some_gt2_belts_to_failure_on_a_tensile/
   
   I choose to use the iron cored belts. They look more rigid but this absolutely dont impact in any bad mode to the movement. For Delta printer is suggested use those ones despite the standard ones just because the head is always in tension on the belts.
   

7)As I started with the intention of build ABS parts i read about the necessity of build an enclosure for keep the worm.
I used some aluminum bar . For the big windows I used 3mm plexiglass and for the smaller window I used the PVC material. All those parts , with the relative screw and rubbers are available in common DIY stores.
For the small windows I tried to use the plexy but it crack for vibration and torsion.
now with the black panels is more cool ^_^.
For the closing mechanism I used dome adhesive magnet.
I have done some holes on the top and bottom frame for block the corners that sustain the enclosure.

8)End filament guide/sensor , it is well explained here:
https://www.thingiverse.com/thing:2629228
I just used the remix version for add the Teflon tube for a better guide and less friction.
Just keep attention at wall close the mechanical sensor. The must be super flat and i added also some grease for a perfect slide.

I found this that should be where you lies at this point:
https://duet3d.dozuki.com/Wiki/Connector_and_spare_part_numbers#Section_VSSA_fuse
But right now I'm not capable enough to give suggestions

OT/
Bot , so this is you !!! (just kidding )
https://www.reddit.com/r/3Dprinting/comments/fohhwo/muahahaha/?utm_source=share&utm_medium=web2x
/OT

As told I added the top insulation.
And also added some clip because now the sponge create too much pressure on the magnetic closure.

The next step is build the air mechanism for the hot chamber

Ok Thomas.
Deck is right , you are using the v2 firmware with v3 settings.
For upgrade the firmware from 2 to 3 you have to make before 2.xx.x>3.0 then 3.0>3.1.1
If you have the panel due don't forghet to add this line on top :
M575 P1 S1 B57600; enable panel due to connect properly
Here all the info:
https://duet3d.dozuki.com/Wiki/RepRapFirmware_3_overview#Section_Summary_of_what_you_need_to_do_to_convert_your_configuration_and_other_files

ps:
damn ctrl+shift+enter had tripled the post...

Ok,
Also I suggest you to verify those alignments.
Those must be at the same equal distance.
Doing this I reached that the X and Y of M665 are gone from several decimal to some cents.
In those trap we must gain as much precision everywhere
In my case for obtain the more possible equal distance , I was not able to keep the tower aligned with the top frame.

Dear absolute !!!! Maybe you nailed it !

Look at this , the six rods:
1> -0.25
2> -0.25
3> -0.15
4> longhest
5> -0.1
6> -0.6 !!!!!!!!!!!!!!!!!!!!
Poor auto calibration , It cant reach those parameters.

From the Duet guide (and your linked pdf too):
https://duet3d.dozuki.com/Wiki/Calibrating_a_delta_printer
All 6 rods must be the same length, measured between bearing centers

If you are building the rods yourself, make them one by one in the same jig. If you are buying them, check that the supplier guarantees a maximum difference in rod length, which should be less than 0.1mm. It is particularly important that the rods in a pair are of matched lengths, because any difference will cause the effector to tilt.

I lost damn ages because I trusted the manufacturer REALLY My BAD ... I had should check this hundred time before all the attempt I made for calibrate it.
My mistake was : the product is already made , it will be good. Such a sheep.

Now what? Buy hundred of them to make sure found SIX equal ?!?!?!?!? Damn Tevo.

I feel so bad for wasted your time... All the people had helped here , damn ... sorry.
I should had to think as the printer was made by me and check ALL the steps as reported in the guide. Inexperience here docet.
Now I'll go check all the rest of the hardware hoping that the frame didnt have absurd variations

I'll keep you informed about the evolution of the story...

Ok,
I found the culprit. Electromagnetic fields.
I designed a new duct for the fan and everything worked fine , then I re-designed the duct for a more efficient flow and the fan now stay 5mm closer to the effector than before and tadaaaa , still this fan didn't want start. Same behavior.
Some blink trying to spin and nothing else.
So I took a common aluminium sheet (the cooking one) and bent on itself and finally placed on the perimeter of the fan and magically now it start to spin regular.

Hi all,
More or less noob questions...
Aside all the reading stuffs, I would like to know the direction on how to interpret the autocalibration results.
I leave the M666 to zero so that the autocal build all the parameters by it self all the times.
The length of the rods are fixed. 6 factor for the bed , max radius as i can set, etc etc.

 6/4/2020, 6:56:45 PM 	Calibrated 6 factors using 16 points, (mean, deviation) before (-0.009, 0.045) after (0.000, 0.043)
6/4/2020, 6:55:32 PM 	Calibrated 6 factors using 16 points, (mean, deviation) before (0.009, 0.039) after (-0.000, 0.034)
6/4/2020, 6:54:20 PM 	M98 P"0:/macros/AUTO CALIBRATIONS/3xG32"
Calibrated 6 factors using 16 points, (mean, deviation) before (-0.002, 0.048) after (-0.000, 0.045)
6/4/2020, 6:45:48 PM 	Calibrated 6 factors using 16 points, (mean, deviation) before (0.007, 0.034) after (-0.000, 0.031)
6/4/2020, 6:44:34 PM 	Calibrated 6 factors using 16 points, (mean, deviation) before (-0.001, 0.042) after (0.000, 0.040)
6/4/2020, 6:43:20 PM 	M98 P"0:/macros/AUTO CALIBRATIONS/3xG32"
Calibrated 6 factors using 16 points, (mean, deviation) before (0.010, 0.034) after (-0.000, 0.031)

If the result before the pass present less deviation and then more , there are mechanical issues , right? This mean that the printer rebuild new parameter at any pass.
If the pass are all similar , same deviation more or less, it mean that the autocal is coherent and should not be present much mechanical assembly errors, right?
Which is the ideal results? Make the after = to 0.000 should mean zero mechanical errors? Or maybe just that printer compensate very well?
Could be interesting put in the guide how to read those data for give the right meaning to them.
https://duet3d.dozuki.com/Wiki/Calibrating_a_delta_printer#main

Thanks for your time!

After 2 years of digging with abs and than ASA i build up some "experience" and I try to share it.
Unfortunately abs , like ASA, are beast to deal with. They have "a lot" of material retraction depending on temperature. (ApolloX have a little less bending but is expensive)
So , start to become far more important all the temps on the field.
Bed adhesion must be strong. Really strong and despite the part didn't detach from the bed the part could cum still a little bended.
This depend also by the bed temp. And are two different banding causes , bed and volume air.
Lots of guides tell you the the bed temp should be close the class transition (100degree) but in my experience 100/110degree are too hight and the first 5mm of the part come always severely bended (big prints). I discovered that a good adhesion and 80/85 degree (for all the surface of the bed - used thermo-camera and modded bed resistor for achieve this) produce a better result. Still no perfect , but ok till the hot chamber will be finished .
Yes, because you probably will need an hot chamber (the enclosure alone could not be enough). I can't say the exact temp you need to reach inside because depend also by your specific material.
By your pictures seems that the bed temp is too hight (could be confirmed also by the guide in the bottom link).
https://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide#wallcavein
And...I found useful print with "draft". If you modify this setting properly (Cura slicer) the heat of the bed come a little less on the part avoiding too much different from the top layers and the first.
With small parts , "brim" could be sufficient.
Also, air on the part must be avoided (of course not if the part is really small). So check if your tool fan don't create turbulence.
Because of this the good suggestion of mrehorstdmd of print more part at ones could be useful.
By the first pictures seems not even regular the two corners (one convex and the other concave) and this is not because the temps but geometric calibration.
All the parts have their specific setting and attention required. Some doesn't need particular work on but others are really tricky.
Especially block and infill at 100% generate lots of tensions.
If you want print only one small part Maybe you could try to print the cube test with draft and the part fan on at low percentage.
With low object (till 1cm or so), there is no problem , but when the part rise the tensions become stressful.
Also the design of the part will make a good part in the full equilibrium of the print.

Here there are good suggestions that can help you to found you specific settings.

https://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide

https://forum.duet3d.com/topic/6951/not-yet-solved-tevo-little-monster-duetwifi-errors/139
1)In my case the top frame had holes not aligned with the extrusion holes same as the bottom frame.
2)the 3 extrusion (tower) are bended.
3)bars have different length (six time the maximum allowed)
4)the glass bed is not glued planar in the aluminium socket.
I'll redraw with Freecad the top/bottm frame and some lateral connection for make the build very rigid. (all will be CNC milled)
Also I'll use the 8x2 extrusion for leave the linear rail the right space to be mounted...
I'm building a pretty amazing (for my standard) CoreXY 300ZL and at the same time I'll rebuild my delta.
I'll post all the stuffs here

Ah, when I told this frame is crap...finally got a long rule (1m) et voila' !!! All tower are bent but the z axis is the worst.


Just remain to build the frame by my self...damn.
Still here I can't believe such poor quality can be sold.

@dc42 said in Tevo Little Monster scratches print:

light grease

With "light grease" What do you mean?

I'm using this grease of Teflub (PTFE) : http://82.185.148.242/B2C/SchedeTecniche/Cat_Generale/Cat_Gen2016_ristampa/CatGen_ristampa016017_15.pdf
Is it good? Or I should use the silicon one instead?

@justus2342
The frame of this printer is really crap. I'm managing to rebuilt it with a CNC machine for eradicate all the mechanical issues.
Those of the the Tevo really steal nonsense amount of time to so much people. By the way after 2 years on the delta I could build it by my self and it will be !

Finally , I'm in contact with Peter of Hightemp3D (EU channel). Seems all the stuffs he have are CNC milled components and laser cut parts. Misumi rails, etc etc. Also the kinematic bed will be included, full metal extruder and so on.
I'll update this post with the moving
Then I'll try to keep also the delta. I'll produce by myself the top/bottom frame, then buy new towers and linear rail.
Thanks everyone for the suggestions.

Some one of you know where to found the RailCore II Kit? Or maybe a good used one. It seems sold out everywhere

WOW thanks mrehorstdmd !!!
I'm already entering in this mode...of the CoreXY , I mean.
Hope with a good hardware finally I will get some satisfaction.

edit:
In Europe I just found this one:
https://www.ratrig.com/3d-printing-cnc/3d-printer-kits/all-3d-printer-kits/rat-rig-v-core-pro-linear-rail-701.html
Did you ever listen of them? Can be they trusted?
Ok , seems an other Chinese crappy brand. And is expensive too !
Not original linear rail , not auto bed leveling. And looking at some videos the machine dance when go a little fast.
They mount those Chinese rails?!
https://www.youtube.com/watch?v=5phwhocuXWc
The RailCore II is completely an other product.

Outstanding...before I have to manage the curse of a crappy delta frame and when I realize that is time to change , the curse try to keep you with your best enemy making unavailable the substitution
BLV cube is available on aliexpress so NEVER buy there again.
The Voron2 didn't have the auto bed leveling.

@mrehorstdmd said in Suggestions for hight precision CoreXY:

kinematic mount

Ok for the kinematic mount, added to the features to have.

High level Kit (pre-assembled) ?

Introduction:
Today I decided that I give up with my delta . I'm so tired. But really. Are two years that I make any sort of modification but I have still problems. This come to be so frustrating that I prefer go to the field with a hoe. Or crush the hoe on the printer...maybe is better.
Now it won't even print flat. Despite how I put the bed , the calibration stay constant even at 0.02 of deviation BUT when I print the bed seem always inclined , if I rise the bed where the print seems too hight and recalibrate the printer > SAME behavior, still print as the bed is inclined.
S6 or S8 don't make any difference. Mesh compensation tried tons of time , reporting a pretty decent flat bed but with no impact on the print.
Duet -wi-fi , Haydn bars, smart effector, disassembled countless times for put it in square, super sturdy carriage , iron core belt (tied not to death) , bed leveled with digital caliper , 7 round different glasses to put on it, 0.9 motors, bondtech extruder , capricorn tube, copper block, and.....a lots of other stuffs. Still problems.
The only part I know , the frame , is a shit. So maybe can be the 3 tower to be bended twisted or whatever, or maybe consumed in some areas, BOH or other magical spites. I don't mind anymore.
Change those part (frame with carriages) with other crappy parts is pointless. Then I should adapt from the start all the enclosure and all the other mods. The final result would be always something not of hight precision. So maybe time to make a change.

Needing:
I saw two frame that look interesting:
RailCore II 3D Printer : https://railcore.org/
Or the Motion System and ToolChanger , but this one didn't have 3 motor for auto level the bed and have "just" 200x300x300 part's area.
300x300x300 would be better so for the auto bed leveling . I would go for the RailCore II.
I would like NOT use self printed part but already made precise components.
I'll need to print ASA and ABS (or hotter materials) so I'll build (or adapt) the hot chamber system I already have .
I'll scrap this stupid delta for use all the part I can. Even the smart effector if I can adapt it for the CoreXY.
There are other CoreXY with much sturdy frame out of the box? I would not lose other 2 years for put in line the frame.

Availability of the printer, of course. This RailCoreXY seems disappear from the market. Everywhere sold out.

Thanks for the suggestions or argumentations. They will be really appreciate.