TEVO Little Monster Duet Ethernet Conversion

inachisiojexus · 7 Jun 2017, 15:49

I also recommend these: http://www.ebay.com/itm/3X-NEMA-17-Vibration-Damper-noise-3D-printer-stepper-motor-dampener-screws/302320633635

Running my TEVO delta in the living room was misery prior to installing the dampeners. They work magic with this printer.

The seller on eBay sent me one defective part (the vulcanized rubber was loose) but I managed to fix it with superglue. The seller was so embarrassed that he sent me a fourth one for free, so I can at least recommend him for the upstanding service.

Ak Eric · 4 Oct 2017, 03:27

I ordered my TLM kit with this exact upgrade in mind : And look, someone has already done all the heavy lifting, super awesome.

Only one question (right now): Is there any reason to get the whole kit built hooked up to the MSKBase first… or should I skip all that and just hook up the Duet directly? I ask because I haven't actually purchased the DuetEthernet yet. If I'll save a bunch of time going that route directly (straight to Duet), the I may as well order now so it's all ready to go at the same time…

inachisiojexus · 4 Oct 2017, 11:03

@Ak:

Only one question (right now): Is there any reason to get the whole kit built hooked up to the MSKBase first… or should I skip all that and just hook up the Duet directly? I ask because I haven't actually purchased the DuetEthernet yet. If I'll save a bunch of time going that route directly (straight to Duet), the I may as well order now so it's all ready to go at the same time…

No good reason that I could think of, aside from using it to verify that none of the parts are faulty.

What you could do in advance is modifying or swapping the connectors for compatibility with the Duet. I went the "modify" route and used side cutters and a precision knife to peel off plastic fins off the motor connectors and elsewhere where they would cause the white plastic back wall on the Duet board connectors to bend. I also replaced or split some Dupont connectors (e.g. BLTouch 1x3pin and 1x2pin to 3x1pin and 2x1pin). Be sure to at least check the wiring, as some of my kit's Dupont connectors had pretty awful crimping applied…

Be extra-attentive with the SSR (enclosed in the big black box on top, together with the PSU), and remember to generate your own PID for the hotend (and preferably the heated bed, although I skipped tuning that and just used OP's values which seem to work for me).

EDIT: You probably know, but just in case... Remember that the frame is grounded via the screwed connection to the aforementioned black aluminum case containing the PSU and SSR, so if you ever decide to relocate the PSU you have to remember to pull your own wiring from the PSU's protective earth connectors to the frame and check with a multimeter that the separate parts of the whole structure are grounded, with the most important part of course being the aluminum around and beneath the mains-powered heated bed. Checking that these parts are properly grounded is smart even if you modify nothing. I would go as far as making certain that the PSU's protective earth is in fact connected to proper pin on the back of the enclosure where the power cord is connected, and use a power cord that definitely isn't defective.

Ak Eric · 4 Oct 2017, 19:20

Great info, thanks for the tips!

AmrasElensar · 6 Oct 2017, 10:19

@Emulsifide:

I ended up ditching all of these parts in favor of genuine E3D parts, a .6mm nozzle, a Duet Ethernet controller, and a 7" PanelDue:

Hi
I've been looking into replacing the knock off E3D stuff for genuine parts myself. I keep having jams.
Would you mind specifying what you bought on the E3D website?

Thanks

vsch · 6 Oct 2017, 22:22

@Emulsifide:

I've now concluded that I seem to have been provided with a defective MKS SBASE controller board.

The MKS-SBASE controller is unreliable garbage. Mine worked for about 6 weeks.

Thank you for publishing your success. I was debating whether I should change to the Duet Wifi from the stock MKS-SBASE disaster of my TEVO. Seeing your success and the fact that Duet comes with Trinamic drivers tipped the scales.

I made a board with TMC2130 step sticks for my TEVO and these drivers made a huge improvement in printing quality and printing is nearly silent. I could not go back to the whiny sound of standard stepper drivers.

I agree with you on all the shortcomings of the software and controller combination. There are also absolutely no fail checks or safety limits for anything on this printer.

I bought my TEVO Little Monster thinking that for the price I was getting a 3D printer instead of a good mechanical frame, stepper motors, power supply, some cheap cloned parts for the extruder and hot-end. Oh, lets not forget a small chance to have all these come together as a working 3D printer.

I had small issues:

1. The BL-Touch failing and causing the printer to drive the hot nozzle into the bed, melting the liner. I wound up checking its status every print, just in case it failed.

2. One of the end stop sensors getting blocked by a loose filament, causing homing operation to think this axis is already homed and running the other two at 400 mm/s until they locked because the other carriage was low. The printer wasn't the wiser and kept grinding the belts until I turned off power.

3. No supports for the umbilical and filament coming to the effector meant that the filament got caught by one carriage during homing and could not reach home position. The printer kept going, grinding the belt.

I got it set up and running decently. Added printed mods to support umbilical and filament, added shrouds to protect the end stop sensors. However, I kept having intermittent failures with the printer just stopping once in a while but I was learning to live with it because it was very rare.

Then two and a half weeks ago (six weeks after I got the printer) I got a "filament jam". Since then I haven't been able to get it to extrude reliably and all attempts to fix the problem only seemed to make the situation worse. I haven't had the printer working since then and spend over $200 trying.

I wound up replacing all the cloned parts with genuine e3d parts, hoping it will resolve my issues and wanting to eliminate variables. As I kept diving deeper into the workings of the extruder and hot-end I realized that it was a miracle I managed to print at all with such poor quality components. I can vouch for the much higher quality of e3d components but my real issue turned out to be a slowly failing controller board reading higher temp than actual.

If it all went at once I would clue in faster but it was a slow degradation process. The hot-end thermistor channel must have gone first and caused the original "filament jam" by lowering the actual temperature at the nozzle. Finally, the bed channel also failed. Not realizing the two issues were related, I re-configured the bed and extruder to use the spare channels TH3 & TH4. It seemed to work but the actual temperature was 30 C below what the controller was showing.

This morning, just when I thought I could print again, the two remaining channels started reporting 93 C at room temperature. This is when I finally clued in that my problem from the beginning was an erroneous temperature reading by the controller and the rest of the failures were symptoms.

I am glad I now have all genuine e3d parts. I did not want to blindly replace them without doing some testing to assure myself that the change to genuine parts makes a difference. My trust in 3D parts and components has gone to zero unless I verify them myself. I used a Fluke multimeter thermocouple probe which I can trust and lowered it into the filament path. Stripping the outer teflon insulation, which keeps the red/yellow wires together, reduces the diameter so the probe fits where 1.75mm filament does. By controlling the depth of insertion I could measure temperature all along the filament path, right down into the nozzle.

I ran combinations of TEVO stock components (with the TEVO fan and fan mount) against the e3D parts (e3d fan shroud, quiet 30mm fan I bought at DigiKey) and found that with TEVO stock parts and configuration the heat-break temperature just inside the heat sink is 48 C with hot-end at 190 C. With e3D components and the quiet replacement fan it is 39 C for the same nozzle temperature.

I will place an order for a Duet Wifi and hope to have the printer working again over the weekend. I have a backlog of a few projects that are waiting on printed parts. I never expected my printer would be out of commission for almost a month after less than two months of use.

Vladimir.

vsch · 6 Oct 2017, 23:20

@dc42:

It's usually possible to convert 5V optical endstops to 3.3V. Identify the resistor in series with the IR emitter in the slotted opto switch and reduce its value by about 50%. If it's a surface mount resistor and you don't have SMD desoldering equipment then it's easiest to solder a second resistor of equal value on top of the existing one.

Does the Duet Wifi not have the ability to use the Stall detection of the stepper drivers for end stop detection?

I know this is possible according to Trinamic information and also by the Prusa MK3 implementing this exact feature.

This is definitely something I would like to use and if not available to work on the firmware enhancement to make it work.

I hate relying on the optical end stops. They are not as reliable as the trinamic stall detection because the latter will work if an obstruction stops the carriage from triggering the optical sensor.

dc42 · 7 Oct 2017, 06:06

See the other thread on the subject of using stall detection instead of endstop switches.

vsch · 16 Oct 2017, 22:46

Just got my TEVO Little Monster printing with Duet Wifi with the LCD interface, and the WEB UI. Wifi seems to loose connection all the time. Sending [c]M562 S0[/c] to disable it then [c]M562 S1[/c] to enable it on the LCD console, reconnects every time. A bit of a pain but I will deal with it later.

The upgrade was not complicated except for a couple of loose pins in connectors that only showed up after a few days of working with the printer.

In the end the real cause of my problems was poor temperature control of the MKS-SBASE controller in the machine, which resulted in the PTFE in the hot-end melting and lining the nozzle (two actually because I switched to a new nozzle hoping to make it work) with thin ribbons of PTFE that would peel off at random and cover the 0.4 mm hole, causings extrusion to become very uneven, sluggish or blocked.

Nothing worked consistently, not the Titan extruder, not the e3d hot end. Only when I cleared out all plastic out of the nozzles by heating them with a hot air gun and cleaning them out with a 1.94 mm drill bit, slowly by hand turning it. Then soaking them in MEK to pull all the crud out. Only then did I realize what the issue was when I saw thin strands of plastic floating around that MEK did not affect.

Now the printer is running and better than before. Finally, after a four week struggle trying to figure out what the issue was.

dc42 · 16 Oct 2017, 22:53

I'm glad you have your printer working well.

WiFi disconnections are typically caused by low RSSI (signal strength), but not always. See https://duet3d.com/wiki/WiFi_disconnections_and_AJAX_timeout_errors for guidance.

Ak Eric · 29 Oct 2017, 23:20

Just finished doing this conversion: Huge thanks to Emulsifide for gathering all this info and providing all the config files. Only two gotcha's I ran into, one I have solved, one I have not:

#1: The endswitches wiring is all sorts of different between the MKsBase, the switches themselves, and the Duet. I didn't reailze this at the time, but when none of the switches were working I quickly relized it. Cutting & wiring new dupont connectors solved this.

#2 : I'm getting this error from the web control for my heated bed:
Error: Temperature reading fault on heater 0: sensor open circuit

Any ideas? Everything 'looks' wired correctly:

Thermistor plugged into Duet.
Heated bed output from duet is plugged into the same terminals that would have been pluggged into the MKs Base, that actually connect to the connector in the side of the case.
Those wires run into the PSU, presumably connecting to the SSR, which controls the output to the heated bed, which is also plugged in.

.
Anything I'm missing here?

While I've not printed anything yet (want to solve this last issue), it homes and bed levels like a boss.

Cinpro · 29 Oct 2017, 23:48

You put it with the terminals right beside the BED power wires on the board right?

Also there is a Facebook group for this combo of printer and board; Little MOnster Duet WiFi Ethernet Users Group

Ak Eric · 30 Oct 2017, 01:32

@Cinpro:

You put it with the terminals right beside the BED power wires on the board right?

I'm… not quite sure what you mean by that . I have it wired up just like the pic here shows:
https://thingiverse-production-new.s3.amazonaws.com/renders/8b/40/85/43/2e/03e4de45ef0e423ff95199fd8deccd3b_preview_featured.JPG
The bed-out terminal is on the bottom right of that pic, and mine looks wired just like it.

I'll check out that FB group, thanks.

Ak Eric · 31 Oct 2017, 03:20

Just to follow up: The TLM kit came with an extra thermistor…. so I just tried plugging it into the bed instead: Now getting a temp reading that matches the hotend, only off by about .5c. Shot in the dark: Anyone know by chance what setting to use for it, if stuck on the bed? Since I presume this was a spare for the hotend, should I just dupe my hotend M305 settings? Currently have this, since I just copied what Emulsifide had posted:

[[language]]
M305 P1 T100000 B4138 C0 R4700             ; HOTEND :  Set thermistor + ADC parameters for heater 1
M305 P0 T100000 B4607 C8.950070e-8 R4700   ; BED : Set thermistor + ADC parameters for heater 0

number40fan · 31 Oct 2017, 03:53

I am sure the hotend and bed uses the same thermistor, so you should be safe copying.

Ak Eric · 31 Oct 2017, 16:40

Thanks: Swapping sensors, changing settings, heating it up, and testing with my IR thermometer, it's within just a few deg, so I'll call that a success.

dc42 · 31 Oct 2017, 17:14

I'm glad it's working for you. If you are using glass on top of the bed, then it's normal for the temperature on top of the glass to be 5C to 10C lower than the temperature you set.

Ak Eric · 18 Nov 2017, 19:35

@Emulsifide : Any chance you wouldn't mind posting the Simplify3D profile you've been using? I've been tuning mine, and slowly progressing with better results, but would like to have something to compare against.
Thanks!

Ak Eric · 18 Nov 2017, 23:28

@Ak:

@Emulsifide : Any chance you wouldn't mind posting the Simplify3D profile you've been using? I've been tuning mine, and slowly progressing with better results, but would like to have something to compare against.
Thanks!

I'll answer this myself since discussing this with him elsewhere: I totally forgot That S3D provides lots of default profiles, and they have one for the TLM. Derp.

Ak Eric · 27 Nov 2017, 01:44

General question (for Emulsifide or anyone else) : How did you come up with the numbers for the M665:
M665 R157 L397.1073 B175 H525 ; Set delta radius, diagonal rod length, printable radius and homed height
Specifically the L and R values? Was this based on the measurements of your machine, or did you actually find official looking numbers online somewhere?
Just wondering simply because my numbers based on measurements seem slightly different, I'm coming up with:
M665 R155.58 L395.416 B175 H525
Again, just wondering.