3D Printer problems - Monoprice/Wanhao D6

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ddmckee54

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willray:

I agree, I'm already down the rabbit hole, that's why I said I didn't want to go TOO far down it.

Somehow I managed to fumblefinger my printer profiles in S3D, I deleted them. Using the factory default settings in my D6 printer I have significant discrepencies between my 20x20x20mm cube and the actual measurements, X was about 0.5mm out and Y was worse, but Z was fairly close. This would be fine if all I was printing was artsy-fartsy type stuff like pencil holders and dragons, but I'm trying to print actual usable parts - parts that will fit to something else without fettling. So far I've printed 20 of the 4" adapter rings for my dust collector project and have at least 6 more to print - so NO fettling.

The cube errors were inconsistent between the axis so I couldn't write it off as a scaling issue. I had the same problem on my I3 clone, and this calibration procedure of the steps/mm was how I fixed it. I am currently sacaling all 3 axis in the slicer to 103% to compensate for shrinkage, so even though the parts are built using the equivalent of Lincoln Logs the part SHOULD be close. I agree, a thou or so error from a 3D printed 20x20x20mm cube isn't bad, but when I print a larger object and the error scales up with it, THAT I can fix - at least get it closer. When I can print a small part, and a larger part, with about the same error, then it's time to click my heels together 3 times and leave OZ. (Sorry about the mixed references, couldn't remember how Alice left Wonderland.)

S3D doesn't have a printer profile for my MP10. When I tried printing a 20x20x20mm cube, I got a 20x20x10mm cube. I found several references on the ole Interwebb suggesting that this or that printer profile would work - for me, not so much. This wasn't really that unexpected, the Z axis lead screws on my other printers have a 2mm pitch, and the MP10's Z axis lead screw has a 1mm pitch. So I had to fix the calibration on the MP10 too. I load the new steps/mm setttings in the g-code when I start the print, then reset them at the end of the print. I may not have to do that, but the MP10's got a bed leveling function built in and I didn't want to screw that up.

I'm not too concerned about the accuracy of the Z axis. Unless the 3D printing gods smile on me and deliver a miracle, that height could be off by up to 1/2 of the layer thickness. If I'm within that +/- half layer thickness, and it stays that way with when printing a larger object, then Z is "crose enuf".

Don
 

awake

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Don, do you have the ability to update the settings in the EEPROM of your printer(s)? If it runs Marlin or similar, it should be possible to write updated settings to the eeprom, where they will be loaded each time when powered on. Thus not something that has to be kept in your Simplify 3d profile ...
 

willray

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I have significant discrepencies between my 20x20x20mm cube and the actual measurements, X was about 0.5mm out and Y was worse, but Z was fairly close. This would be fine if all I was printing was artsy-fartsy type stuff like pencil holders and dragons, but I'm trying to print actual usable parts ...
Hehehe -- I will never understand why people are willing to spend hundreds or thousands of dollars for a device to recreate crap that they wouldn't pay $5 for at the trinket store.

S3D doesn't have a printer profile for my MP10. When I tried printing a 20x20x20mm cube, I got a 20x20x10mm cube.
I like S3D (liking it less, as they continue to refuse to release an update), but they do seem to have some problems with their printer profiles. On one of mine, their default profile produces an object that is skewed diagonally, moving over by 1 extrusion width per layer...

I'm really surprised you're getting the type of calibration issues that you're seeing though. Lead-screw pitch errors, sure, but off by a few percent on a cartesian is pretty hard to implement! The only one of my FDMs that isn't accurate to the accuracy of the lead screws is a delta.

Good luck!
Will
 

ddmckee54

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willray - All of my printers are belt drives on the X-Y axis, and lead screws on the Z axis.

I have officially EXITED the printer calibration rabbit hole. I can consistently print a 20mm cube to within 1-2 thou in both the X and Y axis. I then printed a 40x40x40mm hollow cube as a sanity check. The D6 printer kept the 1-2 thou error on X-Y, so I callied it crose enuff. The error on the MP10 printer held at 1-2 thou on the X axis, so I left it alone. The Y axis error went up to 3 thou, so I tweaked it slightly and tried it again. This time the error was 1-2 thou for both X and Y, so I called it good enough for guvmint work. I think I only changed the X-Y steps/mm by about 4 steps/mm from the original settings on both the D6 and the MP10. The MP10 started out with a Z steps/mm of 404, which gave me a 20x20x10mm cube. If I remember correctly the final Z axis steps/mm setting was about 796 steps/mm.

I needed a 4" to 3" offset transition for the dust collector branch to the drill press/bandsaw/whatever and none were commercially available, so I 3D modelled one. I loaded the gcode into the MP10 and fired it up, S3D estimated the print time at 16 hours. I had printed a 14 hour print on the MP10 so I figured it'll be fine, and let it print overnight. The next morning I noticed a dicey looking area in part of the print and hoped it was just a bad spot in the filament. It got progressively worse and at about 14 hours into the print I aborted it, there were significant defects in the print. Mostly it looked like it was under-extruded, to the point where the print was so spongy that if I wanted to I could have poked my finger through the 3mm thick wall. I have seen a similar issue on my D6 printer, on that printer it means that the Teflon liner in the hot end is swelling up and needs to be changed. I was getting ready to tear the hot end apart when I remembered that the MP10 has an all metal hot end, so no Teflon liner - there had to be a different cause. What I eventually found was that for some unknown reason the extruder drive gear had started grinding chunks off the filament. The teeth of the gear were mostly packed full of bits of filament, I'm amazed that it was able to drive the filament at all. I'm going to babysit this thing for awhile and keep an eye on it. It'll be some time before I trust the MP10 to extended unsupervised printing again.

The good news is that the D6 pooped out that same transition piece in 14 hours, and it's a keeper. I have printed several smaller parts in the MP10 since then without any issues, but now I know to regularly check the extruder drive gear for tell-tale bits of filament.

Don
 

awake

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Hmm ... let's think through the possible causes for the filament grinding / under-extrusion:

1) tension on the drive system in the extruder is not sufficient
2) printer cannot lay down filament as fast as called for (e.g., it cannot keep the filament hot enough as it passes through the print head)
3) print head nozzle is blocked (e.g., due to dusty filament or to filament staying at temp but not moving for too long and getting "cooked" in the print head)

Of these, I've never had #1 occur ... instead, I hear the extruder stepper motor missing steps.

I've had #2 occur primarily with TPU filaments. Solution is to slow the print speed down.

I have had #3 on more than one occasion; most of the time, it is a problem with dust; most of the time, I can clear the blockage by heating the print head up, pressing in some filament, letting the head cool down, and at around 170 - 180°C pulling the filament out. The idea is to let the blob of plastic begin to solidify but still be able to pull out, hopefully pulling out with it anything that is blocking the nozzle. Over several years of occasional printing, I've only had to actually replace the nozzle a couple of times.
 

ddmckee54

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I don't think the problem is #1 , but if it is there's not much I can do about it. I don't see any way to adjust the pressure of the spring loaded roller.

I also think we can eliminate #2 as the culprit. Every part that I have printed using the MP10 has been run at 50mm/s print speed with a 0.175mm layer height. That was the layer height sweet spot found by other users of the MP10 - so I took their word for it.

I also think we can eliminate the plugged nozzle. The filament while not new, I've had it for a while, was still in the un-opened vacuum sealed package. So the filament was clean and dry. I had a previously run a 14 hour print using the same filament, same speeds, and same temperatures with no issues. I don't let the hot end sit running at temperature for extended periods, so for now I'm going to look for other causes.

I'm going to propose option #4, filament of questionable quality. This was a low-buck Ebay spool of filament, chosen because I really liked the dark blue color. The extruder drive gear on the MP10 is a worm wheel, not the straight cut spur gear like on my other printers. Something caused it to slip initially, this embedded bits of filament into the teeth of the gear, which caused more slippage and more grinding. There was a significant amount of ground up filament around the gear, and in the gear teeth. Once I found the problem, it took me a quite a while to get all the crap cleaned out of the gear. Now I keep an old tooth brush handy to keep the drive gear clean while the printer is running. I'll probably also avoid using filament from unknown manufacturers in the future, no more impulse buys just because I like the color.

Don
 

awake

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Ah, good point - I had neglected to think of #4!

Of course, #4 could lead back to #3 ... :( I've also had #3 when I've had either the bed or the Z-compensation way out of adjustment - but that should be obvious if you watch the first layer being printed.
 

RM-MN

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I also think we can eliminate #2 as the culprit. Every part that I have printed using the MP10 has been run at 50mm/s print speed with a 0.175mm layer height. That was the layer height sweet spot found by other users of the MP10 - so I took their word for it.
Not all filament, even though the same material, is the same. I've had to adjust the nozzle and bed temp with a change of PLA filament.
 

willray

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Hmm ... let's think through the possible causes for the filament grinding / under-extrusion:

1, 2,

3: print head nozzle is blocked (e.g., due to dusty filament or to filament staying at temp but not moving for too long and getting "cooked" in the print head)
I've had a different, and reliably-reproducible version of 3 - it took me a while to figure out what was going on when my postdoc started having this problem with his prints, induced by an updated version of Cura:

Print-bed temperature too high. I leave a TAZ 6, with a dual-extruder all-metal hotend in the lab for the kiddies to play with. An update to Cura increased (for reasons as yet bewildering to me) the default print-bed temperature for PLA from 60C to 80C. Because the dual extruder hot-end has minuscule fans, and the extruder is huge, most of the air that's passed over the hot end to cool the heat-break, is sucked from near the print bed.

That 20C increase in print-bed temperature resulted in the melt-zone on PLA extending above the heat-break during the first few layers of printing, and as the head got further from the print bed, the cooler air available brought the temperature of that region back down to where the melted filament formed a constriction, and sometimes a complete blockage.

The symptoms were consistent with what you're describing - prints that started fine, but that then began grinding filament after they got up an inch or two into the build. Took me far too long to figure that out, as my test prints printed just fine, but my postdoc's attempts at the same parts consistently failed. Somehow looking at the first couple lines of the g-code didn't occur to me for the better part of a week.

Best of luck chasing your gremlin!
Will
 

willray

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willray - All of my printers are belt drives on the X-Y axis, and lead screws on the Z axis.
...
Don
You know what, most of mine are too. I was just up to my ears in the guts of our Stratasys machine, which is the only one of mine that I'm sure is lead-screws all around, so I'll claim that that's the source of my brain fart, but yeah, of course, small variations in pulley diameters are going to result in needing to tune X/Y on belt-drive machines.

Duh!
Will
 

awake

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I've had a different, and reliably-reproducible version of 3 - it took me a while to figure out what was going on when my postdoc started having this problem with his prints, induced by an updated version of Cura:

Print-bed temperature too high. I leave a TAZ 6, with a dual-extruder all-metal hotend in the lab for the kiddies to play with. An update to Cura increased (for reasons as yet bewildering to me) the default print-bed temperature for PLA from 60C to 80C. Because the dual extruder hot-end has minuscule fans, and the extruder is huge, most of the air that's passed over the hot end to cool the heat-break, is sucked from near the print bed.

That 20C increase in print-bed temperature resulted in the melt-zone on PLA extending above the heat-break during the first few layers of printing, and as the head got further from the print bed, the cooler air available brought the temperature of that region back down to where the melted filament formed a constriction, and sometimes a complete blockage.

The symptoms were consistent with what you're describing - prints that started fine, but that then began grinding filament after they got up an inch or two into the build. Took me far too long to figure that out, as my test prints printed just fine, but my postdoc's attempts at the same parts consistently failed. Somehow looking at the first couple lines of the g-code didn't occur to me for the better part of a week.

Best of luck chasing your gremlin!
Will
Wow, that must have been a hard-to-diagnose gremlin!
 

ddmckee54

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willray:

S3D hasn't updated in far too long, so a recent update is not the issue. I'm keeping an eye on the MP10 and if what's left of the spool of dark blue screws up again, well then it's going to get an up close and personal look at the inside of the trash bin. There's only about 1/2 of the roll left so it won't be that big of a sacrifice. Whatever initially caused the problem seems to have gone away. Since I cleaned the teeth of the extruder drive gear the MP10 hasn't been causing any problems - then again I haven't done any extended prints on it either.

I need to reprint some of the RC Benchy parts, for the 3rd time, now that I've got the printer dialed in. I've printed these parts on both the MP10, and the D6 and I get a layer shift on one side of the hull about 100mm-ish up into the print. It's not in exactly the same spot on both prints, so I suspect that the stresses are building up as the print progresses and part of the print is letting go from the print bed, allowing the free end to move slightly. It doesn't move THAT much, maybe 1/4mm to 1/2mm. There's not really that much contact area with the print bed in the area where this happens, so I'm going to print a brim on the next attempt and see if that helps. If the brim doesn't help, well to paraphrase AvE - Filler and paint makes me the printer I ain't.

Don
 

awake

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Don, I recall a roll of off-brand PETG, some years ago. Initial tests seemed to work well ... larger prints failed, and I think maybe in a similar way to what you are describing. Clearing the nozzle with the half-melted filament trick and trying again, a small test worked well ... and larger prints failed again. I am pretty sure that I remember this filament being responsible for one of the few nozzle replacements I have had to do. I was able to send it back to Amazon and get my money back.

I'd be interested in hearing from others what their favorite filaments are. I have generally had good results with Hatchbox and almost always buy that brand for PLA and PETG. Occasionally I buy eSun instead, due to price or availability, and don't recall any problems there. I have one spool of 3d Solutech that ran well for the one small project I needed it. And I have a couple of spools of off-brand that I have not used yet - we'll see how much I regret buying them!
 

ajoeiam

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Don, I recall a roll of off-brand PETG, some years ago. Initial tests seemed to work well ... larger prints failed, and I think maybe in a similar way to what you are describing. Clearing the nozzle with the half-melted filament trick and trying again, a small test worked well ... and larger prints failed again. I am pretty sure that I remember this filament being responsible for one of the few nozzle replacements I have had to do. I was able to send it back to Amazon and get my money back.

I'd be interested in hearing from others what their favorite filaments are. I have generally had good results with Hatchbox and almost always buy that brand for PLA and PETG. Occasionally I buy eSun instead, due to price or availability, and don't recall any problems there. I have one spool of 3d Solutech that ran well for the one small project I needed it. And I have a couple of spools of off-brand that I have not used yet - we'll see how much I regret buying them!
This rating of filaments if a great value to a newbie (like me!!!).

Is there any way of making this a thread or something where those using 3D printers could chime in.
That way poor quality stuff is left alone and good price stuff is 'findable' and good quality producers are rewarded.

Dunno how to achieve this but this is a start - - - at the very least!
 

awake

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Let me hasten to add that the filaments I mention above are at the lower end of the price spectrum - not the bottom, but generally in the $20 - $25 per kg. range. I have seen reviews of filaments that rank HatchBox fairly low ... but in comparison to $50/kg rolls of filament. I've never ponied up the money for that sort of roll, and haven't felt the need, since I have generally gotten good results. If I have problems with HatchBox or eSun, it is generally due to dust that is getting into the extruder and causing a blockage.
 

ddmckee54

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I only print PLA, so I can't say anything about any other flavors of filament. Like Andy, I generally look for something in the $20-$30 range per 1Kg spool. I've also had good luck with eSun fialment. I tend to shy away from filament that is below $20/Kg, there's got to be a reason that they can make it that cheap.

I've been looking for specific colors and haven't had a lot of luck so far. I do RC conversions of Bruder construction toys and I've been trying to match the red and yellow that they use - so far I'ved got nothing that matches. I've got several close matches, butg nothing that close enough.

If you are just starting 3D printing start with PLA, it's more forgiving for a beginner. Then look at the prices of what's available and pick something that's about in the middle of the range. If you go middle of the price range the odds are that you'll get a decent quality filament - no matter whose name is on it. You don't need to spend big bucks at first since the 3D printing learning curve will be causing you to trash an awful lot of prints - we've all done it. You also don't need to be fighting the issues caused by poor quality filament when you're trying to learn HOW to print.

Don
 

stanstocker

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Hi Folks,

Esun PLA Pro (AKA PLA Plus) is quite a good filament. The Inland PLA+ sold by Microcenter has given quite good prints. The Inland regular PLA is OK, but does not print as well as the PLA+. Hatchbox has been a reliable filament that prints well also. Since moving 3+ hours from the nearest Microcenter I've been getting eSun filament online. The biggest issues most folks seem to have with filament is not keeping it dry and using it so slowly that it gets too old to work well. I had a few three or four year old rolls that were in ziplock backs with desiccant packs kept in a dry shop with heat and AC. The filament would snap easily, almost like spaghetti strands. No way to use such stuff. Tried drying out a short (maybe ten foot) length in a warm oven but there was no improvement.

Have fun,
Stan
 

ddmckee54

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I went so far as to justiify the purchase of a vacuum sealer to try and save filament. (OK, I got a deal on one in a damaged box - 75% off! Couldn't pass it up, and it was just the box that got mangled.) Since I got it I've been using up already opened/used spools of filament, I haven't had a chance to try the vacuum sealer on used filament yet. The blue stuff on my MP10 was the first roll that I've taken out of a vacuum sealed bag that I can remember. Since I've been having troubles with it on the MP10, I'm not sure I'll try vacuum sealing it either.

I did have one partial roll of filament that gave me some trouble like Stan had. It had been sitting for months, maybe longer, sealed in a zip-loc bag with some desecant packets. It would be fine while printing but if you let the printer sit overnight, the filament would be snapped the next morning. That roll printed most of the 4" adapter bushings for my dust collector before I got it used up. I don't know how long it had been sitting, maybe a year or more? SOMEBODY forgot to date the stuff. (Note to self and anybody else interested: When you store a roll of filament - DATE IT!)

Don

I've been trying 3 times to add an edit saying that I got a food dehydrator and tried it on the brittle roll of filament. Each time the site kicked me out of the edit mode when I tried to add the degrees symbol. (I just realized that I didn't have the Num-Lock on - makes a BIG difference.) I put the filament in the dehydrator over-night at about 110-120°F but it made no diffference on the filament, so it wasn't a moisture problem. (The dehydrator does make some quite tasty Granny Smith Apple chips though - just not at the same time.)
 
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awake

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Interestingly, I have never had any trouble with PLA or PETG filament getting too old or too wet. I do store filament rolls in ziploc bags with dessicant, but I have sometimes left a roll of either type on the machine for a month or two between uses, and when I use it the next time, it still prints fine. Not sure whether that means my house is rather dry ... ? Or just blind luck ... ?
 

ddmckee54

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Andy:

Not sure about your humidity, or your luck. The low-buck roll of blue that I'm currently printing with on the MP10 is one that's been hiding at the bottom of the bin for a while. I'm pretty sure that it's low-buck because there was no name on the spool, and nothing in the vacuum bag either.

The troublesome spool of filament that kept breaking was from when I was trying to match a filament color to the red color Bruder used on some of their construction toys. I must have had 6-8 spools of red that were close, but not close enough - too red, not red enough.... I finally got smart and started e-mailing the various companies explaining what I was trying to do, and requesting samples. (I still haven't found a close match in the US though so if you know of filament colors that are a close match to the colors Bruder used in their constreuction equipment let me know.) I was actively looking for a color match over 18 months ago, so that spool of red had sat unused in the zip-loc bag for over a year.

Now that I think about it, I did have another spool of dark blue that also gave me fits. I could not get it to to print reliably on my D6. The extruder drive kept making popping noises which turned out to be the filament slipping on the gear. I was running my normal print speed of 45-50mm/s and tried slowing it down but it had no effect. I even ran the hot-end up to 230°C with no effect. I don't believe that this was moisture in the filament, because I never saw any defects in the print, it was just an audible popping sound. I eventually just tossed that roll. It was another low-buck roll of dark blue - maybe I just need to avoid dark blue filament?

When I got my first 3D printer, 2015 or 2016, I got 2 rolls of filament with it - one a dark blue, the other was white. I REALLY liked that dark blue, unfortunately MOST of that roll wound up in the trash bin. I had a LOT of failed prints when I first started printing. Of course it didn't help that my 0.4mm "E3D" v6 hot-end wasn't. It wasn't E3D, found that out when I tried ordering replacement parts and couldn't find any that looked ANYTHING like it. It didn't have a 0.4mm nozzle, how about 0.7mm or bigger. The opening in the nozzle looked about the same size the lead for my 0.7mm mechanical pencil. When I looked at the heat-break all I could think was mine doesn't look anything like that, and where's the Teflon liner - mine's got a Teflon liner. How was I supposed to know it was a conglomeration of crap probably assembled from a spare parts bin? Most of the parts matched a v5, while a few of them matched a v6. Ahhh... the joys of a kit-built 3D printer.

Don
 
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