intermittent overextrusion

Hello,


I understand this is probably a software issue. I'm a very novice user so I'm hoping for some tips. I've had an issue of blobbing and "zits" on my prints with ABS. I thought it was an issue of retraction. I've played with the setting from 1mm to 1.5mm retraction but here's where it got weird. I printed 3 copies of the same small item. About 30mm tall and maybe 18 wide. I only have this problem on the middle one though.


Maybe this is an issue of the retraction kicking in on the other 2 models based on a certain setting. I've tried this in cura, makerware, and Simplify3d. Same issue in all of them with varying retraction settings.


Qidi Tech 1 dual extruder
ABS 235
Bed 115
Print speeds 50-80mm/s (with slowdown on initial layers etc.)




Any ideas?

I can't seem to get the photo attachment, upload, or insert to work. Tried on mobile and PC. Maybe because I just registered? I will edit this post or add it in another post shortly when I am able to upload photos

When I view this thread on my mobile it's like 10 pages of blank. Maybe because I tried to attach my photo so many times? I see now that my ability to post attachments is turned off. Maybe because I'm a new user? If a mod sees this thread and it looks like a long blank post to you too please delete it.

edit: looks fine on PC. Maybe my phone is acting up.

Since I cannot post attachments I would like to add. The top of the models that looked great started to get this overextrusion as well. Maybe the last 10 layers or less.

Quote:

---

Originally Posted by number40Fan

That is the weirdest thing I have seen. But, with the issues I had with mine, I wouldn't put it past the wiring that goes down to the carriage. Mine was rubbing at only certain parts/stretches of the print causing the temp reading to swing all over the place. Look carefully at the top-back screw that has the silver washer on it, that the cables are zip tied too. Check the wiring around it. Cut the zip tie off to relax the wiring and try printing that again.

---

Interesting thought. Thank you for the idea. I hadn't considered a physical solution to the problem. I'll take a look at the wiring and how it's sitting shortly

Quote:

---

Originally Posted by number40Fan

You could also try placing the print on a different spot of the build plate and see if the results replicate.

---

I will also try this. The next thing I'm going to try is same orientation to the floor but turned 90 degrees so the wider sides will be closer together. These parts are small enough and they're a specific design to where I will need a decent amount of them so I don't mind reprinting these for testing.

Update: I checked the retractions. They're showing every layer, all parts, always on the left or right side (respective to the photos) I'll take a closer look at the parts but I'm starting to believe retraction is not my issue.

Maybe my Qidi bed is weird. Some quick info, the blue sticky layer popped today on one side in the middle of my first large print. I pushed it back down mid print and then pressed out any air bubbles when print was done. I don't think that's the issue since this is happening middle and not left or right but maybe my bed is an issue. I will level it again (I just trued both extruders last night. My left was lower by just a bit)

I will also check out the wire harness you mentioned.

Good call on checking the hardware. I was dead focused on a software solution (because I'm so new this software is very complicated)

Also, my first thread. I hope to be around here a lot. I run a very small ecommerce business, I survive on my research, and I am truly hoping to incorporate 3D printing into my business (probably not directly but as a completely new diversification of what I already do)

Quote:

---

Originally Posted by number40Fan

If you haven't yet, print the following, in the order of importance.

https://www.thingiverse.com/thing:1463521 ABS

https://www.thingiverse.com/thing:409297 PLA

https://www.thingiverse.com/thing:1675208 ABS

Go the local parts store and get some 1/8" glass cut to 9 1/8" x 6 1/8". Grab some #4 machine screws with counter sunk heads, about an inch long and some wing nuts, 2 of each. Get some cheap Aqua Net hairspray. Print the first thingy, the corner clip holders in ABS. Once they are done, pull the bed out of the machine. Rip the blue pad off. Remove the front right and rear left screws and nuts on the aluminum plate. Replace with the new #4 screws and attach your corner clips with wing nuts. Spray down your glass with the hair spray and set it out in the sun for 30 minutes. Replace the bed plate and tighten down the wing nuts for the bed leveling quite a bit. Go into the bed level setting and grab your glass. With the carriage over the middle of the bed, with the bed raised up to begin leveling, see if you can sneak the glass in between the bed and the nozzles. If not, tighten the wing nut screws some more. Once you can get the glass in, cancel the leveling and push the bed down some. Tighten up your corner clips to hold the glass. Start pre-warmup of the bed. Once warmed up, go back into the bed leveling and do it properly. With the glass and NOT USING A Z AXIS SHIM, you'll have tighter springs.

---

Great tip about the glass setup. I had some pretty bad PLA deformation on the right side so I printed a dual fan duct right away. Really helped. I'll work on that glass upgrade. I've got a menards and lowes here and even window shops but I haven't ever seeked out glass cut to my specs. Hope one of them will do it for me. Do you think getting tempered glass from one of these places is truly comparable to the borosilicate upgrades sold online?

Since I'm starting to figure out this is more of an issue of hardware instead of software I should also ask about upgrading the hot end. Obviously during searches I am consistently running into the Micro Swiss upgrade. How worth it is it and is there comparable stuff out there or should I go with Micro Swiss?

Good to know. I won't worry so much about extruder upgrade then.

UPDATE:

I believe I have solved this issue. It looks like it was a combination of software and hardware. It seems to have been directly related to acceleration and jerk settings as well as good bed leveling.

I started by removing the zip tie holding the wires down to the hotend as well as changing the orientation of the parts. I was still seeing the issue on one part more than the others. After watching closely I realized that using simplify3d my priming line up front primes the extruder then at the end of the line moves another 10-20mm or so VERY slowly with no extrusion. I don't know if this is a retraction setting, a wipe setting, or what. Having come up short there I solved this issue by printing a 3 line skirt around my parts.

What was happening was that last movement on the priming line was doing something to take pressure out of the extruder (please help me if you know what is causing this slow movement with no extrusion). The first part wouldn't get but a little bit of filament laid down. Basically was a layer skip that caused the rest of that middle part to look crappy. After adding the skirt I was getting solid application and a solid part.

After doing that I still saw some really ugly parts. I went down to two parts and both were coming out pretty gnarly but at least they looked the same. It was basically "ringing" that I was getting. It just looked way worse on that part with the missed layer.

Since Simplify3d does not have acceleration and jerk settings and I could only find an Mcode script for acceleration but NOT jerk settings I did some further research and loaded up ReplicatorG. I connected ReplicatorG to my QIDI Tech 1 and looked at the acceleration settings (had to learn to open the makerware program and turn off background service so that RepG could connect). I changed them to the recommend 800/8 and wrote those setting changes to my printer.

After doing those things (some small changes but mostly adding a skirt, a fresh bed level, and changing accel/jerk settings) I'm watching a fresh set of 2 print and they're looking better than ever. However, I'm going ALL the way back to looking at retraction settings now because the only noticeable issues are falling in line with where S3D is showing the retractions. I'm going to start by turning off retraction and then move on to negative priming after retraction.

Once again if anyone knows what that movement is at the end of my priming line please tell me. Wipe and coast are not turned on but in the advanced tab there are some options ticked such as wiping for outside perimeters. Those shouldn't do anything if wiping is turned off though I would think

Found it. Here is a section of my starting script in my Qidi profile in S3D. I'll assume the "fast wipe" or the "wait for ooze" is what is causing my priming issue. I received the full script from someone and I honestly don't know what is "safe" to remove from it. Any tips?


G1 X90 Y-68 E24 F2000 ; Extrude a line of filament across the front edge of the bed
G1 X100 Y-68 F180 ; Wait for ooze
G1 X110 Y-68 F5000 ; Fast wipe
G1 Z1 F100 ; Lift
G92 A0 B0 ; Zero extruders
M73 P1 ;@body (notify GPX body has started)

Line 2-5 I'd like to remove completely but I don't really understand anything but the wait command

Triple post I know. New info, I've got a good amount of stringing on one of the pieces since the slowdown. It is where the retractions are showing on the print preview where the head crosses to the second part. Based on S3D's troubleshooting page and my recent changes I'm going to try and figure out if it is a retraction distance, restraction speed, or maybe I can change an acceleration/jerk setting that only relates to when the head is not extruding (because I haven't had this kind of string before) or a combination of these.

on the gcode side of things.
comment out the lines you want to remove and see what happens.
to commen out - just put a ';' at the start of the line and s3d will ignore it.
This way you keep the gcode in case it's needed and just ignore the bits you want to check. :-)

so:
G1 X100 Y-68 F180 ; Wait for ooze
G1 X110 Y-68 F5000 ; Fast wipe
G1 Z1 F100 ; Lift

becomes:
; G1 X100 Y-68 F180 ; Wait for ooze
; G1 X110 Y-68 F5000 ; Fast wipe
; G1 Z1 F100 ; Lift

Thanks I'll change that on my next test.

I've got the printer functioning pretty darn well but I'm super frustrated. These parts all look ripply on the center flat area. I can tell it is a retraction issue because when I change retraction settings it gets worse or better. I just CAN'T find that sweet spot. It's weird too because I've printed these with other slicers with not as much of an issue and I've even opened those up to copy some of the settings over.

I'm going to keep trying

Edit: Maybe I'm wrong. I went back to the basic retraction settings that gave me best results and chose to print thin walls as perimeters only. As I'm watching it print it kinda looks like it's printing perimeters weird and they're laying on infill or something.

printed ignoring thin wall infill. Looked best yet, still some rippling at the bottom but it didn't print another perimeter inside now matter how high I put the overlap. It's a part that is 1.5mm thick and a .4mm line width, should easily be able to fit a third in there but I guess it won't do it unless it can complete a full rotation or something.

So I went back and put the gap fill in and lowered that gap fill overlap to 5%.

We shall see

At this point I'm just going to make sure I update this because I can't let this part beat me. I'm mostly messing with infill and speed now.

I changed orientation and watched them print some more. Still hardcore rippling and I guess "blobbing". I slowed it down to half speed for more than half the print just to see and it helped a lot. When I slowed it down it had like 6 good layers and 1 bad one repeating.

Since I can't change acceleration settings in S3D (I wish I could, I don't like messing with my printers firmware) I don't know if I can justify slowing the acceleration down more just for this part because I would continually have to go in and change my firmware back to standard accel settings. I might try it just once to see if it helps even more

hmmm

Edit: spoke too soon. There's too much for it to be oozing. The more I mess with this the more I believe this is related to hidden settings within S3D. I think it is laying down gap fill. But it is laying it down when it has already laid the infill for the thin walls. It doesn't need this extra line. It's laying it down like goop too. Super loose. The ACTUAL infill it lays above and below this goop layer is laid correctly and it does not show this goop layer on the preview. Maybe it's oozing but it's an awful lot and I've already tested with ABS @ 225. That should have at least lessened it and it did not

IT'S OOZING!

Ok I got this. It is an oozing issue. On each side of these parts there is a thicker section that the head is moving to extrude a square on each side and when it does it is ooing across the thin section during it's travel move and messing up the laying down of the next outer layer

Obviously I can fix this with temperature, travel speed, retraction settings, and "ooze control" settings in S3D. However the rest of the part is great now so pretty much all of these settings should be considered dialed in. I'll start with temp and see what happens

Now that I'm not in the dark just trying random things I will change 1 setting at a time from

temperature
retraction distance
retraction speed
travel speed (doubt I will change this, speed is at 150mm/s and with my acceleration settings turned down it probably won't help to increase that)
S3D supposedly has an ooze control extrusion multiplier but I keep not being able to find it. Might try this setting too.

You da man. I really appreciate that. In doing this I've learned quite a bit and I've got this thing printing like a dream but there's something up here that I'm either not understanding or that S3D is computing weird because of the nature of the thin wall section on this.

Let me know what happens.

There's a solid section at the bottom. About 19 layers. The issue creeps up as soon as it passes this section and has just the thin areas to worry about

I've been running ABS out of my left extruder so all these settings are for that. If that is an issue give me a heads up and I can switch it to right extruder and export again. It wouldn't let me upload an x3g file so I zipped the gcode and x3g together

Attachment 10822

I edited that post a bunch of times. At first I had a 1 shell version in there. I had tried that before but I had a new way I was going to do a 1 shell version so I gave you the standard 2 shell version that has been giving me issues nonstop. My next thing to try is 1 shell (then it won't need to go do a small square on the left and right because it will only do 1 outline) and a much higher infill percentage and see how it goes.

Just to add some more. In the preview for the print if I show it by line. After printing each square in the shells (when it moves left and right and lays down that goop) as I'm going forward line by line there are 5 moves in between the squares where on the S3D preview the toolhead doesn't move at all. So I click forward 5 times and it just shows it sitting over one side of the model. I'm assuming this is when it is actually laying down this goop. Maybe in a wipe or ooze control maneuver (edit: it's a retraction. When I turn retraction off it doesn't sit there for 5 clicks like that. So I guess this has come full circle. BUT I have no stringing so I wouldn't know what to do about it)

Oh sorry yeah no problem. One sec


Edit: Here is the STL. My bad. Designed in Designspark

Attachment 10823

Quote:

---

Originally Posted by number40Fan

I'll try printing it with the settings I use and go from there.

---

coolio

Quote:

---

Originally Posted by number40Fan

I think I do have PLA in the left. Make it right and what layers/print height are you using?

---

I've got it at .2

Here are the files changed to right extruder. You don't have to print it though. No worries if you can find something slicing just STL file itself

Attachment 10824

Quote:

---

Originally Posted by number40Fan

Do you want me to do one piece or three like you were attempting at the beginning of this post?

---

I changed it to two pieces for speed sake. Either/Or should show the issue so you can go with 1

To add, I just printed 1 shell (which made it not need gap fill and only did true infill) and they're looking pretty good. Not 100% perfect but no crazy goopy throwing off my layers

Maybe your settings work better for the gap fill issue when printed with 2 shells?

Rock on man. Thanks. This has been one heck of a learning experience. I've invested a lot of time into these specific parts but I know I'll be able to use this knowledge down the road so I'm not as frustrated as I was. I'm glad I've continually narrowed the issue down. I want it solved though.

So now that I printed those two with 1 shell and 50% infill they look good. Little bit of ringing. Maybe retraction, maybe speed issue but that shows me the biggest issue is the way the gap fill that S3D auto generates is laid down. I'm going to test back to 2 shells with the gap fill and mess with those settings a bit

Yeah I'll take some pics and post.

Ok so most recent setting change is that the checkbox for "force retraction on layer change" was checked and I unchecked it. Now I'm only showing the issue about every 5 layers or so. So now maybe I'll play some more with retraction.

Pics incoming

Edit: Not bad. My single walled one with no gap fill looks close to that. That's bringing me back to these darn retraction settings again /sigh

First pix shows most recent tries oldest to newest. They do get better. Second pic shows what I'm printing right now without forcing retraction every layer. It still has issues. Retraction setting is 1.5mm@25mm/s

What are your retraction settings?

http://i65.tinypic.com/24oyb93.jpg

http://i64.tinypic.com/123nnvb.jpg

Better yet if you printed that with S3D can you export the profile and send it to me?

I haven't even tried that yet. I'll give it a shot if it's gonna put out quality stuff like that!

Sure thing. Thanks again. I'm so close to get this nailed down I can taste it

I did it! It all came down to seriously tailoring my retraction and ooze settings. Any issues with the surface seen in the photo aren't even felt. It's smooth all the way around. To be honest this got way too specific for me right off the bat. I wish I had attacked something like this in stages as opposed to all at once but I'm starting to feel like I understand retraction and ooze settings within S3D on a level that I would never have guessed this early on.

I'm working on some new product designs and most of my products will be small so getting these settings tailored as well as understanding them is really gratifying

http://pickapolish.com/imagehosting/cartridge.jpg