Posts made by wwmotorsports

Have you seen this adapter from 713Maker?

713Maker - Smart Effector Ballcup Adapter

Hi all,

I have been working on calibrating my E3D Titan Aero for extruder non-linearity, and while it does work and seems to make an improvement it is very filament and temperature dependent.

So, I was going to start making a library of correction factors for different filaments at different temperatures, but immediately stopped when I realized how long that was going to take and the hassle it was going to be to remember to change those factors for every print I run.

That got me thinking, there must be a better way...

Has anyone ever thought of / tried to implement an idler wheel with a hall effect sensor (or any other rotary sensor) on the filament before it gets to the extruder that actually measures the extrusion distance, compares it to the expected value, and tunes the extrusion rate in a closed feedback loop?

Just a thought.

Happy printing!

@garyd9 Sure! The final result is admittedly more "cobbled" than I usually prefer as a result of the RobotDigg carriages having a 40mm distance between the flats compared to the 35mm on the printed effector of the D300VS+, but here goes any way:

• Purchase 3x 700mm MGN12H rails and carriages from Iverntech on Amazon.
  • I started with the ones from RobotDigg, but they were really terrible quality, so I wound up using the rails from Iverntec.
  • I found that carefully pulling the carriages off of the rails, cleaning with isopropyl alcohol and re-lubricating with Slick 50 Supercharged One Lube is really worth the effort because they move completely smoothly now
• Purchase a set of RobotDigg carriages MGN12H-OP-BLACK
  • Carefully chase the threaded holes with an M3 tap as deep as you can go because the anodize inside the threaded holes really gums the threads up
  • Again carefully, file off 0.5mm from the faces that each ball stud will mount to for a total distance of 39mm between the faces (this will make more sense later)
• Thread the ball studs in as deep as they will go on each carriage by hand and note that one side has a shallower hole than the other. Remove that ball stud and shorten those threads by that amount and re-install the ball studs on to the carriages so that they are fully seated.
• Get ahold of some NO snap acting microswitches with a lever arm and replace the ones that came with the printer because without the lever the switch will not activate on the top of the MGN12H carriages (the screws for the wipers are taller than the switch plunger)
  • While you are doing this, re-route the wires for the switches to the sides of the towers because you will be using the inner-most face of the towers to mount the rails.
  • Go ahead and slide the switch mounts up as high as they will go and tighten the mount back down there
• Get some M3 x 8 screws and some 2020 T-slot "hammer-head" M3 nuts and install the rails on to each tower, facing inward.
  • I did this by putting bolts in the holes of the rail at even spacings (I think I started one hole from each end and left 4 holes between bolts on my rails) and loosely starting the nuts on the threads.
  • When you put the rail against the tower and start to tighten the bolts, the nuts should center the rail on the tower nicely.
  • Place the top of the rails just beneath the lever arm of the end stop switch so that when the carriage comes to the end of the rail, it will hit the endstop switch before balls start to fall out of the carriages.
• Assemble the RobotDigg carriages to the linear rail carriages with the tensioning screws pointed down, install the belts and tension them
  • If you watch the video on their website, they show wrapping the belt around the tensioning blocks and pressing them into the carriage. Save yourself the headache, it doesn't fit like that. Just run the belt down one side and get some slightly larger washers to pinch the belt in place when you tighten the tensioning blocks in place.
• Purchase some 1m thick shim washers from McMaster (PN 98055A099) and place two between each ball stud and the effector. Now both the carriages and the effector have 39mm between the ball studs.
  • I originally planned to shim the effector to the full 40mm of the carriages, but I couldn't get the nuts for the ball studs in the effector to catch. With the 39mm spacing, the nuts just catch on the ball studs in the effector and you can tighten them to the point that they start to compress the plastic in the effector.
• After all of this work you'll frustratingly notice that the springs between the carbon rods don't fit over the carriages anymore. For a moment I thought that was game over myself, but then I just decided to try getting some zip ties and strapping the springs slightly down the rods, away from the carriage so that there would be clearance. To my surprise, this actually works very well.
  • The zip ties do walk around on the rods a little, so I may add a little epoxy to hold them in place at some point. For now, however, periodically moving the zip ties back to where they should be seems to be working ok.

Now, after ALL of that work, you should have a rock solid, smooth moving delta carriage system that will eliminate what appears to have been the source of all of my problems. Run the auto delta calibraion a few times, upload the values to your config file and smile at how nice your prints come out all of the sudden!

Happy printing!

Hello all,

Sorry for the long silence here, but I thought I would share my findings and final satisfaction with this printer in case anyone runs into the same problem.

I wound up building a new effector to use a standard E3D V6 hot end and built a 9:1 belt reduction drive bowden extruder since I was so certain the extruder was the source of the issue, but low and behold, the exact same surface ripple persisted...

At this point, I was at the end of my rope and almost gave up but just started really trying to shake stuff around. It wasn't until then that I noticed that the carriages on the printer were flexible enough that I could pretty easily get one of the three wheels to come off of the aluminum extrusion if I pushed in the correct directions. So, I ordered some 12mm knockoff MGN12H rails and carriages and the delta carriages from RobotDigg. With a little bit of cursing and filing, everything fits up pretty great and the first test print shows that the artifact is GONE!!

So, I put the E3D Titan Aero back on and the result repeated, NO MORE SURFACE RIPPLES! After all of that, it was just an issue with the carriages being a little too flexible and creating what must have been some kind of stick/slip where the wheels are supposed to roll up the towers...

In the links below, you'll see a picture of the installed rails and the before and after test print comparison. The black print is with the new rails and the blue print is with the old carriages. The horizontal sections you see are my experimenting with different speeds and extrusion rates.

New Rails Installed

Printed Results Comparison

With that change, this is now hands down the best "consumer" grade printer I have ever been around and would gladly recommend it to anyone that can get their hands on one.

Any way, happy New Year and happy printing!

@phaedrux YES! That looks identical to the pattern I'm seeing, glad I'm not the only one.

Out of curiosity, can you tell me the length of one of the straight walls and count the number of bands you see where they interesect the top edge? I'll throw your numbers in to my calculator and see if we are getting the same volume of extrusion/band.

If it turns out that the volume/band is the same on your CoreXY as on my Delta, then we may really be on to something.

I ran a print last night that really shows this issue as clear as day. Normally, I would immediately say it is an under extrusion issue, but my single and double wall test prints come out at the exact right wall thickness, so I don't think that's the. See the link below to see what I'm talking about.

Extrusion Pulse Photo

Anyone else have further thoughts?

@dc42 The period of the banding corresponds with 0.17mm of linear filament movement into the extruder, or roughly 0.405mm^3 of volumetric extrusion. As far as I can tell, that coincides with the following movements in the extruder (roughly):

• 9 full steps of the stepper motor/pinion gear
• 8.2° degrees of rotation of the stepper motor
• 2.7° of rotation of the large drive gear
• 1/2 of the pinion gear pitch

The only thing that I can relate any of those numbers to (and this is a stretch, I'll admit) is that there appear to be only 2 teeth meshing between the pinion gear and the drive gear, so it is possible that this phenomenon is related to every time a tooth in the gear drive makes or loses contact with its mating gear. I wonder if switching to a helical cut gear set of the same size would eliminate the issue?

@Phaedrux FYI: I replaced the bearings in the extruder last night with brand new replacements from E3D with no impact to the banding. Nice to have that eliminated as a possible cause though.

@JoergS5 Thanks, I am interested to see what the community thinks as well. While that may be a great explanation for other controllers, the Duet Wifi hasn't used segment approximation for delta movements since 2015, one of the major reasons that it has taken the delta printer market by storm. There may be some funky back torquing going on for other reasons, but I don' think it is as a result of segmentation.

It also turns out that I was moving too fast when doing those calculations and put the gear ratio of the extruder in the wrong place (how embarrassing), and the volume/step doesn't line up with the ripples at all... Sorry for the red flag folks... See my updated calculations with the gear ratio in the CORRECT place below:

CORRECTED Extrustion Ripple Calculations w/ Extruder mm/Step

The extruder is still roughly 4X less precise than the movement of the print head, but not nearly as bad as I was thinking. I guess I'm back to digging for a mechanical issue and I'll come back if I find any solutions.

EDIT: I had the extruder gear ratio in the wrong place in the calculations, please see my comments in the next post

Well, I am not 100% sure, but I think this may all stem from a full step positioning error of the extruder stepper, at least in my case.

I was updating to the 2.02 firmware last night when I noticed that the StealthChop mode was now available, so I thought I would give it a try. First thing, it was really impressive how much quieter the printer was with that chop mode enabled. Second, there was a noticeable difference in the print quality changing the chop mode, which I did not expect. In the picture below, the part on the left was printed with StealthChop and the part on the right was printed with an old firmware version using constant off time chopping. The difference isn't dramatic, but it is noticeable:

StealthChop vs Constant T-Off

I wondered why that might be and I did a little research about that chopping method and saw that they claim it helps minimize zero-crossing positioning error. That got me thinking and I calculated the volumetric flow of the Titan Aero per full step of the extruder and compared that to the length of extrusion required to consume that same volume of filament (accounting for the fact that the edges of the extrusion are actually radiused). Lo and behold, the spacing between the ripples in my prints match the volume of extrusion per full step of the extruder almost exactly for all of the layer heights I have tested. See a screengrab of my calculations below (note: I'm tessting with a 0.6mm nozzle):

Extruder Ripple Calculator

I figured this all out pretty late last night, so I haven't had time to experiment more, but my next step is to switch the extruder stepper to the other driver that I am currently not using to see if that helps. However, after a little more math, I'm not wildly optimistic that even the most precise stepper driver would fix this.

I have a 400 step/rev stepper with a 16 tooth pulley on my towers, giving me 12.5 full steps/mm of travel for the motion components, which seems reasonable that the human eye would not likely detect the stepping error at that close proximity.

The extruder, on the other hand, with a 400 step/rev stepper, a 3:1 gear ratio and a 7.3mm hob printing with a 0.6mm nozzle at a 0.2mm layer height has a 2.86 MM/STEP ratio when you compare the volume of extrusion per full step to the motion required to consume that volume. In other words, even with a geared extruder and a 0.9° stepper, the extrusion is 35.75 TIMES less accurate than the motion of the carriage...

It seems to me that the only way to remedy that is to run an extremely high gear ratio on the extruder which would cause significant speed issues, or run a filament diameter smaller than the nozzle diameter to alleviate the natural "inverse gearing" that happens when you squeeze a 1.75mm filament through a 0.4mm hole (inverse volumetric ratio of roughly 19:1 by my math).

Someone, please tell me my math is wrong because otherwise, this is a pretty sad realization...

@dc42 , any thoughts on this?

@JoergS5 : that's definitely a possibility, but I have tried two different brand new E3D steppers (compact and pancake) and had the exact same defect so I doubt that's my issue in this case.

@kuhnikuehnast : what kind of extruder are you running?

@garyd9 , sure thing. See the link below:

https://forum.e3d-online.com/threads/titan-aero-repeating-pulse-pattern-on-prints.3138/#post-32237

@Phaedrux , thanks for the tips! I definitely agree that this thing appears to be pretty picky. I have already clocked the body and adjusted the large gear on the hob to get the hob and filament path to align. I have replacement bearings on their way as I type this, so I can eliminate that as the issue soon.

The only other thing that I can think of is where the stepper shaft gets centered into the heat sink. Since there is not a bearing in there and I'm sure that the idler is moving the shaft around a little, I wonder if the shaft is actually making contact with the aluminum housing and causing a repeating stick-slip condition? Hmmm...

If I can't get this resolved shortly, I'm probably going to nuke the Titan Aero and go get an effector from 713 Maker and put an E3D V6 and a Zesty Nimble on it since I had such good luck with that basic setup in the past. I'll report back on whatever I find that actually fixes this!

Well, everyone who had money on the extruder as the source of the problem can cash their chips in.

@DigitalVision and @JoergS5 , thanks for pushing me to take a closer look at the extruder, because I was dead convinced it was an issue with the motion system.

I considered that under extrusion might have been the issue, so I just cranked up the extrusion multiplier during one of my test prints, and sure enough, the pattern immediately changed. Interestingly, there was no actual under extrusion as the printed width was exactly what was requested, so I did another test.

In the image linked below are three test prints at different layer heights with otherwise identical slicer settings. On the largest layer height print, the imperfections are so close together they are almost hard to see, but as the layer height gets smaller the "ripples" get farther apart and at a shallower angle. I repeated the test at all kinds of amperage and micro-step combinations and got the same result. For grins, I also tried another extruder stepper and different filaments but got the same result. So, as far as I am concerned, there must be some mechanical issue with the E3D Titan Aero that repeats at a constant volumetric extrusion amount, causing the issues I have been having...

Layer Height Comparison

For now, I'm going to take this to the E3D forums for some more focused discussion, but if anyone has any other suggestions, I'm all ears!

Thanks again for the help everyone.

@Phaedrux : I really wanted you to be right because that would be an easy fix, so I broke down the extruder last night to check the bearings, but unfortunately, both bearings were smooth as butter...

@Alexander-Mundy : My last printer (that I sold to build this one) was a Rostock V2 that I had put a Duet Wifi on and a Zesty Nimble as well. I had some growing pains with that extruder including the bad gear mesh inside of the extruder, so that was one of the first things I checked when I had this problem. Last night when I had the extruder apart, I even used an old Nimble trick and added some 30K diff lube to the gear mesh to make sure that friction in the gears was not my problem.

To be sure to eliminate the belts/gears as the source of the issue, last night I double checked the alignment of the frame top to bottom, checked that all of the bolts in the frame were tight, shimmed the gears and idlers so that the belt was within +/- 0.1mm parallelism to the towers across their whole length and removed the guiding flanges from the pulleys. One of the belts was rubbing on the flange of a drive gear a little, so I was optimistic that this change would be the magic fix. Unfortunately, even with all of the above checked and tweaked, the ribbing still persists...

The only other thing I might try to completely eliminate the belt/gear interface as the source of the issue is to try to run smooth drive and idler pulleys on the back side of the belt, but that is obviously not a long-term fix.

I was starting to think I might just be crazy, but then I picked up a project I had printed with some parts from my old Rostock and some from the D300VS, and unfortunately, there is a visible difference in print quality between the parts. In the picture linked below, the upper portion was printed on the D300VS and the lower portion was printed on the Rostock using the same slicer and the same roll of black PLA filament.

D300VS vs Rostock Print Comparison

I'm 100% sure that the geometry and design of the D300VS is better than the Rostock, so I'm really stumped as to what is still causing my issue.

@dc42 : Is it possible I just have a bad stepper driver?

Just in case I'm missing something obvious, here's a link to my config file if anyone wants to comb through it.

D300VS Config File

Thanks again for trying to help everyone!

@JoergS5 The frame is rock solid. The D300VS is an all metal frame design with delrin roller wheels, carbon rods with spring loaded ball-cup ends, SLS nylon carriages and effector and a direct drive E3D Titan aero extruder (D300VS Kit Link). By all accounts, it should be a really very excellent printer because the components are all top notch, I'm sure there is just something I am missing.

I printed a tall single walled 40 x 40 tower in vase mode to show what the surfaces look like. The pictures of the 4 sides are linked below:

Side 1

Side 2

Side 3

Side 4

As you can see, the pattern is pretty consistent up the height of each side, but changes from side to side, which makes me think it has to be something wrong with the motion system (whether mechanical, electronic, config settings or slicer, I have no idea) not the extruder.

Any new thoughts with the added pictures?

Hey guys, thanks for all of the quick and thorough responses! Sorry for the delay in getting back, but I was out of town for a long weekend.

@JoergS5 : I had the same thought, so I tried printing in different areas of the bed and at different angles. While the effect changes in pattern slightly, there is no perfect position or alignment that I could find that would make the pattern disappear. In the past, I printed a single walled, 3 sided "propellor" with each one of the legs perpendicular to each of the towers increasing speed every 5mm of print height from painfully slow to right at the max flow rate of the E3D Titan Aero that came with the printer. I have made a lot of changes to the printer since then, but at the time I was not able to discern much of a difference in the pattern with changes in speed. I may try to print something similar again tonight, but make it 6 sided so that each pair of towers is split by a leg of the print to show the effects of that.

@dc42 : I am running 0.2mm layer height currently. I tried the "Golden Ratio" height of .1618 with no discernable change in the effect. One thing I did notice last night while messing with this is that the LED lights on the printer flicker at the exact frequency of the "PID" pulses of the heated bed. I was very optimistic that these power fluctuations may have been the culprit and forced both heaters back into bang-bang mode and turned the heated bed off after the first layer for good measure. While this did get rid of the LED flicker, the surface pattern persisted.

@DigitalVision : I was very optimistic that your suggestion was going to be the winner because I have had luck with improvements in quality on my old Rostock V2 (heavily modified, the only thing left of the original printer was the frame) when changing the V6 nozzle from a 0.4mm to a 0.5mm. I have been printing a single wall 40mm x 40mm tower with rounded corners to try to isolate this problem because that really seems to show the surface defect, and unfortunately increasing the extrusion width to 0.6 made a very little discernable difference to the surface pattern. I didn't get a chance to take any pictures of the print at 0.48mm vs 0.6mm extrusion width, but I will do that tonight when I get home to give some more examples of what I am dealing with for everyone to ponder.

I'll make some more test prints tonight and post the pictures for everyone to take a look at and hopefully one of you will find the answer I haven't yet!

Thanks again, everyone.

Hello everyone,

I have what seems like an unsolvable problem with my recently built Ultibots D300VS+ that I cannot work out the route cause for and I would love some tips or ideas!

Ever since I built the printer, the movement of the machine has seemed pretty smooth and the repeatability and accuracy of the calibration results absolutely blew me away, but there has always been some distinct banding/rippling that I cannot get rid of.

I finally printed an object with a long enough straight wall to be able to see that the defects, in fact, do not repeat exactly with distance, but change in spacing and angle along the X-axis of the printer. See the images below:

Print Defect Overview

Print Defect Positive X Direction

Print Defect Negative X Direction

As you can see, the ripples get closer together and steeper as the print head moves in the positive X direction, but I cannot for the life of me figure out what is causing it.

Things I have tried to eliminate the issue so far:

+Increase/decrease stepper current
+Increase/decrease microstepping
+Increase/decrease speed/acceleration/jerk
+Increase/decrease print temperature
+Change microstep chopping mode
+Twist stepper motor wire pairs
+PID tune hot end and heated bed
+Increase wire gauge to hot end and heated bed
+Belt/Pulley changes
-Gates brand GT2 x 2mm timing belts
-High quality 16 tooth drive pulleys from SDP/SI
-High quality 16 tooth idler pulleys from SDP/SI on 4mm shaft and bearings
+Check belt tension with resonance gauge
+Check carriage wheel tightness with the recommended drop test
+Increased amperage 24V power supply
+Changed stepper motors to SteppersOnline 17HM19-2004S
+Rebuilt Titan Aero countless times to check for gear/pulley alignment
+Checked rod lengths to all be the same
+Shimmed under balls for rods to have identical spacing between to +/- 0.05mm on carriages and effector
+Lubircated rod/ball joints

Does anyone have any recommendations or insight as to what I can do to fix this??

Thanks ahead of time and happy printing.

It appears that there was an error with the data in my config-override file not being used that was causing the issue. I deleted the config-override file and added the M501 command to the end of my startup script after the probing and the first layer height is perfect every time now. Thanks for the expert advice as usual!

I have a similar issue, but I am running auto-calibration and bed mesh in my startup script and do not home between the end of the bed mesh and the start of the print.

I still wind up baby stepping down .15mm at the beginning of each print, regardless of what I set my z-probe offset at...

As an interesting test before making the longer arms, I just reduced the calibration radius to 87.5mm and reduced the probing radius for the bed mesh correspondingly, and the results were pretty astounding. Previously, the best calibration I could get was roughly 0.18 deviation, and with no physical change the the printer, the deviation went down to 0.021!

The bed mesh in the smaller radius was also greatly improved. Linked below are the results of the bed mesh at a 140mm radius followed by the 87.5mm radius.

140mm Radius Bed Mesh

87.5mm Radius Bed Mesh

I will post my results when I change the rod lengths as well.

Perfect, that's exactly what I needed to know. Thanks!

Sorry to dig up an old thread here, but I am fighting the same issues with my Rostock with all of the trick laser components.

I eliminated the "ridges and valleys" in the bed mesh by upping my stepper current and lubricating the joints of the 300.15mm Trick Laser arms with some 50K diff lube for RC trucks. When I got that result, I was initially very excited, but with the ridges gone I could see the same three point high/low shape described by many other users across this forum.

I have the components to build some new arms to whatever length I choose, but I am having a hard time deciding what length to go with as a compromise between a) getting a good bed leveling result and calibration via FSR by eliminating the effector tilt and b) having the arms become dangerously near vertical when getting near to the edge of the bed near a tower.

Can anyone report further on the performance of their Rostock with longer arms? Have you had any trouble with being too close to vertical on the arms when near a tower?

Thanks ahead of time!