So many strings

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Norsker
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So many strings

Post by Norsker »

How do I eliminate all the strings that I'm getting. I haven't adjusted any of the values in matter control.
Last edited by Norsker on Sun Jan 29, 2017 7:05 pm, edited 1 time in total.
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mhackney
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Re: So many strings

Post by mhackney »

Assuming you are talking about PLA?

Stringing is complex but the basic process is:

Use as low temperature as possible to print. Too much temp exasperates stringing.
Use 6mm of Z lift
Use 1.5-2mm of retract at 25mm/s
Sloooowww Dowwwnnn your prints to about 25mm/s until you sort this out and gain experience. Fast speeds result in fast extrusion which can result in excess back pressure from frequent extruder moves.

Make sure your extruder is calibrated - if you tell it to extruder 100mm of filament you should measure 100mm going in.

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Ravitch
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Re: So many strings

Post by Ravitch »

Have you ever gotten that to work with the HE280? I've tried those settings in every temp in the low range with multiple brands of filament and slow speeds and still have had bad stringing with those settings. The only filament it looked ok on was my stock of colored transparent filaments, but not sure if the see through is hiding other errors. And that much Z lift leaves nasty blobs and zits on my prints every place it lifts.

I tried printing your reel design last night using your kiss profile and it also was a stringy mess. I'm just curious if you dialed those settings in with the HE280 or the E3D. The least amount of stringing I've gotten is with the Simplify3D Rostock Max 3 profile, which has a silly amount of retraction length.

All this might be for not for me to worry about, since I'm getting my 713maker parts in today and swapping to the E3D.

mhackney wrote:Assuming you are talking about PLA?

Stringing is complex but the basic process is:

Use as low temperature as possible to print. Too much temp exasperates stringing.
Use 6mm of Z lift
Use 1.5-2mm of retract at 25mm/s
Sloooowww Dowwwnnn your prints to about 25mm/s until you sort this out and gain experience. Fast speeds result in fast extrusion which can result in excess back pressure from frequent extruder moves.

Make sure your extruder is calibrated - if you tell it to extruder 100mm of filament you should measure 100mm going in.
morgandc
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Re: So many strings

Post by morgandc »

Ravitch: Any update on reducing stringing? Did the swap help?
djarmag
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Re: So many strings

Post by djarmag »

(I'm on stock Rostock hardware)
Most times it is temperature related, too high temp just oozes and cannot control flow. Then there's the extruder needing calibration and verifying 100mm extrusion = 100mm filament past the Bowden tube. Then settings using Z-lift, retraction length and speed, wipe, etc.

If you are using MatterControl, try having a base starting point with settings. I set all my parameters to the same in this guide http://wiki.mattercontrol.com/SETTINGS

Then download calibration test prints using http://www.thingiverse.com/thing:5573

Also you can try following mhackneys guide and import his settings in MC/Cura/Kiss http://forum.seemecnc.com/viewtopic.php?f=36&t=7361
Polishing and rounding the tip greatly helped me.

I just printed http://www.thingiverse.com/thing:337957 and manually changed my temps every 10 minutes by 5 degrees to see where it starts to look sloppy. I found my PETG looks best at 210 (recommended range 230-250) and with 4mm z-lift I literally watched the filament break away. After printing was done I could actually see my nozzle :lol: With PLA I think 190-195 was average around 50mm print speed
morgandc
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Re: So many strings

Post by morgandc »

My problem is that as I bring the temp down the extruder starts clicking long before I get down to the low stringing temps. If I run PLA below 215 or so click click click. With the high temp PLA I am using I get a few clicks even at 222c. Same with the PETG just much higher temps.

based on this I am trying to figure out whether I need to replace the extruder, hotend, or I suppose find the setting that increases the power to the steppers to be able to run cooler temps.

(Using KISS) Still trying to decipher mhackneys finding min. temp for the filament. I get lost at the add 1mm and redo it section.
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Re: So many strings

Post by djarmag »

To me that sounds like your nozzle has blockage, regular pla (unless contaminated) should flow very easily at those temps. Heat the nozzle to 110-140 and at the same time during warming up, pull the filament out from the hotend and it should release as soon as possible (mine does it around 110). If you see a hockey puck thingy then your Bowden tube isn't fully seated in the hotend. Verify your Bowden tube is cut at 90 degree and sand the outer diameter a tiny bit to make it chamfered. I had to do this as well to get best results as the end of my tube was slightly angled.

Example of the blockage is in this post
http://forum.seemecnc.com/viewtopic.php?f=6 ... uck#p96719

If that is good then maybe the assembly of the he280 hotend has a slight gap when installing the nozzle and the heater block. Use an open end wrench 15mm or 5/8 that fits the heater block and remove the nozzle with a 6mm or 1/4 and verify there is no trapped filament between the nozzle and Heat Break as shown in Step 14 of the assembly instructions.
morgandc
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Re: So many strings

Post by morgandc »

The other option I thought of this morning was too much cooling. What fan % do you run when printing PLA? My main project has lots of overhangs so I tend to over cool which would effect the temp setting significantly.

On the blockage option, I don't see a puck when I pull it. I will try again. Seems like it released around 115, but the PLA in there right now is high temp and a bit different. In trying to make a chart for actual temp I found where you stuck the thermistor made a huge difference and didn't get consistent enough results to chart it. I should try again.

I haven't pulled my bowden since install and haven't had any blockages over the last 4 months or so running PLA,PETG,ABS.
djarmag
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Re: So many strings

Post by djarmag »

I had it running 100% after a few layers but not enough to cause issues as you describe. The temp should stabilize after a few seconds with fans full on. This includes stock fan mounts as well as http://www.thingiverse.com/thing:1792867.

Try this while you are still assembled...
Heat the hotend to 200, then turn it off and manually extrude until it hardens and stops. Then heat it again to 115 and pull on it until it releases. That's how I check for hockey puck blockages and verify Bowden tube is seated fully anytime I need to remove the tube for some reason.

You might be onto something with the thermistor, if it isn't touching the heat block properly (if there is an airgap) then yes, your hotend thinks it is not hot enough and continues to rise which will explain the oozing, but does not explain the extruder clicking. Check that and make sure it is not damaged (remember this is a very fragile part) and verify it is touching the aluminum block when clamping it down with the screw. Also verify the two wires are not damaged and the insulation is intact as well.

Have you messed with extrusion multiplier at all? Maybe you are overextruding and your extruder multiplier setting in Matterhackers/LCD interface is >1. That matches your symptoms more imo where it is trying to extrude more than normal and creates the blockage, causing the ooze, then leading to filament grinding/clicking. Check your extruder gear is centered on the filament as well since you are here.

I can't wait to see what fixes this problem! :ugeek: :D
Last edited by djarmag on Tue Feb 28, 2017 10:39 am, edited 1 time in total.
djarmag
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Re: So many strings

Post by djarmag »

As far as the min temp calculation, 1mm = 60 so gcode you would send G0 E100 Fxx (multiples of 60, so 60=1mm/s, 120=2mm/s, 180=3mm/s)

I saw at 195 my max was 120mm/s (gcode was G0 E100 F300) which is about what you should see since F300=5mm/s and using that in the calculations was 120mm/s speeds.

I used http://www.thingiverse.com/thing:337957 and start at a known good temperature, then manually lower the temp 5 or 10 degrees until you notice extruding issues. Make note of what temp doesn't look so good, as well as your average print speed and you can get an idea of profiling your filament. Set your Zlift to 4mm, retraction 2 to 4mm @ 40mm/s, 0 extrusion during restart and watch how the filament breaks or if it still strings during the lift. These settings are default in the MatterControl guide so my numbers might be a bit different so use theirs.

The walls of this print will go from glossy to matte while lowering temps so you should see a difference. Look at how the walls are flat, once the temp is too low then you'll see artifacts and layer/banding issues. That's where you'll know your lowest temp at a certain print speed.
morgandc
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Re: So many strings

Post by morgandc »

I found that my extruder was significantly out of calibration, (over extruding)I can now get down to around 204c before any clicking starts. Running my test print now to see if the stringing is better at a lower temp.

It was interesting running lower temp tests which caused a blockage. Bumping the temp back to 230 would clear it and then I could get back down to 204 without clicking. Running 200 did some clicking, 195 was full blockage.

-Dwight
Last edited by morgandc on Wed Mar 01, 2017 8:24 am, edited 1 time in total.
djarmag
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Re: So many strings

Post by djarmag »

That's good news, one problem fixed. Different Brands have different temp profiles, I use Hatchbox for PLA (190-195 temps) and E-sun for PETG (210-220). Do you have access to a IR Temp meter of some sort? It may help to check if your hotend (not the nozzle but the heatbreak section) is the temp advertised or close to it.

When you think you have a good basis for extrusion, start with a fresh beginning of filament. With the filament grinding, you might do a test print and get false output because the messed up filament is still in the tube. Snip off the old filament and test again with new ungrinded filament. Also make sure your hands are clean when handling the filament. Oils, food, dust, etc. can contaminate the filament/Bowden tube/nozzle and give you inconsistencies. Doesn't have to be like a scientist lab but it won't hurt to be as clean as possible. :lol:
morgandc
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Re: So many strings

Post by morgandc »

Switched the filament out to normal matterhacker black PLA, clicking starts at about 195c, 200c is solid no clicks a all. The lower temp helped stringing some and the part exterior was nice as usual. The material temp was too cold, no bonding between the internal fill and the walls.

I am running the same part out of normal PLA now to see what happens.

Note: likely I need to recalibrate my flow tweak to 1 in order to get bonding/accuracy again after calibrating the extruder.... which will put me back where I started?
djarmag
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Re: So many strings

Post by djarmag »

Not necessarily. What setting do you have for infill overlap? I think mine is .06. Having too little will make a gap and the bond will never touch, having too much will slightly block the nozzle and you'll have an irregular layer or oozing mess.

Is the room you are printing in hot by chance?? I remembered when my room was hot I had issues extruding and I read the overheating can play a role.

Check your extruder multiplier is set to 1 in MatterControl, as well as on the machine LCD - Speed and flow parameter is set to 100%. Have a starting reference point and go from there. If you did calibrate the 100mm extrusion, did you update the setting in EEPROM? https://www.matterhackers.com/articles/how-t ... r-extruder

Sorry, just trying to be thorough and if you can post pics that would help too.
DeweyOxberger
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Re: So many strings

Post by DeweyOxberger »

I had extreme stringiness and it was caused by the bowden tube not being fully seated. I had a 2mm "hockey puck". Once I cleared that up I have hair (very, very fine strings). It also caused me to have to run the head hotter than I do now. If I go slow I can get it to extrude around 180 degrees.
morgandc
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Re: So many strings

Post by morgandc »

I am doing some more testing, I could get down to 212 with normal PLA, no external stringing, just internal. I will try pulling and checking for a puck :) I have very small strings that add up depending on the path/object. Got distracted by working on my enclosure design again.
djarmag
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Re: So many strings

Post by djarmag »

I have a E3d V6 on the way. There's still a tiny bit of stringing on stock hot end using Hatchbox filament at 195C - 20 to 40mm/s and 210C - 60mm/s and 5mm prime/suck - 25/50mm/s. Using PETG is at 240/245C - 50C same settings, similar results.
morgandc
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Re: So many strings

Post by morgandc »

I will be very interested to see if that makes a difference.
djarmag
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Re: So many strings

Post by djarmag »

from what I have researched, few users switched and had great success swapping from stock HE280. Not saying that you can't have good results with HE280. I'm just binge buying upgrades so I can get up to that level :lol:
morgandc
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Re: So many strings

Post by morgandc »

I did find that I had a "puck" in the hot end when I did a cold pull. But even after fixing that on the part I care about I have stringing...running the high temp PLA colder than it wants to go.
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