Wall/short wall wall is overextruded, causing a huge mess.

[626Pilot]

Short wall mess.jpg (79.74 KiB) Viewed 7572 times

It seems the Wall is overextruded on purpose, probably to help purge the last filament color for multi-extrusion. That's a nice idea, but the way it's implemented drags filament all over the place and leaves ugly pockmarks on the finished object. It might work OK with ABS, but this is PLA, and frankly the results look terrible. You can see telltale blobs on the left edge of the wall.

The filament is PLA. It's being extruded at the lowest temperature possible. Filament diameter was set by taking the average of ten measurements, each a few feet apart on the spool. Filament flow was further tweaked by printing a single-walled object, and modifying the Flow Tweak until the average wall thickness matched the specified extrusion width. In other words, the filament's extrusion rate and hot end temperature are as they should be.

I'm using KISSlicer Beta 2.20 for Linux. There doesn't seem to be a setting specific to the wall's extrusion rate. There is a flow rate setting for support, but that also effects the main support, which I don't want it to.

I also tried making prime objects of my own, to use instead of the Wall. Unfortunately, even if I give the STLs sequential file names (1, 2, 3, etc.), so they show up in the directory in the right order, I can't make KISSlicer use them in the right order. It will draw the objects in whatever random order it wants, meaning the prime objects never get drawn at the right time and there's some nasty color bleed.

Is there anything that can be done about this? I really need this slicer to do two-color work, but at the moment it seems incapable of doing a good job.

[EddyMI3D]

Hello Pilot!

That looks really nasty
May I ask, what the lowest temperature really is? Even PLA can have different temperature parameters depending where you get it from.
I usually work at 185°C, some PLS need to have a bit more.

Second, how did you set your Destring parameters in the "Matl" tab? (lower left box)
I also had issues with this "hair". So I raised these parameters.
Prime 4, vP 65
Suck 5, vS 15
Min Jump 1

Btw: I work with 3mm filament

You may have to experiment with these parameters for different PLA material, but with some effort, you can get great results.

Eddy

[626Pilot]

The temp is 185, which is the absolute lowest I can go on both filaments. This is with a Cyclops hot end, so the retracts have to be fairly short or the hot end will jam.

Prime: 2mm, vP=20
Suck: 2mm, vS=15
Min Jump: 0.1, Trigger: 1
Z-lift: 0 (have also tried 0.1 and 1)

This is with 1.75mm filament and a 0.4mm nozzle.

[lonesock]

Hi!

Question: does increasing the wipe length in the material's destring settings improve matters? What is it set to now?

Edit: hmm, never mind, the wipe for the wall is not affected by that. I've been away too long. I'm looking into this.

thanks,
Jonathan

[inventabuild]

626Pilot, I'm also printing with the e3d Cyclops hot end, KISSlicer Beta 2.2 using Wall (all layers) and Hatchbox PLA and I am getting awesome prints without any stringing:

dragon with heart and wall.jpg (97.7 KiB) Viewed 7518 times

dragon with heart.jpg (88.89 KiB) Viewed 7518 times

I doubled the size of the dragon + heart integrated stl by entering the value 2 in KISSlicer's "Scale by X" feature and I had to set the Wall's "Inflate Raft & Prime Gap" = 80 in order to purge the old color out of the nozzle upon extruder change. It's a pain figuring out how large to make the Wall in KISSlicer in order to purge the old color out plus there are other issues associated with having the Wall so far away from the part. This is why I requested Solid Prime Pillars here viewtopic.php?f=13&t=830. I like your idea of utilizing infill as part of the purge process even better (viewtopic.php?f=13&t=793). If I remember correctly my print time about doubled with such a large Wall radius so utilizing infill to help purge the old color out would drastically cut down on print time and save some money on filament too when printing with hot ends like the Cyclops. I really hope Jonathan can implement these features soon.

Here's my Matl settings:

Matl Settings.JPG (55.18 KiB) Viewed 7518 times

I have 800 mm bowden tubes so I need the 4.5 mm Prime & Suck. I discussed this with e3d (their web site says 1.5-2 mm max for the Cyclops) and they said they also use 4.5 mm Prime / Suck numbers when printing with the Cyclops and longer bowden tubes like mine. I also found if there is some of the old color still coming out with the new color this can adversely affect the flow of the filament. In general one of the big reasons I've been successful printing with the Cyclops is because I'm printing with Bondtech QR extruders. These extruders are awesome at eliminating slippage and providing smooth primes / retracts. They accomplish this utilizing two counter rotating drive gears. The Cyclops is a high pressure extruder so I needed an extruder that was up to the task. If you're interested here's where I got mine http://shop.bondtech.se/ec/extruders/bo ... ersal.html and here's a picture of my set up:

IMG_0835.jpg (61.9 KiB) Viewed 7518 times

Martin (the developer) sells mounts and both left and right hand versions.

Based on my experience Jonathan does a good job with Wipe on the Prime Pillar and Wall, but I'd like to see the option to set our own distance for the Wipe. I'd also really like to see the ability to change the location of the Prime Pillar (N,S,E,W).

If there is an issue with the KISSlicer Wall I'm not seeing it, but that's not to say there isn't an issue that for some reason you are experiencing. If there's any other settings or info you'd like to see please let me know.

[lonesock]

I just posted an updated build which (hopefully) fixed an issue where retractions weren't issued when they should have been. There's a decent chance that fixing that bug may really improve the prime wall / pillar behavior.

Regarding switching materials in a single extruder, then purging a certain amount of filament, would it work if I let you (optionally) specify one object be the prime object? That is, on each layer it would go first? That way you could size it to use the proper filament.

thanks,
Jonathan

[inventabuild]

Jonathan, I too was trying to create my own purge prime pillars for the e3d cyclops hotend (viewtopic.php?f=11&t=826) and failed because KISSlicer would not let me pick the order of objects to print. If, as you suggested you would let us specify one object to be prime object that would always print first, would KISSlicer manage that object as follows?

1. Automatically extrudes the correct amount of filament whether one or both extruders are used on a layer?
For example if I made the prime object a cylinder would KISSlicer extrude a full layer height if only one extruder is used on a layer and extrude a 1/2 layer height / extruder if both extruders are used on a layer? Or would you want us to configure the prime object a certain way in order to work with your proposed feature?
2. Extra long wipe for the prime object regardless of wipe setting for the part? The current extra long wipes on the existing Wall / Prime Pillar are really helpful at preventing drips on the part so I'd like to keep them (unless you want to make it a user defined value).

I really like the idea of letting us design our own prime objects so long as KISSlicer can manage them as prime objects in order to take some some of the complexity out of the design process (and let me concentrate more on designing my parts and less on my prime objects).

[626Pilot]

I wrote a post-processor that does coasting. I'm working on pre-retraction, but the code isn't on GitHub yet. Anyway, you can get the coasting plugin here: https://github.com/626Pilot/KISSCoast

If you need any support for this plugin, post here. Keep in mind that it's experimental, designed as a proof-of-concept so lonesock doesn't have to wonder whether he's wasting his time building it into KS. Also, please don't ask for help until you've read the instructions at that link. If you're on Windows or Linux, you can't expect it to just run out of the box. You need a PHP command-line interpreter. That's included in all MacOS versions, starting from OS X 10.0 fifteen or so years ago. On Linux, you'd install either php-cli or php. On Windows, you'd install PHP. Instructions for this are on the GitHub page.

[626Pilot]

I just posted an updated build which (hopefully) fixed an issue where retractions weren't issued when they should have been. There's a decent chance that fixing that bug may really improve the prime wall / pillar behavior

It seems better now, but it still leaves tiny dots where it pauses in the outer loop to retract. With the filament flowing, the effector comes to a dead stop. No matter how fast you retract, some plastic will always ooze, leaving blemishes. I believe either pre-retract, or some falloff in filament feed rate, would correct this. Presumably, pre-retraction - where it figures out the ratio of retraction speed to head speed, and scales retraction to fit the remaining segments in a path - would be more "bulletproof" because it would be actively sucking the plastic back up into the hot end, rather than passively halting extrusion and waiting for voids to form. With coasting alone, it will drool a lot when it primes after going to the start of the new path. I think a falloff in extrusion rate might have the same issue, which is why I'm focusing on pre-retraction.

[626Pilot]

I've decided to abort work on pre-retraction. I don't know how to make it work across a wide range of head vs. retract speeds (for example, head is 80mm/sec, retract is 20mm/sec, and it has to figure out how to pre-retract at the right speed without running past end-of-path, etc). I also thought about doing an extruder speed falloff, but that would require splitting lines into many individual steps, and my head is already spinning from trying to do pre-retraction.

lonesock, I think you should try falloff first, and if that doesn't work, maybe pre-retraction. Programmatically modifying a text file without stepping on the existing formatting (comments, empty lines, etc.) is not the easiest thing to do, and this is making my head hurt too much to continue.