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I’ve been trying with a new CTC dual extruder printer from ebay (read lots about them on here), but so far I seem to always get the issue that the layers start stretching upwards and then getting tagged by the next pass and dragging it. I’ve tried with some different settings, but not sure what the issue could be. I’ve tried setting the minimum layer time to 15 seconds and reduced the movement speed to 40mm in makerbot before exporting the x3g to the SD card, but I don’t think it’s actually waiting for the 15 seconds.

Any suggestions would be appreciated!

See the examples below, from left to right:

1- default settings, 230oC, 0.1mm, 110oC heated bed

2 - default settings, 190oC, 0.2mm, 110oC heated bed

3 - 200oC, 0.1mm, 50oC heated bed, 40mm speed, came unstuck apparently!

4 - 200oC, 0.1mm, 50oC heated bed, 40mm speed, new sticking tape base

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IMG_20160916_235748 (3).jpg3286×2432 1.57 MB

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I have spent the last 10 minutes looking at your photo, and here are some suggestions.

#1. You are printing too hot. This is apparent in the way your prints look, as they are very shiny. If you compare the plastic going in, to what you have printed, you will see it is shinier on your printed model than it is on the spool. For now, lower your printing temps, until you get dialed in, then- if you like the shiny, which I do, you can move back up.

The other sign that you are printing too hot is that your prints are sagging in areas they really should not be.

I am guessing your 4th (headless) print is cooler.

#2 Active cooling, if this is PLA. This will cool the layers as you print, preventing the curl that your extruder is hitting previous layers.

#3 probably lower you extrusion multiplier, as you are overextruding, which makes the plastic too thick, helping the extruder to hit previous layers.

Finally, I would suggest you start with calibration cubes. No point in trying to dial everything in with a model that takes so long.

Read the sailfish manual. Print 100% infill until you get everything dialed in for a great print. (100% shows temperature issues and overextrusion issues well)

Finally, if this is ABS, then you dont necessarily want a fan on your print, as it will help it curl, if it is PLA, use a fan on your print, and it will help it not curl.

Also, 15 seconds may not be enough. Or print two at a time, or a cooling tower (tall cube) so each layer has enough time to cool before the next layer is put down.

I can help you further if you tell me what the material is, if you have a heated bed or not, if you have a fan or not, etc.

One other note: Watch your print closely. I am not sure this is curling, causing the print to warp upwards, and getting caught.

This looks more like hot plastic has poor bridging or layers on itself on the print, causing it to spaghetti, leaving curls that get hit by the extruder. This is a cooling issue, probably combined with an overextrusion issue, and probably not warping or curling, if I am guessing, which I am.

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Good advice from perry there, but the shininess might not indicate too hot. The PLA that came with my printer was oddly shiny but did print ok with the right cooling.

You have to regard active cooling as essential really. Print the active cooling fan duct v2 from thingiverse, but the mosfet and hook it up to the extra output in the motherboard.

In the meantime, a desk fan positioned 4’ away from the printer will make the world of difference.

But it the best advice, always, is to practice practise practice with 20m calibration cubes until you find settings that work for you and learn what’s not right. There’s a perfect STL for this included as a test print with ReplicatorG

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Thank you for looking and all the useful feedback! I can’t believe I forgot to say that I was using PLA, I’ve cursed everyone else on the forum who doesn’t mention it too…

I think the main thing here is getting a fan set up. I’ve got a fan that came with the CPU heatsink, but I’m not sure about hooking it up. I’m not sure that I’m too hot, the 4th (on the right, headless) is hotter than the others (left to right: 230, 190, 200, 200). I think that it was too cool, and I was having issues where the output was patchy, I think maybe the extruder was struggling to push through, perhaps.

Before seeing your message, I’ve disassembled and cleaned everything out, then I’ve done one more print at 210oC and 40mm/s and it seems to have gone better, although the model is wider. It was also cooler on the day, which may have helped.

I think printing the fan mentioned in the other comment will help, but hooking up the electronics might be a bit of a challenge!

Also, you’re right, I should do calib cubes, but I got bored after the first one! Christmas morning feeling over here :slight_smile:

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Thanks for the advice. I think it’s more an issue with cooling than running too hot. I actually dialed it up to 210oC and slowed the movement speed down for one yesterday and it was the best print so far.

That additional fan design looks like a great plan, is it easy enough to hook up the electronics? I can see the explanation on the thingiverse post, but I can’t work out what will need to be soldered to where…

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as an aside, of all my PLA, it’s the black one from which I get the worst results. The layers never seem to merge very well and you end up with very well defined layers - almost string like - just like in your photos. All my other PLA spools (maybe 6 different colours) perform better than this.

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Now that I know the printer is working to a ‘passable’ level, I’m going to pick up some other colours. Didn’t want to go all in until I knew it was ok!

I’m being recommended to go to ABS though, and that it will be easier to work with and you can do the acetone smoothing. What’s the benefit to PLA? You seem to like it enough to have 6 different colours!

Thanks

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PLA is a lot easier to print. ABS is difficult - first you have adhesion issues (I use acetone+abs slurry on glass, it sticks ok). You need the HBP hot (mine wouldn’t go hot enough til i fixed the thermistor - see my thing on thingiverse). But ABS is very prone to warping if it cools too much whilst printing.

I do recommend you try some ABS though - you can then print the cooling duct.

I quite like printing PETG these days. It prints almost as well as PLA but has many of the properties of ABS (it’s quite strong, not brittle, doesn’t biodegrade like PLA)

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Buy good filament. Cheaper filament, particularly from places such as china where monitoring this is not necessarily happening, can have a lot of random plastic thrown in as filler. Black is harder because it deflects heat, but also because if you are going to throw crap filler in, black is the color you are going to do that with. Better brands seem to print better.

Also, get good with PLA first, I always recommend. Once you get dialed in with PLA, then experiment with others.

ABS is harder to print with. Once you get good at it, you can get really good prints, but it is hard to keep it from warping, sticking, etc.

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Thanks, I’ll try getting another filament and see how it goes. Is there a brand or two you’d highly recommend? I’m seeing so much variety out here!