I feel like I've taken 10 steps backwards in a losing battle :/ My first spool was silver 3mm PLA from PPD and it was fantastic stuff. I recently ran out of that and picked up some blue 3mm PLA from Maker Shed on special. As the last of the silver was disappearing into the bowden tube I fed in the blue so that (even though retractions wouldn't work) it would feed the stuff in and be all fine. It turns out that wasn't the case when I went to check on the finished print the blue got stuck somewhere near the head. After feeding 1mm at a time and pushing on it I got it to feed into the head and melt through the nozzle. I attempted a couple of prints of [www.thingiverse.com] but they came out funky (like some layers were missing) and the tops were completely screwed up. The bases were even though and I didn't see any issues there.

Today, every print I've tried to make has failed. The base layers just will not print evenly. I feel like I have to keep my hand on the filament to keep pushing it through. You can see in the video as I explain it, but the extruder starts by feeding seemingly normally, but as I place my finger near the hold for the extruder, I can feel like filament almost slip a bit, loosen up, then tighten up again as plastic melts and the section it's printing becomes more opaque.

Feel free to ask me what all I've changed, any settings, etc. I'm really at a loss.

[youtu.be]

I have had similar problems and there seem to be several possible causes. It could be the filament - different colours have different additional chemicals in them to make the colour but this can change the way that the filament feeds and prints. However, I find that it often has to do with the tension on the extruder motor. I am not familiar with your printer but on mine there is a tension screw that can sometimes be too tight or too loose depending on the filament. Since you changed filament today it is possible that the new filament is a different size (e.g. 3.0 mm or 2.6 mm instead of the normal 2.8mm). Also, you may need to clean the extruder motor wheel as the teeth can sometimes get filled with filament shavings! Hope this helps.

There are two things I would do if you have not done them already.

1) Get a scriber (or pointed metal thing) and clean the hobbed bolt. They get clogged and the feed can be unpredictable. Make sure there is lots of pressure on the bolt too.

2) Clean the j head. A method that was taught to me that works extremely well is: Remove the bowden from the head. Heat the j head to printing temperature. Ram some plastic through it. Set the temperature to 80c and keep feeding plastic until it gets hard to push. Wait for the head to reach 80c. Pull/stretch the filiament out the j head using a rotary motion. A lot of the time this works so well I can see right through the hole in the j head.

Cheers
Robonz

Cleaning the hotend and checking the idler tension are both good ideas but may not be the issue. With the simple fact the issue started with the new filament I would say it has issues. I have had cheap blue cause similar issues and when I use cheap filament I only use Natural, Orange, Red, Silver, Grey, White. I avoid Blue, Green and Black as all my issues seemed to be with them, not all the time but when I had an issue it was almost always with one of those colors.

The jam during the second filament load could be from too big of bowden tube. Also you need to cut both ends of the filament really square. I usually score it and snap off both ends. Last thing is if there is a big gap between your bowden tube and the hotend it can cause the filament to catch. If that is the issue just screw the nut onto the bowden further so it goes down the hole to the hotend.

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@Sublime great point. That got me thinking to a problem I had. The filiament was not moving freely through the bowden cable on my printer at one stage. Where the PTFE was threaded, the tube got a tad deformed and made a tight spot. I used a round needle file to smooth it out.

Cheers
Robonz

Thanks a lot for the tips guys, I'll try these this evening and let you know how it goes.

Can anyone recommend a good place to buy filament? I'm currently using translucent green and, while cool to look at, might be contributing to some of the printing problems I'm having. I've heard good things about Ultimaker's filament, but they're in Europe (I think...) and I've procrastinated on my printed christmas gifts and need something quick Anyone know of a good supplier on Amazon Prime?

It is probably Ultimachine that you have heard of and they are in the US.

Also Diamond age solutions, Faberdashery, Maker gear and Makerbot are a few I can think of that demand a premium price but provide a higher degree of quality control and consistency.

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Thanks for the tip! I just ordered some 3mm red pla from ultimachine so hopefully it will work well for me.

My printed case Tantillus is printed in Ultimachine red on my Prusa.

The filament is 2.8mm and is pure 4043D pla which is much harder than the china stuff which is blended with something else, you could even call it brittle. You may need to tighten your extruder idler to compensate for the smaller diameter and harder material.

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Just a quick update, it looks like this stuff was a bit wider than the PPD I was using previously. I ended up feeding some filament through the tube after pulling it off and it jammed on the hotend side. Took a slightly larger drill bit to both sides and it pushed through nicely. Made this last night.

[www.youtube.com]

On a side note, octoprint is pretty neat.

So I received by Ultimachine red and I'm experiencing problems I hadn't before so I thought I'd see if anyone had any ideas on what's going on here and how I might be able to fix it.

Pic 1
Pic 2

I suspect it might be flow rate as by the second or third layer, the nozzle seems to dig into the previous layer. If that is the case, how would I fix that? Could temperature also be playing a factor? Too hot / cold? Any other ideas? Thanks a ton for everyone's help.

Nick

I agree it looks like it is over extruding.

Be sure the extrusion multiplier in the slicer is set to 1 (flow tweak).
Then check the filament diameter in a few places on the roll and enter it into the slicer.

I would recalibrate the extruder with this new filament. It may that the old filament caused the extruder to slip and thus result in higher steps per mm than it should have been.

Also if you were having flow issues with the previous plastic you were probably also having issues with getting the first layer to stick. This may have lead you to make the first layer much lower then it should have been so you will have to set the Z-offset again.

Both of those procedures are on the tutorials page of Tantillus.org

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Thanks for the suggestions Sublime. I did as you said and now my prints are turning out MUCH better. I started by checking the E-axis calibration which was pretty accurate (~49mm measured) so I didn't change anything there. I then had to fine tune the flow quite a bit (brought it down to 315 from 450) and it's not quite perfect yet (printed quite well at 299 flow and 100 precise printing, but left small holes between perimeter and solid infill at 315 flow and 75 precise printing) but now I know what to do to fix this issue. Once again you've saved the day

Pic 3

Edited 1 time(s). Last edit at 12/20/2013 12:43PM by Nick101.

Those number do seem a little strange but if they work they work. The picture does look like you are getting the correct flow now.

Check the "extruders" tab in the "printers" section of Kisslicer and make sure the gain is set to 1 . It does the same thing as the flow tweak in the filament tab but is paired with the extruder being used not the filament being used.

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Hey guys,
Recently fired up my Tantillus again after a long hiatus and I'm still having a tough time with the first few layers of a print over-extruding (even with flow set ~ 320). I've tried setting flow to 300 with better success but once the infill layers start printing, the print looks under extruded, with small gaps between passes. At this point I bump the flow rate back up to ~375 and it seems much improved. Is there a way to implement some sort of variable flow rate depending on where the print is in completion? Would this be a reasonable solution or is there an underlying problem I'm not considering?

Quote
Nick101
Hey guys,
Recently fired up my Tantillus again after a long hiatus and I'm still having a tough time with the first few layers of a print over-extruding (even with flow set ~ 320). I've tried setting flow to 300 with better success but once the infill layers start printing, the print looks under extruded, with small gaps between passes. At this point I bump the flow rate back up to ~375 and it seems much improved. Is there a way to implement some sort of variable flow rate depending on where the print is in completion? Would this be a reasonable solution or is there an underlying problem I'm not considering?

I did not re-read this thread so I hope this has not been tried.

It sounds to me like you are too close to the bed at the start. You would change the ; Z-offset positive in the prefix section of Kisslicer's Ptr g-code section from G92 Z0 to something like G92 Z0.1 (or greater maybe) and make sure the Z-offset negative is set to G1 Z0

Also I would recommend trying some diluted PVA glue (kids white glue or wood glue) or even simpler is a glue stick like these

or

etc on the bed (dry) so it is easier to print the first layer without having to squish it down.

Edited 1 time(s). Last edit at 04/08/2014 04:04PM by Sublime.

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I'm getting good adhesion with Power Pritt. on blue painters tape. The flat top of the stick is also useful for flattening down the tape too. For large prints it may be necessary to soak the whole lot in water to release the tape from the glass and then the tape from the print.

Quote
beekeg
I'm getting good adhesion with Power Pritt on blue painters tape. The flat top of the stick is also useful for flattening down the tape too. For large prints it may be necessary to soak the whole lot in water to release the tape from the glass and then the tape from the print.

Have you tried directly on the glass without the tape?

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A long time ago, before I was on the precipitous face of the learning curve, so I don't recall having success with glue on glass. I will give it another go now my printer is consistently laying down decent first layers.

I've done a few tests using the Power Pritt direct on glass over the last week. I still get a bit of lifting on large objects with sharp 90 degree corners, but I get a much nicer finish. If lifting is a problem printing on a raft works OK, but it is a real pain cleaning the raft off afterwards.

For the glue mix I use I must clean the glass well first and sometimes I will apply more than one coat. I have also sanded the glue after a few coats. Last thing I do to get parts to really stick is wipe the glue with acetone right before starting the print. It seems to activate or soften it a little as well as remove the shiny top coat from the glue air drying.

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This evening I printed an 'L' shaped part that stuck so well that I broke it getting it off the glass. A shame as there was no lifting at all. What do you find to be the best way of releasing the print from PVA? I have tried hot water, but then there is a risk of warping the part.

For delicate parts just soak it in room temperature water. For large strong parts you can tap the side of them with a hammer or other hard/heavy object and the piece usually will release. For the stuff between delicate and strong I use a scraper or medium size olfa knife blade (be very careful not to cut yourself) to get under the part and pop it off.

Edited 1 time(s). Last edit at 07/04/2014 08:12PM by Sublime.

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Thanks, I'll try those techniques.