Why am I having to run with an extrusion multiplier of 60%?
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Latest update. I'm getting very similar results using S3D. That is to say, I get all the issues that suggest over extrusion using an "Extrusion Multiplier" of 1.00 but almost perfect results when I set it down to 0.80. So it has to be my machine but at this moment in time, I'm still stumped.
As an aside it's taken me 2 full days of jumping through hoops to get S3D to do what I ask and even so, 3 colour prints are just about impossible. What's the point of having a priming tower that gets printed after the object rather than before? S3D has some nice features but it is the biggest PITA to use (in my humble opinion). Now to see if they'll honour their refund within 2 weeks policy. (Rant over).
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I haven't yet found a way to switch S3D quickly and easily between generating gcode for my Cartesian and Delta printers. With slic3r it was really easy.
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I just keep multiple profiles, a set for my Delta, and a set for my Cartesian.
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Be sure to set the machine parameters in the individual profiles, and check the box to enable them upon use.
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Latest update. I'm getting very similar results using S3D. That is to say, I get all the issues that suggest over extrusion using an "Extrusion Multiplier" of 1.00 but almost perfect results when I set it down to 0.80. So it has to be my machine but at this moment in time, I'm still stumped.
As an aside it's taken me 2 full days of jumping through hoops to get S3D to do what I ask and even so, 3 colour prints are just about impossible. What's the point of having a priming tower that gets printed after the object rather than before? S3D has some nice features but it is the biggest PITA to use (in my humble opinion). Now to see if they'll honour their refund within 2 weeks policy. (Rant over).
Thanks for reporting back Ian.
Unfortunately S3D does not solve the problem, and for the cost, I would expect more cutting edge features, and more attention to people's needs, so far slic3r wins, but least you are making progress going from 60% to 80%
Since we are back to considering the hardware as the culprit, I would tear down the extruder and check the measurements, perhaps even count. I might do it tonight. -
But what I can't get my head around is that the extruders deliver exactly what is being asked of them - all 3 of them. i.e. I ask for 100mm to be extruded that's exactly what I get (well with a percent or so). That's by doing the "normal" 100mm test both with the hot end disconnected and with the hot end connected but heated. Also, if I mark the filament at 500mm, then print an object which should use 417mm of filament, then measure the filament again, it's within a percent or so of 417mm (but the finish is god awful - covered in blobs, lumps and stringy as hell with the nozzle dragging over the previous layers). Drop the extrusion down to 80% or so and all is sweetness and light.
Just doesn't make any sense…........
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Are you 100% sure the nozzle diameter in your slicer is correct? I have a J-head that I thought was .5mm but it turns out it was much smaller than that and the first couple layers of the print I did with .5mm settings came out funny (the increased pressure caused the material to wiggle out like a snake causing some funky waviness)
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@Nyl0cke:
Are you 100% sure the nozzle diameter in your slicer is correct? I have a J-head that I thought was .5mm but it turns out it was much smaller than that and the first couple layers of the print I did with .5mm settings came out funny (the increased pressure caused the material to wiggle out like a snake causing some funky waviness)
Measured with drill bits (measured the drill bits with calipers). A 0.5mm drill goes in, a 0.6mm doesn't. I guess it could be 0.55 or thereabouts. Tried setting the nozzle diameter to 0.6mm in Slic3R - result just the same. (Thanks for the thought though).
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But what I can't get my head around is that the extruders deliver exactly what is being asked of them - all 3 of them. i.e. I ask for 100mm to be extruded that's exactly what I get (well with a percent or so). That's by doing the "normal" 100mm test both with the hot end disconnected and with the hot end connected but heated. Also, if I mark the filament at 500mm, then print an object which should use 417mm of filament, then measure the filament again, it's within a percent or so of 417mm (but the finish is god awful - covered in blobs, lumps and stringy as hell with the nozzle dragging over the previous layers). Drop the extrusion down to 80% or so and all is sweetness and light.
Just doesn't make any sense…........
Its a slicer setting somewhere
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I have a feeling it's infill that's wrong and I have a feeling it's accumulative, as if each layer adds a bit more to the problem. Just observing with the naked eye, it looks as if the infill is always proud of the perimeter and gets a bit worse with each layer. It's very noticeable on the topmost layer. Strange though that Slic3R default settings do the same thing as S3D default settings. Also strange that I can use the same Slic3R settings that I used to use on my old RRP Mendel which worked well, but don't work on this machine. I have them set to default again at the moment but I'll try setting the same nozzle width and speed for perimeter and infill in Slid3R (but I'm sure I've done that before). Manyana - it's getting late.
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Here's mine.
I'm running a Zortrax M200 converted to DuetWifi and PanelDue. Both are running latest firmware that isn't beta.
The direct extruder in these is extremely reliable, and the hotend is a common aftermarket called Z-temp than runs a Mk8 0.4mm nozzle, also very reliable.
Extruder steps/mm works reliably and consistently at 120 steps/mm @ 600mA. Never a click/jam/skip, always been bulletproof even before the conversion.
Pics below are generic ABS at 235 degC. I initially thought only minor changes would be necessary:
After speaking to Deckingham, I went harder at it:
For my money it seems that lower than 85% shows signs of under extrusion, in that I think I can see the previous layer.
I don't really care what the value is, I just want the best surface and would rather keep the actual steps/mm set at an accurate figure.
Please let me know your thoughts as to which surface looks best to you.
Sorry, should have said that's 0.2mm layer height with width set at manual/0.48mm. Filament was measured in 5 places and averaged to 1.714mm. I hope to use the extrusion setting across all other layer heights without going through all this process for each variation.
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My twopence worth - difficult to compare with the lines being orientated in different directions (also looking at the real thing with the naked eye is better than photo's). If I had to make a choice, my personal favourite is 80% - just they way the infill joins to the perimeters. It does look to me that with higher extrusion multipliers the infill is raised above the perimeters (something that I'm seeing too) but we'd need some close ups looking sideways on, which might be difficult to achieve. I guess you are in the best position to make that judgement (sorry - that wasn't very helpful was it?).
It could be that whatever the reason, it might be different for other filaments or temperatures or speeds (not that I've observed any difference with speed and temperature with respect to this issue) or some other setting that we have not yet tried, so personally I think keeping the steps per mm and changing the extrusion multiplier is the best approach.
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Are these all with 100% infil? I think what you are seeing is what was mentioned previously about filament packing.
For background reading I recommend Nophead's blog post about this here:
http://hydraraptor.blogspot.co.uk/2011/03/spot-on-flow-rate.htmlAlso interesting but for a different but not totally unrelated issue see this:
http://hydraraptor.blogspot.co.uk/2011/02/polyholes.htmlNot that when Chris was writing these the slicer used was skienforce which is now truely prehistoric. It did alow for significant customisation of how the Gcode was generated. Later slicers had abstracted this a bit more.
The potential issue with simply dropping to 80% flow is it affects a wide range of things. Such as hole sizes, layer adhesion etc.
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Are these all with 100% infil? I think what you are seeing is what was mentioned previously about filament packing.
For background reading I recommend Nophead's blog post about this here:
http://hydraraptor.blogspot.co.uk/2011/03/spot-on-flow-rate.htmlAlso interesting but for a different but not totally unrelated issue see this:
http://hydraraptor.blogspot.co.uk/2011/02/polyholes.htmlNot that when Chris was writing these the slicer used was skienforce which is now truely prehistoric. It did alow for significant customisation of how the Gcode was generated. Later slicers had abstracted this a bit more.
The potential issue with simply dropping to 80% flow is it affects a wide range of things. Such as hole sizes, layer adhesion etc.
These are all done the way I was instructed by David.
The multiplier was set to 1.0/100% in the slicer, then I used the extrusion slide bar in the DWC to drop 5% per square until I was happy with the surface, then use that setting in my slicer next time around.
I think 85% leaves plenty of meat there, but meets the level of the sides pretty much smoothly.
I'll read the links, but what do you think of the surfaces in the pictures? Which setting would you use?
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If I read nophead's blog post correctly (I have to say I got a bit lost in all the technicalities) it seems that he concluded that the optimum flow rate for infill was about 5% more than for perimeters. If I instigated that, it would make my situation worse because as near as I can tell, the infill is what is being over extruded. I have to say that I'm about to give up and just accept that it is what it is. The 200 colour vase that was printed at an extrusion factor of 0.70 looks OK finish wise and it survived a drop of about 4 feet onto a wooden floor without any sign of damage so layer adhesion is fine too.
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Corexy
I agree with you about the surfaces of the pictures - What I think it that 100% infill overfills by default because of slicers not taking into account the filament packing issues that Chris talks about in the flow rate post. My solution generally is to use 100% flow rate and not use 100% infill except for top and bottom skins. I am not saying that doing this is better, just trying to narrow in on the root cause.
Ian - Chris had the advantage of being able to specify things like the amount of overlap between different printed lines which I am not sure you can do in S3d or Slic3r - you can't in the version of cura I am using
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Tony,
Slic3r has an Infill/Perimeter overlap setting. Default is 15%. I've played around with it but haven't found a value that works any better.
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Corexy
I agree with you about the surfaces of the pictures - What I think it that 100% infill overfills by default because of slicers not taking into account the filament packing issues that Chris talks about in the flow rate post. My solution generally is to use 100% flow rate and not use 100% infill except for top and bottom skins. I am not saying that doing this is better, just trying to narrow in on the root cause.
Ian - Chris had the advantage of being able to specify things like the amount of overlap between different printed lines which I am not sure you can do in S3d or Slic3r - you can't in the version of cura I am using
Bugger, I should have mentioned that was only 20% infil.
I've now read you are supposed to print a 20mm cube at 100% to set extrusion??
Bloody fickle all this.
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Corexy - no not necessarily - I just assumed you had printed them at 100% infil.
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FYI you can also set the overlap percentage in S3D.
