Is there a way to set printing speed and feedrate independently?
Dominik Meffert wrote 04/11/2020 at 17:04 • 1 pointHi,
for my Wire Printer Project im searching for a way to set the printing speed and the flowrate independent from each other to find out the right settings.
At the moment I'm using Simplify3D, but when I set the printing speed and then increase the layer height or extrusion multiplier the speed drops down a lot.
Is there an easy way in another slicer software in which both settings don't affect each other?
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This is just a example.... not intended to print with your wireprinter... You should add your values for layerheight and first layer height. I don't know the values you need here.
And your 'printbed' is really warped... you should look for a better bed (5mm sheet metal) and/or something like 'auto bedleveling'.
The gcode you've sent is a bit weired because layerheight is 0.2mm and first layerheight is 100% BUT the first layer starts with 2.2mm ???
So you should:
* look for a flat surface to start with, the warping of your 'bed' should be way smaller than your (first) layer height(s).
* determine layerheight (lets call it 'hl') and set it in S3D, i don't know whats a reasonable value for your printer/process
* determine the first layer height (lets call it 'hfl') for your needs, maybe in the range of 2 to 2.5mm, this is the intended layerheiht + the desired clearance
* calculate first layerheight setting for S3D: first layerheight = (hfl / hl) * 100%
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Ok I will buy a new buildplate and try again like you said.
At the moment it's only trial and error and I don't know which settings I need to get it to work.
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Here Is the gcode from Simplify3D which works for the first layer.
https://cdn.hackaday.io/files/1694127248123008/First%20Layer.gcode
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Just did a simple test...
Created a wireprinter profile (derived from default profile) in S3D with the settings:
* layer height 0.2mm
* first layer height 150%
A simple test cube gives the following Z gcode coordinates:
grep "G1 Z" quader_50x50_leer.gcode | head
G1 Z0.300 F1002
G1 Z0.500 F1002
G1 Z0.700 F1002
G1 Z0.900 F1002
G1 Z1.100 F1002
...
Is this what you want?
Test-stl, s3d profile (wireprinter.fff) and gcode in http://www.ibrieger.de/sites/default/files/wireprinter.tgz
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Thank you :)
I tested it out, but it has not worked. Maybe it's too close to the buildplate sheet which is deformed due to the heat.
https://youtu.be/tFoWuT38u0M
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So you want your nozzle 'hoovering' at a certain fixed distance/clearance above the layers you are printing, right?
For example: layer height should be 0.2mm and clearance is 0.1mm. Then your first layer should be printed with a nozzleheight of 0.3mm and the second layer with 0.5mm and so on.
E.g. nozzle height = layernumber*0.2mm + 0.1mm clearance.
I think this would be possible with S3D using *first layer height* and/or a starting/layer change gcode script...
BUT, just a thougth: maybe this clearance thing is not feasible at all and you will get a problem here: Your layerheight will no longer be fixed/determined by the nozzle...
Normally with FDM printing, the nozzle is limiting the layerheight by 'squisching/smearing' it to the desired layerheight. Just like a mason is smearing its mortar with his trowel...
This will no longer be the case if you add clearance...
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Hi Erwin,
you are right but the problem is: The wire melts between the nozzle and the printed object, heated by the current which flows through it. If the nozzle would touch the surface of the printed object the current would no longer flow through the wire, but directly from the nozzle to the printed object.
Because the wire melts only after exiting the nozzle it should be able to push the melted material down a bit (some 0.Xmm).
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Yes I wanted to do it like you said (with Simplify). I set the global gcode offset to Z+2mm so that the printer started at 2mm height with the first layer (because of the uneven buildplate). I used the default layer height which is 0.2mm for the first layer, but increased the extrusion multiplier to x5 and saved the settings in a separate Simplify3D Process, which worked for the first layer.
For the second and all other layers I wanted to use 0.6mm layer height and a lower extrusion multiplier (which should create the clearance by high layer hight but a bit underextrusion) but with increasing the layer height the printing speed got decreased, what was my problem at this moment.
I tested out to install and use Slic3r but for any reason it freezes every few seconds on my pc, so I installed the Prusa Slicer which has the max volumetric rate setting, too. At the moment I haven't figured it out how to use it but I hope it can prevent the printspeed from dropping at different layer hights or extrusion multipliers.
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As I said, just set "max volumetric rate" it to something high, like 500mm3/s, that's about 25cm/s of filament with 0.8mm radius. If you set it lower, slicer will decrease other speeds so that filament is not extruded faster. If you set it higher, nothing changes, it's just maximum allowed rate to prevent too much pressure in chamber.
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Hi I tested it out and it worked the way I wanted it to work in terms of speed. But for a reason which I don't know at the moment, I got a very brittle result only consisting of hundreds of stubs...
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If speed drops, maybe there is some extrusion limit? I don't use simplify, but slic3r has "max volumetric rate". Higher layer = more volume per second, extrusion multiplier = more volume per second. In order to satisfy max volumetric rate, slicer will decrease speed. You can easily set it to something like 500mm3/s, it's just limit.
Page 17 here: http://www.breathflute.com/pdf/S3D_SettingsCG.pdf
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Yes it's exactly as you said. I will try out Slic3r to experiment with max volumetric rate. The thing is ... I want to use the layer height for controlling the clearance between the nozzle and the printed object. After the wire exits the nozzle it should travel some 0.1mm to heat up until it fuses to the printed object. Doing so should also prevent the nozzle from heating the part up and damaging the surface of the printed object.
not like >|
but like >-|
Maybe it also makes a difference that the wire doesn't melt in a hotend with a 0.xmm nozzle but melts between the nozzle and the printed object.
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It would be good for testing if I could change extrusion multiplier and layer height without affecting the printing speed.
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