settings flow rate

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duke666
Posts: 67
Joined: Tue Oct 24, 2017 6:53 am

settings flow rate

Postby duke666 » Thu Apr 05, 2018 9:35 am

Hi, tell me please, in the thread settings there is a fluidity of 97%, in the slice settings for each operation there is a fluidity of, for example, 95%. When printing on the touchscreen, the fluidity is 97%. I understand, on the touchscreen only shows the overall fluidity, which was specified in the thread settings. If I change the fluidity in the printing process on the touchscreen, then does it change all the fluidity parameters in percent?

Jetguy
Posts: 2700
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: settings flow rate

Postby Jetguy » Thu Apr 05, 2018 1:15 pm

Yes, the on screen is a global adjustment.

My concern here is we really need to get to a deep level understanding on this to be truly effective and master 3D printing.
The first concept is what is slicing, how does it create gcode, in terms of extrusion, what are the key parameters.
So in a slicer, you give it:
Layer height
Nozzle size or extrusion width. The actual value used is extrusion width, but extrusion width can be determined from math around nozzle size.
Filament diameter
The STL file
Notice, I'm not listing flowrates in this section. We'll get to that, but wee need this first.
So, the slicer reads the STL, cuts the object into 2D layers, they represent outlines of the object, and we begin the gcode creation process for each layer. Using extrusion width, the slicer places the extrusion centerline path adjacent to the logical edge of the outline. Then once you get past the shells or permiter, it's creating the infill segments. But, this is the moment we really want to get to, discussing a segment. Any curve is not a curve in current gcode, it's short polygon like segments. A gcode segment long or short, is a straight line noodle in 3D, the width and height are the extrusion width and the layer height and then the total segment length (the XY path total length). Those 3 very simple values give us a cylinder of extruded filament and that cylinder is easy to figure out volume. Again, we just used a few of the parameters to get a segment, specifically extrusion width, layer hieght, and the STL and other detail got us a length for that exact segment (the XY coordinates in the line of gcode). The slicer then uses the filament diameter to determine the exact length of filament to be pushed such that is equals the volume of the segment. Again, the filament represents a cylinder of a known diameter of infinite length. So that is how we get the E length.

Now what you are asking is that yes, there are flow rates for specific layers and features. Then, there is also a global flowrate, and this where I feel Ideamaker does this wrong- and that's an opinion- but here is the logic why. The individual values for a layer or feature flowrate, they directly adjust gcode E length for those segments that make up that 3D printing feature or layer. Again, they literally multiply the percentage against the "ideal" calculated volume of a segment.
But, there is that global Flow rate setting for filament. Now let me explain why that is there. When we started this hobby back in 2009, all there was on the market was ABS filament- taken from other plastic manufacturing industry. So, when you setup firmware, you set steps per mm so that the extruder feeder pushed exactly the commanded distance of filament. Pretty simple, ABS has a known surface hardness, the drive gear teeth bite into it predictably, the result is generally all ABS should (within reason) give the same steps per mm. However, as other filament types and thus hardness and other factors that DO affect grip and bite of the drive gear- resulted in slightly different steps per mm to get the same result of commanded gcode distance to equal actual distance of pushed filament. So, long ago, a precedent was set that ABS was the "the standard" and that PLA and other filaments required a percentage adjustment to match ABS. Why? because again, the idea was not to twiddle with steps per mm in firmware. You set it once for the hardware and that's the value. But again, we know that different filament has a slight but noticeable difference. This is how the 94% flowrate for PLA became commonplace.
But again, this is where I and Ideamaker/Raise 3D are at odds with each other. Instead of adjusting the E lengths in the gcode, this filament based setting is sending a gcode flowrate command for global flowrate changes and the FIRMWARE in the printer is applying this percentage to the gcode E lengths when determining how many steps to send the stepper. This means MORE math for the 8 bit processor to do VS normal 100% flowrate.

When you edit the touchscreen flowrate, this is the same setting- the firmware is taking that line of gcode, reading that E distance value, and changing actual moved distance by that percentage. You effectively override the filament flowrate set in the slicer.

Jetguy
Posts: 2700
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: settings flow rate

Postby Jetguy » Thu Apr 05, 2018 1:25 pm

The reason I say all that, and this has come up with Mosaic palette users and people using other slicers.
Again, "the standard" in most/all other slicers except Ideamaker is to use any flowrate setting in a slicing profile adjusts the final gcode E lengths in the final print file. The logic here is your computer doing the slicing has all the computing power, memory, and disk space and flys through these changes to produce a simple gcode file that is ready to print 1:1 with no modifications.

Ideamaker- they throw in gcode commands for global flow rate based on filament type. This appends a starting gcode line that sets the printers active flowrate in firmware from 100% to 94% if using the default PLA profile in Ideamaker. Worse, the ENDING gcode does not reset the printer BACK to 100% flowrate!!!!!

So if you use another slicer, and you first printed an ideamaker generated gcode print, it will set the printer up for 94% global flowrate. When you print that file made by Cura or Simplify 3D, it assumes the firmware is at 100% flowrate but in actual circumstance, that may not be the case due to the sequence of events.

To combat this rather painful system, I went and edited every single profile in my Ideamaker for 100% flowrate for filament settings.
Now I'm on par with the rest of the 3D printing world. I also then added the flowrate command in the starting gcode of my slicers M221 S100 and in my ending gcode in ideamaker, set the same command to ensure ideamaker print files return the printer to a known 100% flowrate.

duke666
Posts: 67
Joined: Tue Oct 24, 2017 6:53 am

Re: settings flow rate

Postby duke666 » Thu Apr 05, 2018 3:45 pm

thought I understood. I can be sure that all the flow settings that I make in the slicer are taken into account and work? And the touchscreen only shows me the global fluidity. And when I printing and change flowrate the touchscreen, the fluidity will eventually change all the fluidity parameters in percent?

Jetguy
Posts: 2700
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: settings flow rate

Postby Jetguy » Thu Apr 05, 2018 3:59 pm

Yes, the screen change changes global flowrate VS how much linear length of filament is moves VS commanded length in the gcode file.

TDP
Posts: 2
Joined: Fri May 25, 2018 12:52 pm

Re: settings flow rate

Postby TDP » Thu May 31, 2018 2:00 pm

Jetguy-

I was wanting to do the same thing that you mentioned with keeping the global flow rate at 100% in Ideamaker since I switch between slicers and Ideamakers method makes thing much more difficult than necessary.
If you do that, and set keep the global at 100%, how are you adjusting the flow rate for different filaments?

I know if I set the global to 100%, I can then set first layer, infill, solid infill, and bridging flow rates in the advanced settings and this will change the E value in the Gcode. BUT... where is the flow rate control for perimeters? How are you controlling that if need be?


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