What's the status on Linear Advance?
Browsing through the topics labeled with LA and reading JP's article on LA, made me wonder about a few things. Maybe Prusa can clarify??
- Is LA enabled in the FW 3.3.0?
- Is it required to be enabled in FW to work or is setting it by M900 Kx sufficient?
- Does M900 K0 disable it?
- Do K-Factors, once set, REMAIN IN EFFECT for all following prints?
On a side note: I set K120 for unnamed TPU print and the numerous retracts rendered the print into a big mess, disabling it with K0 made it perform way better. I know, my observations partly answer the questions above, but I would like to hear from Prusa what is actually happening.
Cheers
Re: What's the status on Linear Advance?
Recent Slic3r versions are inserting M900 Kxx gcode lines. I haven't heard a lot of buzz lately, although it was a major issue a couple of firmware releases back. It is interesting that a lot of the coasting parameters used to deal with related print issues are missing in Slic3r.
Re: What's the status on Linear Advance?
As far as I know, it is in there and properly working
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Re: What's the status on Linear Advance?
Why did you put the Linear Advanced M900 K100 value to the printer settings? As the value differs by the used filament it should be used/added there and per know filament!
I don't know in which order the start g-code is written to the g-code file, but if there is a M900 Kxx start g-code defined in the filament settings it should overwrite any other M900 Kyy g-code coming from the printer settings!
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Re: What's the status on Linear Advance?
The per-filament gcode is inserted after the printer custom gcode in the files Slic3r produces. It should over-ride anything added in the printer settings. The Prusa defaults include values for Bowden and direct drive configurations.
Re: What's the status on Linear Advance?
One question I don't see asked, or have is if you should turn off retraction, wiping, Z lift, etc. when using LA in Slic3r. It appears that the default profile is using LA but these options are also enabled. I haven't bothered to test, however, I find it just a bit fuzzy as I recall the pitch originally using LA indicating that these features could degrade the results or were unnecessary. Any thoughts?
Re: What's the status on Linear Advance?
The explanation in https://github.com/prusa3d/Prusa-Firmware/pull/457 implies that even with printing fromSD various parts take too long to compute, using serial just makes it worse.
I'd recommend applying that PR locally and give it a try if you want LA.
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Re: What's the status on Linear Advance?
As far as I know, it is in there and properly working
Hmm, guess work is not what I am looking for. Official clarification would be nice tho
Why did you put the Linear Advanced M900 K100 value to the printer settings?
I didn't. M900 Kxx should go into filament g-code section, right. But as DeeKay claims that K-Factors, once set, REMAIN IN EFFECT for all following prints (in comments section) it messes with older gcode files. So on top of the M900 Kxx in filament g-code section I put M900 K0 in Printer End G-code as well to reset LA for older gcode files.
Maybe the latter part is not required, which led to my fourth question above...
One question I don't see asked, or have is if you should turn off retraction, wiping, Z lift, etc. when using LA in Slic3r.
True. AFAIK retraction could in theory and / or when K is dialed in properly be turned off. I just reduced the value by 50%. No idea about wiping, Z-lift etc... Prusa 🙄 ???
even with printing from SD various parts take too long to compute, using serial just makes it worse.
I second that oberservation. With LA enabled, the printer keeps stopping randomly for 2-3 seconds during my prints, without LA it doesn't. Seems that the 8-bit CPU is struggling.
I'd recommend applying that PR locally and give it a try if you want LA.
Me no want. Why should I test stuff a) the bossman writes about in the blog and b) not even get a response from support to my straight forward questions in the first place? 😳