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Why the unnecessary waits before printing?…  

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Tobycwood
(@tobycwood)
Estimable Member
Why the unnecessary waits before printing?…

First wait is right at the start. The ui panel says “absorbing heat” with a two minute countdown! What’s up with that? Been 3d printing for over ten years, never heard of anything like this before. Looks like nonsense to me. The second wait is right before it actually starts to print. It parks the tool first… why? Then it sits there and does not report any extruder temp at all! Then it takes the tool and starts to print. Seems to me someone does not know what they are doing. Looking at the start gcode and I think I see the problem… so one used way too many Boolean statements!

This thing is definitely not fully baked!

Posted : 05/10/2023 8:57 pm
nhand42
(@nhand42)
Trusted Member
RE: Why the unnecessary waits before printing?…

Print with ABS and you get an 11 minute countdown. Count your lucky stars for only 2 minutes!

Posted : 05/10/2023 9:58 pm
Tobycwood
(@tobycwood)
Estimable Member
Topic starter answered:
RE: Why the unnecessary waits before printing?…

What?! Really? Uh-oh…

The support chat person told me that the absorbing heat thing is related to the temp sensors and if you bypass the time you could get a temp error.

 

Posted : 06/10/2023 3:27 am
SeattleDavid
(@seattledavid)
Estimable Member
RE: Why the unnecessary waits before printing?…

Printing with PETG is a 6 minute countdown for "Absorbing Heat." It's a long long wait.

It could have something to do with trying to compensate for very spotty heating of the build plate. Here is a thermal image of the build plate just right at the end of the "Absorbing Heat" phase:

Posted : 07/10/2023 2:25 am
John1M
(@john1m)
Member
RE: Why the unnecessary waits before printing?…

I believe it's intentional, per: https://blog.prusa3d.com/original-prusa-xl-now-shipping_75721/

"Differences in temperatures (heatbed vs carriage vs print sheet), heat dissipation, and transfer can also affect the initial Mesh Bed Levelling. We added an “Absorbing heat” function to MBL that waits until the heat from the heatbed is at least partially transferred to other parts, and only then the Nextruder performs the MBL procedure to achieve a perfect first layer."

Posted : 07/10/2023 2:37 am
SeattleDavid
(@seattledavid)
Estimable Member
RE: Why the unnecessary waits before printing?…

Here is thermal imaging of the XL build plate at the start, middle, and end of the arduously long (6 minute) "Absorbing Heat" phase before anything can be printed.

  • There is no discernable difference at the start and end of "Absorbing Heat" on the build plate.
  • It is quite odd that the front right corner is always being heated (Shown top left as the imaging camera is upside down.)

All in all, it's about a 10 minute wait before the XL printer actually accomplishes anything.

 

Posted : 07/10/2023 3:35 am
Jeggo
(@jeggo)
Estimable Member
RE: Why the unnecessary waits before printing?…

The Prusa slicer places small parts always in XL front right corner. So this heating tile is always used. This was mentioned in a Prusa video.

Posted : 07/10/2023 8:25 am
SeattleDavid
(@seattledavid)
Estimable Member
RE:

The Prusa slicer places small parts always in XL front right corner. So this heating tile is always used. This was mentioned in a Prusa video.

A poor implementation doesn't become a good implementation simply because it is documented in a video.

The concept is that only the tiles that are needed are heated. If the user moves the part to a different location then only the tiles that are needed should be heated. Duh.

I happen to like to place parts in various locations, to even out the wear on the build plate. Also, edges are notorious for their unpredictable heating compared with the center.

I can't think of any justification for heating the front right tile if it isn't needed.

Posted : 07/10/2023 12:09 pm
Pintie liked
SeattleDavid
(@seattledavid)
Estimable Member
RE: Why the unnecessary waits before printing?…

The Prusa slicer places small parts always in XL front right corner.

Um, no. It doesn't.

Posted : 07/10/2023 12:40 pm
Jay liked
Pintie
(@pintie)
Trusted Member
RE: Why the unnecessary waits before printing?…

only if you activate "auto center tile"

Posted by: @seattledavid

The Prusa slicer places small parts always in XL front right corner.

Um, no. It doesn't.

 

Posted : 07/10/2023 2:24 pm
SeattleDavid
(@seattledavid)
Estimable Member
RE: Why the unnecessary waits before printing?…

only if you activate "auto center tile"

I didn't, but it may be the new default. But this is irrelevant.

The XL should not be heating tiles where there is nothing. THAT is the issue.

Posted : 07/10/2023 2:50 pm
Tobycwood
(@tobycwood)
Estimable Member
Topic starter answered:
RE: Why the unnecessary waits before printing?…

Yah I’d agree, but luckily it’s an issue for fw/sw so it can eventually be changed and btw, there are many more things that need to be changed besides this.

Im still in preliminary testing of my xl5, but so far every print I do where I’ve bypassed the wait worked fine. Too many Prusa users simply assume that Prusa knows better and just go along with things like this. IMO that do not know better. They know what they know and unless forced to by users they don’t look beyond what they know.

Posted : 07/10/2023 3:22 pm
SeattleDavid
(@seattledavid)
Estimable Member
RE:

They know what they know and unless forced to by users they don’t look beyond what they know.

My opinion: Prusa is brain constrained.

The quality of their software is below average. It is slow in coming. It seems like they start writing it before thinking things through.

Perhaps they are using the model of having a few "rock star" programmers, and haven't scaled up software development, or the senior developers won't delegate to staff, and so these managers become the constriction point. Instead of instilling quality, they impair it. I have seen this happen in multiple companies that have grown up. Of course this is just speculation.

But firmware releases are far between, "obvious" and simple features are missing, nothing seems 100% finished (under the guise of beta), and the thing Prusa built its business on (reputation) is waining. Their stuff is still good, but it's all 80% polished and finished, but never at 100% anymore.

Posted : 07/10/2023 10:18 pm
gkas
 gkas
(@gkas)
Estimable Member
RE: Why the unnecessary waits before printing?…

 

Posted by: @seattledavid

They know what they know and unless forced to by users they don’t look beyond what they know.

My opinion: Prusa is brain constrained.

The quality of their software is below average. It is slow in coming. It seems like they start writing it before thinking things through.

Perhaps they are using the model of having a few "rock star" programmers, and haven't scaled up software development, or the senior developers won't delegate to staff, and so these managers become the constriction point. Instead of instilling quality, they impair it. I have seen this happen in multiple companies that have grown up. Of course this is just speculation.

But firmware releases are far between, "obvious" and simple features are missing, nothing seems 100% finished (under the guise of beta), and the thing Prusa built its business on (reputation) is waining. Their stuff is still good, but it's all 80% polished and finished, but never at 100% anymore.

I totally agree. Just about all the problems seem to stem from 'minimal or no testing'. They say it's done, so it must be. No configuration control or mandatory testing. With as many Major screwups as they've had lately, things seem to be worse, not better. Team management should have better control of the software releases. I am not as familiar with the hardware side, but parts for the serial comms should never been acceptable. That worries me about the rest of the hardware.

Posted : 08/10/2023 1:58 am
Tobycwood
(@tobycwood)
Estimable Member
Topic starter answered:
RE: Why the unnecessary waits before printing?…

lol! Interesting opinions… on the Prusaforum too! I suggest not posting these opinions on the XL group on Facebook or you’ll get flamed! Like I did.

Regardless… I’m getting good quality from the XL-5 and I’ll post here more. Yet it IS half baked and it seems to be mostly fw and sw. PS needs a new approach for the prime tower ala Cura. Without it toolchanging will not be optimal.

 

Posted : 08/10/2023 3:46 am
nhand42
(@nhand42)
Trusted Member
RE: Why the unnecessary waits before printing?…
Posted by: @tobycwood

lol! Interesting opinions… on the Prusaforum too! I suggest not posting these opinions on the XL group on Facebook or you’ll get flamed! Like I did.

Regardless… I’m getting good quality from the XL-5 and I’ll post here more. Yet it IS half baked and it seems to be mostly fw and sw. PS needs a new approach for the prime tower ala Cura. Without it toolchanging will not be optimal.

I'm printing without a prime tower and getting very decent multi-material results with PLA. I've only racked up 125+ hours printing so far take my opinion with a grain of salt, but zero-tower is possible right now.

But staying on OP topic I'm not sure why the "heat soaking" isn't based on sensor info rather than time. It seems like were aiming for something smarter with the heatbed but ran out of time? Maybe the countdown is a quick and dirty compromise so they could ship the product, hoping to deliver the proper feature in an OTA update. What do they say about delivering an imperfect product is better than never delivering a perfect product.

I'm sure some of this will be improved in software updates. But yes I agree with OP this firmware seems rushed and beta quality. I'm still getting good prints but the software has these rough edges everywhere.

Posted : 08/10/2023 4:05 am
Diem
 Diem
(@diem)
Illustrious Member

From informal talk at TCT3sixty it seems that the huge range of working environments constrain a lot of the start sequence - users may be in arctic air, centrally heated arctic air, tropical air, airconned tropical air - and everything in between.  Apparently they toyed with asking during setup but then seasonal changes compound the problem.

Cheerio,

Posted : 08/10/2023 5:52 am
luma
 luma
(@luma)
Member
RE:

That wait is triggered via GCODE sent by PrusaSlicer, if you go to Printer Settings > Custom G-code you'll find one of the stock lines looks like the following:

G29 G ; absorb heat

Checking Prusa's KB on the topic, they offer the following:

In Prusa Firmware this G-code is deactivated by default, must be turned on in the source code.

So what we know is that the docs haven't been updated.  You can edit that line out and the printer will skip the warm up step, but I've noticed that it does impact first layer quality.

Posted : 09/10/2023 4:41 pm
Papy_Yosh liked
xenon
(@xenon)
Trusted Member
RE: Why the unnecessary waits before printing?…

my guess the wait is there so the metal frame of the heatbed can get up to temp and do its flexing before mbl and starting the print.

you might be able skip it if you have thick (first) layers, small parts, tolerances dont matter much, ...

Posted : 09/10/2023 7:41 pm
Erik
 Erik
(@erik-3)
Estimable Member
RE: Why the unnecessary waits before printing?…

 

Posted by: @tobycwood

The second wait is right before it actually starts to print. It parks the tool first… why? Then it sits there and does not report any extruder temp at all! Then it takes the tool and starts to print. Seems to me someone does not know what they are doing.

I watched the display as mine did exactly this. So the process seems to be that it heats the (PLA) extruder to 170 to probe the bed and do the whole startup sequence. Then it parks the head so that it can heat. There's a brief message saying as much, and if you enable all extruder temps in the footer you can see that as soon as the nozzle reaches print temp the tool is picked up, flown to the start area super fast, and then primes and goes. It's parking the nozzle during warmup to prevent oozing.

Posted : 11/10/2023 8:06 pm
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