Anet A8 3D Printer.

[ukracer]

Squish ....................................as in the tip of the nozzle & combined flow of hot filament flattening the hot extruded material into the rest of the print whilst it's very hot to fuse the two layers together? ( aka lower th nozzle as TFL said ?)

So my in my sclerotic brain conversion this is ...... the stepper motor feeds the filament at microscopically faster speeds in the slicer programming to feed a little more molten filament through the print nozzle at the right time to fill known to the programme voids that are a result of the slicer doing it's job?

As has been said above...Yes and No.

Squish encourages adhesion. But also squashes the 0.4 mm bead coming out of the nozzle.

With no squish you end up with a line of plastic just touching the build plate at the very bottom. (Like a round garden hose)

So the no part is the stepper motor does not compensate to fill in the voids. To confuse things it might do something similar when creating a smoother finishing shell. But NOT at the start.

Does the prusa have baby stepping?

Sorry I am not too much help as I don't have a prusa or use prusa slicer.

 

[tflnemesis]

Your slicer will be set to produce a 0.4mm wide line of filament at 0.2mm layer height (depending on how you have set it up, you could be using smaller layers or set the extrusion width higher or lower.).

Knowing this your slicer will produce a toolpath for each layer that completely covers the layer, irrespective of where you have physically set the height of the nozzle this is what it is trying to do. If as in your case the nozzle is too high it will still only extrude enough to produce a 0.4mm line at 0.2 layer height hence the filament is not being pressed down onto the plate by the nozzle giving very poor adhesion.

Messing with extrusion rate will definitely produce problems later on in the print.

 

[DAPPH]

Racer ,
What you have said is good , but to my mind does beg the question is how does the liquid fill increase enough to fill the known sliced void unless the filament feed stepper motor it told to feed the filament a tad faster when the program asks for more filament fill to fill & smooth over the void .

Yes I have baby stepping thnk my POM calls it along the lines of ( adjusting the Z height in small steps ) not " Tune " as that is a separate area of the control programme ( feed , flow , fans etc )


I can rotate the control pointer wheel to get to Z adjust to raise the nozzle & axis in one go .
Rotate it clockwise ( IIRC) and negative figures from the set up exercise , the machine being 0.000 at the start of the screen display . Read in the POM max of - 2.00 but never ever go below - 2.500 of you'll crash the nozzle into the plate .

I've been keeping a diary of the printer & printing noting as to how & what I've adjusted in the settings & running of the machine , these days my brains just not capable of remembering things as easy as I did when I was 26 nearly half a century ago .

I think I'm starting to see the individual trees in the wood rather than just a forest.

 

[DAPPH]

Your slicer will be set to produce a 0.4mm wide line of filament at 0.2mm layer height (depending on how you have set it up, you could be using smaller layers or set the extrusion width higher or lower.).

Knowing this your slicer will produce a toolpath for each layer that completely covers the layer, irrespective of where you have physically set the height of the nozzle this is what it is trying to do. If as in your case the nozzle is too high it will still only extrude enough to produce a 0.4mm line at 0.2 layer height hence the filament is not being pressed down onto the plate by the nozzle giving very poor adhesion.

Messing with extrusion rate will definitely produce problems later on in the print.

Thanks for that ,
I did wonder about the effect altering the extrusion rate ( currently pre set to 100 )might have .
Had a play there earlier today & decided to reset it back to 100 as in the altered state all I got were tens of tens of tiny black curly hairs of filament curling off the plate & nozzle .

 

[daedalusminos]

@DAPPH as I understand, you have a Prusa Mk3(s) and you're using Prusa ABS filament?

You've resolved you bed adhesion problem (model not flat on the bed) so now I would print as Prusa intended, use the default settings as a starting point - I would rec 0.2mm quality for layer height and set your infill % (20 is Ok) and check brim.

The only thing left is to calibrate 1st layer height - you can do this by running the 1st layer calibration and/or perform live Z adjust as it prints the first layer.. This simply sets an offset from the PINDA signal height, once set for a particular build plate it shouldn't need changing

 

[tflnemesis]

@DAPPH Here is a small video of how a first layer should look:

First layer video

 

[DAPPH]

@DAPPH as I understand, you have a Prusa Mk3(s) and you're using Prusa ABS filament?

You've resolved you bed adhesion problem (model not flat on the bed) so now I would print as Prusa intended, use the default settings as a starting point - I would rec 0.2mm quality for layer height and set your infill % (20 is Ok) and check brim.

The only thing left is to calibrate 1st layer height - you can do this by running the 1st layer calibration and/or perform live Z adjust as it prints the first layer.. This simply sets an offset from the PINDA signal height, once set for a particular build plate it shouldn't need changing

Thank you very much that is very helpful , it makes a lot sense now I have a bit of ( dangerous ) knowledge in my coconut ......

Found it terribly difficult trying to read the POM and recall it all in one go , it looks like it won't improve .

So I'm going to redo my designs and pop them on cleaned cards then try to print them out .

 

[ukracer]

@DAPPH as I understand, you have a Prusa Mk3(s) and you're using Prusa ABS filament?

You've resolved you bed adhesion problem (model not flat on the bed) so now I would print as Prusa intended, use the default settings as a starting point - I would rec 0.2mm quality for layer height and set your infill % (20 is Ok) and check brim.

The only thing left is to calibrate 1st layer height - you can do this by running the 1st layer calibration and/or perform live Z adjust as it prints the first layer.. This simply sets an offset from the PINDA signal height, once set for a particular build plate it shouldn't need changing

The last bit is what I think is going wrong BUT I am trying not to confuse Dapph as I just don't have a clue about prusa.
Ender 3 with marlin I have to use baby stepping every print just to fine tune the first layer.
It's that quick I have usually got it spot on before the brim is completed.

 

[ukracer]

@DAPPH Here is a small video of how a first layer should look:

First layer video

That's even thicker than my first layers..lol.

 

[DAPPH]

Guys & gals , you've all been a tremendous help in rekindling and re infecting my brain wrt 3D CAD & 3D printing .
Who'd think that 40 yrs ago my bread & butter was as an industrial electronic test & service engineer who played at industrial repairs , hexadecimal & machine coding . Now , it's not quite a problem tying my own shoelaces but might be heading there in a few more years

Many thanks to you all

Dave

 

[DAPPH]

Up date ...
I've re drawn the clamp & sliced it .. the went to print it off the memory card .

Spent the first hour baby sitting at the start of the print .. waaah .. It failed in the first layer ,, they all turned up like four pairs of Turkish slippers.

Sp I killed the print cleaned & re juiced the plate with my thicker juice. watched it like a hawk using a super bright led torch to get a clear view . notices a few pencil strands not really melded together and a few tiny unmarried ones in th print outer edgein one place.. that been repeated on each item printed .
Took your advice on board played with adjust z going further down to - 0.349 ..terrible .. moved it up to - 0.138 . Yeah Alleluia success ..now I know what you guys meant wrt squishing the extrusion to the eplate ..
cancelled the damaged print . reset thing up & baby sat the print for another half hour still a few tiny microscopic tags every now & then..
Think the slicer needs to be picking more points to work with .

I'm having my tea time in a few minutes ... keeping my fingers crossed to find 8 new beautiful babies on the printing plate in a couple of ours time .

Question for my Sensei.

If I've got the Z to - 0.138 and it's a good setting at present providing I don't move the printer will that - 0.138 setting still be applicable for all my future prints off the same roll of filament or do I have to check & adjust for every new print?

I've also discovered a first layer setting on the screen but will be reading the POM a lot more to get it right first time every time.

More fusion 360 play time tonight .. The stainless steel drop down arm/ assistance bar to help me get on & off the pan need two new plastic caps the originals are 15 yrs old and have gone very brittle & broken up I might have two new black one's by this time tomorrow .

 

[carbon]

You should be ok with the same z offset for that roll of filament. If you cant get the same make when that one runs out you may need to change it a little. I use a different z offset for different materials as I find they don't all adhere to the print bed the same

 

[tflnemesis]

That Z offset should be ok for most materials.

The only time I have to change my Z offset is when using PETG or TPU as these are very 'sticky' and too low a Z offset can cause the nozzle to catch the first layer and rip it up from the bed.

 

[DAPPH]

We have babies....
eight of them the sides & tops are great the bottom layer is looking like a log mill's yard.
I can see the need for the first layer adjust on the LCD screen ..just need some practice in getting to using it in a short time period.

 

[DAPPH]

I've reset the Prusa i3S printer up as it should be for a new self build with the latest filament sensor modification , as no matter what suggestions that you guys gave me worked .

Sadly I was still getting the rubbish first layer and several subsequent not so good layers. They looked like a pile of chip stick in a small in of wet spaghetti . Some of the smaller part looked like wing feathers you coud see day light through either side of every stand of print.

Disappointed I contacted Prusa via their on-line chat help service , over a couple of hours or so they took me through everything . I had a couple of off line breaks whilst I tried out their suggestions .. sent them pictures all to no avail.

I happened to repeat that I'd set the nozzle to Z -0.178 lower than the initial new build basic setting which registered when initially calibrated as being Z -0.000 .
Paula the gal handling my session said , " That's strange .. I can see the top of the prints are good but those bottom 10 layers are really bad .. try setting Z to -0.600 as that what she normally used for ABS_T .

Botty butterflies flitting with visions of a bed crash I set the nozzle to the Z -0.600 recommendation .. finger on the stop flap ready in case I heard , saw or felt anything was wrong ... I've got the most beautiful melded first layer I've ever had , all subsequent layers are simply melting in leaving a quality surface .
A couple of things come from this , the actual diameter of the extrude on the actual print is like a fine catscokhair not as I was thinking like a thick pubic hair
Second it's been brilliant learning from you guys & trying to put your suggestions in to practice .
Piccies to follow


My waitress in fish nets & high heels is calling me .

 

[ukracer]

I've reset the Prusa i3S printer up as it should be for a new self build with the latest filament sensor modification , as no matter what suggestions that you guys gave me worked .

Sadly I was still getting the rubbish first layer and several subsequent not so good layers. They looked like a pile of chip stick in a small in of wet spaghetti . Some of the smaller part looked like wing feathers you coud see day light through either side of every stand of print.

Disappointed I contacted Prusa via their on-line chat help service , over a couple of hours or so they took me through everything . I had a couple of off line breaks whilst I tried out their suggestions .. sent them pictures all to no avail.

I happened to repeat that I'd set the nozzle to Z -0.178 lower than the initial new build basic setting which registered when initially calibrated as being Z -0.000 .
Paula the gal handling my session said , " That's strange .. I can see the top of the prints are good but those bottom 10 layers are really bad .. try setting Z to -0.600 as that what she normally used for ABS_T .

Botty butterflies flitting with visions of a bed crash I set the nozzle to the Z -0.600 recommendation .. finger on the stop flap ready in case I heard , saw or felt anything was wrong ... I've got the most beautiful melded first layer I've ever had , all subsequent layers are simply melting in leaving a quality surface .
A couple of things come from this , the actual diameter of the extrude on the actual print is like a fine catscokhair not as I was thinking like a thick pubic hair
Second it's been brilliant learning from you guys & trying to put your suggestions in to practice .
Piccies to follow


My waitress in fish nets & high heels is calling me .

Ironic as mine is usually happy at 0.585 to 0.650 negative baby steps.
But I think that's a total coincidence rather that a similar setting on two totally different machines...lol

 

[DAPPH]

The massive difference from what was in the manual surprised me too ..all seems good . I've printed off another set of 8 blocks , now the bottoms are like a smoothing iron with very very little bulge on the outer edge of the first layer.

I'm putting up some pictures with comments , not to brag or show off but to leave a record on line for current & future Mig -Welding forum member " Makers " who might have / have had the same problems but didn't know what they were looking at wrt how things should look nor the solution to improve things.. ( it might help me too as I have a dreadful seniors memory problem ).

You guys have been tremendously helpful in getting my addled brain up & going.
Thanks. Dave .


This is how the early soles of the block I was printing in ABS_-T turned out , the mess petered out at about the 6 th layer up & ended with a reasonable side & top above the fault line .

This is the adjusted Z - 0.600 setting print, the camera shows the surfaces a lot rougher than they are .. A wipe with a lint free make up removing pad damped in cellulose paint thinners acetone will clean & polish them ..but I've no need to do this as the birds & caterpillars out in the garden where the block are going won't notice the finish .

Things were so far out that with this " feather " of print from the first layer of the blocks you can actually see daylight between each nozzle extrusion pass .

Final picture ..this was the disasterous partial first layer of an end cap for a pipe . It didn't help that I hadn't understood how to or the need to set the first layer face flat on the print plate using the Prusa slicer


I just couldn't understand why the programme didn't do what I expected it to do, till I wrote the logical steps out on a sheet of paper. IE Find the object , high light it , rotate it till you get your desired first layer face facing down on to the plate .
Click level face to plate. After much frustration I eventually realised that you have to repeat that same operation for every part on the plate that you want printing .. Cockitup & you don't get all the objects in the same plane sitting on the plate ready to prints... had loads of tangles & miss prints before I found that out.

That's it folks

Dave
PS

If I've said something in this post that's incorrect let me know , tell me what it should be & I'll edit it accordingly.
I'm dyslexic due to meds ( 16 per day ) .when trying to read the handbooks & on line documentation ..it's been a night mare , hence me using this thread to get help & advice that I can assimilate in small doses .

 

[tflnemesis]

Glad to hear you got it sorted! I would never have guessed that you needed to bring the nozzle down that far. I am so used to levelling on the fly that I can usually dial it in fairly quickly when I need to except for the times it goes disastrously wrong then it can take me a day or 2.

 

[DAPPH]

Oh one thing Paula said .. the Z settings will vary for different types of filament used . I'm writing the Z numbers that are successful for each filament type on the wooden wall of the printer enclosure cos I don't have a snowball in hell's chance of remembering them tomorrow , let alone in a week or more's time .

 

[PhillipM]

I just set them up on different filament profiles, although tbfh I normally just adjust the bed itself to be perfect.