Spiral vs single wall for composite core

[jaysenodell 18]

Consider a no top, no bottom, no infill, cylinder sized {140,180,230}. Wall is 1.0 with layer at 0.6 (noz 1.0). Cylinder will print in PLA and is used as a core under a composite structure. 

 

When I print in sprial I get a nice, no stings no holes tube that is flimsy as hell with a minimal seam. When I print single wall I get strings, gaps/zits (can be tuned) slightly stronger tube with very obvious steams (even in random) that require a crap load more material or prep to hide. It's also slower to print. 

 

Given that core is less about strength and more about providing structure for the composite materials, is there a real reason to avoid spiral mode? Considering the hights I'll be printing is one less likely to be problematic that the other? 

 

Thanks!

[GregValiant 1,342]

I tend to push the Line Width when I use spiralize.  The airplane folks worry about weight but a boat hull doesn't care as much and the added strength helps when bouncing around on the water.

Unless you have some restriction on the wall thickness you can push that 1.0 nozzle to 1.50mm Line Width.  The question becomes "how fast can you melt the plastic?".  You will be moving a lot of volume.

 

At higher layer heights, and with no material on either side of the extrusion the extrusion to help hold it's shape, the extrusions will have radiused sides.  The larger the radius, the less the bonding to the previous layer so strength can be compromised.  As long as it is in compression it shouldn't really make a difference.

[jaysenodell 18]

1 hour ago, GregValiant said:

As long as it is in compression it shouldn't really make a difference.

This is the problem I'm actually solving with moving the print to the core and using additional material to laminate a structure on it. Core surface texture is less important as the core will be covered on both sides. 

 

1 hour ago, GregValiant said:

The airplane folks worry about weight but a boat hull doesn't care as much and the added strength helps when bouncing around on the water.

There is a balance in hull weight though. Light boats are faster and more fuel efficient. 😛 

 

That said, these are boat use but not hull. I've had significant structural failures due to the weight of the print and the excess loading forces created by that weight on key areas. I figure if I move to a composite (currently testing ester based resin/glass with ester gel but may switch to something else), I can make it lighter and stonger while letting the printer do the hard work (core). 

 

If I'm understanding your suggestion:

• Spiral with 150% noz width.
• Reduce layer height a bit.
• Slow it down to allow hotend time to melt booger string.

did I get it right?

[GregValiant 1,342]

Yea, that's a suggestion.  You can try upping the temperature if you don't want to slow down so much.

Pushing so mush plastic through the hot end of most printers will have a definite cooling effect.  Not may "regular printers" can push more than around 12mm³/sec and hold their temperature.  At 1.5 Line Width and 0.60 Layer Height you hit 12mm³/sec through the nozzle at a print speed of 13mm/sec.

At a print speed of 50mm/sec you would be flowing 45mm³ / sec through the nozzle, or about 19mm/sec of 1.75 filament through the extruder.  My Ender 3 Pro would give me its best "Are you @#$%$ nuts?" look.

[jaysenodell 18]

Well now.. challenge accepted! 

 

I will try a sprial at diffent speeds using one of those "change at layer" and monitor with octo. It will alarm if the hot end gets too low. I'm running 1.75mm Creality "ender" pla (blue) at 200C for 1.0x0.6mm@25mm/sec with the 1.0 noz. I'll move the settings to 210C (won't burn the PLA), 1.5x0.6mm@10mm/sec line same noz (printed a test object a couple days back). 2mm speed increase every 4th layer. Will s

 

I say the e3s1p stock sprite hot end chokes at about 25mm/sec since I print there with 100% flow. 

 

test file attached. *original was bad (all flows at 150). new file added (only outer wall at 150)*

 

highflow-speed-test-spiral-e3sp1.3mf

Edited August 21 by jaysenodell
original file was bad

[GregValiant 1,342]

I print silky PLA at 215 because the layer adhesion is so bad and I haven't had a problem with it breaking down in the hot end.  At 200 you are on the lower end so you definitely have some room to move up.

 

When I first got my printer I did a speed test.  When I got to 175mm/sec the starts of extrusions were dry.  Once it got going it was OK.  That worked out to 14mm³/sec.  So I figure my max is 150 and 12mm³/sec.

 

One loop of your model is 127.6mm.  At 12.7mm/sec you'll bump up against the Minimum Layer Time if you leave it at 10 seconds.  For your test print you should lower the minimum time so you have more adjustment room.

[jaysenodell 18]

Let’s just say I was too stupid to make it print fast last night. I’ll work on this this afternoon with more real sized but shorter “single speed” samples. My gut tells me that this time I might be genuinely impressed with creality. 
 

 I’m not holding my breath though…

 

[jaysenodell 18]

4 hours ago, jaysenodell said:

Let’s just say I was too stupid to make it print fast last night.

Well... in my defense, crealty has the E stepper limited. That has been "altered" to make this sucker faster

 

This is also lies. It looks like my UI LCD was showing the 24% limit on print speed. WTF!? not sure how that happened. Now I'm wondering if all my print settings are whacked. Let me try this again. 

 

 

Edited August 22 by jaysenodell

[jaysenodell 18]

Wicked underextrusion starts at 32mm/s. At 45mm/s you can hear the sprite slipping on the filament. I'm going to up the temp by 10C on the 45 run see if that gets it though faster. If not, then it's the routing on my system and I might, just might,  pull the shelf out to get is back to no tube. thing is I fed slack between the hot end and runout sensor and it was still slipping. has to be "hotter" or "slower". 

 

This is stupid fun. 

[GregValiant 1,342]

"This is stupid fun. " 

You sir, are a glutton for punishment.

And the correct spelling is "Stoopid".  The dumber the idea, the more "o"'s you get to add.

 

[Slashee_the_Cow 410]

5 hours ago, GregValiant said:

The dumber the idea, the more "o"'s you get to add.

Mooing is not a dumb idea, and it has two "o"s, so that's not a universal rule.

[GregValiant 1,342]

It should really have 6 "o"'s in it.  After all, it's something that's supposed to be done in the middle of a field.

 

"Lowing" is a noun that refers to the sounds cattle make, which are often described as deep and long. Synonyms of "lowing" include "mooooooing", "bellow", and "bellowing". The word "lowing" comes from the Old English word "lowen", which means "to shout".

[Slashee_the_Cow 410]

15 minutes ago, GregValiant said:

It should really have 6 "o"'s in it.  After all, it's something that's supposed to be done in the middle of a field.

Is there something wrong with mooing in a barn? Although we should be able to moo anywhere since humans are allowed to talk anywhere. If humans wanted cows to be quiet, you wouldn't make us improve all music by giving it more cowbell.

[jaysenodell 18]

hey now... I'm an inclusionist and I only want people to be quiet if they are being obnoxious while I'm swearing at a printer that WON'T ACT PREDICTABLY! So moo, low, bellow, bell, hell, smell, fell eat taco bell to your hearts content. 

 

If I could interupt for a minute and ask...

 

Print setting format == Temp/width/height/flow/speed(mm/s)

 

Using 215/1.0/0.6/150%/30+ with my default PLA I'm getting what apears to be slipping of the extruder on the PLA (direct drive) based on the "chunking" and the touch based "it didn't move" when the sound happened. I have ensured that there was no tention on the PLA supply going into the extruder. I believe I have not maxed out the stepper limits in firmware (I can raise them). Temp variaion is ±0.2C at full speed. There is a noticeable texture that looks to be cyclic under extrusion in the print.

 

 

Everything to me points to the extruder being too slow/weak to run at this speed. Thoughts/ideas?

Edited August 23 by jaysenodell

[Slashee_the_Cow 410]

12 minutes ago, jaysenodell said:

Everything to me points to the extruder being too slow/weak to run at this speed. Thoughts/ideas?

Try increasing the extruder tension (there's usually a screw on the side of it somewhere that's different the screws you use to take it apart, turn it clockwise, but only a turn or two at a time). That'll make the extruder bite down harder on the filament in its efforts to pull it through. And if that perchance makes things worse, then decrease it! 3D printer tuning: Experimentation 'til the cows come home. Except me. I experiment after I get home because home is where my printer is.

 

16 minutes ago, jaysenodell said:

So moo, low, bellow, bell, hell, smell, fell eat taco bell to your hearts content.

I'd hate to but I couldn't if I tried. Taco Bell opened some outlets in Australia a few years ago but they failed miserably and gave up.

[GregValiant 1,342]

With the "Flow" at 150% you have an effective line width of 1.5mm.  That works out to 27mm³/sec at 30mm/sec.

 

How about this for a test...

Set Cura up for a layer height of .50 and 1.00 line width (the numbers make the math easy).

Use Search and Replace (to get fancy)...

Search = ;LAYER:0

Replace = ;LAYER:0\nM221 S80

Regular Expressions = False

 

At the start of the first layer the 80% flow rate will give you a line width of 0.80 and a flow rate of 12mm³/sec.  Every few layers you can dial up the "Flow rate" using the LCD control.  When the extruder starts to skip steps you know you have exceeded its capability.

The hot end can only melt the material so fast and you will reach it's upper limit.  You need to know what that limit is.

 

[jaysenodell 18]

Solid plan. I may not get a chance to try it until next week.