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Volker Jaenisch
(@volker-jaenisch)
Trusted Member
Topic starter answered:
RE: Print contracts below Bridge

@chocki

I use in general the default setting from prusa slicer. I do not like to deviate too much from the base line - the people at prusa did a really good job with prusaslicer. MANY thanks to YOU!!!

The speed is 30mm/sec. Best results for bridging with PETG i have with fan speed 100% and bridge flow 0.7. The bridges become better if I reduce the bridge flow even more, but then the filament becomes really thin and the next layers disturb the lilament. So there is an optimum and IMHO it is around 0.7.

to be honest I have never printed anything like this where this could happen, but it will be good practice for when I do.

Me, too. :-). If I had an other option I would never do such a crazy thing. But since printing fillets on the heatbed is not possible for geometric reasons (if one will not rely on support material which damages the smoothness) there seem to be no other way.

Cheers,

Volker

Posted : 30/09/2019 12:20 pm
Chocki
(@chocki)
Prominent Member
RE: Print contracts below Bridge

Just waiting for the printer to start, I'm just printing the largest bridge test square to see what happens with some SUNLU petg, prints quite cool this one at only 230 Deg C. I also use T-Glass which needs 250 to 255

This post was modified 5 years ago by Chocki

Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.

Posted : 30/09/2019 3:56 pm
Chocki
(@chocki)
Prominent Member
RE: Print contracts below Bridge

Well, 100% fan makes no difference. I printed it with 0% infill to make it as weak as I could, and it pulls in!. First bridging layer started very well, nice and flat bridge, but then subsequent layers caused the first layer to sag, then a bit more with the next layer then a bit more still!.

Sorry about the stringing, this an end reel with about 10m on it and has not been dried.

I really must figure out how to stop pictures rotating in this forum.

Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.

Posted : 30/09/2019 4:32 pm
Chocki
(@chocki)
Prominent Member
RE: Print contracts below Bridge

Jeez, no wonder it was so bad, I hadn't changed the settings for this particular filament since the mods to the firmware I made, so the K value was all wrong hence the hairy monster. I was a bit alarmed at that first print!

Right I tried orienting the infill direction so it went length ways rather than at 45 Deg across the print and reduced the cooling to 30%. To see if the contraction made things any worse

Oh for Pete's sake, this rotation is driving me nuts!

Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.

Posted : 30/09/2019 5:17 pm
Volker Jaenisch
(@volker-jaenisch)
Trusted Member
Topic starter answered:
RE: Print contracts below Bridge

@chocki

Nice to see that someone can reproduce my findings.

With this design the effect can be cured with PETG as well as PLA. Here the STL file bridge_fachwerk.stl

Cheers,

Volker

Posted : 30/09/2019 6:43 pm
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(@)
Illustrious Member
RE: Print contracts below Bridge

If you add a support mid frame to limit droop you can also reduce the warp effect 50%, add three and the effect drops to 25%.  My printer is busy, but the weight pulling in on the towers is real and inescapable.

Posted : 30/09/2019 6:51 pm
Chocki
(@chocki)
Prominent Member
RE: Print contracts below Bridge

Tarrah! 😀 

You will have to change the K factor, but have a look at the startup G code etc, it may be useful to you.

Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.

Posted : 30/09/2019 7:06 pm
Chocki
(@chocki)
Prominent Member
RE: Print contracts below Bridge

I'll get the hang of this forum, one day maybe....

Attachment removed

Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.

Posted : 30/09/2019 7:09 pm
Chocki
(@chocki)
Prominent Member
RE: Print contracts below Bridge

Its not perfect, but better.

Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.

Posted : 30/09/2019 7:26 pm
Chocki
(@chocki)
Prominent Member
RE: Print contracts below Bridge

There is another thing you can try and that is to use less top and bottom layers, like 2, I think the issue is the solid infill, it heats up the bridge which allows it to sag as the infill cools slightly. Slicer uses bottom layers on top of bridging.

Try it with two, or even 1 bottom layer and 2 or three top layers, this should work, but you will have to see if it is strong enough.

Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.

Posted : 30/09/2019 9:07 pm
Chocki
(@chocki)
Prominent Member
RE: Print contracts below Bridge

Maybe an enforcer can be used to prevent so many bottom layers just above the bridge.

I will see if it is doable when I get home from work.

I've got the sides about right without the step, now to tidy up the droop / sag.

I'm determined to get this printing nicely, BUT, there will have to be less material, no choice, so strength will be reduced, but maybe not enough to affect things too much, maybe on a section that has a wide section of bridging, enforcer blocks to create a comb type internal construction, although I suspect the same could be achieved just by rotating the infill pattern to be better aligned, just so long as there is less material directly over the bridge.

It won't be seen anyway.

Is there a minimum thickness you are using for this print as this would determine how much space can be retained inside the print and ultimately it's strength. You may have to print this a little thicker, but we'll see later.

 

This is good practice for future projects. I think I will have to start a little blog with details if successful.

Anyone know a good free preferably hosting site?, not much required, just some notes in effect, so no database, no flash etc etc, just basic stuff, some pictures, text, static graphics.

Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.

Posted : 01/10/2019 5:46 am
Sembazuru
(@sembazuru)
Prominent Member
RE: Print contracts below Bridge

I seem to remember a recent thread here where someone had something similar with long, drooping bridges. As I recall they seemed to get good results by using supports with zero interface layers , zero contact distance, and pattern spacing fairly large (1cm or so). This created easily broken off thin walls similar to the supports under a long road bridge span.

A search of the forums might find that thread to verify my poorly remembered details.

See my (limited) designs on:
Printables - https://www.printables.com/@Sembazuru
Thingiverse - https://www.thingiverse.com/Sembazuru/designs

Posted : 01/10/2019 1:34 pm
Sembazuru
(@sembazuru)
Prominent Member
RE: Print contracts below Bridge
Posted by: @chocki

[....]

Anyone know a good free preferably hosting site?, not much required, just some notes in effect, so no database, no flash etc etc, just basic stuff, some pictures, text, static graphics.

Check with @bobstro for where he hosts his Muppet Labs online notebook. I've seen other sites with similar structure so I suspect he is using an existing framework for organizing his notebook.

See my (limited) designs on:
Printables - https://www.printables.com/@Sembazuru
Thingiverse - https://www.thingiverse.com/Sembazuru/designs

Posted : 01/10/2019 1:41 pm
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 --
(@)
Illustrious Member
RE: Print contracts below Bridge
Tetra Tech *Network Ninjas" - Love it!

ps: just a name I found ... not a free site or anything as far as I can tell.
This post was modified 5 years ago 3 times by --
Posted : 01/10/2019 2:32 pm
Chocki
(@chocki)
Prominent Member
RE: Print contracts below Bridge

Just tried the quick bridge test model adding an enforcer, I think PS is broken as I cant see any box when I add anything until I slice the model, then its a case of adjust values until I get it where I want, and change the type to a modifier to which I set layers and perimeters to 0 on all values.

This rectangle is placed precisely inside the top part of the bridge so it has the bridging layer and one solid fill layer then switches to the normal internal infill for 5 layers, followed by bridge infill then 3 solid infill and finally a top infill.

It is just printing, lets see what the result is in a few minutes.

Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.

Posted : 01/10/2019 2:45 pm
Chocki
(@chocki)
Prominent Member
RE: Print contracts below Bridge

Damn, still got some droop, another tweak I think.

Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.

Posted : 01/10/2019 2:52 pm
bobstro
(@bobstro)
Illustrious Member
RE: Print contracts below Bridge
Posted by: @sembazuru

Check with @bobstro for where he hosts his Muppet Labs online notebook. I've seen other sites with similar structure so I suspect he is using an existing framework for organizing his notebook.

I'm hosting my site on an Amazon AWS micro instance running Debian Linux. With 100G storage and 1 GB RAM I'm paying about $17 per month (IIRC, will verify). I run my email and web experimental stuff off it. DNS and domain are extra of course.

The pages are generated using Sphinx for static web pages (no dynamic stuff, minimal requirements). They're served with a basic nginx setup.

Definitely overkill but I want control over everything.

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 01/10/2019 3:38 pm
bobstro
(@bobstro)
Illustrious Member
RE: Print contracts below Bridge
Posted by: @tim-m30
Tetra Tech *Network Ninjas" - Love it!

ps: just a name I found ... not a free site or anything as far as I can tell.

You doxed me! That's actually another static Spinx site on my server. I have attempted to dump 30+ years of network and cybersecurity info out of my brain for some of the younglings at work. 

How'd you locate the cyberdojo? It's in DNS but I put a basic login on it to reduce unknown traffic. 

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 01/10/2019 3:53 pm
bobstro
(@bobstro)
Illustrious Member
RE: Print contracts below Bridge
Posted by: @chocki

[...] Anyone know a good free preferably hosting site?, not much required, just some notes in effect, so no database, no flash etc etc, just basic stuff, some pictures, text, static graphics.

Sounds like you're after a static site generator. There are many to choose from. I'm using Sphinx. You basically create your pages using a markdown syntax, then the generator spits out pretty HTML that can be hosted anywhere with no other requirements.

The editor is mildly annoying (though they've improved lately) and embedding images is a bit annoying, but it's not bad once you get used to it.

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 01/10/2019 3:59 pm
--
 --
(@)
Illustrious Member
RE: Print contracts below Bridge
Posted by: @bobstro
Posted by: @tim-m30
Tetra Tech *Network Ninjas" - Love it!

ps: just a name I found ... not a free site or anything as far as I can tell.

You doxed me! That's actually another static Spinx site on my server. I have attempted to dump 30+ years of network and cybersecurity info out of my brain for some of the younglings at work. 

How'd you locate the cyberdojo? It's in DNS but I put a basic login on it to reduce unknown traffic. 

When I retired I went back to school and got a couple IT degrees ... not that they helped much ... but I learned a couple of things.

Posted : 01/10/2019 4:13 pm
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