Organic Supports Falling Over---Solve the Problem with "Reinforcing Rods"
 
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DenisFoster
(@denisfoster)
Active Member
Organic Supports Falling Over---Solve the Problem with "Reinforcing Rods"

A problem I have encountered on both my Mk3s and my XL twin head is organic supports dislodging after they have printed to about 18mm height.  This just recently occurred for me using a brand new spool of Jesse filament fresh out of the bag.  First layer height is spot on by all means I can test on MK3 and XL just does it right.  I have made sure the nozzle is clean and extrusion rates have been checked and are correct.  So despite following most of the usually recommended fixes the problem still recurs too frequently for me.

A work-around reliable solution for me has been to make my model with thin bars suspended maybe 12 mm above the print bed and coursing through the support area perhaps 6mm and 10mm wider than the part width and length dimensions. I slice the model as "parts" to maintain orientation of the bars relative to the primary model. The bar dimensions don't seem to  matter much.  I have successfully used bars .5mm thick and 3mm wide.  By placing the bars in this way, the supports come up and envelop and incorporate the bar.  This locks all of the supports together and results in supports that previously were very fragile and required perfect technique to print reliably and converts them into a very solid unit that will never break off.

I personally would like to see Prusa address the fragility issue by making software adjustments which would eliminate the need for this workaround:

1) Instead of the rows of solitary organic "trees" only making contact at the very top extreme of their printing, adjoining supports could "lock arms" a few mm above the build plate and, for very tall supports, interlock at intervals as the supports build

2) Avoid/eliminate stand-alone supports.  Where one broad tall single-base support would have been invoked, instead print three supports somewhat spaced and have them interlock a few mm off the plate as suggested above.  This triangulation would greatly strengthen the unified support.

I am quite happy to model reinforcing rods/bars for the organic supports in my own models.  But including the above suggestions would make life easier for everyone.  I also recognize that a lot of people download models pre-drawn and may not themselves be inclined or able to do work the work suggested around.

I will apologize, if as a newbie to the forum, I have failed to find many prior references similar to this post.  I did look some, but did not see them.  I also recognize that by fiddling and tweaking with print settings I might increase the reliability of my organic supports.  But I ma mainly interested in simplifying the printing process by trying to weed out potential pitfalls.

Denis

Posted : 16/06/2024 7:47 pm
DenisFoster
(@denisfoster)
Active Member
Topic starter answered:
RE: Organic Supports Falling Over---Solve the Problem with "Reinforcing Rods"

Here is a failure I had moments ago after 5 hours of printing.

(It looks like the photo is of poor quality and not cropped as I intended.  Looks like I need to learn how this site's photo insertion works.  I have more photos but I'll post them when I know better how to have them represent the information better.   Sorry.)

 

Posted : 16/06/2024 9:38 pm
DenisFoster
(@denisfoster)
Active Member
Topic starter answered:
RE: Organic Supports Falling Over---Solve the Problem with "Reinforcing Rods"

So in the second post I started to write about the fact that I neglected to reinforce one free-standing organic support at each end of print.  All the rest of the supports were reinforced.  I thought I might "get away" with those two.  Well, they printed to 19mm and, sure enough, one of them snagged.  Only a few more layers and the overhang would have tied the whole works together.  Back to the drawing board quite literally.

I extended the bar so that it would include those end supports as well.  3.5 hours later the reprint has gotten up to and beyond the reinforcing bar and all is well.  The degree of stability added by that simple bar is, to me, amazing.  I will try posting some pics though my first try here did not go well.  (I am used to being able to post images directly into posts on other forums I participate in.)

Here is a pic of one of the free-standing, unreinforced, and still-intact supports .

This shows the bar being printed in among the supports but not extending into the end support.  Again the image is cropping off the bottom some and the left side of the image I uploaded to the "media library."  Again sorry.

 

Here in yellow is the reinforcing bar as seen from the build-plate side added to the desired model in green.  (Again, oddly cropped image)

 

Here is the new reinforcing bar extending into the previously free-standing end support.  (This time allowed for this software to crop the l side and bottom of the image.)  That bar will stabilize the support.  

In summary, short organic supports have worked fine for me.  But supports over maybe 15mm have been iffy.  A bar reinforcing them seems to make them very robust.  FWIW. 

I hope there will be comments as to how to deal better with the supports as they are programmed presently by Prusa.  I wonder if other folks have/are having issues similar to mine.  And, as a sort of side issue, how do you do images better in this site's software?

Denis

Posted : 17/06/2024 2:37 am
Mike B
(@mike-b-3)
Trusted Member
RE: Organic Supports Falling Over---Solve the Problem with "Reinforcing Rods"

To me, for some reason, your print looks like it's over-extruding.  They could be falling over because of a blob on top of the support.  Is this PETG (I'm not familiar with "Jesse")?

I just finished printing a 60 mm high box with a 20 mm "flange" with organic supports that look just like yours.  I had no issues with detaching.

Maybe try dialling down the extrusion to 90% or something?  I don't think this is a wide-spread issue although I remember somebody mentioning it before.

Other opinions welcome!

Prusa MK4 since Jan 2024, Printables: @MikeB_1505898

Posted : 17/06/2024 5:42 am
Eef
 Eef
(@eef)
Reputable Member
RE: Organic Supports Falling Over---Solve the Problem with "Reinforcing Rods"

When I look at this object, I wonder why you want to print it, laying this way, with so many supports? 
Without knowing what you are exactly doing it is hard to give good advice, but certainly I would try to print it standing in 45 degree position. Maybe cut in 45 degree so it will stick nicely to the plate, with some dowels, to fit them exactly together with some superglue, etcetera (there are many options). 
- Please upload the 3MF file (save as project) and compress to ZIP.  We can do suggestions on positioning and printing with much less supports. (so less what can go wrong + less to remove later). 

We will do what we have always done. We will find hope in the impossible.

Posted : 17/06/2024 1:00 pm
DenisFoster
(@denisfoster)
Active Member
Topic starter answered:
RE: Organic Supports Falling Over---Solve the Problem with "Reinforcing Rods"

First, thanks to the people who have taken time to respond.

Sorry for the omission in the first post --- I am printing Jessie PETG.

With respect to the orientation of this part on the build plate.  This part and a previously printed mating parts will make a mold for a core used in casting iron.  As these parts are mold pieces, surface finish and seam orientation are of prime importance to me.  So, printing them in an orientation that requires fewer supports is not an option and interior faces have to include draft angles around 1.5 degrees relative to each other.  This part and its mate were designed so that largish flat surfaces on the mold faces are parallel to or perpendicular to the build plate surface in order to avoid steps seen in surfaces printed with faces not quite parallel to the build plate.

While this support collapse that I am experiencing may not be a widespread problem, a general web search turned up more than half a dozen references to this issue.  The solutions suggested were all along the lines of "improving print parameters will allow fairly reliable printing of supports."  And that may well be true.  However, I think:

1) It would also be useful to make the supports more fault tolerant.  They are nice as they are.  But could they be improved?  I think so.  And I think such an improvement would be relatively easy.

2) Assuming Prusa does not chose to change this software design or at least until changes are made, the method I am suggesting does make the organic supports far more fault tolerant.  And I offer it as a suggestion to those folks who, like me, may benefit from some fault tolerance.  😉

The print I made with the bar as shown in yellow above was just fine.  And the supports were very robust.  

Here is a close-up of that print cantilevered with nothing holding it except me grasping the reinforced end support---the one that previously failed unsupported--- and the second shot was supposed to be less close-up.  For some reason both ends of that photo are cropped off as reproduced here.  (what am I doing wrong?!)

Here is the zipped 3MF file.

12 Prism1 Core top-reinforced

 

Denis

Posted : 17/06/2024 2:48 pm
DenisFoster
(@denisfoster)
Active Member
Topic starter answered:
RE: Organic Supports Falling Over---Solve the Problem with "Reinforcing Rods"

Ah, I finally found the size of image selection area of the insert image screen.  Here is the cantilevered image I wanted to upload above showing the strength of the reinforced support.  That shows the 13-inch part supported only by grasping one end with my thumb on the same support that was, prior to reinforcement, prone to simply falling over at the slightest provocation.  But when locked together with all the other supports it is very robust.  It is possible to support the print in the same way at any point in the long line of supports along the side.

 

Since my original inquiry I have printed 3 more prints.  Each has printed just as modeled.  The supports have been bullet-proof (in my world that means fault-tolerant and that is a good thing.)

I am in the process of doing the finishing touches to get these prints working as core molds.  Happy happy!

Denis

Posted : 18/06/2024 1:58 pm
Eef
 Eef
(@eef)
Reputable Member
RE: Organic Supports Falling Over---Solve the Problem with "Reinforcing Rods"

The print I made with the bar as shown in yellow above was just fine.  And the supports were very robust.  

Well done !.  And nice solution with the bar around it. (I can imagine with tall objects, several bars on more level will help). 

We will do what we have always done. We will find hope in the impossible.

Posted : 18/06/2024 7:06 pm
DenisFoster
(@denisfoster)
Active Member
Topic starter answered:
RE: Organic Supports Falling Over---Solve the Problem with "Reinforcing Rods"

 

Posted by: @eef

The print I made with the bar as shown in yellow above was just fine.  And the supports were very robust.  

Well done !.  And nice solution with the bar around it. (I can imagine with tall objects, several bars on more level will help). 

Thank you, Eef.  Your imagination for this solution and mine run in similar veins.  From my first post:

"1) Instead of the rows of solitary organic "trees" only making contact at the very top extreme of their printing, adjoining supports could "lock arms" a few mm above the build plate and, for very tall supports, interlock at intervals as the supports build"

Bolding in both quotes is mine.

I did report this support problem on github as an "issue" in hopes that Prusa might consider it.

Denis

Posted : 19/06/2024 10:54 am
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