Please help with MAKE torture test cube  

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crypxtic
(@crypxtic)
Active Member

A friend recommended I try doing this torture test by MAKE.

I've gotten pretty far with it, and actually I've been pretty happy with the results of my other prints.

But now I feel like something is not calibrated right with the printer, or what have you. Here are some pictures of how the cube is turning out. Everything is pretty much perfect except once it gets about 60% through the arch fails, and spaghetti monsters appear.

What I've Done:

  • Clean the surface with Alcohol

  • I've calibrated the first layer like 100 times to the point where I think it's pretty much perfect.

  • I've tried lowering the speed all the way down to 70% (This was using the Prusa MINI's interface, to slow the overall speed to 70%),

  • My friend had even suggested I slow down travel times, and infill speeds, but these had no effect.

 

1st attempt

2nd attempt

3rd attempt (70% Speed)

This topic was modified 5 months ago by crypxtic
Posted : 28/05/2020 5:09 pm
crypxtic
(@crypxtic)
Active Member

Also just wanted to add that the first part that seems to fail is the portion of the arch that is off by itself, it seems to become adhered and then all hell breaks loose. 

Posted : 28/05/2020 7:27 pm
darcshadow
(@darcshadow)
Trusted Member

Have you tried adding a brim?

Posted : 28/05/2020 7:33 pm
crypxtic
(@crypxtic)
Active Member

@darcshadow

I think the point of the test is to try to build it without any supports or brims no?

My friend guided me through PrusaSlicer on the settings, and helped me export it. He told me you don't want any supports since it defeats the purpose of the test.

Posted : 28/05/2020 8:09 pm
bobcousins
(@bobcousins)
Reputable Member

Benchmarks are always tricky things. Surely the point is also not to tweak slicer settings, or print speed? Because you don't change those for a typical print (well, I don't).

The idea of a common benchmark for a printer test, is to test the printer performance "out of the box", as well as ultimate performance. However, there are a lot of variables in play, so how meaningful it is is quite relative. For example, of the "makes" posted on thingiverse, we have no idea what settings they tweaked, what slicer they used, what material was used, how many attempts they took, etc.

At the end of the day, it tell you the limits of what you can do with your setup, but it's still artificial. There are probably few prints that have an unconnected end like that, for the obvious reason it is difficult to print.

Anyway, I think it is perfectly valid to add a brim. You could also try different layer height.

Posted : 28/05/2020 10:12 pm
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bobstro
(@bobstro)
Illustrious Member

FWIW - You should be able to print that arch without a brim. A brim helps with adhesion. If your part is coming loose on a Prusa printer, that means you have adhesion issues. Those are related to Live-Z calibration, PEI print surface contamination or both. Start with a good clean of the PEI surface. A dunk under the kitchen sink with Dawn dish soap is the most effective method of cleaning. Scrub it with a few drops of Dawn unscented dish soap (or your local equivalent) using a plain paper towel and dry it with another. Do nothing else to the PEI. Then work on your Live-Z calibration. Until that is correct, don't bother with more complex prints as you'll get exactly this same sort of result. Print the bottom layer of the Prusa logo STL and post a pic here for additional suggestions.

Once you've got the PEI surface properly clean and Live-Z set, then start with the more complex benchmarks that are intended to show shortcomings.

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 : 28/05/2020 10:24 pm
crypxtic liked
crypxtic
(@crypxtic)
Active Member

@bobcousins

Thank you for this clarity. I too had my doubts due to the myriad of variables out there that can affect a print, but my friend was trying to convince me it should work "out of the box".

So far I'm happy with the overall quality of my other prints, I just want to make sure the mini is performing 100%!

Posted : 28/05/2020 11:04 pm
crypxtic
(@crypxtic)
Active Member

@bobstro

Thank you for replying bobstro!

I'll perform these steps right away and report back with the Prusa logo print.

I actually have a question about the First Layer Calibration (Z-adjustment): Are we aiming for that final little rectangle to be fully intact, or come apart like an accordion? I have a hard time telling the shape of the bead, even with the manuals diagrams.

Posted : 28/05/2020 11:06 pm
crypxtic
(@crypxtic)
Active Member

@bobstro

Here are the results after a fresh wash, calibration, and prusa logo print:

 

This post was modified 5 months ago by crypxtic
Posted : 29/05/2020 2:06 am
crypxtic
(@crypxtic)
Active Member

I can't even print this without it coming unstuck from the plate halfway through. 

https://www.thingiverse.com/thing:3898469/makes

Posted : 29/05/2020 2:52 am
bobcousins
(@bobcousins)
Reputable Member

Ah ok, you said you had first layer perfect... but you need to be lower on the first layer. The beads should merge together, when you peel it off it should be like a single sheet and not come apart.

Posted : 29/05/2020 9:12 am
crypxtic and bobstro liked
bobcousins
(@bobcousins)
Reputable Member

I tried printing the torture test with my regular setup*, and it failed around the 50% mark. The contact patch for the arch end is 5x3mm, which is not something I would ever expect to print successfully. If this was a real piece I wanted to print, I would add a brim or support and not worry about it.

OTOH, the whistle should be printable, although printing vertically can be challenging, it should be doable. Although again, a brim here would not be the end of the world.

 

* Prusa Mini R2
Prusa smooth PEI
unbranded PLA
Prusa Slicer-2.2.0
Firmware 4.0.5 RC1
0.20 mm Quality profile ,10% infill, no brim, no support
Room temp ~28 degrees C

Posted : 29/05/2020 11:32 am
crypxtic liked
crypxtic
(@crypxtic)
Active Member

@bobcousins

Thanks for replying sir, this honestly makes me feel a lot better.

I think my friend just set unrealistic expectations for me regarding the capabilities of the printer, maybe he's not as experienced as he touts.

Since my initial post I've been experimenting with getting my first layer down even better, and as I lower it I'm definitely noticing the quality of the prints getting a bit better.

Thanks again for taking your time to reply to me and share your knowledge guys, I am enjoying my first 3d printer so much, can't believe it took me this long to get here!

 

Posted : 29/05/2020 6:21 pm
bobstro
(@bobstro)
Illustrious Member

You don't want to use torture tests as diagnostics or calibration prints. They're meant to be difficult to print, and can test the limits of both the printer and the user. That arch is particularly tricky because of the likelihood of the two sides not aligning perfectly and knocking the narrow part off.

For actual prints like the whistle, if you've got your Live-Z properly calculated and the bed clean, you should expect to get good adhesion for small prints:

Even the 3x5mm footprint is not a problem on the Mk3:

An angled 5.25x5.25mm print is also not a problem without a brim:

In reality, there's no reason to attempt to print a part with an overhang like the stress test in that orientation without support, so don't read too much into the fact that it's a difficult print. It's meant to be. I gave it a try and had the same failure at the top of the arch, but I'm not going to read too much into it beyond that.

 

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 : 30/05/2020 7:42 am
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