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The last thing you want to see!!!!
#1
So came home today and found this!!! :<<<<<<


The main support for the centre leg just snapped into various pieces.

The damage is bad but could of been worse.

Will have to reprint and replace many parts and try to repaint some parts still on the body.

I will reprint the parts in 100% fill to see if that fixes it.

Not to put a scare into people but check your centre leg frame.

Its been on display for 6 months and not an issue. Its inside and its been very cold lately so not sure why?

See pics below and try not to cry.
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#2
NOOOOO thats terrible man, really sucks. actually lost for words, my heart sunk when i saw the title SadSadSad
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#3
Ouch, that really sucks big time.

What was it printed out of? ABS? PLA?
Could it have taken some damage while being driven around previously?
Did it let go at a part join first?

Makes you wonder what was the straw that broke the camel's back, why did it let go when no one was home.


I'm planning on the motorised centre leg lift, so hopefully it will be a bit stronger.
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#4
Oh No!! That is terrible. At least you know how to fix it. I am sure it will be as good as new in no time.

Was your center leg frame PLA? I am scared I have made a mistake with going PLA and CA glue for my build.
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#5
It was PLA, not sure about the infill. Now printing as I type frame A,B,C +D in PLA + at 100% infill!!!

The centre support was the main culprit.

It has never been moved from its spot so only time has caused the issue.

Live and learn there are worse things out there that could happen so suck it up and move on.

Will also plastic weld the parts used CA and epoxy of most joins and none of them have broken at the join.

Best wishes to all

Phill
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#6
Ouch! That sux. I have never liked that piece. I notice you still have the screws in there and it still did it.

It looks like you had separation between the infill and the top/bottom layersj - higher infill will help, not sure you need to do 100% though -usually anything over 50% is overkill.

I'm thinking different material (PETG usually has better layer adhesion) or maybe cut from a sheet of plexi?
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#7
Oh no!!! that’s terrible, really sorry. Mines ABS, but PLA can be more brittle so PETG would improve things. As Larry said, over 50% is overkill but maybe the centre frame needs thickening up and reinforcing. It’s hard as I test the build but only on my print (ABS) as it’s impossible for me to test everything in all materials. I’ll take a look at he frame and see if we can thicken it up or reinforce it :-(
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#8
(07-24-2018, 08:55 AM)Martyman Wrote: Oh No!! That is terrible. At least you know how to fix it. I am sure it will be as good as new in no time.

Was your center leg frame PLA? I am scared I have made a mistake with going PLA and CA glue for my build.

PLA will be fine - the sun is still the biggest issue with PLA.

This looks like a print failure, could have happened with any printed material.
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#9
The only good thing to come out of this, 
is this discussion of what may have been the cause,
and what the possible solution is to prevent it from happening again.

Looking at the pictures, I wound guess the infill at around 10 - 15%.
For low load non structural parts, 10% infill on PLA would be OK, but on high load parts like that mount piece and the side legs RTopShoulder and LTopShoulder higher infills of 30% to 40% will be necessary.
The other potential problem is the part that failed, FrameCentre.stl, is only 5mm thick, maybe we need to consider that,
Maybe double the thickness of that and the associated parts, FrameA.stl, FrameB.stl, FrameC.stl and FrameD.stl.

Some other things we should ask about the failed parts, Were they painted?
We know from the initial report that its been very cold of late, from memory Phul007 is in Australia, 
Australia is currently in the middle of winter.
PLA does absorb moisture from the air if it i not protected and can become brittle once that has happened.
The part that failed is not typically visible so it is possible it may not have been protected by a layer of paint.
Most of us are only painting the visible parts, after all the paint is for looks.
Do we need to consider that painting parts is a requirement for all parts in a PLA build?

I know Mr Baddeley spends a lot of time in the design of droid, and has said on his patreon page and in his build note that he prefers to use ABS for both the strength and the ease of joining parts together.  That's something else we should take into account as a group as a whole, when we choose to use different materials than that used in the design, we need to make allowance for the properties of the materials.

Most of the other parts MrBaddeley listed 10% infill on ABS, but on those parts, that was increased to 35% infill in ABS, the only other parts with a higher infill were the dome gear and foot assemblies at 25% infill. 
We really do need to take note of the instructions given by the designer, he has after all proven to have done a great job with the design so far.
When using PLA, it might pay to use a higher infill level than suggested for the ABS builds?
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#10
Thanks for all the info.
So the infill was 15% after checking the gcode files. (I saved everything).
It was painted and yes its been down to 2 degrees celsius where I live . (35 F)

I have reprinted most of the parts  (10 hours on two printers overnight) the other parts are still printing the 6 supports will take 12 hours at 100% infill

I printer them at 100% infill with PLA+ they are much stronger. (you can see the BB9-E sphere I have been printing also lol)

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(07-24-2018, 03:41 PM)MrBaddeley Wrote: Oh no!!! that’s terrible, really sorry. Mines ABS, but PLA can be more brittle so PETG would improve things. As Larry said, over 50% is overkill but maybe the centre frame needs thickening up and reinforcing. It’s hard as I test the build but only on my print (ABS) as it’s impossible for me to test everything in all materials. I’ll take a look at he frame and see if we can thicken it up or reinforce it :-(

Thanks Michael. see below I have reprinted it at 100% and will plastic weld the parts for more strength. Keep up the great work and thanks for the input.


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