How to cool filament faster/How do tighter tolerances

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Cyber_Gram
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How to cool filament faster/How do tighter tolerances

Post by Cyber_Gram » Tue Sep 29, 2015 4:42 pm

Hello, I am fairly new to the MakerGear M2 (I've had it for 3-4 weeks), and 3D Printing in general. I am trying to print a platform jack (http://www.thingiverse.com/thing:925556) and a wrench (http://www.thingiverse.com/thing:139268). I am having problems with the different pieces getting fused together. I am currently printing with 190C Nozzle, 70C Bed (With Hairspray), and Hatchbox PLA. I am printing with the 50mm fan on at 100% after the first 2 layers, and I have installed a shroud (http://www.thingiverse.com/thing:773095). I am using Slic3r and Pronterface, but I am upgrading to S3D within a week or so. My nozzle is the stock 0.35mm.

Here are my travel rate settings:
Image

Also, how long does it take for PLA to go too bad to use from moisture? I am in a moister (Probably 40-50% humidity) environment.

Thanks for the help,
Cyber_Gram

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Jules
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Re: How to cool filament faster/How do tighter tolerances

Post by Jules » Tue Sep 29, 2015 5:20 pm

Both of those files are designed with hidden internal support that does create some fusion. They are supposed to be twisted or cut with a sharp knife to remove the support and allow the parts to move freely. (Check the descriptions.) Any of the "fully assembled" models you see on Thingiverse are likely to have that support in there.

And the humidity thing for the PLA varies - it's best to store it in an airtight container with some kind of desiccant when it is not in use. I use 5 gallon buckets with screw lids, and a small bag of rice with a bunch of pinholes poked all over it. You can store from 4 to 5 spools in 1 bucket with the rice tucked alongside. (GammaSeal lids for the screwtops.) There are more expensive dehydrating alternatives, but the rice works fine. It will actually suck out moisture that has already absorbed into the PLA if you leave it in there for a week or two. :D

(But if you've got the PLA inside with Central air, you've got a while before it absorbs too much humidity. Mine sat out for a month or so while i ordered the lids and a spool will sit on the machine for a week or two at a time. 80% humidity here.)

Cyber_Gram
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Re: How to cool filament faster/How do tighter tolerances

Post by Cyber_Gram » Tue Sep 29, 2015 5:38 pm

Jules wrote:Both of those files are designed with hidden internal support that does create some fusion. They are supposed to be twisted or cut with a sharp knife to remove the support and allow the parts to move freely. (Check the descriptions.) Any of the "fully assembled" models you see on Thingiverse are likely to have that support in there.

And the humidity thing for the PLA varies - it's best to store it in an airtight container with some kind of desiccant when it is not in use. I use 5 gallon buckets with screw lids, and a small bag of rice with a bunch of pinholes poked all over it. You can store from 4 to 5 spools in 1 bucket with the rice tucked alongside. (GammaSeal lids for the screwtops.) There are more expensive dehydrating alternatives, but the rice works fine. It will actually suck out moisture that has already absorbed into the PLA if you leave it in there for a week or two. :D

(But if you've got the PLA inside with Central air, you've got a while before it absorbs too much humidity. Mine sat out for a month or so while i ordered the lids and a spool will sit on the machine for a week or two at a time. 80% humidity here.)
I read/did all the instructions for the files, and I am still having fusion problems. When it is printing, I can see parts that are suppose to be separate in Slic3r, but are fused together in the actual print. (I am using the greater tolerance file for both the wrench and jack lift)

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Jules
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Re: How to cool filament faster/How do tighter tolerances

Post by Jules » Tue Sep 29, 2015 6:01 pm

Ahhhh....okay. Hmmmmn.

You're doing all the right things, your nozzle temps are on the low side, which is good. You've got extra fan directed towards the prints which should help with the cooling and keeping things from sticking where they are not supposed to.

i can only think of a couple of things that might help - one is to check your extrusion multiplier and make sure that it is exactly on the money for that filament. You might want to knock it down a point or two to just see if it helps. If there are any other settings in Slic3r that might be giving you a multiplier for the extrusion width that is greater than 100%, cut them back to 100%. (There is a separate one for infill in S3D, and that is sometimes set higher to speed up the infill and add strength.)

The other thing it might be is uneven cooling. If the sticking is happening on the side of the print that faces away from the fan, you can improve it on the backside by pointing a small desk fan at the back.

Can you upload a picture of the problem prints? (It's easier to tell with a pic.)

Cyber_Gram
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Re: How to cool filament faster/How do tighter tolerances

Post by Cyber_Gram » Tue Sep 29, 2015 6:32 pm

Jules wrote:Ahhhh....okay. Hmmmmn.

You're doing all the right things, your nozzle temps are on the low side, which is good. You've got extra fan directed towards the prints which should help with the cooling and keeping things from sticking where they are not supposed to.

i can only think of a couple of things that might help - one is to check your extrusion multiplier and make sure that it is exactly on the money for that filament. You might want to knock it down a point or two to just see if it helps. If there are any other settings in Slic3r that might be giving you a multiplier for the extrusion width that is greater than 100%, cut them back to 100%. (There is a separate one for infill in S3D, and that is sometimes set higher to speed up the infill and add strength.)

The other thing it might be is uneven cooling. If the sticking is happening on the side of the print that faces away from the fan, you can improve it on the backside by pointing a small desk fan at the back.

Can you upload a picture of the problem prints? (It's easier to tell with a pic.)
I'll try to get some pics of a chain I am printing (http://www.thingiverse.com/thing:710893), which also is having cooling problems.
I tried lowering the extrusion rate to .96, but it made the print very brittle.

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Jules
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Re: How to cool filament faster/How do tighter tolerances

Post by Jules » Tue Sep 29, 2015 7:03 pm

You're selecting some pretty tough files. (I hadn't even tried any of those yet, because all of that internal architecture is difficult in the first place.)

I am currently running that wrench print, to see how it goes, and if it works, I'll have another recommendation for you to try. (It was the quickest printing of your three choices.) ;)

You did do the Extrusion Width Calibration and the Z-Offset height Calibration, right?

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Jules
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Re: How to cool filament faster/How do tighter tolerances

Post by Jules » Tue Sep 29, 2015 8:57 pm

Okay, ran the wrench, and had one devil of a time prying one of those supports out of there. Matter of fact, it chipped a little piece off of the wrench end trying to pry it out (very low infill). Did manage to get the other two supports out after running an Exacto knife down along the movable jaws.
wrench.jpg
Supports in purple.
wrench.jpg (178.54 KiB) Viewed 4535 times
Might just be the tight tolerances on that one support behind the movable jaw - you'll probably have to get that one out before you can remove the others. Everything else printed just fine, without any filament sag, but i have removed my bed fan guard. That really cools the whole thing - (might even be better than using a shroud, since it hits the whole thing at once.) You could try it if nothing else works.

For files like this one - with a lot of internal bridging that needs to stay neat to keep from sagging down onto a print below, you could try increasing the bridging speed by about 10-15% or so. (PLA is usually very good for bridging though, so you wouldn't need much.)

Cyber_Gram
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Re: How to cool filament faster/How do tighter tolerances

Post by Cyber_Gram » Tue Sep 29, 2015 9:10 pm

Jules wrote:You're selecting some pretty tough files. (I hadn't even tried any of those yet, because all of that internal architecture is difficult in the first place.)

I am currently running that wrench print, to see how it goes, and if it works, I'll have another recommendation for you to try. (It was the quickest printing of your three choices.) ;)

You did do the Extrusion Width Calibration and the Z-Offset height Calibration, right?
No I have not, but shouldn't the assembled M2's already have been calibrated?

Here is a photo of the chain I am printing:
Image

This isn't turning out too bad, but you can see that around the outer edges of the circle it is having problems (Sorta hard to see on the photo, sorry). On the platform jack, the screw looks like it is fusing with its "socket" (for lack of better term), and the scissor arms are fusing together. I was able to print a gear bearing (http://www.thingiverse.com/thing:526566) that came out fine.

By the way, I am doing .2mm layer height.

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sthone
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Re: How to cool filament faster/How do tighter tolerances

Post by sthone » Tue Sep 29, 2015 9:30 pm

No.... Extrusion Width Calibration and the Z-Offset height Calibration need to be set for every roll of filament you run.

See the Guide, Read the Guide, Live the Guide.... :mrgreen:
(#3 and #4 under The Quick Start Guide Part)

-Steve
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Jules
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Re: How to cool filament faster/How do tighter tolerances

Post by Jules » Tue Sep 29, 2015 10:47 pm

:lol: ROFL! Steve, i worry that you might be getting into the guide thing a leeeetle too much! :lol: :lol: :lol:

He's right though, you do need to run some calibrations to get your extrusion width set correctly. Might be why you are over-extruding. (The chain is going to be impossible to separate - it's fused solid.)

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