3D printer

[Perplexed]

Have you played with the infill percentage as well as the infill pattern?

Yep, from 20% up to 80% and a variety of patterns. I’m using a CR-10 and several different makes of PLA if that matters.

To the OP, those are issues you need to be aware of. I had high hopes until I saw how fragile my print jobs could be when subjected to pulling forces. Compacting forces were less of an issue, though.

 

[conditionzero]

Yep, from 20% up to 80% and a variety of patterns. I’m using a CR-10 and several different makes of PLA if that matters.

To the OP, those are issues you need to be aware of. I had high hopes until I saw how fragile my print jobs could be when subjected to pulling forces. Compacting forces were less of an issue, though.

I would also try increasing the wall thickness and count, also printing a little hotter if I can sacrifice dimensional accuracy for some strength. After that I would probably look at another material for the application.

 

[Perplexed]

I would also try increasing the wall thickness and count, also printing a little hotter if I can sacrifice dimensional accuracy for some strength. After that I would probably look at another material for the application.

Did all that, too. I was thinking more along the lines of post-print treatment to strengthen the pieces. I guess I just expect too much of PLA, so I should try ABS or other material.

 

[conditionzero]

Did all that, too. I was thinking more along the lines of post-print treatment to strengthen the pieces. I guess I just expect too much of PLA, so I should try ABS or other material.

I have definitely seen people anneal PLA prints, that may help a bit.

 

[-Pjackso]

I've seen that ABS can be smoothed with an Acetone vapor bath.
The smoothed finish looks really nice.

 

[JR777]

What do you folks do to keep your PLA print jobs from breaking apart under the least amount of torsional stress? My jobs can’t handle more than perhaps a bottle of water in weight before I start having delamination issues.

Could be the brand of filament, but more than likely you're not printing hot enough to fuse the layers.

Anything to be loaded though is usually better with PETG.

 

[JR777]

Have you played with the infill percentage as well as the infill pattern?

Infill doesn't add much strength. It's 95% about print quality and 5% about adding a tiny bit of compressive strength. If it adds any torsional strength it's negligable. 20% infill is going to max out both things though. Anything beyond 20% is just superfluous.

For increased strength, you can turn up the perimeters and or add internal supports to the model itself.

 

[Perplexed]

Could be the brand of filament, but more than likely you're not printing hot enough to fuse the layers.

Anything to be loaded though is usually better with PETG.

I’ve been printing at the upper end of the recommended temperature range, even 10° C beyond that, just to see what would happen. Still fairly brittle, but like I said earlier, I’m probably expecting too much out of PLA. I’ll have to try other materials.

Would be nice if the jobs would come off the printer smooth with no glaring evidence of layering; I tried acetone vapor in a paint can, but it turned the PLA rather soft and flexible.

 

[JR777]

I’ve been printing at the upper end of the recommended temperature range, even 10° C beyond that, just to see what would happen. Still fairly brittle, but like I said earlier, I’m probably expecting too much out of PLA. I’ll have to try other materials.

Would be nice if the jobs would come off the printer smooth with no glaring evidence of layering; I tried acetone vapor in a paint can, but it turned the PLA rather soft and flexible.

Yea the vapor smoothing will absolutely eat away the strength. Which is ironic because the types of plastic it works on, namely ABS, are difficult to print and used only because of their strength for functional parts. So it doesn't make much sense to weaken them with vapor.

PLA can be quite strong. If you don't mind telling me more about what you're doing I might be able to help. It might be just a matter of printing in a different orientation or adding a bit of material somewhere. Prints CAN be strong and functional, despite what many think. Case in point:

 

[Perplexed]

Yea the vapor smoothing will absolutely eat away the strength. Which is ironic because the types of plastic it works on, namely ABS, are difficult to print and used only because of their strength for functional parts. So it doesn't make much sense to weaken them with vapor.

PLA can be quite strong. If you don't mind telling me more about what you're doing I might be able to help. It might be just a matter of printing in a different orientation or adding a bit of material somewhere. Prints CAN be strong and functional, despite what many think. Case in point:

It’s been a while since I tried printing anything, so I can’t recall the details of orientation or such. If the gray braces on that storage unit were also printed and weren’t made from castings, I’ll be impressed. How thick are the walls overall, 1/2”?