Speed and Temperature

[mark-hale 0]

Hi

Have just noticed in the Basic settings under speed ad temperature. Only speed is shown?

Where in Cura can temp be changed as I have looked in the advanced and also the Expert config but unable to spot it.

The reason I ask is that i am having problems with a print, where it keeps lifting early on, even with Brim, I notice that if I use the glue on my UM2 Bed and set the bed temp to Zero it does't lift. Well so far ..... its a 15hr print so a long way to go

I have tried glue and left the bed heat to default 75deg but it lifts.

The other settings I have are 100%fill. Also note that if I have say 25-50% fill it doesn't lift with the heated bed so guess the 100% could be a factor?

 

[IRobertI 428]

For the UM2 the temperature settings have been moved to the printer. Look under the material menu on the printer and you'll find it there.

You can also temporarily change the temperature by going into the Tune menu while you are printing.

Maybe you can try increasing the number of lines that are used for the brim?

Also make sure that your bed is nicely leveled so that the first layer is pressed onto the bed and not sitting very loosely on top.

 

[illuminarti 16]

If you have 100% fill that's a lot more plastic to exert shrinking forces and pull it off the bed.

[mark-hale 0]

If you have 100% fill that's a lot more plastic to exert shrinking forces and pull it off the bed.

 

OK I did wonder if this was a factor. Would you suggest a minimum or does it really depend on the print?

Sorry iRopertl - forgot to say I had seen it in the tune menu. Just curious as to if it could be done in cura.

Will try increasing the brim as ideally I would like 100 fill as it needs to be quite a strong structure, might have to look at ABS or Nylon I guess.

Cheers both

 

[aaronalai 2]

Greetings Mark,

I have run across this in my filament research: http://www.formfutura.com/3mm-filaments/specialty/smartabs/

Supposedly it's as strong as ABS but not shrink as much, if you are doing 100% fill for a strong part this may be helpful. I haven't used this material myself, but perhaps some further research can yield some good reviews.

 

[illuminarti 16]

I think you really have to do some tests to see just what is 'strong enough' for your needs. It will depend on the geometry of the part, and the directions that forces are applied. For instance I would assume that in general, compressing forces parallel to (and through) the walls (assuming they are appropriately thick) would be resisted much better than stretching forces in the same plane (since those might tend to cause delamination).

You also need to consider the temperature requirements for the piece, since PLA has a low glass temp, and will start to deform at as little as 60ºC - e.g., inside a car on a sunny day.

I'm not sure how good Cura's internal support structure really is for strength. There has been a lot of debate about this. With an infill percentage up to 24%, you get a full grid on every layer; above that it switches to running the lines in one direction per layer, so that each layer mostly prints over a 1 layer gap; I think that tends to reduce the cohesiveness of the infill quite a bit, and may reduce the strength benefits.

Other slicers offer alternative infill patterns, such as honeycomb, that might have better strength benefits.

However, I suspect that in general a good way to get strength, while keeping down weight is to go for a thicker shell, and lesser, but uniform, infill pattern.

 

[gr5 898]

Most strong things are hollow inside or at least they can be. On my house, the plumber and electrician only cut holes through the *middle* of the studs and the joists. Never the edge. Light weight beams tend to have hollow centers. I beams have almost all the material at the top and bottom of the I. Tubes and pipes can be very strong. The drive shaft on my car is hollow.

So...

Making a part solid might not increase it's strength measureably. And solid parts have shrinkage/printing issues.

Instead consider giving it a very thick shell or designing interior support exactly where needed for how the part will be used.