Stringy Print 1st layer after Support

[frank-pitkat 0]

I am working on a project that i'm printing an octagon and i'm using the follow settings:

Layer Height: 0.20

Shell Thickness .8

 

Bottom/Top Thickness: .8

Fill Density: 25%

 

Print Speed: 35

Bed Temp: 62

Nozzle Temp: 205

 

Support Type: Touching Buildplate

Lines

90 degree

15% infill

X/Y Distance: 0.5

Z Distance: 0.15

 

 

The problem that i'm having in that the first layer that prints over the support material is stringy.

 

What could help me solve this issue?

 

Pictures:

https://www.dropbox.com/s/z00zjpmceib04wt/First%20Layer.tiff?dl=0

https://www.dropbox.com/s/qaz48jlbpqq3r3n/First%20Layer%202.tiff?dl=0

 

 

 

[iefbr14 0]

are you talking about the infill ?

are these strings like crappy leftovers, or nicely aligned fully drawn lines ?

could you post a pic of the object while it's being printed ?

 

[frank-pitkat 0]

Nicely drawn lines that don't connect to anything. giving it a horrible look

 

[iefbr14 0]

not sure how seasonned you are, so please dont mind if i tell you what you already know :

printed parts are composed of

- a shell (the periphery)

- a top and a bottom cap

- an interior

the shell is drawn with continous lines, it's thickness is determined by the Shell Thickness parameter

in your settings, it's set to 0.8 , that is, 2 lines drawn with you 0.4 nozzle

the top/bottom caps are made with a tight cross hatched pattern, one direction at each layer.

how many layers are used depends of

- the Layer Height parameter, 0.20 in your settings

- the Bottom/Top Thickness parameter, 0.8

that means that you should see 4 layers being laid when printing top/bottom caps

the interior is filled with a loose square pattern. how loose it is determined by the infill parameter (25% for you)

it means that 25% of the surface of an interior slice will be covered in plastic

the support is something that gets added to the model in order to provide foundations to what would otherwise be printed mid air. i dont see any part needing support in the model you show.

so, with these informations in mind, how would you describe your problem ?

 

[frank-pitkat 0]

It would be when the first layer of shell is printed over the support layer. the second layer is sticking fine but the first layer that is touching the support material is stringy.

Pictures:

https://www.dropbox.com/s/3r287p5wgq4zcdh/Untitled.tiff?dl=0

https://www.dropbox.com/s/5p380gzc5s57cnc/Untitled2.tiff?dl=0

 

[iefbr14 0]

not sure i understabd what you mean..

could you post actual pics of problematic layers being printed ?

maybe a short vid including a few layers before and after ?

 

[tinkergnome 927]

It would be when the first layer of shell is printed over the support layer. the second layer is sticking fine but the first layer that is touching the support material is stringy.

 

I think, this is (unfortunatly) pretty normal.

The material sags down and the part looks ugly (from the downside).

You can try to use a support grid (insteads of the lines) and increasing the fill amount should also help - but it will be harder to remove he support.

Edit: although we dont't know the function of this model - it could be a better solution to print it in two pieces (without support) and screw / glue the parts together... :?:

 

[frank-pitkat 0]

Think I fixed the problem.

 

• Changed Layer Height from 0.20 to 0.15
  
• Changed Print Speed from 35 to 40
  

 

I was originally printing in two parts but I was worried about durability. The tip on the top slides into a belt clip. Never thought of putting threads on it!

Also having some issue getting Cura to print the parts separately even though "Print one at a time" is check.

 

[iefbr14 0]

oh ok got it now.

kind of 'bridging effect' on top of the support, right ?

and so, print faster with thinner layer helps... makes sense.

thanks

 

[nallath 1,123]

Print one at the time does nothing if the objects are too high. This is indeed not communicated as well as it could to the user.

 

[pm_dude 27]

Anything above 48mm of height will disable the print one at a time mode. This is to prevent previously printed objects to be smashed by the Y axis rod.