build plate adhesive

[kingfisher-tam 0]

PLA to extruder 1

PVA to extruder 2

The other day, when I suddenly set cura's build plate adhesion type to raft, the extruder 1 side filament was not ejected until the 3rd layer.

Even if I change the version of cura to an older version, I am in the same situation and I am very troubled.

 

Please tell me what to do

Edited May 27 by Slashee_the_Cow
removed formatting from text

[Slashee_the_Cow 493]

Hi there! AFAIK rafts are usually printed with the support material - in this case I'm guessing that would be the PVA - so the actual model (in PLA) will only start printing on top of the raft.

 

Rafts themselves aren't nearly as useful as they were in the past - bed adhesion has gotten a lot better, especially from the printer's side. I've never had to use them, although I know some people do to make sure they don't have any trouble removing the print from the bed (I just don't understand why someone would do it on a single extruder printer because you then have to separate the print from the raft).

[gr5 2,270]

1) I'm not sure why you want a raft as it is an old technology that you shouldn't need.

2) If you really want a PLA raft, just disable the PVA extruder altogether.

3) Not sure why you care if the PLA doesn't start until several layers later?  That's how it's supposed to work with raft.

 

I suggest you turn off raft.  If you are using raft to fix some issue, please explain that issue instead.  I guess we need more information.  Maybe you want the raft to be part of the final model?  We need some more details please.

[gr5 2,270]

I just checked and you can indeed choose which extruder to make the raft with.  If that's your goal.  or if you don't want the left core to be idle you can enable a prime tower (if it's not already enabled).

 

Please explain your issue in more detail.

[jaysenodell 18]

As to “why a raft”…

 

Because of stupid creality build plates. 0.3mm variance is a problem when I’m making things that have to be flat and parallel top and bottom plane (cnc fixtures, spacers for mechanical pieces, etc). With the raft I just remove the raft cruft and I’m good to the design spec. Without the raft I get to pray that my flattening efforts are parallel to the  upper plane. God help me of my the bottom isn’t flat by design. 
 

hope that makes sense. 

[kingfisher-tam 0]

Slashee_the_Cow
PLA is set on Extruder 1 and PVA on Extruder 2.
The raft is set to print on Extruder 2.
When you start printing in this state,
the raft and prime tower on Extruder 2 will be printed.
However, filament will not be extruded when printing on Extruder 1 after this.
This non-extrusion state continues until about the third layer, after which normal extrusion will begin.
Even when a prime bobble was set on Extruder 1, there was no ejection there.
When the build plate adhesive type is set to brim and the build plate adhesive extruder is set to 1,
after the prime bobble is ejected, it will print as shown in the preview.

 

[translated to english by gr5 using google translate]

Edited June 3 by gr5
translation to english

[gr5 2,270]

Please post your project file.  In cura go to menu "file" and then "save project" and post that file here please.

[Slashee_the_Cow 493]

On 5/28/2024 at 5:11 AM, jaysenodell said:

God help me of my the bottom isn’t flat by design. 
 

hope that makes sense. 

Not really.

*/me runs internal spelling and grammar check*

 

On 5/28/2024 at 5:11 AM, jaysenodell said:

God help me if the bottom isn’t flat by design.

That actually sounds like a better circumstance because then you have less area contacting the (apparently uneven) base plate. Still, rather than a raft, usually if I've had a problem with the very bottom of something not coming out right I just move it up a few layers' height into space so it gets build on top of some support.

 

On 5/28/2024 at 5:11 AM, jaysenodell said:

Because of stupid creality build plates. 0.3mm variance

I'm not sure if I should if I should be jealous or not. This is the ABL data from my E3V3SE (I'm assuming relative to the home position, which isn't actually on the grid):

╔═════╤═════╤═════╤═════╗
║-0.07│-0.07│-0.22│-0.23║
╟─────┼─────┼─────┼─────╢
║-0.10│-0.05│-0.05│-0.10║
╟─────┼─────┼─────┼─────╢
║ 0.13│ 0.15│ 0.13│ 0.08║
╟─────┼─────┼─────┼─────╢
║ 0.36│ 0.36│ 0.34│ 0.28║
╚═════╧═════╧═════╧═════╝

And just as a reminder, this is a printer where there is no way to manually level the bed. Unless you can take those values and fashion your own plate which is level (it just attaches to the printer magnetically).

[jaysenodell 18]

I know they say glass is a step backwards, but I'm about to go there just to get the needed "flat means flat". All the systems that other folks are using to make fixtures seem to always end in glass plates with ABS or poly-glass/carbon (cnc gets hot and tends to care about 0.000X at times). 

 

At some point I may just need a better printer.