v4 rafts - first object layer not filled

[bludin]

Rafts used to work very well for me in V3.1.
In V4, the first object layer appears to be much less filled than previously and sometimes, strands are ripped out of the layer and stay with the raft upon removing the latter.
So here is what happens:
The first layer is dropped onto the raft from Z=(separation distance + layer height) in order to decrease adhesion. The problem seems to be that the second object layer is the extruded from Z=(separation distance + 2x layer height), i.e. the extra height is maintained, leading to poor adhesion between the first and the second layer.
Now if I define two processes, set them switch over between the first and the second layer, and set a Gcode Z-offset of -(separation distance) for the second process, the second layer is extruded at Z=(2x layer height). The outcome is much better and I wonder whether it shouldn't be that way in the first place. (Maybe a bug intruced in V4?)

[bludin]

I'm really surprised at the lack of responses here.
We find that the default raft in V4 is much worse than in V3 but becomes good again using the workaraound above.
Does nobody else share our experience (we're several people here seeing the same problem with two very different printers)?
Or am I overlooking something?

[dkightley]

Try dropping the separation distance down to much less that you used to use for pre-v4.

I found dropping down from 0.15mm to 0.04mm gave superb results. I also use 1 bottom layer and 1 top layer for the raft. The raft separates nice and easy, leaving a few strands lightly adhering to the bottom of the first layer of the model.....which zip off easily with a light wipe with a scalpel.

[brian442]

v4 rafts have been significantly better for me than v3. As dkightley said, you might need to tune your separation distance, but the stock settings have been working great for me.

[bludin]

thanks for your answers.
I've played around with the separation distance and indeed, the results became much better.
I just wanted to let you know that in my hands, the method I described (larger separation distance, Z-compensation of the 2nd layer) yields still slightly better results (with my favorite materials that is, i.e. Polymaker PC-Max and Extrudr Greentech).
So S3D, if you hear me,, here would be an ER for an additional parameters

Cheers, Beat

[supercazzola]

I have no experience with v3, so for me this was always a problem. Thank you for starting this thread @bludin and to @brian442 and @dkightley for providing additional hints. I will try the suggestions, and hopefully see positive results.
I am very grateful !