Seperation from raft

[earthcaretech]

Hi all.
I'm having issues in getting my part to separate cleanly from the raft.
I'm printing PLA (210C, bed 60C) on a Formbot T-Rex 3 +.
The attached photo shows the best result I have got so far, but it still has "threads" hanging off it. I've also attached a screenshot of the S3D Skirt/brim & Raft settings.
Can anyone suggest how to improve the release?
Thanks.

[dkightley]

The first thing I'd suggest is to kill the heated bed!...set the temp to 0. PLA doesn't need any sustained heat, in fact it really needs a cooling fan running flat out after the first layer!

I print a lot onto a raft.....mainly as its more convenient to do so, but also as I print model buildings that benefit from not having a mirror-finish on the bottom!

I normally just have 1 top layer and no base layers, set the separation distance to 0.02 to 0.04mm. I then set the first layer height to 200% to 300% and the Global-z to give a reasonably squashed raft. and vary the raft top layer infill to get a compromise between good adhesion to prevent warping and an easy to release raft. A good starting point is 45%. I also have a single layer skirt at zero offset ….mainly to hold the edges of the raft down.

Most of the time I can peel 90% of the raft off by hand.....and a quick slice with a scalpel gets the rest off.