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So in a bid to learning a bit more refinement from the basic default settings lets talk about RAFTS. This is something I've found a little tricky to find out actual info on since whilst a lot of articles say "use a raft" like a religious mantra, not many go into the actual settings, whilst many manufacturer style articles tend to summarise the meaning of the definitions, but then tend to advise/stick to the default program settings for what they recommend (which makes sense, its what they recommend after all).


Right now my rafts are at Chitubox's defaults with
Raft Shape - Skate
Raft Area Ratio - 110.00
Raft Thickness(mm) - 1
Raft Height(mm) - 1.8
Raft Slope - 30

This produces quite a thick raft that I've not really had any problems with getting off the build plate (in fact I'd wager most of my issues are more because the standard metal scraper that comes with a Phrozen 4K Mini has a blunt flat edge instead of a sloped edge to it, which makes it better at scraping the build plate than at actually getting anything off it...)

However as I'm also printing at 0.02mm in the Zaxis this creates quite a lot of layers doing nothing but building up a big raft which ultimately I'm throwing out. I've also had a few issues with the auto generated raft creating gaps when two corners intersect and creating a hollow region. I've had a model peel off the build plate because of this because suddenly the raft size got a lot larger without any undersupports.



My solution thus far has been to simply change the raft area ratio (typically increasing it) which smooths out the corners that it generates and thus solidifies the region.


However doing some reading around it seems I might be using a raft that's way way way too thick and might actually be causing me potential problems or just wasting resin, at least according to Ameralabs article, and these guys seem to know what they are on about when it comes to resin!
https://ameralabs.com/blog/default-3d-printing-raft-settings/

This would suggest that my raft settings could be adjusted too:
Raft Shape - Skate
Raft Area Ratio - 110.00
Raft Thickness(mm) - 0.80
Raft Height(mm) - 1.8
Raft Slope - 30

ALSO
adjusting the bottom layer count to 6 to cover the layers moving from the raft to the bases of the supports upon the raft.



However they only mention the slope aspect in passing and don't specify a setting, though its suggested to be 90 (max Chitubox goes too) and they don't mention the raft height at all (which might be due to variation in how different raft software function/list the raft stat). Though one would assume if you're making the thickness much thinner and then not using much of a slope, the height should also be reduced. Interestingly reducing the height to the same as the thickness actually results in quite a few of the supports forming outside of the raft area and I had to increase that to 120.00 to cover all the supports.


This is just one article from a respected source, meanwhile I've found it tricky to find others. I'd be interested to hear of your thoughts and what you use for your rafts and what you've found works and does not work for you.


I should note that if you've got one of the magnetic build plate attachments, then clearly a slope isn't needed at all since you're not going to have any need to push a scraper under the model. For myself this is one upgrade I'm strongly considering making in the semi-near future (along with changing from FEP to nFEP)

I mean, you should absoltuely get a plastic scraper. I can't imagine having your build plate scratched to high heaven is a good thing for keeping your prints stuck to it, and the fact that their flexible helps them to get underneath the raft.

My raft settings are fairly similar to yours. They work fine. The one thing I've generally done because I'm a lazy bastard is be OK with a fairly big raft underneath the model, because most of my build plates are super crowded with stuff (why print 1 warp spider when you can print 10, carefully interlocked with one another to fill the plate?) so i just need to successfully get the spatula underneath in one spot and then the whole plate comes right off super easily.

Funny thing, but on the Mars 2 Pro's building plate the prints stuck like mfing GLUE.

So much so that the plastic scraper mostly don't do anything unless I got first with a metal scraper (more like a straight razor, really) and manage to unstick a corner so that I can actually put the plastic scraper under.

Seriously, it sticks so much it's nearly ridiculous.

 Albertorius wrote:
Funny thing, but on the Mars 2 Pro's building plate the prints stuck like mfing GLUE.

So much so that the plastic scraper mostly don't do anything unless I got first with a metal scraper (more like a straight razor, really) and manage to unstick a corner so that I can actually put the plastic scraper under.

Seriously, it sticks so much it's nearly ridiculous.

Weird. I really only have any kind of problems if I print something large and flat directly on the build plate, like a road or a river or something.

the_scotsman wrote:

 Albertorius wrote:
Funny thing, but on the Mars 2 Pro's building plate the prints stuck like mfing GLUE.

So much so that the plastic scraper mostly don't do anything unless I got first with a metal scraper (more like a straight razor, really) and manage to unstick a corner so that I can actually put the plastic scraper under.

Seriously, it sticks so much it's nearly ridiculous.

Weird. I really only have any kind of problems if I print something large and flat directly on the build plate, like a road or a river or something.

I never had a problem with the Photon or the regular Mars, but the plate of the Mars 2 Pro has a layer of something much rougher, it almost feel like very fine sandpaper at the touch.

I have never had a problem about the base not sticking, though, so there's that.

I tried the metal scraper only once on my Mars build plate and never again, as it did scratch it. I just use the plastic and setting the rafts will make it easy to use a plastic scraper to get off.

If you are putting large flat areas directly on the build palte, it will be hard to get off, unless you go with the flex plate solution.

Here are my settings which work great and easy for me:
Raft Shape - none (this way you will not get that thick double base you see)
All of the next settings are disabled when you set the above to 'none':
Raft Area Ratio - 110.00
Raft Thickness(mm) - 0.60
Raft Height(mm) - 0.60
Raft Slope - 30

Where you want the 'skate' setting is in the 'Bottom' setting:
Platform touch shape: skate
Touch Diameter: 10.00
Thickness: 0.50 (when selecting the 'medium' support setting I have this set to .80, just to give it a slightly thicker base)

I hope this helps, as it works good for me and the plastic scraper gets under really easy to peel off. I totally agree w/ the_scotsman about getting all of the bases to touch so just getting under one corner gets the whole thing off in one pop.

Here is pic of what my raft/base looks like:

I have had to literally chip prints off my Mono print bed when over exposing the base layers before remembering that a 0.01mm layer will cure a lot more easily than a 0.05 layer. Like a sharp paint scraper and smack my fist off the rear to even make any impression. This has led to significant skin damage when the scraper slipped.

I have seen no reduction in stickiness of the print bed after scraping the remaining bits of welded on resin off the bed.

MDSW - I see where you're going with that approach, basically using the supports to build the raft underneath rather than building a dedicated raft as a separate entity. I can see merits in both approaches, the raft built on its own will at least cover the entire base area without having to worry about supports that might end up far from the others (esp now I've learned how to fan out support tops from one support column).
Meanwhile your method might well use far less resin and is only attaching where needed. I can see it working well save with really big sculpts that might benefit additional support that a larger raft creates in bonding and holding to the build plate.

Yes, as the benefit of saving resin is always a good thing, the nice angled base for the supports allow you to use a simple plastic scraper to get them all off cleanly.

As long as you have proper first layer exposure settings and your base and supports settings are thick enough, your lone supports out and away from a pack of them should have no trouble sticking - mine work good.

My Mars 2 Pro's plate also, if anything, holds too well.

Scratching the build plate helps with adhesion so go nuts with the metal scraper. Just make sure you don't create any raised edge on the scratches, that's eff your FEP up instantly. Sandpaper is your friend.

My preferred raft is Lychee's Pixelated. It's made of 1mm cubes with hairline cracks between them so it crumbles easy.