Problems Removing Raft

[roller]

Doug, thanks for the effort in your long posts. Thing is I remove rafts about 3 or 4 times a day because I have UP printers here and sometimes there is excessive adhesion due to running a filament too hot, too slow, building up too much heat in the raft or an unlevel bed. To get these print off safely I have techniques to help the raft shear away leaving minimal raft behind to clean up.

What I am seeing with Simplify3D is something different because I am getting adhesion at the edges in one axis and the edhesion is extreme - those are not remnants that are a little bit stickier but the adhesion on those raft edges is actually greater than the final part layer to layer adhesion. It is a very strong mechanical bond.

Don't be too distract by the ring print. I use it to test because it doesn't consume too much filament and the final part is useful because it's a lower tolerance part. This issue happens on every print without fail.

I have:
- gone up to 7 layers of raft
- disable raft base layers
- obsessively levelled the bed (people usualy get me to level their beds for them because I do such a good job) - though this is usually clear because in such cases the raft tends to be stuck more on one side.
- played with the inital layer height from smooshed right onto the bed nearly to the point of nearly jamming (missing a step or two) to barely sticky to the bed due to it being at nearly 100% layer height.

Everything yields essentially the same result just in greater degrees i.e. some are completely impossible to remove ... to the best example in the picture above.

As to your theory, the raft is actually peeling best where it is in the same direction as the raft and worst where is is at nearly 90degrees ... this is the opposite of what should be observed ... at 90 it should bond less and aligned is should bond more. Further it is not worst at 90 ... it is worst near 90 specifically about 75degrees. This curios angle really doesn't lend itself to making any sense. That said I'll take a look at more angles to see if there is correlation.

Mostly I wish support would reply more than once a week ... and when they do reply I wish it was even vaguely useful rather than suggesting something I have told them I have already tried.

[Elvis007]

One more thing. In my common test print you can see that in some areas the raft does remove acceptably (shown in the image in cyan) but in other areas it is very strongly adhered to the print layer (yellow). Separation distance is 0.25mm on this example which is printed with a 0.2mm layer height.

Sticking Raft.jpg

Hello! The separation distance in Simplify 3D Where can I find ?? thanks Alessandro

[JoeJ]

click "edit process settings", choose the Additions tab, and look for the setting in the raft section labeled "Separation".

[Elvis007]

click "edit process settings", choose the Additions tab, and look for the setting in the raft section labeled "Separation".

Hello Jose! Let's say I guess the proper separation distance and therefore can remove problems without the raft, but 'if the first layer that goes to print the prototype can not deposit it well, in the sense as if the proper publisher slightly raised, where' that I can intervene in uleriormente Simplify 3D ??? Any suggestions ??? Thanks a lot! Alessandro

[KC_703]

I've just started playing with rafts on my TAZ5. I'm getting good results with a separation of .4. There is still some of the raft sticking , but I've noticed its the areas where filament accumulates... basically, the edges of the project, or holes within the bottom surface.

With that said, it seems as though those are areas which have additional heat build-up from the extruded filament. I haven't tried, but maybe lowering the initial layer temp, or increasing the fan cooling of the first layer would help.

[furicks]

I print with rafts on occasion and I have found that anything less than 3 layers results in a completely impossible to remove raft. 3 Layers is the minimum.

I always disable raft base layers. I see no value in this at all it's just a waste of filament.
It's important to create as solid a raft as possible. I usually go with 90% Raft Infill.
I scale my rafts to be 1 complete layer of separation - 0.25mm layer height 0.25mm separation.
I then preview the raft before printing to make sure the layer is there. When you added excessive separation to the prints were you able to see a significant gap in the preview?

See the screen shot for "excessive separation" of 1mm which should really just create a big mess but the raft would be easy to remove.
A raft shouldn't just fall away from the print which I'm sure you know. But the nice solid 3 layer raft can easily be removed in one consistent piece with minimal effort.

Separation 1mm

[bapro]

It was no problem at all with 0,14 separation in V2. The raft angle goes the other way in V3 wich makes it difficult. Since they also managed to take away the possability to control the solid infill angle in V3 , there is nothing else but to go down to a minimum of temp for the first bottom layer. I go down to 190.