Raft separation distance and next layer height problem

[dkightley]

Hi Tesse

You've either not read the thread, or you've read and not understood the thread fully.....because the symptoms you've described are exactly the same as what has been described at least once.

Yes. there is something that needs addressing....but its not quite as simple as "The 2nd object layer (layer 6 on the pictures below) is then located underneath the 1st object layer. BUG!" And yes, I totally agree with you that something needs to be done. The whole concept of what is done to ensure the raft can be separated needs to be revisited...as what is done at the moment doesn't seem to be right...and cannot be reliably adjusted.

I would have thought that one of the development team would have seen this thread and thought that this would be a nice and interesting issue to get really stuck into. Something more than a boring old error that needs correcting - but an interesting and meaty conundrum that needs lots of thought to get to grips with! HInt....hint!

[Tesse]

Hi dkightley,

thanks for the reply. I know that the symptoms have been described before. In fact, the issue was first stated in August, I belive. I am new to S3D and the community, but I would expect that this problem would have been fixed by now. I, like many others spend some money on this otherwise very fine piece of software. This is something I can not easily accept as a paying costumer, knowing that this feature seemed to work in a prev. version.

I just wanted to share my findings with you, I didn't mean to offend anyone by repeating the symptoms.

Cheers, Tesse

[generesque]

I wanted to chime in on this thread because I was experiencing similar issues with raft adhesion using Simplify3D and a MakerBot Replicator 5. Whenever I printed a items sliced and prepared with the MakerBot software, my rafts would separate cleanly. With Simplify3D, however, the top layer(s) of the raft would adhere strongly to the print and I would have to trim the excess away with a knife.

I tried different separation distances in the range of 0.15mm - 0.35mm and got identical results each time. Working on the theory from this thread that Simplify3D was making incorrect Z axis moves for the first few layers of the actual print, I generated a 20mm box .makerbot file with a raft from both Simplify3D and the MakerBot software. When printing, the MakerBot raft separated cleanly, and the Simplify3D raft stuck to the bottom of the print.

I then unzipped the .makerbot files (they are just zip files) and compared the .jsontoolpath files in each. What I found is that both Simplify3D and MakerBot handle the first few layers of the model identically. Here is what they did:

Simplify3D:
Last Layer of Raft: Z=1.993mm
1st Layer of Print: Z=2.657mm (+0.664mm)
2nd Layer of Print: Z=2.607mm (-0.05mm)
3rd Layer of Print: Z=2.907mm (+0.3mm)
All subsequent layers incremented by 0.3mm as per the Fast print settings

MakerBot:
Last Layer of Raft: Z=1.38mm
1st Layer of Print: Z=2.04mm (+0.66mm)
2nd Layer of Print: Z=1.98mm (-0.060mm)
3rd Layer of Print: Z=2.28mm (+0.3mm)
All subsequent layers incremented by 0.3mm as per the Fast print settings

As you can see, within a 0.01mm tolerance, the two programs are generating identical behaviour. This leads me to believe that the problem with Simplify3D rafts is not in the way it prints the first few layers of the model, but in some other variable. I checked and both programs also set the extruder temperature the same, and had the fan running at the same speed (50%).

My latest test was to set the raft infill in Simplify3D to 100%. This was based on the observation that the MakerBot raft top layer was much more solid, and thus well bonded to itself. With this setting I finally got an easy separation of the model from the raft. It still wasn't as good as MakerBot, but it is close. I will keep testing but for now my advice is to set the raft infill to 100% in Simplify3D if you are having these issues.

[PPLDC3]

Which is weird because Makerbot rafts do not print at anywhere near 100% infill. Their hardware is trash, but I've been consistently impressed at how well Makerbot nailed their slicing. Even with all the customizability, Simplify3D is still banging rocks together when it comes to support material generation.

[eVenom]

No news on this problem? I cant beleive that its been so long and still this hasn't been addressed.

Its obviously worng and it just needs to go back to the way it was done in v2

Should be an easy fix but i dont think the dev team is even looking at it and that is disappointing since there is such a premium price on this software

[burtbick]

I recently purchased S3D so I have the latest version. I'm using a PrinrBot Simple Metal that I built from a kit a couple of years ago.

I've been printing in PLA with no heated bed.

I also just purchased a PrintInZ Zebra Plate for the PB Simple Metal and had been working though some issues getting Z offset set for optimal printing. I was able to get excellent PLA prints for larger ones that used to warp a bit with Blue Tape, but now they are perfectly flat with the ZP. But I was having issues with smaller models if I used the Z offset that gave clean prints for the larger models.

So for the first time ever I tried a raft. And unlike the issues everyone else had commented on my first test was perfect. It was very easy to remove the raft from the small models and it came away very cleanly. Did not require any clean up of the parts. And the way it broke away from the parts I would suspect that it would also work well for larger parts. But I haven't tested that yet. And likely would not need a raft when using the Zebra Plate for larger parts.

My basic S3D settings for this model test are:
Layer Height .3mm
1st Layer Height 120%
1st Layer Width 100%
1st Layer Speed 20%

Skirt 1 layer 4mm 5 outlines

Raft 3 layers
3.00 mm offset
separation dist .4mm (2.5 x layer height)
infill 100%
disable raft base layers checked

Extruder temp 215 all layers

Cooling Fan off until layer 3 then on 100%

Some of the settings are due to the PLA filament and the Zebra Plate, but they did provide a decent adhesion of the raft to the ZP and just enough stick between the part and the raft to allow things to stay in place during printing and still allow very clean removal of the raft.

Maybe I just got lucky and should run out and buy a lottery ticket but maybe this is another data point that could help others who are struggling with using rafts in S3D 3.x

Burt

[illusionest]

Hi fellow S3D users,

In the latest release, version 3.10, I had no troubles with the raft separation distance. I changed it from 0.14mm to 0.34 and the rafts removed perfectly fine. I also had trouble removing the rafts on default settings, but adjusting it to match the Replicator 2 settings (which, is the machine I tested on) worked perfectly fine!

[jomireyn3]

So glad to hear it. I'd given up on using S3D, so I'll update it and try it out.

Hi fellow S3D users,

In the latest release, version 3.10, I had no troubles with the raft separation distance. I changed it from 0.14mm to 0.34 and the rafts removed perfectly fine. I also had trouble removing the rafts on default settings, but adjusting it to match the Replicator 2 settings (which, is the machine I tested on) worked perfectly fine!

[drvertigo]

Using Simplify 3D v4.0.0

Object and raft separate very easily.

I found the default Seperation Distance of 0.14mm to be problematic, but 0.25mm separated easily.

Using: ABS @260deg, layer height 0.25mm.

Appears issue is resolved.