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raft is larger than necessary #2568

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jsprenkle opened this issue Jun 26, 2019 · 14 comments
Closed

raft is larger than necessary #2568

jsprenkle opened this issue Jun 26, 2019 · 14 comments
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@jsprenkle
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Version

PrusaSlicer 2.0.0

Operating system type + version

Windows 7

3D printer brand / version + firmware version (if known)

Prusa i3 mk3s

Behavior

The problem:
Model a flower pot. Print with the open side down. Add a raft to keep it on the bed.
The raft fills the entire interior of the part.
Expected Results:
Raft should only be placed near points that contact the print bed.

Is this a new feature request? Yes

@neophyl
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neophyl commented Jun 26, 2019

Sounds like you need to use a brim instead of a raft if you want more surface area but don't want it under the whole part.

@jsprenkle
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jsprenkle commented Jun 26, 2019 via email

@neophyl
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neophyl commented Jun 26, 2019

Then I don't understand the problem.
A raft by design covers the entire area under a part, a brim goes around the edge. Both are methods of increasing surface area and thereby bed adhesion. If you don't want the inside of your part to included in the bed adhesion then that pretty much leaves the brim option. Increase the brim size so that the surface area is the same as with a raft.

btw the usual cause of poor bed adhesion at least with PLA, is surface contamination from various things, usually skin oils from touching the bed. A thorough cleaning with basic unscented dishwashing soap (fairy liquid in the UK) and water scrubbed with paper towels until there's no streaking produces great adhesion. I've printed quite tall (10cm high tubes that are 2 perimeters thick and about 16mm diameter) without having to use any brim or other supports since I started properly cleaning the bed.

@jsprenkle
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jsprenkle commented Jun 26, 2019 via email

@neophyl
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neophyl commented Jun 26, 2019

Whenever I use a brim it is connected to the part. It does easily removed but it is physically connected.
It sounds from your further description of the problem that it’s isnt bed adhesion at all but curling. If it’s further up the print and the print head is hitting and tearing off then that is usually caused by the contracting plastic rising up. Fixes for that can depend a lot of the part design itself but common advice is to increase cooling. Not always easy but sometimes slower down the speed giving the part fan more time to cool the part sometimes works. If you are more adventurous then a different fan shroud or a better fan for cooling is a possibility.

I’ve only had one model where this happened to me and nothing I tried speed wise or any other software setting fixed it. I ended up modifying the design to reduce the areas that were curling up (a couple of upwards sloping overhangs). I made them straight across bridges and model printed fine.

Sorry to not be more help but I don’t think this is a software related issue. Try the print speed reduction first though as you may have more luck than I did.

@jsprenkle
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jsprenkle commented Jun 26, 2019 via email

@jsprenkle
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jsprenkle commented Jun 26, 2019 via email

@bubnikv
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bubnikv commented Aug 1, 2019

A picture is worth thousand words. There is always a compromise between stability and the amount of material wasted for the support structures.

@Goury
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Goury commented Aug 13, 2019

Dear developers, can we please stop this hostile behavior and just accept the reality?

What is clear: PrusaSlicer lacks a lot of necessary settings, including raft settings. Such as filling raft inside and distance from part edges, with separate setting for inside and outside expansion. And also raft distance setting is missing yet it was reported many times over a decade.
What is happening every time I come by: someone is looking for an excuse to not improve PrusaSlicer and to not accept a feature request.

@bubnikv
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bubnikv commented Aug 19, 2019 via email

@Goury
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Goury commented Aug 19, 2019

Then how's about you ask Patric or Joseph to stop ignoring me on email/skype?

Because not only I've got a job offer from Prusa Research some (long) time ago and was ready to help you with all my skill and knowledge (and one of my skills tells me so that you have to have a separate issue tracker manager to spend time here), but I was later just ignored.

I can clearly see flaws in Prusaresearch's software development process and in project management and I know I can help, and I don't ask for too much money in return (because doing the right thing and stuff), but giving a job offer with salary number and conditions and stuff and then just ignoring every single message from me is not just insulting, it shows existence of some greater problem that I can't even imagine.

@bubnikv
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bubnikv commented Aug 19, 2019

@Goury Then how's about you ask Patric or Joseph to stop ignoring me on email/skype?

That is not true. You and the Prusa Research company did not meet a mutual agreement on your contract at Prusa Research. You received a response from our HR representative, to which you did not respond. That's all.

@Goury
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Goury commented Aug 19, 2019

No, @bubnikv, This is not true.
There was some questions, but I've received no response nor did I got anything but being ignored from anyone else.
Not a single message.
Nothing but complete silence.

bubnikv added a commit that referenced this issue Feb 24, 2021
Fixes [Request] Add optional perimeter to raft #756
Fixes First support layer does not stick to bed #2101

New parameters raft_first_layer_density and raft_first_layer_expansion
to influence the 1st layer of raft or support.
Fixes Allow to disable raft under support structures. #3772
Fixes raft is larger than necessary #2568
Fixes Supports on the build plate should have a solid bottom interface for better adhesion #1165

Changed the 1st layer infill to rectilinear even for soluble materials.
Fixes first layer of support for multi filament support oddly spaced #1445
Fixes Full Soluble Materials interfacing into Models + Soluble material noise on Bed #684
@bubnikv
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bubnikv commented Feb 24, 2021

Implemented with fcb714c

New parameters raft_first_layer_density and raft_first_layer_expansion
to influence the 1st layer of raft or support.

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