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Ultimaker / Cura

3D printer / slicing GUI built on top of the Uranium framework
GNU Lesser General Public License v3.0
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Flow options for raft top surface #8766

Open viper0078 opened 3 years ago

viper0078 commented 3 years ago

I make rafts with ABS filament, but the rafts often stick to the printed material and are difficult to remove.

By increasing the flow rate of the raft top surface, the strength of the raft is increased and the raft does not adhere to the printed material. On the right is the raft with a 20% increase in flow rate. IMG_20201114_103726 無題 Making the raft thicker will not work. Increasing the horizontal adhesive strength of the raft top surface makes it easier to peel off. Please consider it.

Timocop commented 3 years ago

I think you just need to tune the raft still. By looking at your pictures seems like you are pushing too much on the raft, making the model stick too well. The problem with Cura's raft is that most of it is hard-coded. Means, if you use a different nozzle or line width's than 0.4mm you will run into problems. Either sticking too well, or never stick at all. I've spend months finding the perfect universal raft air-offset math using different nozzles (0.3mm, 0.4mm and 0.6mm), line width's and have successfully printed ABS even without top layers now. Here it is what i call 'universal air-offset': Initial Layer Height: (Line Width / 2) Raft Air Gap: (Line Width / 2) Initial Layer Line Width: 100% Tested with ABS and PLA.

viper0078 commented 3 years ago

My printer's nozzle size is 0.4mm, and the settings are as follows

Initial Layer Height: 0.2mm Raft Air Gap: 0.13mm Initial Layer Line Width:100%

It is best because it is easy to peel off from the raft and does not warp. The filament is Pxmalion ABS.

The optimal value for RaftAirGap when I use PLA is 0.15mm.

If I set Raft AirGap to LineWidth/2 (0.2mm), the ABS will have a weak fixation and flake and warp the printout. Wouldn't the adjustments be different for different printer models and filament types?

My old printer used to adjust the level of the bed with spring screws. Sometimes, though, there was a slight shift in the level and the raft would stick badly to the printed material. So I thought of a way to increase the strength of the raft so that it would be easier to peel it off the printed material. I created a program in C# to convert the GCODE. I still use it today. However, my current printer is a SnapMaker, so I don't have any misalignment at bed level. It is useful for both strengthening the adhesion between raft and printed material and making it easier to peel off. I posted this because I wondered if some of you may be having the same difficulty.

viper0078 commented 3 years ago

I'm also making another conversion process to make the printout beautiful. If the raft is hard to peel off, part of the first layer of the printout will come off. To prevent this, I increased the flow rate of the second layer, except for the shell, a bit. The second layer is strongly attached to the first layer, so the first layer won't partially peel off when the raft is removed.

It probably won't be adopted. Haha.

Timocop commented 3 years ago

My printer is a cheap Geeetech i3 Prusa Pro W and the filament is also pretty cheap too haha. Normally ABS sticks to itself very well. Never had any problems with my universal air-gap. Mostly because i was finding a sweat spot between ABS good sticking and PLA less sticking. PLA on raft is a pain to remove, mostly breaking the raft in the process. If i wanted to make the bottom finish nicer, i'd increase "Initial Layer Line Width" a little so the filament doesn't touch other lines making them bend.

I surely hope they implement raft flow rates, not just for the top layers, also the bottom layers which are way more important. Already opened an issue on this: https://github.com/Ultimaker/Cura/issues/8525

Timocop commented 3 years ago

The current workaround for you is to increase the Raft Top Line Width, but keeping the Raft Top Spacing the same.

Ghostkeeper commented 3 years ago

The "line width" settings effectively function as flow settings for the raft, indeed. It's one of those things that has been weird since Cura's conception but we never really get around to changing.

bishop-5 commented 3 years ago

I can achieve the same function with line width and line spacing. I didn't notice it. Thanks for the answer.

viper0078 commented 3 years ago

Sorry, I commented on a different computer, so my ID was bishop-5.