I’m trying to print a tall item that requires tree supports and the A1 mini seems to knock off one of the supports very early in the print (layer 140ish / 720). The plate is clean and I’ve seen the same issue with two completely different models so I’m ready to eliminate model and plate issues from the likely list of suspects.
I found an older post suggesting switching the z-hop type to normal instead of the default (slope) and I am currently trying a new print with this new setting.
Is this still the recommended solution? I could add a brim or make the supports stronger, but it wouldn’t solve the collision issue in the first place, so it seems a rather unreliable patch.
If I publish a model, what happens to this setting? As far as I can tell the z-hop type setting is part of the printer settings, and in my case are specific to the A1 mini (because that’s the printer I’m working it). Would the z-hop setting be saved in the project for other users?
Just wanted to follow up for posterity’s sake.
The A1 mini and I worked things out and we are friends again.
I ended up reverting the z-hop change I mentioned above because it did not prevent the collision. I was already using Gyroid infill. My solution, which led to successful prints, was to add an outer brim and setting ‘support wall loops’ to 1 (from the default of 0).
Thanks for the follow up! I’m doing something quite similar, instead of a brim I’m using a raft (2 layers) that my supports can attach to so they won’t get knocked off so easily.
For extra stabilty I increase “initial layer expansion” so the invidual rafts combine and make a stronger big one.
There is another thing worth to consider…
The nozzle bumping into things is the result of filament curling up or warping.
Can’t really fully avoid this, especially for tree supports.
In terms of physical properties - what is a tall tree support ?
A really great lever!
A tiny force at the top creates massive forces as the fulcrum point.
Since our fulcrum point is also the end of things it tends to stress and snap.
Try a few tiny testprints.
Like a thin, vertical wall with a 90 degree ‘beam’.
Use use one manual tree support for the end of the beam and print.
Check how well it holds at the base using the default settings.
Now try again but make some minor changes:
Set the tree support brim width to at least 5mm.
Set bottom Z-distance to ZERO.
Reduce the base pattern spacing to 3mm or less.
Bottom interface layers ZERO.
Should make a big difference already…
I like to go one step further…
I prefer the slim trees but do a mix of auto and manual to place them.
In the pic above you can how there is a ton of supports.
By far no all are required as bridging can cover quite a few of them without issues.
And using a variable layer height with enough wall loops helps to get a better surface finish in those critical areas.
The manual supports I try to add so I won’t have too much support in one tiny spot and also to provide some extra hold on the model.
E.g. for a really tall branch I would try to find a spot half way up to connect a small branch to the model.
After all: They often have to support critical spots in this air and if they wobble too much the result looks ugly.
Last but not least: If you increase the z-hop to like 0.4mm the possible collisions will be less severe…
Add a little bit of time but for a large model that otherwise might fail mid print still worth considering.
Agreed that tall spindly things will flex and be a lever, but FWIW my issue does not have to do with the height of the tree support. My print was failing below layer 150. That’s only 3cm height and the base of the support that got knocked out was well over 2cm considering the natural brim of the tree.
And using a variable layer height with enough wall loops helps to get a better surface finish in those critical areas.
I thought you couldn’t use variable layer height when tree supports are enabled. Edit: Ah never mind. It seems to work in the latest version of studio.
With normal supports they are printed at the same layer height the model uses.
With tree supports, especially the slim ones you often reduce the supports requirements as the thinner layers for overhangs mean in some cases you won’t need any support.
Anything hanging in free air or with impossible overhangs needs support where bridging can jump in for the rescue.
For rather complex models that require a lot of supports I often try to split them.
Like along one axis to get a flat base with only very supports.
I prefer to have one seam I can fix quite easy over having to clean up delicate surfaces with sandpaper for a few hours.
If you slice the model in your pic with variable layer heights you should able to use far few supports.
I was looking for this, it can be said that for miniatures in general, especially when talking about a 0.2mm nozzle, normal support is superior to tree both in terms of delivering a finished print and removing the thing itself?
I try to avoid supports if possible and where I have to use them often adjust the settings until the preview shows me acceptable results.
Means you have to know what to look for and also need a properly calibrated filament.
I would not trust the standard calibration for a 0.4mm nozzle to work with a 0.2 one - I calibrate for the smaller size.
Miniatures can be VERY tricky…
They often come with fine details that can be weaker than the supports holding them.
Or you have to tweak the support settings a lot to avoid vertical binding with the model, get the best density and pattern for the interference layers and all that.
There is no all in one solution unfortunately
Try some waste prints to hone these supports to your needs >
Something like a flat ceiling that ends in a pointy drop shape comes to mind if you want to get creative…
Or some little figurine that you keep struggling with - does not have to be with lots of infill, lightning will do fine with minimal walls as we try the supports.
Check the filament calibration is accurate and if not calibrate it for your 0.2mm nozzle, including the k-factor.
This ensures that things like over- or under-extrusion would drive you nuts later.
Start with plain standard settings for the supports, and check if the normal supports provide enough bond with the model.
Enough means they should stick to the model but be relatively easy to remove - without brute force or damaging the model.
Too much means - well, you know what it means and same for too little if these supports make the model fail or just fall off.
The top Z distance is what you need to slightly increase or decrease to affect the bond strength.
The pattern and spacing is what can be tweaked depending on the model needs.
E.g.: for a flat ceiling you might want a really dense spacing but a pattern that lets you rip the interference layer apart to aid with complex structures.
Once you have those supports snap right off while still offering proper support the worst is over.
What applies for normal supports works pretty much the same for other and tree supports.
The difference between the support types and even interference layers are explained in the Wiki.
No matter what type of support you use it will always be a compromise and balance act between quality and printability.
Plus of course the required after work and waste material.
They key is to learn what your model needs and where it needs support.
Sometime it is dead obvious as we can’t start printing something in mid air.
In other cases bridging might give the same surface quality without added support.
And don’t forget > Adding a base/raft to support a model you DON’T print at the default angle might allow you print it without the nightmare of having supports in impossible reach locations.
Sometimes the waste for this is preferable over the nightmares of wasting one print after the other.
You will find that once you calibrated not just the filament but also your basic support settings that the rest is surprisingly easy
