I’m unsure if it’s a feature request or if it already exists and I can’t find it: I would like to avoid using a prime tower when the object I’m printing is short.
As it’s possible to print objects “in sequence” instead of “by layer”, I would assume it’s technically possible to avoid a prime tower when the object is short enough that the nozzle can still print on the bed.
It would allow me to still prime the nozzle while avoiding a full-on prime tower.
Granted, it’s not too much plastic wasted when you make objects short enough that it would be a possibility, but I would be happy with wasting less plastic nonetheless.
I don’t think I was clear.
I would like to prime the nozzle between color changes directly on the bed instead of on a prime tower when the height of my print allows it.
The prime tower is only a tower because it needs to be at the same height as the print when switching color.
We already know that we have some algorithm to print by sequence when the objects are small enough.
Couldn’t we just have a prime line on the bed instead of a prime tower when the object we’re printing is short enough?
I am a little confused by your request, as you have not provided an example.
If your question is this:
Can I disable the prime tower when printing a model when the colours only change at layer heights and there is only one colour per layer?
The short answer is yes.
I disable the prime tower for all my published profiles for all my models, where the colour changes and only one colour per model. This accounts for over 400 models I have shared here.
There is no loss of quality.
Having a prime tower in such cases is simply a waste of filament and an increase in print time.
I don’t want to simply disable the prime tower, I want to retain the benefits of the prime tower.
When using the Bambulab slicer, there’s an option to print “by object” (I called that “by sequence” in my previous messages) instead of by layer. This feature is applicable when printing multiple short objects, and that the toolhead is able to reach the bed even while other objects are already printed.
The purpose of the prime tower is to maintain nozzle priming during color switches.
The prime tower’s height matches the print’s height out of necessity (or, the print’s last color change).
However, is this height requirement truly necessary, when the conditions are met to print “by object”?
For straightforward and shorter prints, I prefer the option to prime the nozzle directly on the bed (or on a smaller tower) between color changes.
For example, on this model: AMS Test Only 24min Fast AMS Test Print Pyramid.
Having a full prime tower means that we need a prime tower that is as tall as the last color change.
However, this print is small enough that it could be printed by object. This means that at any height the nozzle could still reach the bed.
If the nozzle can reach the bed, this means it could easily prime the nozzle with a short line on the bed for each color changes, instead of having this big tower. Or maybe it could have a tower of just 3 layers instead of 148.
I understand that for this specific model, maybe priming is unnecessary, it was just an easy example to find.
I get what you’re saying but here’s the difference in doing that verses the print by object feature. When you do print by object it’s starting with the 1st layer and going all the way to the top, then moving to the next object and going from the first layer to the top layer and so on. With what you’re proposing it would print a layer on the object and then print a layer on the tower, then print several more layers on the object until it came to a color change. Then it would move back down to the plate or the top layer of the prime tower. Then back up to whichever layer it was on with the object. That much moving back and forth on the z axis between two objects is leaving a LOT of room for error. I’m not saying it’s impossible, just probably not something that would create a perfect print most of the time.
The prime tower is an old way to solve all problems.
Your suggestion wouldn’t fix your use case.
If your model had multiple colour changes per layer, your logic would be a solution, if not for the complexities of the constant raising and lowering of the head to the bed.
The “print-by-object” feature does this infrequently and ONLY based on rules of how the parts of the print can hit the model being printed.
You postulate that priming is not necessary, therefore there is not much debate to be had.
If your model had multiple colour changes per layer, your logic would be a solution, if not for the complexities of the constant raising and lowering of the head to the bed.
That much moving back and forth on the z axis between two objects is leaving a LOT of room for error.
Is the z axis less precise than the other axis?
Alright, this is something I do not understand. Why is moving the X and Y axis leaving a LOT of room for error, but moving the X and Z axis different? If the prime line is on the bed, only two axis moves are necessary.
My answers are based on facts, experience and lots of it.
I do not know if you are purposely ignoring what two people have told you.
This is less about a lack of precision about the Z-axis and far more about…
Moving the head up and down (relative to the bed) makes it far more likely that the head will hit a part of the model in question.
Your imagined model is one of billions of models having different shapes and volumes, making your suggested solution problematic.
I didn’t just answer for your now redacted example. I am answering as a software designer with 35 years of experience who understands the underlying issues.
Could it be done? Yes. Should it be done as a high or even a low priority, probably not.
Why? Because it is such a low-impact problem, it begs for different solutions. The number of times this would be needed vs the types of improvements that could be added that have a higher benefit to many is a no-brainer.
Your imagined model is one of billions of models having different shapes and volumes, making your suggested solution problematic.
The “print-by-object” feature does this infrequently and ONLY based on rules of how the parts of the print can hit the model being printed.
Why can’t we use the same exacts rules? This is what I am struggling to understand, and what I am suggesting.
I didn’t just answer for your now redacted example.
I have not redacted my example, just fixed typos.
Because it is such a low-impact problem, it begs for different solutions. The number of times this would be needed vs the types of improvements that could be added that have a higher benefit to many is a no-brainer.
Sure, I’m just debating the feasibility of this. I didn’t ask anyone to drop everything and work on it this moment.
Because, as I said, there are billions of models out there.
The solution would need to be able to do this for all of them.
What you are not considering is the amount of space needed for the prime lines you suggested for colour changes, as the head needs to keep going back down to the build plate, depending on the model being printed and the number of times required, making the space required ever-increasing.
You stated you have seen the build-by-object mode, I guess you haven’t considered what those exclusion zones are for.
They are there so the head doesn’t get close to any other model.
A small cube in the middle will not be a problem, but who prints just a small cube when they want your stated scenario, no, they need something more complex.
The solution would need to work out how to arrange everything, including the exclusion zone around these prime lines.
You didn’t cite an example, and when I asked for one, you provided one, I responded to it, and you told me it wasn’t a good example to use!
That is true, but I also mentioned the possibility of having a shorter tower.
you haven’t considered what those exclusion zones are for.
Of course I am considering them, that’s why I’m saying this is a solved problem. Sure it won’t be able to be applied to a lot of models, I didn’t say this is a solution to replace the prime tower in every case, just in some specific cases. Same as the “print by object” solution. It is NOT an option for most cases, but when it is, I welcome it.
Let’s roll back a little bit. Why is priming not necessary when changing colours at a layer height and there is only one colour per layer?
I can’t give you exact numbers on Bambu printers because the firmware is closed source, but on most printers the run current on the z steppers is significantly lower. Sometimes as low as half of the x and y steppers. Their main attribute is holding torque. They’re meant to hold the bed in place and slowly lower it one layer at a time. Moving the bed up and down while printing would add a ton of time on to the print. Like I said, not impossible, just impractical.
