I’m curious to learn how specific one can (should) get when it comes to fine tuning and calibrating filaments. The parameters seem to be type (PLA, PETG, etc), Brand (BBL, Overture, etc), and possibly color. Do you need to tune for each nozzle size (0.2mm, 0.4mm, etc) as well. So basically a potential of 4 parameters; type, brand, color, nozzle. If you really wanted to get that specific I mean? And what order of priority would be recommended?
But do you also need to tune specific quality presets for each as well (layer height, infill, wall thickness), or are those more specific to the job rather than something you store as a preset?
It’s easy to get into the weeds, and I’m one for optimizing a process for best results. As a process engineer, it’s kinda the job description. LOL
Myself, I say no…but there will be other s that say yes.
I have a specific set of setting I use across all my printers (Bambu & non-Bambu).
I will tweak them as needed per model, like Vase Mode.
I will only set a specific filament if I have issues with it.
Interesting. Thanks for the insight. And you don’t notice a significant difference in say Max Vol. Speed and PA between printers. Color I can understand not being a huge influence, but I would think each printer could have a much more profound impact on those numbers.
No, I haven’t noticed any difference. I thought I might with the Bambu being so much faster, but I haven’t.
For Bambu Studio, I used the Generic Profiles & basically just tweaked the Hotend, Bed temps, & Fan settings to match what I was using in Cura.
I thought I would have to do more, but I really haven’t.
The funny thing about it is my settings are lower than what Bambu Studio had set.
This is my first 3D printer, but am very familiar with process optimization, so it’s probably just me being overly detail oriented and neurotic about getting the best printer possible. Thanks again.
I’m gonna give the same answer.
I’ve said it before, I bought a printer, not a car, motorcycle, or child. I don’t want to spend more time working and worrying about the smallest thing that will only be noticed by me.
The only problem I’ve had is dampness. I beat that drum as I beat that dead horse. Dry your filament.
I have a Revo on my P1S and I honestly only care about flow when I have a .6 on it and I’m printing big and I want it to finish before (insert deity here) comes again…or the first time…not judging.
I’ve not had any issues with any one of the multitude of little numbers one can fiddle with. Well not with the Bambu Printer. Sometimes I cruise the Elegoo or Creality forums just to see what I’m not missing.
Now that I’m on this, we should have an awards ceremonyt for sharpest corner, perfect line…
If I were to answer that question candidly; it’s all too easy to get caught going down a rabbit hole without anything to show for it. However, one can’t really know that until one climbs down the hole, can we?
So the overriding advice I might give someone is you have to ask yourself; what am I trying to achieve? Perfection? Or just close enough?
I’ll link to the optical clear filament challenge of last year here. The goal was to see if we can get true optical clarity out of so-call transparent filament. I found only one that could do so.
On the right, you have just close enough. On the left you have hours of trial and error. Which one was worth it? That’s subjective.
Yeah, it does boil down to what level you choose to accept, but I’m also learning a lot down this rabbit hole.
It’s ironic that you link this, because my job is working on optical additive manufacturing, but we print with an optically clear resin. Basically it’s a giant inkjet printer, but one that does slices. I’m the laser process engineer who has to trim the lens from the bulk substrate.
I go down rabbit holes to learn what I don’t know. To paraphrase, “There are those who make it happen, those who watch it happen, and those who wonder what happened.” I don’t like mysteries; I enjoy getting to the bottom of things. As a hobby, I can afford to fail without consequences. If this were my job, I’d hate it—too many uncontrollable variables, especially Bambulab support. If I had to rely on them under a deadline, I’d quit.
Well I’d be interested in knowing your perspectives on the odds of building a Fresnel lens using FDM. The recent posts here on multi-access 3D printing was fascinating to me because one of the obstacles is laying down filament on an access that is at an angle but I am only an amateur physics major dropout so my remembers of Planks equations have long faded away…
I have gone through more rolls of filament than I can count.
But I not really selling my creations, nor using my printers to make money - pure hobby use for about 2 decades now.
For me filament calibration IS vital.
Not to reach perfection though but to overcome what defaults settings often fail to provide.
No problem to print at over 400mm/s AND to get great looking prints.
Optical quality though is something that in world simply does not go along with FDM printing.
So what do I calibrate for ?
Flow ratio, extrusion temp, k-factor.
The max flow rate I no longer bother with and only check once per new filament to check if I need to go below the 40 mark.
What I need is:
Great (top) surfaces that won’t require additional ironing or sanding to get smooth.
Good layer and plate bond.
Dimensional accuracy! I print parts to fit together then they shall fit together without afterworks and cutting/sanding the mating faces.
For me nothing is worse than having to drill out a bunch of holes just because they ended much smaller than in the 3D model.
For me calibrating a new type or batch filament is second nature - I just won’t go without.
A friend of mine got his first ever 3D printer last year.
Not a Bambu one but not one of these nasty no-name ones either.
Of course he went all in like so many and expected all he has to do is to download some nice model and hit a button to make it happen LOL
We downed a few beers on the weekends until he got the hang of the basics.
And while he prints did not look shabby or unacceptable they all had the tell tale signs of calibration shortcomings.
Then came the day where he wanted to impress the wife with a huge print of one of her favourite movie characters…
After going through two rolls of filament that only produced failing prints he offered free beer if I would be able to make his printer works as advertised on this model…
Imagine my predicament here: A slab of my favourite beer waiting in the fridge and I had to somehow get enough out of it…
And so I offered a bet: If I can make the print come out good enough I get what’s left of the beer! Deal
What did I do?
First I made some changes to the required supports so they won’t pop off the plate all the time, then I properly cleaned the plate with soapy water and window cleaner.
After that came about three beers worth of calibrating the filament:
The flow ratio was off by 0.185 - more than enough, especially if it was lower than what it should be.
The extrusion temp was about 12 degrees to high, as was evident by the stringing and such.
There was no k-factor calibration, just a manual PA calibration that turned out to be the longest part of the calibration journey.
After that I hit the print button for the big model, watched the first three layers and wanted to grab my beer…
My friend insisted I wait at least as as to where most of his previous prints failed, so we put a movie on…
Let’s just say the beer was eventually gone, we ordered pizza and I had to get a ride home - but since that night my friend at least checks the filament calibration before trusting the recommended defaults.
Bambu did a reasonable job to provide defaults that work just fine for most users and applications.
Sometimes though just fine just isn’t good enough.
If you paint your models you probably know all about the relationship between good print settings/calibration and the amount of required work once the model is printed…
Should you calibrate your filament ?
Only you can answer that but if you are not happy (enough) with your print quality you should at least consider it before blaming the machine, slicer or filament
Thanks for the reply, and I agree. It’s a totally subjective decision, and I like to have my stuff dialed in “reasonably well” without going TOO crazy. My question though is one of granularity. How specific, generally speaking, does one need to get with filament. Is brand and type enough, or is brand/type/color too much without some specific call to tweak a calibration? I assume there should be a calibration for each nozzle size used, regardless. I have already noticed a large difference in values of PA going from 0.2mm to 0.4mm. I mean, the beauty of a calibration is that you really only need to do it once, and things tend to be excellent from then on (until something major occurs).
Hey, I like getting things dialed in just so. hehe I even thought about using my lab equipment to run image analysis on thing like the PA lines and calcluate which was the smoothest, or use the 3D laser confocal surface profiler to measure surface roughness on the flow dynamics chips. LOL Maybe not.
The problem with Fresnel lenses is that it depends on the structure of the gratings. 3D printers, at least in the FDM variety, tend not to have the resolution needed to create those kinds of structures. The second of course has to do with the optical clarity of the material, and the roughness of the printed surface. There isn’t a good solution to the stair-step nature of the deposition. Even in my lab, using a resin, you still have to fill in the pyramid steps with another material with a low enough viscosity that it flows properly, but not so much, before you cure it with UV. And then you run into issues with refractive index, and the potential RI change between materials.
Calibration is relative!
If you have a GOOD working filament profile and a reliable filament supplier then there is usually very little you need to change.
For example for my PLA I only need minute adjustments for the k-factor and nozzle temp between normal, matte, translucent and silk.
The flow ratio is usually not much affected.
Going to a different brand though can mean starting from startch - thankfully the overall quality is more even these days than just 10 years ago.
As for your lens project:
I tried for a few days to print translucent blue PLA as clear and flawfless as possible.
Not worth it if you ask me.
PETG MAYBE but it still IS a total pain and the printing will make a snail overtake the print head LOL
And when I check those fresnel lenses I see these lens rings ANGLED.
It is like the surface of a normal lens but with the curvature split into stacked rings to safe material and get better optical properties at these thing levels.
Like a small, normal lens in the centre while the ‘rings’ are more like saw teeth - next to impossible to do in FDM, at least in optical quality and the required thickness.
Is it these patterns you refer to as ‘grating’ ?
A few years ago I tried to make a fresnel lens using my CO2 laser.
Basically used the same approach as for a relief engraving, just that I selected the shape of a fresnel lens I created in CAD.
I was NOT expecting a usable result, all I wanted to check was IF the laser could engrave with enough precision.
I used black acrylic for this and polished it after the engraving.
While it had the overall shape the lens did not have the required surface quality, way to uneven and rough.
There is an interesting process though where people use a wax mould to make their fresnel lenses.
The wax goes into a metal mould - or on an original glass lens to copy.
Then an outer mould is added once removed so the resin can be cast and the air removed in a vacuum chamber.
They did not specify the resin used only that it was optically clear and with a high refraction index.
Yeah, you described a Fresnel lens exactly. By condensing down the curved section of the lens surface and eliminating the bulk material in the lens, you can replicate the same refractive properties of the light passing through it. Since refraction happens only at the interfaces, at least in the non-linear realm.
And yes, when I talk about grating, i am referring to the pitch of the rings, or the thickness of the slices that make up the rings. But I fear with FDM printing the scattering effect of the layering will destroy the functionality of the lens. If only there were a way to smooth the surface with acetone like with ABS. Do they make clear ABS even??
I’m not sure about resin printing, and by that I mean the kind that uses a tank. I use a giant resin printer at work to print our lenses, but ours is essentially a giant inkjet printer and FDM printer combined. It prints a layer of resin like ink, then cures it (pinning) with UV light before printing the next layer, and so on. Then another process is run over the top with another resing that flows down into the stairs, filling them, resulting in a smooth and optically clear surface. It’s really cool.
You can smooth almost any filament using a solvent vapour treatment.
And while it helps with imperfections caused by the FDM process it also smoothes wanted features - like the peaks of the lens segments getting rounded.
The scattering is actually depending on the print orientation.
Whenever light passes through a layer line things get messy.
Ideally you would print the lens upright and with a variable extrusion width to limit these effects.
No FDM printer today can do this though in a circular fashion as that would require a 5 axis printer.
Since you have access to plenty of suitable resin:
Take some smaller lens you have and make a wax copy of it - does not have to be pretty, just a negative to get resin in.
Fill it with the least amount of resin to cover the lens structure and to get enough thickness.
Cure in short intervals if a long exposure results in too much shrinkage or cracking.
Remove the wax and check if the resin filled all the tiny voids and replicated the fine details without having to use a vacuum.
If it is thin enough to do this without having to remove trapped air with a vacuum:
Use a 0.2mm nozzle, very thin layers and a low speed to calibrate a clear filament for best optical clarity when printed as a small block of about 3mm thickness.
You might have to use rather high extrusion temps in order to eliminated those gaps between the lines and this can result in things turning brittle.
To try a lens this way:
Have at least 5 solid layers on the plate to not end with a fragile lens.
Match the model so that the top of those ridges will be no wider than 0.18mm.
A flat top here is much better than a sharp top that is impossible to print, would create a mess.
What you end up with is a staircase that comes with lots of distortions.
And being all flat layers means there is no lens effect worth talking about either.
With a lot of chance your resin has a refraction index not too far off the filament.
You could use a spray gun or airbrush version to apply thin layers of resin under UV light for a fast cure.
With the right timing it should mostly fill the steps and smooth them out.
Not sure if that is good enough but it could be worth trying for prototypes or such.
But then again I would probably just get a half decent resin printer like an Epax with a 5K screen and try the resin in there…
Good enough for small lenses and you can print in very fine layers and use the same finishing steps as used for your big printer.
And to save a ton of time for producing many of the same lenses I would opt for using moulds and casting the resin rather than printing it.
If the resin allows for casting that is…
If I had to rely on them under a deadline, I’d quit.