Tolerance Test - Print in Place

Does your filament really fit? 🔧🎯

While developing my Next-Gen BB Shooter, I ran into an annoying problem:
My first prototype worked perfectly with PLA Basic White 
but when I switched to PETG HF Gray, the mechanism suddenly started to jam.
 

Although there were no visible signs of moisture and the print looked perfectly clean, the mechanism suddenly stopped working properly.
Since I had been using this spool for a long time without any fitting issues, I assumed the filament just needed to be dried and sure enough: after drying, the shooter parts fit perfectly again.

Even if your filament doesn’t look like it has absorbed moisture yet, it can already start to change its expansion and shrinkage rates long before any visible signs appear.
A print may look perfectly fine on the surface, but the parts might no longer fit together properly… or not at all.

🧪To avoid such failed prints in the future, I created this tolerance test plate.🧪
It primarily checks the fit and clearances and also gives a visual impression of the surface quality.

🔧 How it works:
– The five circles at the top are print-in-place rings with different clearances:
  1 = 0.14 mm | 2 = 0.16 mm | 3 = 0.18 mm | 4 = 0.21 mm | 5 = 0.24 mm

✅ Ideal result: Rings 1–3 can move after printing (may need a gentle break free), and 4–5 are usually loose or fall out on their own.
☑ Still acceptable: If only ring 1 is a bit tight but 2–4 move and 5 falls out.

❌ Needs adjustment: If 1–3 are stuck but 4–5 still move → dry the filament or calibrate flow.

On the right side of the test plate, you’ll find a transparency and layer thickness test.
The bars start at 0.24 mm layer thickness and increase by 0.2 mm per step.
This lets you quickly check how much light passes through your filament at different layer thicknesses.

My experience:

As mentioned before, I first printed with PETG HF Gray and got a visually clean print 
but the new shooter model and its mechanism didn’t run smoothly and started to jam.

After drying the filament, I reprinted using the exact same profile 
and this time the shooter worked perfectly!

👉 Conclusion! Even slight moisture can noticeably affect dimensional accuracy and fit, even if the print looks fine at first glance.

I mainly focus on designing models! not on creating the perfect print profiles down to the smallest detail.
Thanks to BambuLab, I don’t really have to👍😄 their default profiles are usually more than good enough for my needs.

Of course, I still pay attention to important factors like proper part orientation and other key settings that influence printability and strength.

But in general, I’m perfectly fine using the basic settings that Bambu provides out of the box.
Most of the time, it’s enough to simply dry the filament properly or run a flow calibration once in a while.

For my projects, that’s usually all it takes to achieve clean and well-fitting prints.

I know there are many other factors that can affect accuracy and quality.
But in practice, the problem is often just slightly moist filament and that’s exactly where my little tolerance test comes in:
Quick, simple, and an easy way to check if your material is ready to print before wasting time or filament.

 

⚡ A small frustration at the end

I always pay close attention to tolerances when designing my models - specifically to what the BambuLab printers can reliably achieve.
I don’t have much experience with other printers, but after every print I check my work very carefully and refine almost every model until the fit and function are right.
 

Many other creators will know this feeling:
You spend a lot of time optimizing, testing, and even showing videos as proof that your model works 
yet you still get the occasional feedback like:

“Your boomerang doesn’t work!”
“Something doesn’t fit!”

…often followed by an instant 1-star rating,
without first checking whether the issue might actually come from the user’s own print setup.

These ratings can seriously hurt the print profile score and don’t help anyone.
I show my models in my videos to prove they work 

yet some people still assume the problem must be with the design.

Of course, mistakes in my models can happen 
and I’m truly thankful for every hint and report!

Only through this kind of constructive feedback have I been able to improve and refine so many of my designs.
What isn’t helpful at all:
giving no details, no explanation, and just dropping a bad rating.
 

➡ My appeal:
If you run into a problem, please describe it clearly, maybe add a photo or details about your print settings.
That way we can improve the models together and make sure they work for everyone.

🙏 Thanks to everyone who takes the time to give constructive feedback
you make it possible to keep improving the quality of my designs for the whole community!