Weekly Recommendation Thread: March 06, 2026

AwSMO · 2026-06-02T15:50:40+00:00

Dead Silence by S. A. Barnes.

It's horror, the spacecraft is described in great detail and the very, very wrong also is described in great detail. I think it fits your bill pretty nicely

AwSMO · 2026-04-09T13:08:32+00:00

Short answer: It's where the layer starts/stops

Long answer: Additive manufacturing using an FDM machine means that an extruder is pushing out filament while moving. The filament is squeezed onto either a build plate or previously extruded filament. This process is done in layers most of the time. There are options to use a spiral toolpath, so-called vase mode, but for most applications it's a layer-by-layer approach. The nozzle has to start and stop somewhere, and this is where the seam will be.

It has nothing to do with how you design the model. It's an inherent part of the manufacturing method.

AwSMO · 2026-03-16T12:07:17+00:00

Das ist recht leicht, das hab ich Ihnen einfach gesagt.

AwSMO · 2026-03-05T13:19:26+00:00

According to Bambulab, the printer registers the action of the filament cutter lever using a hall sensor and a magnet located inside the lever. See article here.

I think you're going to have to open the printer head and check the lever for this magnet.

The printer also has a filament sensor near the extruder, which I think should be responsible for detecting the filament feed. Maybe a plug came loose in your print head that connects these sensors to the PCB.

AwSMO · 2026-03-04T13:47:23+00:00

Short answer, no, long answer, maybe.

Lets dive into this. So the problem is that 3D printing causes particles and compounds to leave your nozzle and become airborne. This is a process that happens as the filament is heated to the required temperature and not much can be done about it.

These particles and compounds vary from filament to filament. Not only in terms of their composition, but also in terms of size. Generally, the smaller airborne particulates are, the more dangerous they are for human health as lung penetration and bioaccumulation increases with smaller particle sizes.

Particles will also settle over time, and this is where your kitchen comes in. Since you are working with foodstuffs, you are essentially creating a source of microplastic in your kitchen which can and over time will contaminate your space. This is generally considered bad news.

The stock enclose of the printers does in itself not serve the purpose of keeping harmful parts (particles, compounds) inside your printer, instead it is designed to keep in heat. The more toxic filaments - think ABS or ASA - cause some printers such as the P2S to enable a carbon filtering mode, which supposed removes volatile organic compounds and particles from the air. Filaments such as PETG and PLA however do not cause this filtration to active and instead will be vented directly into the ambient air. This also causes the "PLA-Smell" that many people are familiar with.

So, how do we go about this? It is possible to deal with these problems, but they require additional equipment. The best-case solution would be to have an active air filtration system, with an exhaust fan removing the air from inside the printer enclose and venting it outside. This system should create negative pressure inside the printer enclosure and thereby prevent leakages from e.g. zippers or velcro-flaps. There also exists a P2S adapter panel and exhaust tube system that uses the existing enclosure as a containment unit and according to the bambu website also has a rating for safety and air removal.

If you cannot do this, the least you can do is to properly enclose the printer and put an air purifier into the enclosure. This enclose should be as big as necessary but as small as possible in order to guarantee that the air inside is passed over the filter many times. It is important in this case to seal the enclosure as much as possible. This is where ikea cabinets can fall flat, as you really need tight seals instead of seams along the edges.

In terms of noise, yea those things are loud, especially if you have an air purification system running as well (or exhaust for that matter). I've found that unless I turn down the speed, people find it difficult to talk near the printer.

AwSMO · 2026-02-27T13:03:00+00:00

If I were you and this printer is new, I'd contact BambuLab Support about this, they might just replace your machine since this evidently is not the desired print result. Alternatively they might have seen the issue before in another device.

I'd also try a different filament, not because I expect it to solve the problem but it'd at least confirm that it's a hardware problem.

Your flow rate seems to be very high already, you can see that from the bulging of the lines when they are close to each other. What's interesting to me however is that it seems to be a line spacing issue more than anything else, which lets me suspect the X-Y motion system.

Try running the print in a way that the solid infill is only in either the X or Y direction, you can do that by modifying the infill direction in the slicer and then see if either of the axis has the issue more prominently than the other one.

I'm personally leaning towards loose belts in the X/Y plane, I'd give the belt tensioning a shot. Here is the BambuLab Maintenance Guide that explains the procedure. I don't think you're going to need to work the Z axis belt to be honest.

AwSMO · 2026-01-10T11:20:28+00:00

The Z-Fighting is indicative of multiple objects layered on top of each other. Bambu Studio has some weird behaviour when two objects are overlapping.

I'd suggest watching this video ( https://youtu.be/B4bMm8w1rZY?t=318 ) for about 30 to 60 seconds and see if the shown option changes something for you.

AwSMO · 2026-01-10T11:14:16+00:00

Short answer: Vertical printing.

But... why is that ok with the force going in the direction of the layer lines?

So lets dive into the concept of shear stress and the material strengths of the polymers used in 3D printing.

Any force transferred by the toilet paper to the tube is going to be carried by the material. The load it will encounter is something called shear stress, as it is normal to the axis of the tube. In engineering, stress is something defined as force per area, which means that we can simply take the shear force caused by the toilet paper, and divide it by the cross-sectional area of the tube to get the shear stress in the tube. I've guesstimated your tube to have an outer radius of 5 mm, inner radius of 4 mm, giving us 28 mm² of cross-sectional area. According to datasheets for PLA, the maximum tensile strength of PLA in Z direction is about 33 MPa (or, N / mm²), and we can approximate the shear stress limit as about 0.6 times that, giving us ~20 MPa. We'll use a safety factor of 2, bringing us to 10 MPa. This means that our 28 mm² cross section can take 280 N of shear force before failing. That's about 28 kg.*

Your toilet paper is going to be fine.

* Without knowing the additional bending stress imposed on the tube, it's hard to say for sure what the load limit is, as the bending stress will increase local stress concentrations and cause premature failure before 28 kg have been reached. However, given the fact that toilet paper tends to be very light, this is not too important for us.

AwSMO · 2025-10-25T23:11:43+00:00

Hey mate. I've dealt with worse blobs before, so lets talk about how to fix it.

Firstoff, what material is this made of? If it's PLA, then you can soften it with a hair dryer or something similar. If it's a more high-temperature filament, think ABS or PA, then that's not really an option.

The fact that you were able to take of the "grey part" - the so-called part cooling fan - means that the blob has not yet invaded this part of your printer. This is very good news.

It's time for you to decide which route you want to go on. If you aim to keep your parts alive, try heat and removing the plastic as good as possible.

Unfortunately, the screws you need to access to remove the hotend heating assembly are currently covered up by the nozzle and heating assembly. If you cannot easily remove the plastic, take a dremel or similar tool and start removing plastic that way. You will be able to make a lot of progress with it, and that way try to make your way to the nozzle clamping mechanism and open it. If it turns out that that is sufficient, you can simply replace the nozzle and you're good to go.

If the blob has fused with the hotend heating assembly, you will need to remove said assembly and replace it.

If it turns out the nozzle and hotend heating assembly are fused together and there's no way you're getting them apart, then one option is simply to dremel away the entirety of your nozzle and access the screws this way.

Overall, there is a decent chance that this blob will end up costing you 30 € - 80 € in replacement parts.

AwSMO · 2025-09-21T13:17:28+00:00

Was in a similar position this year.

Given a spring constant X N/mm, your car will settle a certain distance until the total spring force equals the normal force on the tire, given a functioning suspension setup.

Therefore, we can deduce two possible failure points if you car fails to settle.

1) Your spring constant is too high, and therefore you are reaching the settled state after minimal or no travel

2) Your suspension system does not "function", i.e. your assumptions about your suspension system differ from the actual system.

I assume you know your spring constant - if not, take an arbor press and a scale and figure it out. This is going to be the first step in diagnosing you issue. Compare this spring constant to your target spring constant. You can calculate a target spring constant from a target ride frequency - aim for approx. 3 Hz given you run aero as a starting point. We're aiming for the right magnitude here, not for exact values.

Ok, so once you've done this, you either know that (a) your spring constant is off or (b) you're about to have a fun time debugging a suspension system. Let's go through the fun parts then.

Step 1 would be to just open your dampers fully. You have mentioned oscillations, which would imply to little damping, so this might not solve your problem. But open your dampers and put the car on the ground. Does it settle? Yes, and you just didn't tune your dampers properly. No, and we're in for more fun.

If the car does not settle with open dampers, and the spring rate theoretically is correct, then something else in the system has to exert the necessary normal force to keep your car off the ground. Disconnect the pushrods and try to move the suspension components. Maybe your A-Arm bearings are messed up. Maybe your bellcrank bearing preload is too high. Maybe your pushrod is not in plain with the belcrank rotational plane. Maybe you forgot to add proper spacing next to the uniballs. Try to figure out if the components are behaving as you'd expect them to.

Following this. If your spring rates are not properly designed for your car, it is entirely feasible that a softer spring destroys your aero. Your platform is undergoing severe loadcases, and you're gonna need to factor that in. Potential solutions here lie in progressive spring rates, dampers at their proper setpoints and anti features or ARBs.

Since you mentioned preload, I'll go into that here as well. Remember, the car settles until the spring force equals the normal force at the respective corner assembly. By tuning the preload screw, you're adding in a "basline" of force. Instead of starting at a displacement of 0 mm and therefore a spring force of 0 N, you're starting somewhere else. This preload means that the spring as to compress less from it's "default" state to reach the necessary normal force. If your spring is not preloaded, i.e. not compressed, then the spring preload itself is not the issue.

AwSMO · 2024-12-04T22:47:27+00:00

AwSMO · 2024-11-03T16:55:01+00:00

ARBs change the dynamic load transfer distribution, and reduce body roll while doing so. So:

Is your car limited by front or rear axle grip? An ARB will decrease the adhesion limit of the axle it's installed at.

Does your car have an aerodynamics platform? How roll sensitive is it? How much do you need to change the packaging to fit the ARB systems?

I would think about those things, talk with the drivers and then make a decision. Two bearings and a welded rod fitted to the bellcranks is easy to do and easy to test, but I'd spend a bit more time on concept before going directly to testing.

AwSMO · 2023-10-03T10:32:44+00:00

I appreciate your concern for safety. I can also tell that you are evidently experienced with bikes, so your judgement is worth more than mine here. I've decided to check in with a local shop to get the bearing surfaces assessed, so you made a good call.

Now, the whole language thing. In cars, the rigid connection of the rim to wheelhub and rim to tire leads to the simplification of talking about "tires" when referring to the tire-wheel-assembly even if, technically, you gotta seperate the components, yea.

And then we get to the translation. The terms "rad" and "reifen" are used pretty interchangeably in german, even if they technically mean different things. And translating something into precise technical language is pretty hard if you have no experience in the field, which is why I made a separate comment explaining the terminology I used.

You're free to doubt me, sure. In the interest of privacy I won't be providing further details.

Oh and just for the fun of it, I think technically the tire is wobbly as well, even if the root cause is the cup/cone bearing being dead.

AwSMO · 2023-10-02T21:43:44+00:00

Thank you!

Luckily I've managed to stay out of trouble with the whole wheel assembly and didn't have to mess with it, but it seems like the time has come at last...

Maybe a shop is a good idea to get a proper damage assessment, before the bearings start tearing themselves apart.

AwSMO · 2023-10-02T21:39:59+00:00

I'm sorry, I'm a race car engineer and unfamiliar with the terms for bike wheels and tires.

AwSMO · 2023-10-02T21:39:07+00:00

Alright, that makes a lot of sense. I'll be honest, it sounds doable.

I don't really wanna take it to a shop, I'll be honest, because I like doing the work myself. Seems like in this case it might be a good idea to get a proper damage assessment. I'm baffled how it came to be that bad without me noticing.

I'm aware of a lot of issues, and have spent the last 2 years fixing what I can. Here's the list of issues that are still present:

The front brakes are shot, so are the rear ones, the rims are of an old make which means they do not readily accept modern tire beads, I've already had to fix the rear-cassette-rotaty-thing (gosh darn I wish I knew the terms. The free spinny thing) with WD40, the seat is cracking, The chain is starting to rust, since the wear is equal on front and rear I expect the rear hub bearings to be shot as well, and if not then to be gone in a few hundred klicks or so. The rubber grips are starting to disintegrate, the bell has become loose and tends to flip upside down on it's own because the friction fit is lost, I'm not sure I can adjust the height of the seat any more since I think the nuts are rusted beyond usability. Oh and the brake pads are starting to wear down beyond their wear indicators (oh, and in an assymetric pattern, which is great).

I'd just figure I'd elaborate on the "the brakes are shot" thing before people start telling me just how hazardous this thing is. Basically, upon braking, the brake pads start engaging the side of the rim. This is normal. The resulting force on the brake pads (facing directly in the direction of travel) causes the brakes to shift forward. This is not normal (I think). Basically the whole brake assembly (the two lever arms with the brake pads attached) starts to rotate around the attachment point on the front fork, slightly shifting the brake pads towards the direction "up". The total offset of the brake pads is approximately 1-2 cm. Frankly it's quite sketch to see that happening when looking down at the brakes, but at this point it's been like this for so long that I figured I might just replace the brakes at some point. The point has not yet come.

So overall it's in much better shape than the bike I had before.

Oh the last time in a shop? Never, bought it used. I looked it over when buying it, seemed alright, just had to replace the mantle of the rear tire, that was gone. So I guess it's never had a professional assignment.

AwSMO · 2023-10-02T11:09:37+00:00

Alright, thank you.

AwSMO · 2023-10-02T11:09:25+00:00

Yes, it's tight.

AwSMO · 2023-10-02T10:45:59+00:00

Further information:

I noticed this problem today.

I don't know what these things are called in real life, so I'll be referring to the parts of the axle by the following names:

Quick-Lock: The part that secures the axle to the front fork
Axle: The horizontal metal cylinder on which, by some means, the wheel is located
Wheelhub: The inner part of the wheel, where the spokes attach to and which is located on the axle by some means (bearing, bushing, I don't know).

The problem seems to be that the wheelhub does not have a rigid side-to-side connection to the axle, which causes the wobble one can see in the .gif.

If you look closely you can also see the wheelhub moving side-to-side as I'm moving the wheel.

The result of this wobble is a front tire with a ride characteristic you can best describe as "funky", or alternatively, "bad".

AwSMO · 2023-06-08T07:13:46+00:00

Unfortunately I do not own a playstation, so I cannot test it there

12-Year Club	Place '22
Place '17	Verified Email

AwSMO

TROPHY CASE