Helical extruder gear

Edit. Adding more data on a second set from Bambu. Set was from a X1C. Runout was 261um.

Still too early to say. I’m not going to measure any more or buy more of the aftermarkets because I have no need. I don’t even use those bambu printers they just sit. But the aftermarket one could be very low average or high I just don’t have a sample size to find this out. But the Bambu I have a sample size of two and 204um and 261um. Still too early but I’m guessing that they are all going to be around 200 perhaps a few lower but I don’t think that will be common.

So how do they stack up against the stock extruder gear set?

Teeth on the stock Bambu extruder. Not good but I seen worse.

Teeth on the Helical gear. Not good and definitely worse then bambu. However yours could be better or worse. Same with the Bambu extruder gears. But I call it how I see it and what I have on hand. These look worse.

So on the Bambu gears I had 204um of runout. Helical has 147um.

How do they stack up? Not good. I think these are absolute trash but I work in an industry where these numbers are just unacceptable. But that’s the nature of these cheap parts. The king is still the Bondtech Ridga that only had 18um. Maybe they make a proper set for the X/P series.

So are they better? Yes. Do you need helical? No. Should you buy them? Not really they are just too much for what you get. They are just too much for what you get. At the end of the day the sample I had was slightly better and you could get something better or worse then the stock gears. Much like Bambu this manufacturer has no spec. So I can’t tell if these are withen spec or out.

I say wait for bondtech to put out something. This is just a waste of money. If you got $20 you have to spend just buy some fillament.


It’s this gear set you are talking about, right?

I threw one on my last Aliexpress order for $12 What can one expect, huh?

A Bondtech extruder would be nice. I’ve never worn out any of my Bontech’s

Yeah same set. What can you expect? Two things that’s it.

Might have less runout. My example does but who knows if it’s a good, bar or average. Same with my stock gears I don’t know if they are good bar or average. I got other sets but I don’t feel like checking them.

Reduced backlash. Could help with extrusion quality. The reduction In backlash combined with less runout. But since we don’t have specs I wouldn’t count on this. Without specs you could get something significantly worse then what you already have…Then again Bambu has no specs so you could get something that is significantly better. No one knows.

Just try it out. Best case you see some improvement or even if you dont it doesn’t really hurt anything if you seen no change or worse case you get them you get some weird artifacts in your print and you wasted $12 and 15 years of your life waiting for the. To get there from AliExpress.

I saw a review of that Aliexpress gearset and they commented that the use of aluminum contributed to heat creep and filament jams. Pass.

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So the aluminum operates at more than ambient temperature? You by any chance wouldn’t know if he’d like to work for Lockheed Martin?

Extruders are part of heat creep - this is why the printer urges you to keep the door open when printing PLA using a high bed temp. The theory is that a warm enough chamber would allow the aluminum to transmit more heat to the gears and thus the filament than would be the stock plastic housing.

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Yes. Because that lowers the ambient temperature of those parts. The aluminum part is the same temperature as the plastic part.

And no it won’t transmit more heat to a stainless steel pin or a hardened steel gear. If anything aluminum would be working as a heat sink pulling heat away from those parts since it’s much more thermally conductive. But again won’t happen because it’s not going to get warmer then it’s ambiant environment…the build chamber. This is pretty basic stuff I don’t see why its so hard to understand. Despite what you are told and what you think Bambu labs printers can’t not violate the laws of physics or thermal dynamics no matter what Bambu bros tell you.

They do not. But the key consideration is the very bad thermal conductivity of air. As you state, Al will efficiently draw energy out of the filament. But it can not efficiently transmit that energy into air. That is why dedicated heat sinks need very large surface areas.
So the Al takes up a lot of energy from the filament, but is not able to pass that on. As a result, it will indeed reach equilibrium temps higher than its ambient air temperature due to its uptake being higher than what it can pass on.
A gear from a material with a lower thermal conductivity will simply not take up as much thermal energy and have a higher thermal gradient across itself at equilibrium.

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It can draw energy out of the fillament?

Through a steel or hardened steel gear… Through a needle bearing… through a steel dowel…then through through a very small contact area. I would show you the formula but you won’t know how to use it.

I can’t help you if you cant grasp the basics. No it has no affect on heatcreap not matter how bad you want it to. This is not an opinion this is facts and can be proven with math and material science.

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Go ahead. My students find it difficult but they usually get the hang of it. :wink:

A first start. But you also need thermal capacity and, most importantly,the heat transfer coefficients between the different materials involved before setting up and solving the PDE’s.
That way, you can check yourself what happens if you have a high heat transfer into a part but a low heat transfer out of a part and how the thermal diffusivity and capacitance affect the dynamics.
While the low contact area between the gear and the filament may point to a low heat transfer into the part, there are two things to remember.

  1. Important is the equilibrium temperature distribution across the gear. So time can be very long indeed.
  2. The gear is turning in a dynamic system. Although the heat influx may be small per tooth, what is the contact surface between the gear and the teeth over the time until equilibrium is reached?

I am not being obstinate here. It is just that in my line of work I tend to work with experts. Every now and then there’s one, who overestimates his or her competence in a neighbooring field. Many then use that opportunity to learn about this new field. All fields can have much more interesting dynamics than originally thought. Thermodynamics is a particularly challenging one.

I hope you realize I don’t read anything you type. I treat you like the technicians on the manufacturing floor. I just ignore anything you say.

So guys I have some bad news. I say 4 hours late today fired up the ThermoStream ECO-810-M. I wanted to see this magical aluminum and document is wonders. So I placed an extruder with a plastic arm and the aftermarket set with the aluminum arm. And then set it to 50c And then wait it eagerly practicing my speech That was going to tell our material scientists. When I came back I was shocked… After a 2-hour temperature soak the parts for the same temperature. It turns out I don’t have this magical mythical aluminum. This special wonder material alloy that generates its own heat.

So I hung my head in shame and defeated I walked back to my office on my way I ran into the intern I told him that this wonder material is not working and I he needs to go get me Chick-fil-A to make me feel better. He then said everyone knows it only works inside of a Bambu printer. He said that I thought of everything except one thing. The reason why the bamboo printer is so fast is because it has quantum phase engine the inverts the reverse trans impedance bipolar rectifier that converts RF into heat. Then I pulled him over into my office we looked The pictures in the layout of the bamboo Labs X1. And then we found it The Wi-Fi antennas. They send out a signal to the quantum phase engine that converts the RF to heat.

Captains log. Start date 2024.20. I coated the parts as per guidelines in order to get a thermal image of them. After spending 8 hours in ThermoStream ECO-810-M. When thermal sensors were initiated It may have triggered a You have to be discovered phenomenon. The park constructed of the 3003 wonder metal what’s showing unexpected results. Car construct of this wonder material was actually cooling at a faster rate than that of the plastic material. It’s well known at the 3003 Wonder material creates a thermal energy when bombarded by Muons. This would explain why this wonder material isn’t that fully activated and generating its own thermal energy.

I will take a shuttle to the Paul Scherrer Institute. Perhaps they can unlock the the infinite thermal energy within 3003 So I may accomplish my mission.

Just to update this, I have a cheap optical comparator but it’s for much bigger gears (race gearboxes) than this so it’s not very accurate down at this level, but my set of helical extruder gears have somewhere less than 100 micron in both profile deviation and runout - I can’t measure less than that at this small scale unfortunately with my setup, not accurately anyway.

The actual tooth profile looks cleaner cut than the OE bambu, but not by much, neither are all that amazing, just acceptable.
The delrin drive gear on the aftermarket set is a little worse in pitch-to-pitch variation - there are hobbing marks on the mating flanks which probably accounts for it, which aren’t there on the OE ones - Bambu’s supplier evidently has a little better finished tooling for that, but I don’t think it’s enough to make any difference.

The aluminium arm is nicely made and the end float on the helical gearset in that arm is much better than the Bambu - it’s less than a tenth of mm, my Bambu one has almost a quarter of a millimeter of slop there.

Whilst a little bit is required, it needs minimising there as both the helical mating gears will shove the gears backwards and forward between the arm sides on extrusion and retracts, so someone put some thought into that - there’s also less end float on the drive side where similar happens with the large helical gear mating the extruder motor too, which is nice to see.

I’m not 100% sure what the nanocoating is but it feels like a polymer fluorocarbon layer, it’s pretty slick, so it should stop buildup of filament fragments (I’d already got a little buildup in my stock gears even after only a few months of printing). It also stops soft filaments like TPU trying to wrap around the gear and distorting at high drive pressures if you do any of that.
That was very important for me I do a lot of TPU so for me it’s worth it for that alone.

The filament drive gears are very nicely hobbed, if anything they’re a little sharper/cleaner than OE, but I don’t think there’s a whole lot in it - both OE and aftermarket will drive filament to the point of the motor skipping all the way to the tension spring backed off to about 2/3rds preload, so there’s not much difference there.

One thing I will note with the aftermarket gears is they don’t have as much root relief as OE - that means the meshing is rough if there’s no filament in the drive path as the teeth bottom out before the hobbed filament drive gears touch.
It’s not really an issue but I guess if you’re using a soft say 60-70A TPU without altering the preload on the extruder* that might compress enough to give contact and inconsistent extrusion.
Or really cheap, very undersized filament, maybe. Does mean the drive gears will touch when loading and unloading filament though, I don’t know if that will be an issue at all so I’ll inspect it regularly and give updates.

One design issue I do have is with the aluminium arm, and helical steel gears, you now have thrust loads taken just by the aluminium face instead of a Delrin/POM arm that’s naturally self lubricating - in my case during installation I tested this for a while, wasn’t entirely happy with it so I greased the contact points there, which should be all that’s needed, but I will keep an eye on it.
I also greased the helical steel gears and the plastic extruder gear during install, I know many don’t but I’m not a big fan of dry gears after many decades in industry, and we’ve seen excessive wear issues on the geartrain on some printers in here, I don’t really think the issue of plastic fume or dust stuck to the gears is anywhere as big an issue as dry sliding surfaces are. But that’s a personal choice - the polymer coating should help there given it’s low friction anyway, but you do as you decide.
I also greased the pivot pin for the arm - for similar reasons.

I won’t expound on the “heat transfer through the aluminium arm” thing as frankly it’s conjecture rooted in nonsense and poor understanding. There’s zero issues. Even with TPU which is terrible for driving with warmth, heat creep is no different to stock.

In terms of actual extrusion quality, I’ve noticed nothing really on stiffer filaments - PLA/ABS/PETG, fibre filled Nylon, no real difference that I can’t put down to usual print-to-print variation.
Softer filaments - Nylon 12, PCTPE, TPU’s, there’s noticeable change, and especially with foaming filaments - retracts especially are cleaner - but there’s definitely less ringing/extrusion variation on sudden direction changes - probably mainly due to the fast speed changes in the extruder with PA’s of 0.1-0.3 for those materials, it’s more noticable when using lower preload on the extruder for soft TPU’s too. At full preload, less so.

I would say for $12-15 shipped, if you need a hardened gear upgrade it’s a fine option but you’re not getting anything out of it vs the OE Bambu gears for most common filaments. Maybe the nanocoating will help with buildup
If you print soft materials, it’s probably worth swapping to it even if you don’t need hardened gears, the wall quality on some NVH vehicle bushes I just prototyped is perfect, they look like they could have been moulded.

  • (Not that I would recommend that, even with 95 shore I’d be backing off the preload unless you like it trying to wrap around the gears at any decent drive speed - but that requires putting a hole in your cover and that’s another topic all together. If you’re happy at stock settings and profiles and not trying to push TPU at 15-20mm^3/s, just leave it alone)
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I am the original reviewer that said i had a problem with these. I am an engineer… but not the right kind! LOL… I’m a computer systems engineer and I know nothing about thermal dynamics. All I have is some anecdotal observations. I print high temp materials like ASA and PA. My printer runs 24/7 often switching materials from high temp to PLA with no cooldown time. I noticed after I installed these I started getting extruder clogs more often than usual. When I disassembled the extruder to clear it, I could barely hold the aluminium arm in my hands it was so hot. So I came to the conclusion its retaining heat for a longer period of time then the stock polymer arm. Again this is all anecdotal and I might be completely wrong with my diagnosis, but i have gone back to stock bambu gears on my X1 and the clogs have stopped. I did install them into my dedicated PLA machine (P1P) and have been running them with no issues.

If your chamber is hot, the part is hot, there’s no real path for these to pick up more heat than the plastic part would. Of course aluminium feels hotter to the touch - it conducts heat to your hand much more quickly than the plastic part would because the plastic can’t transfer the heat into your skin due to it’s poor thermal conduction, the surface cools fast upon touch but the core stays warm - the same reason that you can pick up aerogel out of a furnace that’s glowing red hot and be fine.
But that’s a sensory thing rather than the reality- which is everything in that area is going to be around that temperature in operation, there’s not much heat transfer through any path there from any of the hot parts - which are mainly just the drive motor and the hot end itself, the filament isn’t going to conduct any noticeable amount of heat that far up and through the heat break.
And even if you assume it did, the aluminium would conduct the heat away from the filament ever so slightly faster, not towards it.

Will it retain heat longer with a cooling chamber coming down from being hot? Possibly, aluminium has a higher thermal capacity, but then the higher thermal conductivity would be transfering heat to the pivot pin and casing away faster because of that too, so I’m not convinced it would be better or worse without testing, probably very similar - but either way it would be a drop in the ocean compared to what the already hot, hardened steel mass of drive gears already directly in contact with the filament does.

I would suggest your clogs were possibly some other issue with the gears themselves, rather than heat creep from the arm.

I can send the gears to our lab and find out what the coating is.

Okay one thing I have noticed since getting back off the TPU is, large flat areas in other prints are VERY smooth now, compared to previously, I was getting flat surfaces but they were never this consistant.

Yeah I’m guessing yours are way off and that explains it. I’m guessing from what I seen the stock gears are pretty low quality and these are a bit more precise. I didn’t see any improvement but like I said I might have some of these best.

Any chance you can measure yours? I’m cerious to see how far off your stock gears are

Yea I’ll check them when I get chance.