Neoprene timing belts and silent fans for the X5S

Not postet anything for 66 days now… Well, on one hand I was busy ranting about Günther Oettinger and Axel Voss (read more on  Julia Reda’s page – she’s the one tracking the “Copywrong” things in the European Parliament, including the “Article 11” and “Article 13” #CensorshipMachine *). On the other hand the X5S just worked (more or less) flawlessly.

The constant Gcode-loading, filament changes and print post-processing kept me from posting the last modifications – until today. 😉

The MGN12-clone on the X axis was doing well. It rattles a bit, but thanks to my OctoPi the noise remains in the cellar.

There was some ghosting on my prints, so I thought it was time to go for those glass-reinforced, not-so-rigid timing belt upgrade. Idlers (with teeth for the inside of the belts, without for the outside) and belt were ordered via Amazon and arrived within days. The general reccommendation of 5 meters of belt (GT2, 6mm) is accurate and you can count the idlers yourself => six with and two without teeth had me buying bags of ten and five of each type (both are called 20T / 5mm bore / GT2). Not a far-fetched decision, considering the chance of having a bad bearing in your delivery…

My corner pulley mounts had to be carved out a bit to allow the T-nuts to turn freely, but there were some updates to them in the meantime. So maybe ljbrumfield already fixed it.

Most of the re-belting was about finding the right screws and getting the idler heights right with nuts and washers. And then locknuts on top.

Another issue was, that those Neoprene / pc-rubber belts were not only smelly, but also not as thick as the steel reinforced stock belts. So I had to wedge zip-tie clippings into the Belt Zip Clamps (pictures further below).

And I printed another fixture for the Y endstop: thing:2781597 mirrored.

So. Was the ringing gone then, because the “flexible” belts were now avoiding the resonance? Nope.

My firmware image of Marlin (Configuration.h) still had those definitions:

#define DEFAULT_ACCELERATION 3000 // X, Y, Z and E acceleration for printing moves
#define DEFAULT_RETRACT_ACCELERATION 3000 // E acceleration for retracts
#define DEFAULT_TRAVEL_ACCELERATION 3000 // X, Y, Z acceleration for travel (non printing) moves

…which is a bit high. Even for a CoreXY machine like the X5S.

A quick look into the definitions of the latest Prusa (i3 MK3) showed a value of 1250 – which seems pretty reasonable and optimized. The posts in the FB-Group also suggested values of 1k/2k/3k, so I went for them:

#define DEFAULT_ACCELERATION 1000 // X, Y, Z and E acceleration for printing moves
#define DEFAULT_RETRACT_ACCELERATION 2000 // E acceleration for retracts
#define DEFAULT_TRAVEL_ACCELERATION 3000 // X, Y, Z acceleration for travel (non printing) moves

NOW the ringing was gone – even on the 2_XY-test-1mmWall.stl of Make: 2017 3D Printer Test Files . With “coasting” in Cura activated (“experimental”, right now I am at 0.16 mm³) and 6 mm retraction at 70 mm/s I could also optimize stringing and blobbing.

The green dots in the layer view are “coasted away” – and as you can see on the Benchy it was still not enough at that point.

Problems remained, however, with overhangs. I had printed so much PET and relied on the “4010” part cooling fan, that I totally forgot how much air you have to blow at PLA! Overhangs and bridging were horrible with that blower. So I changed it to a “5015” with CR-10 High Clearance Fang Mod. What was duct tape on the previous installation was closed with TinkerCAD before printing. And I switched to a more silent Sunon HA40201V4-000U-999 fan for cooling the hot end.

The improvement was immediately there. Overhangs worked, bridges could now be blown stringy. 🙂

So what about the other fans? The HA60151V4-000U-999 went into the 12V PSU (which also got some flow resistance removed). So that is really quiet now.

The 24V PSU was a bit more tricky. There are no “silent” 24V fans out there and especially no silent 50 mm 24V fans… and I didn’t want to risk reducing the airflow too much. So I installed two 40 mm 24 V fans.

Looks ridiculous? Well, yes.

The good thing is: it has not gotten any louder. ^^

I would even go as far as to say: the noise is more comfortable. And the PSU now stays a lot cooler. I am even thinking about installing a DPDT switch to change between parallel (24V per fan, full power) and series connection (12 V per fan) to make the printer quieter, when the heatbed is only used for PLA.

* I wanted to totally keep politics out of this weblog, but as the internet itself is threatened by corporate lobbyist influence on conservative and right-wing politicians, I have no problem making an exception here.

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