u/Clogboy82

Starting on my e3ng journey. Got some slight warping in non-critical areas, but also wat looks like uneven shrinking near the bottom. But overall I'm honestly satisfied with the print quality of my parts (other than the warping).

Does anyone know if the Prusa slicer has dog ear brims? I can't find the option.

In short: because of how the belts on the Ender 3 are designed, it's virtually impossible to calibrate your printer in such a way that every part you print will be within 0.1mm tolerance with an arbitrary size (however, 0.2mm overal tolerance might be achievable). This is a rabbit hole where things get very technical very quickly, but it is something to keep into consideration nonetheless.

Following the E3NG build guide I stumbled upon an interesting debate when it comes to calibrating the 3D printer with which the parts are to be printed (in my case: the to-be-canibalised Ender 3 itself). The precision of any given axis would be linear if the belts run perfectly parallel. For the Ender 3, they don't, there's a small angle between the pulley/idler and where they hook into the carriage. This translates into a diagonal pull which introduces a slight horizontal error that gets worse the closer you get to the edge. This forum topic describes it perfectly:

Correct dimensional accuracy - General Discussion - Klipper

To put that into perspective: you can print a perfect calibration cube. You can even print a rail with holes that have the same diameter within perfect tolerances, the spacing between the holes can be absolutely perfect in the middle, but the error that's introduced will cause the first and last hole to be too far apart by roughly 0.5 mm or more.

Now my question is whether this could potentially be fixed by measuring the vertical travel of the belt and install a matching cr2 pulley and idler. I know that the answer is yes, but has anyone tried this? And is this a more significant issue than belt elasticity at high speeds (overshooting) and part shrinkage?

Other options: we could scale large parts up by 0.14% (0.3mm error / 220mm bed width * 100), or increase our x/y steps by 0.07%. This will not fix the relative spacing between details, but it will make sure that errors are within 0.2mm tolerance on arbitrary parts sizes.

All this time I was messing with printing profiles without actually tinkering with the machine limits in Prusa Slicer. I was printing with the handbrake on.

I did adjust acceleration on the X and Y axes, but not the maximum acceleration while extruding, because that seemed a little confusing to me. Because why should that setting exist in the first place.

Above is with 5k on X, 2k on Y, maximum speeds of 220 mm/s and outer perimeters at 100, first layer 20, overhangs dynamic speed between 40 and 80.

I'm considering adjusting acceleration for visible lines to 1000 to try and avoid ringing altogether, but I'll try to set up input shaping on Marlin 2.1 first.

I have acceleration at 8k on X and 3k on Y, travel at 300, and most print speeds set at 500 except for first layer, outer perimeter and overhangs. I know I'll never reach 500 because I set maximum print volume at 20 mm3/s.

This all seems reasonable so far, but I feel like the direction change on solid infill is very slow, is there something in the slicer holding me back? Maybe jerk limits or extruder acceleration etc? Am I overlooking something that should be obvious?

I'm on Ender 3 with a btt skr mini E3 V2 with Marlin firmware 2.1, input shaping enabled, no Klipper. Hotend is a TZ e3 V2 with ceramic heater, directly mounted to a BMG clone, as you can see on linear shafts/rail. I'm using prusa slicer and mostly print with PLA. Video is laying down 0.25mm layers.

All helpful advice appreciated!

I should probably put a few nuts between the probe and the holder, it's pressing down into the bed while homing. Toolhead itself (the printed white parts) clock in at less than 28 grams minus hardware. My ZT hotend is held directly by the BMG style extruder for the shortest possible filament path. Bidirectional parts cooler. Cable guide for those still using pom wheels.

I had to adjust my main body to fit the ZT hotend (is designed for a V6 I think) but otherwise great build.

Small edit: adding a single 2.5mm nut on both sides did the trick. Certified rail compatible direct drive shroud.

For those who asked (and everyone who's interested), a quick video testing with a simple cali cube. This mod is designed by Magichobos on Printables (and posted here a couple years ago). Overall I wouldn't say that this is adding or subtracting much noise, but I made this from a durability and stability viewpoint and also because it looked more fun and much cheaper than the dual linear rail conversion kit.

It's not a very easy mod, definitely need to feel comfortable taking the bed apart and putting it back together. Most importantly: get good heat inserts! None of them are essential for structural stability, but it's not fun when they lift out again when you tighten a grub screw.

Edit: since I'm getting rid of rubber wheels, is the linear X rail worth it if I can get the upgrade kit for less than 30 bucks?

Trying this mod from Magichobos on Printables, given that hardened linear components will always be better for high speed applications than rubber wheels that are in a sideways track...

Friendly note that the insert sizes for the sled in the assembly manual are a size larger than what's listed on the BoM so I modified the sled model for myself.

*Sled looks a little rough, because I used sanding paper to double check that none of the heat inserts were sticking out of the sled. I did notice it warped slightly but this will recover itself as soon as I tighten it to the bed mount.

Is anyone using the bondtech DDX toolhead and what are the experiences with it? It looks really well designed to me, other than the extruder motor being at the worst possible place. If the center of gravity was closer to the rail it would be better for durability and performance.

The parts cooling fan also looks really small, although the fan duct looks pretty effective.

Is this fast? Marlin firmware 2.1, no Klipper (I'm on team Octo). Outputting 10 mm3/s at 0.16mm thickness and only limited by a nema 14 stepper with high internal resistance (17 ohm and overheats at anything above 350 mA). I'm replacing it with a nema 17 (22mm) with 3.5 ohm resistance as a trade-off between weight and torque, which hopefully will help me push 20 mm3 through a ZT V2.

Pushing 5K acceleration with 250 mm/s infill and travel (300 simply seems too rough). I'm very satisfied with print quality at this speed, especially walls after input shaping and calibrating my junction deviation and k factor, although the first and last layer could use some work.

My completed toolhead for now. Config: a ZT E3 v2.0 hotend, BMG clone extruder with nema 14 stepper motor, cr touch and not in view a 5015 parts cooler.

Using a magnetic PEI build plate, BTT skr mini E3 V2 with touch TFT, and will soon upgrade to Marlin firmware 2.1 to enable input shaping (needed to define a different thermistor anyhow).

Is this one good? I'm looking for a known reliable high-output hotend kit (20-25 mm3/s)

https://www.amazon.ca/Temperature-TZ-E3-2-0-Set/dp/B0DZ6J3K94

Test driving my zen duct. This is designed to be as light and unobstructed as possible, taking inspiration from the Prusa XL fan duct.

And yes, the direct drive is next up to shed some weight.

Zen duct mock up turned into a muck up 😂

Photo evidence not available, but the carrier bracket was under-designed and snapped off. Other than that it looks very promising IMO

Dialing in my max speed settings, no Klipper

Max extrusion volume: 50 mm3/s (edit: more like 15 max)

Max acceleration: 3000 mm/s2

Max speed: 250 mm/s infill, 250 mm/s inner perimeters (combined every 2 layers), 90 mm/s outer perimeters (precision)

K factor: 0.007

Layer thickness 0.16 mm

PLA 240 degrees

I know I could bump up my acceleration, but on smaller and more detailed prints it won't save much time.