Add Tuesday: Printer-day

content/blog/wk6day2.md

@@ -1,7 +1,163 @@
 ---
-title: "Week 6, Tuesday:"
+title: "Week 6, Tuesday: Prusa MK4S"
 date: 2024-09-03T21:55:00+02:00
-draft: true
 ---
 
-{{< image frame="true" width="17em" float="right" src="/img/headline/todo.png" alt="Credit: " >}}
+{{< image frame="true" width="17em" float="right" src="/img/headline/harrymack-02.png" alt="Credit: Harry Mack, YouTube" >}}
+
+This morning I got up by a, what do the normal people call it?, "alarm clock" at 08:00. I did not
+like being woken up by such a device, and I begrudgingly turned around a little bit. The person next
+to me was also not really ready to get out of bed, so I did something that is somewhat unique in our
+house: I got up before Marina did! And made her coffee, oh what a loving spouse I am.
+
+I have an appointment at the Stromvelo shop at _Zurich Buchegg_ which is not too far away, and I
+bike past there several times a week normally as I commnute from Br&uuml;ttisellen to Google in the
+city. I remain worried about the Stromer ST5, as it keeps on randomly failing its torque sensor,
+which renders the bike pretty much unridable. But, the Deity of Cycling is smiling upon me this
+morning, and after my morning coffee I hop on the bike -- which works!! These last few months, it's
+been either 'not working at all', or 'super sensitive and immediately wants to go full power'. This
+morning was the latter situation, so biking to Buchegg was ... not a problem.
+
+I arrived there at 09:05 or so, while the shop opens only at 10:00. I locked the bike and dropped
+the key in the mailbox, and decide when I get home, that I will give them a call to confirm. It's
+about 2km from here to Oerlikon train station, and I'm very close to Bucheggplatz which is sure to
+have a few _Bolt_ or other electric scooters. I grab one at the tram stop at Bucheggplatz and make
+my way to the train station. It's kind of fun to have one of those 45km/h (28mph) bikes and then
+crawl forwards at 19.9km/h (12mph) on the scooter. It's sooooo slow. I manage to even take a selfie
+of myself on the scooter, which of course doesn't reveal that I'm on a scooter at all. But, I scoot
+my way to Oerlikon, grab the train and then the bus home.
+
+While I'm in the bus, I get an e-mail from DHL that they have dropped off another package from Prusa
+Research in Prague. Huh? Did they send me _two MK4S_?, I think, and I make myself ... promise ...
+myself (hint: that was an Austin Powers wordplay) that I will not give it back if it's another MK4S!
+But Marina quickly puts my greedy mind to rest - it's merely the second half of the package that was
+already underway. Yesterday the MK4S was delivered, and today it's the MMU3 and some heat elements /
+parts for my currently not working MK2.5S. Fair enough.
+
+### The Prusa MK4S
+
+Building the Prusa MK4S is a treat. Except, I'm a dunce so I download the MK4 (not MK4S) build
+instructions, and about halfway through it asks me to grab some plastic part or other, and I spend,
+I kid you not, a full hour looking for this part. I go through the box, maybe 4 times, inspect each
+part, also look through my trashbin, and pull out a few hairs, lose a few years of my life, only to
+conclude: oh, this is the MK4 manual, and I'm building an MK4S. Whoopsie. First, I backtrack a bunch
+by reading the MK4 to MK4S upgrade guide. Later still, I find that, yes, you dumbass, there's also
+just an MK4S assembly manual. People can be so stupid some times.
+
+Apart from my inability to read instructions or navigate the Internet, the build is a really great
+success. I get most of the way through, and spend most of the afternoon being absolutely impressed
+with the progression of the _technology_ of these printers. I started using Prusa in 2017 with
+the Original i3 MK2, which I later upgraded to an MK2.5S. Then I built and used an MK3, which had a
+lot of clever upgrades. There are a feww upgrades on this MK4S that I am most happy with:
+
+1.  Instead of an inductive sensor, called a PINDA (**P**rusa **IND**uction **A**utoleveling), not
+to be confused with the Dutch slur for Indonesian people, there is now an actual loadcell attached
+to the printer nozzle tip. Before, the PINDA would scan for the metal in the plate, and if the
+Z-distance between the PINDA and the nozzle tip was known, it could be pretty accurate. However,
+a perhaps better way is to use the _nozzle itself_, and measure the pressure as it bumps into stuff.
+Using a very sensitive [[loadcell](https://www.prusa3d.com/de/produkt/hotend-heatsink-xl-mk4/)],
+(which is also found in kitchen scales), it will gently bump into the print surface -- regardless of
+how thicccc or thin it is -- and use up to 49 measurement points to do a direct mesh leveling
+calculation. Result? Absolutely flawless first layer thickness and adhesion on the entire build
+surface, not just the middle. Winner winner, Chicken Dinner!
+
+1.  The hotend is now a
+[[Nextruder](https://www.prusa3d.com/de/produkt/nextruder-hotend-brass-0-40-mm/)], where the whole
+thing is one piece that can be inserted - and released! - using two thumb setscrews. Before,
+removing the hotend and replacing parts within, was a matter of disassembling the entire print head.
+Now, I can replace the hotend + nozzle for different diameters, by simply disconnecting the hotend
+heater wires, and the thermocouple connector, on a daughter board called a
+[[LoveBoard](https://www.prusa3d.com/de/produkt/loveboard/)] for a reason not entirely clear to me.
+But with this new cable, the filament sensor, loadcell, extruder stepper motor, thermometers and
+fans are all connected in the print head, with shorter wires that travel through a cavity in the
+print head PETG parts. It's really clever, and I'm looking forward to changing the hotend more
+easily in the future. This hotend is "high flow" with a 40W heater element, and a 0.4mm nozzle,
+which can push out a huge amount of 1.75mm filament. The flow rate can be very precisely controlled
+by a new planetary gear system in the extruder feeder. It looks very fancy!
+
+1.   Although it's a small thing, the stepper motors are a huge upgrade. They're first of all _much_
+faster than the MK2.5/MK3, and they are also a fair but more precise (0.9 degree steps instead of
+1.8 degree steps - which means 400 steps per revolution). They say it's going to reduce the smaller
+layer offsets called _VFA_ (Vertical Fine Artifacts). Honestly, I never really had issues with the
+MK3 printer, but it's a good benefit.
+
+1.   Finally, the Einsy board has been replaced by an xBuddy board, with a much faster processor and
+more IO. It also couples with an NFC reader (which I think is pretty useless), and a WiFi based off
+of ESP32! (which I think will be super useful). It also has ethernet by default, and the screen has
+advanced from the classic dot matrix LCD display, to a 64k color touch screen. I decide to try out
+Prusa Connect, where the thing connects via wifi to a service Prusa provides, and I can also make
+the Prusa Slicer on my Mac connect to the same service: hence, I can print directly from the slicer,
+and skip my [[Octoprint](https://octoprint.org/)] running on a [[PC Engines](https://pcengines.ch/)]
+machine. Talk about fancy!
+
+1.   A super small detail, but these things really matter. Belt tension has always been somewhat of
+a dark art - I have some experience in this because of my RC Helicopters, some of which also use a
+belt to drive the tail rotor. _Feeling_ how much tension to add, so that the belt doesn't skip, but
+also not that it's so tight that it creates friction on the stepper motor, is pretty difficult.
+Prusa added a really cool progressive web app that asks you to put your cell phone next to the belt,
+and then strum it (sort of like a guitar). It then measures the resonant frequency of the belt to
+figure out if it's too tight, or not tight enough. I've seen a fair amount of cool shit, but a _hat
+tip_ to the engineer(s) who created this.
+
+After dinner, we watch one episode of V-Wars after which Quinn decides to skedaddle. Instead of
+watching some more TV, I retire downstairs with a bottle of Red wine, and finish the printer. I
+completely nailed the belt tension using the app - the X axis at 84Hz and the Y axis at 94Hz, smack
+in the middle of the green. You rock, Prusa microphone webapp! I'm really, really impressed by what
+you've done. 
+
+### The Results
+
+If you're not into printing, [[3DBenchy](https://www.3dbenchy.com/)] was kind of
+a torture benchmark, which would test fine layers, some overhangs, some very small cavities and
+holes, etc. Early printers would often freak out on this, and create spaghetti, push the thing over,
+fail to print the holes, or the overhangs, etc.
+
+It's a little bit of a humblebrag, but the folks at Prusa ship this printer with two _Benchy_
+printer objects. The first is called BenchyRules which is a 14 minute print. The second is called
+BonkersBenchy which strips out lots of the insides, turns the object a little bit so as to minimize
+the head movement, and is meant to print in 7 (yes, seven!) minutes. On my MK3, it'll take about an
+hour to complete.
+
+Now, normally, when the printer is built, the annoying task of doing calibrations, printing a few
+first layers to calibrate the layer heights, doing a bed mesh tweak to make it as flat as possible
+(mostly so that the objects on the outside of the print surface also stick to the bed!), flow rates,
+you know all of that stuff. The Prusa MK4S? Uhh, I turned it on, let it do its self test where it
+makes sure all the sensors and stepper motors are connected to the correct ports, and have
+reasonable measurements. It asks me to tap the hotend tip (while insisting that it'll be turned
+off), and I _tap-dat-ass_. It says things are all OK and that's ... it? In the menu, I click 'Load
+PLA', which it does. Then I click "Print BenchyRules", and I am *fully* expecting it to  either
+yell at me "you did not calibrate yet", or just completely destroy the print, but it does neither.
+
+Here's my unfiltered, unscripted POV reaction a few seconds after it started printing:
+
+{{< video src="/media/vdo/IMG_1116_22.46.16.mp4" >}}
+
+The first thing I notice is that the whole workbench / table starts shaking under the violence of
+the steppers, which are not even making much noise. The second thing I notice is that it is *so
+fast, daaaaryum* this thing flies. People have asked me if this is in real-time, and yes, I can
+confirm this video is directly from the iPhone with no editing, no speedup at all. This thing is
+quick as a hare!
+
+OK, while the BenchyRules and BonkersBenchy are cutting a lot of corners, it was an absolute _treat_
+to build this printer and see it fly. It completed the benchy in 14 minutes, and the speedy
+BonkersBenchy in 7 minutes. So much fun! Before I go to bed, I put on an 8 hours print on ABS
+material to refurbish the MK3 into an MK3S; and for good measure I also put on an 8 hours print on
+the MK3 to refurbish the MK2.5S with a new set of parts for the print head.
+
+This was a fun day!
+
+## Pictures of the Day
+
+{{< gallery-category >}}
+  {{< gallery-photo fn="2024-09-03/IMG_1102.JPG" caption="After dropping off my bike at the shop, I grabbed a Bolt scooter to transport myself to Oerlikon station. The scooter doesn't go very fast, so I manage to take a scooting-selfie." >}}
+  {{< gallery-photo fn="2024-09-03/IMG_1105.JPG" caption="The Prusa MK4S printer is halfway done. The Z and X carriage and the bottom parts are done. This is about 1/3 of the way through the build." >}}
+  {{< gallery-photo fn="2024-09-03/IMG_1106.JPG" caption="For lunch I treat myself to a Smos Gezone (a healthy sandwich) with cheese, ham, lettuce, carrots, tomatoes, a bit of mayo and mustard." >}}
+  {{< gallery-photo fn="2024-09-03/IMG_1111.JPG" caption="The electronics part of the Prusa MK4S showing its xBuddy board and lots of wires for sensors and stepper motors." >}}
+  {{< gallery-photo fn="2024-09-03/xbelt.png" caption="The Audio Sensing application on my cellphone allows me to get perfect belt tension by measuring the frequency. Such a clever idea!" >}}
+  {{< gallery-photo fn="2024-09-03/ybelt.png" caption="The Y belt tension is perfect when it hums at 94Hz. OK then!" >}}
+  {{< gallery-photo fn="2024-09-03/IMG_1115.JPG" caption="The printer is done and booting for the first time. Literally 3 minutes later, I printed the Benchy in the videoclip on this journal. I don't think I've ever been up and running so quickly. So cool :)" >}}
+  {{< gallery-photo fn="2024-09-03/IMG_1117.JPG" caption="The (modified) Benchy is printed in 14 minutes instead of 60+ on my Prusa MK3. There's a bit of trickery going on, but the end result is actually really good!" >}}
+{{< /gallery-category >}}
+
+{{< gallery-modal >}}
+{{< gallery-script >}}