Well, ok. You have been warned
Anyway.. so in late 2019 I decided to get the Photon as that seemed like the best option for a resin printer at the time. While at it, I ordered a set of 10 replacement FET things and a few bottles of Anycubic resin to go with it. At about the same time I had ordered the twin-z rail replacement, manufactured by some guy in the UK. Once that part arrived, I dismantled the up to then unused Photon, replaced the Z rail, put the rest together and... covered it by the plastic wrapper it came in. I think I even did the leveling once back then to make sure it is working and moving before covering it up again. Then some time passed where I for whatever reasons (dog chasing cars type stuff) got distracted. Earlier this year, I bought an Ender V3, did a test print and ordered some upgrade / replacement parts right away. A few successful prints later I was hooked eventhough it was an FDM printer with relatively noticable layers. So at some point I reduced the layer height and print quality improved significantly - as did printing time.
But why did I go for FDM in the first place while already owning a resin printer? Well, a couple of reasons really. The FDM printer was intended for a different type of usage. Where the resin printer would be used for actual models, the FDM was considered a tool maker. What do I mean by that? Well think making jigs for suspension assembly, jigs for (race car) tube frame assembly and also to print parts for my woodworking equipment. It was never intended for actual model prints. However, that is what happened and I was quite surprised by the quality it could achieve - more on that later. The other reason was the assumed toxicity of the resin and having to wear protective gear and what not whereas with an FDM you just slot in the filament, hook up the USB stick, select print and wait for a couple of hours. No real health hazard there other than the smell of the heated filament (which likely isn't very healthy either). So I've carpentered an enclosure for the thing and put it in my bathroom - the room I spend the least amount of time in over the course of a day and where I can leave the window open 24/7 if need be. However, the enclosure was lacking in ventilation, so over time the temperatures within the enclosure started rising - not significantly - but apparently enough. Say over a 10 hour print I would get a rise from 18°C to approximately 28°C. With no extra ventilation to the print head this lead to a number of printing issues, namely the feeder getting clogged up and hence the printer moving on without any filament getting near it -> failed print and feeder gears going messy with filament dust (no sheared gears or whatnot). So unless I begin to actively vent the enclosure this thing is not working for big prints with fine details. As said, after adjusting the layer height within the specs of the printer, even staying below its minimum layer height, the print quality improved significantly. However, with this came an quite large increase in printing times as well.
And that is one of the main differences between filament and resin printers. A resin printer does not care how much stuff you have on a single layer and no matter how complex the structure of that layer is, as it prints the entire layer in one go - actual in the time it takes for the UV exposure of the entire layer to happen (10 secs as per my Photon settings - unless bottom layer(s)) whereas the filament printer has to move along the entire contour of whatever shape you are trying to print plus any fine structure within that contour to allow for future layers to not be created in the air - bridging (aka printing filament covering a gap - hence bridge) is an issue for these types of printers. An FDM printer prints every line, every contour by "tracing" that contour. So if you have 10 concentric circles on a layer it will have to "draw" all 10 circles, one after the other. If one circle takes 2 seconds to print, those 10 circles will take 20 seconds to print - versus the fixed 10 seconds UV exposure of the resin printer for everything on that layer. Add another 10 circles and you're waiting another 20 seconds for that layer to finish - and repeat that for the next layer, etc..
With that in mind a resin printer should be significantly faster than an FDM printer - which to be honest was a surprise to me because I didn't bother thinking about it before (see manuel reference in last post
). If you increase the Z-resolution by doubling the layers, you can very precisely calculate the amount of time necessary on a resin printer. On an FDM printer it's really anyone's guess (not entirely true - it's the distance the print head has to travel / cover).
So again - why didn't I bother using the resin printer sooner? Well, my thought was.. well that resin gunk is toxic, so you have to handle with care - wear gloves, wear a breathing apparatus (/mask), etc. When taking the parts out of the printer, wear gloves again, dunk the part in another chemical agent (isoprop in my case) - which add to the foul smells... so yeah. It seemed like a lot of hassle, whereas the FDM printer is just put in the USB stick, select file, print - and wait an eternity. Now, after having done one or two "test" prints for a diorama / furniture (bedside table lamp) using the resin printer, I have to say it's bleeping easy to do. Take the .stl file, dump it into your favourite slicer, set whatever parameters you want (layer height, feed rate, extruder & bed temperature for the FDM, layer height and exposure time for resin), slice it, save it, stick it into the printer of choice. That part is pretty much the same. And now comes the part where the printers differ. You need to level the printer - which on a resin printer is easy as pie. Slightly loosen the build plate, home it, move it so you can slide a sheet of paper between it and the surface of the lcd screen, move build plate down in tiny increments until you notice the paper being gripped, press the buildplate down so as to have an even spacing all around (with one hand) and tighten it in place, reset Z=0. Done.
With the FDM printer the whole bed levelling is an exercise in patience - which isn't really my strongest character trait (unless dealing with women... for some reason). Anyway, first you have to approximately level the bed using for screws on the four corners of the build plate propped up by springs. You do this several times until you get just about there. As when you turn one of those 4 screws, the screw diagonally opposed to that one will move in the opposite direction (up or down,...). So what you're doing is circling around until you get an ok approximation. Me being me, I've been using a digital angle gauge that I am using for my Dewalt table saw to try and get this done as precise as possible (the screws and springs from the Ender are one of the parts I've replaced with upgrade parts, because the originals are plain crap). That part you basically do once every time you have disassembled the thing. If you didn't change it since, leave it. Now, since I've also upgraded that thing with the CR-touch (an auto bed leveling device), you run that to measure the differences in height of 9 points on the bed. What this does is basically create a virtual heightmap of your build plate to adjust printing offsets while printing. And this really is necessary as the build plate usually isn't flat. Most people report theirs is rather like a bowl with the center being a bit lower than the rest - which can cause issues when you try and print a flat piece as the filament will drop onto the plate and if it is lower at some point or other you will have a dip there... (funny warped shapes ensue). Once the autoleveling part is done you can start the print.
And this is again, where the two printer types differ. With a resin printer you could possibly have issues with the exposure not being long enough ending up with uncured resin that you try to add the next layer to - hilarity ensues - or you could run out of resin. With the FDM printer you can also run out of filament as you don't really know how much is left on your spool unless you decide to unroll it, measure it and then very likely make a hash of it rolling it back up again and causing potential further issues, added to that is the fickle temperature window or rather the cooling of the print head - which is another thing you may want to upgrade for a number of reasons: 1) the default fans are excessive loud, 2) the cooling once you disassemble the print head assembly seems dodgy at best (I seriously wonder how one of the two fans in that part actually makes any difference), 3) the filament can cause you grief because it is slightly to damp - which will cause issues (stringing) when extruding it, etc etc. 4) the position of the print head in regards to the print surface might be off (leveling issue) which can cause any number of issues...
So overall FDM initially appears to be the easier, but the setup is - in my opinion - more fickle with too many variables influencing a good printing result. The influencing factors on a resin printer are fewer in number and easily dealt with. The only annoying bit is that you have to guesstimate the amount of resin in the vat - how much resin is left in there. Needless to say, my first few prints went actually perfect only for the third to fail (ran out of resin), despite me adding some more as per the recommendation. However, when the slicer tells you that you need 120 ml of resin - you never really know how much you have plonked into the vat, as there are only guesstimations floating around. Or you start using a precise measuring cup when pouring the resin. But then again you shall not add more resin than amount x so the vat doesn't overflow - which may require you to add more resin mid-print while not stopping or pausing the print (which I'm told is a big no-no) - which is a thing that really annoys me.
But overall I'd say resin wins over fdm any day if you're thinking of printing models (surface detail, layer lines less visible, print times, ...). I'm not sure if I need to wear a mask, but every time I prepare my resin printer, I'm wearing gloves and my 3M mask (intended for painting use) plus the room (yup, same bathroom) always has the window open when printing, because the fumes of either printer are annoying and likely not very healthy either.
Probably loads of typos in there - might spell check tomorrow...
yes, its a really "present future" and honstly is hard to release your head of all the ideas that come 
