3D Printing and Finding the Range

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I’ve tried recording a video on this three times now, and each time it’s devolved into a rambling mess (even more so than usual!). So instead, I’m going to give words a go.

3D printing has a relatively steep learning curve. There are a slew of arcane rituals you have to sort out. Rituals that you probably have no clue about as you unpack your first 3D printer. Leveling the build plate. Sanding the build plate. Washing and curing. Handling hazardous materials with care.

But by far the steepest and most encompassing part of the learning curve for me has been the slow, grinding process of finding the range.

Finding the range

If you’re familiar with artillery, or archery, or urinals, or pretty much any kind of ballistic trajectory, you’re probably familiar with the concept of finding the range. You fire your first shot, and it goes long. So you adjust a few variables, fire your second shot, and it goes short. But with those two results, you’ve bracketed your target, and now you can start tweaking your variables toward the middle until you hit what you’re aiming at.

3D printing is pretty much like that.

Except, with things like 16″ naval guns and urinals, you pretty much know the results of your firing solution right away. So you can adjust on the fly.

3D printing isn’t like that at all. It’s a long, slow process. In some ways, it reminds me of the days of film (remember film?), where you wouldn’t know how a picture came out until you processed your roll. Even very small 3D prints can take a good hour or so. Larger prints can take literally days depending on your settings. So you fire your shot and then…you wait.

Small, incremental changes we can believe in

I lucked out with my first 3D print, Bold Miniatures’ Lilith bust. It wasn’t perfect, but it printed nicely enough and didn’t fail.

Still, I had no real idea what I was doing, and my next prints became a string of failures.

If you want to really stall your progress, do what I did next – change a bunch of variables all at once. That way, when the print fails again – or even succeeds – you have no idea what lever did what to get you into that position. It’s the best!

With 3D printing, you have a number of variables in play. So many that it can be daunting at first.

You have hardware variables. What kind of printer are you using?

You have consumables issues. What kind of resin are you using?

You have physics variables. How big and/or heavy is the thing you’re trying to 3D print. Just because you can print a little calibration square doesn’t mean you’re good to go on a big 1/12 figure.

You have software variables. What slicer are you using? What CAD and other programs to manipulate your files?

And on top of all of that, you have your print settlings. There are a lot of them, but I would consider only four to be truly success/fail relevant.

Exposure Time

This is how long the LCD screen flips on for. With a mono printer like the Sonic Mini and Mighty 4K, this is rather short – I usually float somewhere between 2 and 2.65 seconds. Going one way or another doesn’t seem to make a huge amount of difference to my eye, but I’ve found that a successful print at one setting with one resin will fail with another resin. So…as you jump from resin to resin, you may need to adjust your exposure.

My pet theory is that this has to do with light absorption. Black seems happiest with lower exposure times, and when I’ve had failures with same/same it’s been switching to something like gray or beige from black.

Layer Height

This should be self explanatory. Resin printers print in layers. Each layer is a certain height. I’ve printed anywhere from .03mm to .015mm and had successes across the range, with the major difference being how fucking long it takes to print something (hint – twice as long at .015 since you have twice as many layers). BUT as you adjust layers, you also need to adjust your exposure settings. What works at .015 may leave your shit pooled in the resin vat at .03mm.

Lifting Speed

After the printer exposes a layer, the build plate lifts up to allow more resin to flow underneath for the next layer. This speed is another crucial setting – at least for Phrozen printers. I know some printers seem happy at relatively fast lift speeds of 150-180mm/min, but I’ve found all those speeds do for my printers is rip shit off its supports. Once I dropped my lift speed to around 40, my success rate shot way up.

Base Exposure

Another critical setting is the base exposure. This is for the first layers of a print, and you want them to really grip the build plate. Otherwise you can have a print completely fail as it fails to adhere and just collects in the resin vat. Or you can have a weak bond that delaminates and results in a warped print.

But there’s a catch. Go too high with your base exposure and you end up backing those base layers to the build plate to the point that they are extremely difficult to remove. One of my early prints adhered so effectively that I had to literally bust out a rock hammer and an xacto with a chisel blade and literally chip it away.

My Phrozen Sonic Mighty 4K is a particular challenge in this regard. In its natural state, it has a very narrow threshold – around 17-19 seconds per base layer – where it will more or less reliably hold a print, but also still be more or less removable at the end.

Fortunately, I’ve found a great solution to this particular setting challenge – flexible build plates like those offered by Wham Bam, Sovol, and others. With these, you install a magnetic pad onto the build plate, then slap a thin, flexible steel sheet on it and use that as your build surface. At the end of the print, pull the plate off, then bend it, and the print either pops off, or lifts an edge enough that it’s easy to get in there with a palette knife to break the rest of the seal. No more chiseling.

Now, the ease of removal and the faster post-print processing is nice, but the real benefit of these things is that they take base exposure time off the table. What I mean by that is that you can absolutely crank it – I took mine up to 30 seconds printing Cobb Vanth on his speeder seat and it popped off just as sure as all the others.

Another variable – supports and support strategy

Perhaps just as important as any numerical setting you choose is the type, number, and arrangement of supports you use.

Supports gave me a bunch of trouble early on – either failing to hold the print…

Or turning the area where they were attached into a pebbly awfulness.

It’s taken me awhile to figure shit out, but I finally had an epiphany. Supports serve two purposes. One is to ensure that details get filled and printed correctly by preventing islands and shit like that. The other is to act as load bearing members to hold the print to the build plate.

And there is no reason these have to be the same supports.

So here’s what I’ve started doing. Using the lightest supports I can for general support work. These are 0.2mm in diameter where they contact the print, and 0.15mm deep. Unless I’m printing something really light, they won’t hold shit. But they don’t have to, because I’ll also drop a few medium and heavy supports in out of the way places where they can hold shit up and wreck shit around them and it won’t matter, because it’s on the bottom of a foot or something.

Ever since I’ve started using this detail-vs-load bearing thing, I haven’t had a single print fail by tearing free of its supports. So I guess I’m doing something right?

How you can find the range faster

Want to take less than two months to figure out some consistent print settings and develop Dunning-Kruger levels of expertise?

Find some recommended settings for your printer and resin. Here are the settings I used on my Mini 4K with Anycubic Craftsman Beige resin to score a really gorgeous print of Russell Crowe’s Maximus from Gladiator:

Keep a print log. Your settings, what you’re printing, and how it fared. If you get a failure, mark it down as a learning experience and try to work out why it happened. I can generally remember back like one or two prints, but not seven! A print log makes it easy to go back and refer to what went right or wrong in the past. I keep mine in Google Slides, because it’s easy to dump screenshots into it instead of typing everything out.

If you get a failed print, don’t panic! Diagnose what happened. Or at least try to. And then change one variable. Think of it like the scientific method. Develop a hypothesis. Test the hypothesis. Rinse and repeat.

Be patient! Even small prints can take HOURS depending on your settings. My recommendation is to try to get into a cadence of doing a print a day (or…as you get into bigger prints, as close to that as you can manage). Take the completed print (or failed print) off the build plate, reset everything, and go again. Check on it a few hours in – once the build plate surface is rising high enough out of the vat to actually see what’s happening- to make sure it’s actually printing properly, but otherwise, just get on with your day.

Sticking with it

I’m not gonna lie. 3D printing can be extremely discouraging at first when you have no fucking clue what’s going on. But as you start to stack up successful prints and really explore what you can do, it becomes rather rewarding – and definitely frees you up in terms of the kinds of things you can build and paint.

It just takes climbing that learning curve and finding the range.

One Comment Add yours

  1. Bill says:

    I am at almost exactly the same point in the journey and this is the most truthful account of what it has been like. I started off way to ambitious but now I have the “range” I’m really enjoying it. I would add that a few traditional modelling skills can just save you a whole lot of time. I have on occasion just sculpted a missing piece or added a bit of wire, no need to wait another day for a print. Thanks for this. Very helpful.

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