Print-in-Place Engine Aims To Be The Next Benchy

While there are many in the 3D-printing community who loudly and proudly proclaim never to have stooped to printing a 3DBenchy, there are far more who have turned a new printer loose on the venerable test model, just to see what it can do. But Benchy is getting a little long in the tooth, and with 3D-printers getting better and better, perhaps a better benchmarking model is in order.

Knocking Benchy off its perch is the idea behind this print-in-place engine benchmark, at least according to [SunShine]. And we have to say that he’s come up with an impressive model. It’s a cutaway of a three-cylinder reciprocating engine, complete with crankshaft, connecting rods, pistons, and engine block. It’s designed to print all in one go, with only a little cleanup needed after printing before the model is ready to go. The print-in-place aspect seems to be the main test of a printer — if you can get this engine to actually spin, you’re probably set up pretty well. [SunShine] shares a few tips to get your printer dialed in, and shows a few examples of what can happen when things go wrong. In addition to the complexities of the print-in-place mechanism, the model has a few Easter eggs to really challenge your printer, like the tiny oil channel running the length of the crankshaft.

Whether this model supplants Benchy is up for debate, but even if it doesn’t, it’s still a cool design that would be fun to play with. Either way, as [SunShine] points out, you’ll need a really flat bed to print this one; luckily, he recently came up with a compliant mechanism dial indicator to help with that job.

Thanks to [Keith Olson] for the tip.

19 thoughts on “Print-in-Place Engine Aims To Be The Next Benchy

    1. That’s an excellent precision test. However, Benchy demonstrates than just raw precision in a way that can help you identify issues. Also, Benchy (and this) result in a fun figure that you can keep. A block with holes and plugs isn’t something you would keep around for fun.

    1. you can ultilize a ball-bar test on a CNC machine to get a reasonably good idea of the performance of the machine both in linear and interpolated moves.

      Otherwise, using an laser interferometer will greatly assist in properly setting up backlash compensation, or just seeing how the machine performs on each respective axis

  1. I’ve never understood the people who pathologically refuse the benchy. Is it just sheer textbook contrarianism? I do love a benchmark for moving parts tolerances and print in place though.

    1. Maybe no one is pathologically refusing benchy. I never printed benchy, but for my own reasons. First, my old kit built Ultimaker 1 got put together before benchy was even around. I tuned it through failed prints. When benchy came along, I didn’t see the point in printing a little toy that I had zero interest in keeping afterward. My printer probably wouldn’t have done a great job on it anyway due to its age and technology, so the probable outcome would have been an ugly toy that I had zero interest in keeping that made me feel bad about all the money I spent on my printer. Why waste the plastic and make myself feel sad? I’d rather design a new part for whatever I was working on and print that. When I eventually get a new printer, I probably won’t print it just because it will still be a waste of plastic on a toy I have zero interest in. I did print a couple sets of the Pocket Tactics by DutchMogul. That told me enough about my print settings.

    2. I think it’s about perception.

      If you see a printer as a tool, not a toy… or you were into 3D printing before it was cool… or you already know your printer is well-calibrated, you don’t need to prove it…

      …and you want to make that visible, you might be visibly against Benchy-ing.

  2. I made one, worked 3rd try, first 2 tries 1 little piece would come loose off the print bed…turned up the bed heat a little and it worked great. Hardly any work to get it turning. neat little thing, I like it

  3. Archeology: ice age, stone age, bronze age, iron age, benchy age, NEW benchy age.
    How many of the bronze spear heads we found where intended for actual hurting, instead of just printer tests?

  4. While it’s a neat print, [SunShine] is being overly enthusiastic to say it should replace Benchy. Both are nice to nice to display after, but unlike Benchy, this doesn’t work as good benchmark. Benchy has specific features designed to help isolate and identify issues with your printer while this does not. If the printed engine fails to spin, how would you know what to adjust on the printer? If something broke while trying to get it to move the first time, was it due to overextrusion, misalignment, wrong temperature, or did you just twist the crankshaft a little too hard trying to break the single-layer piston supports? And that’s just for starters.

  5. This is less about the printer and way more about the slicer, sure your printer needs to be dialed but that’s but a small part of things.

    While the creator says smaller layers and nozzles are fine, that completely throws this off.
    All of the breakaways for the pistons are all dependent on the slicer slicing that one layer exactly as intended, different settings can result in 2 or even 3 layers of bridging material (or more) and it could be 2 or even 3 passes if you deviate too far from the settings. This is an issue I have with Benchy, lower layer heights change how much filament hangs over the last layer allowing you to fake how good the printer is just by messing with the layers.

    Benchmarks in 3d printing are pointless for this reason.

  6. So I’m new to the 3D printing thing…just got a Creality CR-6 SE and have had luck with my prints so far when I used the provided software with the printer config (long story). Anyway, while I realize this might be different for different printers. does anyone know of a good source of information for dialing in your printer?

  7. I was excited to try something else than a benchy, already have enough of those and 20mm calibration cubes. However the first print was kind of a fail on my decently-tuned mid-range FDM printer. And the worst thing is, I can’t pinpoint why it’a fail – the engine took a lot of unbinding to get it to turn and the connecting rods broke after a few turns.

    The problem with benchmarks (another one) is that you want to use one temperature for precision (low) and another one for durability. Printing at low temps will yield beautiful fragile things with impossible overhangs.

    Would be cool to have another benchmark that can be tested with standard things around the house – a simple hinge with a thread and matching nut, that can lift 1kg (1L of water).

    The advantage of Benchy is that you get “something”, even if it’s a failure, and you know where to look. With this print, or my proposal, you get nothing unless everything is perfect.

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