3DBenchy Test Print – would welcome some feedback

[NickN]

Just starting with my shiny new M2. Mostly getting okay results. Not bad for out of the box! I'm now trying to dial in the performance a bit, and I found http://www.3dbenchy.com/.

I'm printing ABS at 240ºC with the bed at 110ºC and using Simplify 3D with the 3D Benchy suggested settings.

I'm interested in two types of feedback:

1) How to improve the look of the print.
2) How to improve the accuracy (details below).

The Look
The results aren't bad, but I'm sure they can be better. Fine detail isn't too good and some surfaces that should be smooth seem very rough. All suggestions welcome.

The Dimensions
The 3DBenchy guys publish detailed dimensions. As you'll see, some of my dimensions are pretty good and others seem quite far off – the numbers in brackets are what the dimensions are supposed to be. Not sure why there's variance, but would love to get some informed feedback. e.g. the bridge roof length seems okay at 23.06mm vs 23.00mm, but the overall length is off by 2.15mm, which seems like a lot.

Bridge roof length – 23.06mm (23mm)
Chimney roundness – 7mm outside diameter (7mm)
- 10.08mm Blind hole depth (11mm)
- 2.9mm (approx*) cylindrical hole diameter (3mm)

Horizontal overall-length – 62.15mm (60mm)
Horizontal overall-width – 30.83mm (31mm)
Vertical overall-height – 47.78mm (48mm)
top of box – 15.50mm (15.5mm)

Cargo-box size
outside - 12.11mm x 10.84mm (12mm x 10.81mm)
inside – 7.51mm x 6.61mm (8mm x 7mm)
depth – 9.57mm (9mm)

Hawsepipe
diameter - 3.75mm (4mm)
flange - 0.34mm (0.3mm)

Bridge front window - 11.11mm x 9.17mm (10.5mm x 9.5mm)

Bridge rear window
inner diameter - 8.65mm (9mm)
outer diameter - 11.94mm (12mm)
flange – 0.34mm (0.3mm)


Any and all suggestions would be much appreciated.

[Jules]

Pretty danged good for right out of the box!

I think if you want to get actual dimensions to match, you'll need to try a filament other than ABS......it shrinks. (Pretty badly from what i've heard.)

A better choice from a non-shrinking standpoint would be PETG, or even PLA.

There are a few little zits and divots where your layers begin.....a little fiddling with the retraction settings, and possibly a small wipe, will help with those, but I'm no expert on ABS. When the guys who print it see your post they can help out with that. And there's a small lip on the bottom where it looks like your first layer might be getting squished a little bit. (Gap between the nozzle and the bed for the first layer might be a bit too tight.)

But i've never printed ABS, and for all i know, it might be necessary to squish it a little to get good adhesion. Might want to wait for the experts to weigh in. (Maybe post your FFF file so they can take a look at the settings. (zip it first)

That's an excellent first shot at the Benchy.

[willnewton]

By roughness, do you mean the stair stepping effect on your model, such as on the roof? That happens on surfaces that are not steeply pitched. The slicer has to compromise for the layer height. Using a thinner layer will help somewhat. What layer height did you print at?

Not a bad looking print at all.

Maybe just some retraction/coast/wipe tuning, as Jules mentioned.

[NickN]

Thanks guys. I've attached the FFF file for anyone that wants to take a look.

@Jules – I was pretty happy. Had a rush job that I needed to run (simple-ish but critical) when I first got the machine, so it was nice to see that it lived up to its reputation. I have several friends with different 3D printers and all of them had horror stories...

I went with ABS on the advice of a friend who has been using a Makerbot for the past year or so. He had a lot of trouble with PLA (not sure on the specifics) and said his life got better once he switched to ABS.

I still have the roll of PLA that came with the machine, so I can give that a shot.

Is there a brand of PETG you'd recommend?

I have some prior experience with 3D, but not much in 3D printing, so bear with me as I'm not 100% clear on what all the settings do.

In simplify3D, my settings are:

Retraction distance 1.00mm
Extra restart 0.00mm
Retraction vertical lift 0.00mm
Retraction speed 2400mm/min

Coast at End is unchecked.
Wipe Nozzle is also unchecked.

So I'm guessing I check "Wipe Nozzle" Is the default wipe distance of 5mm okay? Any suggestions on the retraction numbers?

I'll pick up a feeler gauge tomorrow and double check the gap. I presume the gap for the first layer is the z calibration I did when I first fired up the printer? Or do you mean the "First Layer Settings" in Simplify3D (currently at 90%)?


@willnewton – yup, the roughness on the roof and then the visible grain between layers. I see some prints that look a lot smoother and am therefore terribly jealous

The current Primary Layer Height is 0.200mm, which I guess is quite big. How much smaller can I reasonably go?

[Vandal968]

That's a very nice print in ABS. PLA can probably do better. Depends on what you need.

cheers,
c

[willnewton]

I print most everything at .20 ,sometimes .25 for straight-sided and tall things, even rarer at at .15 if I really need the detail.

Sure you can print at .10 but I seldom if ever do so unless the model is smaller and highly detailed. I have seen many models that look better at .20 than at .10.

As for the stair stepping, you will have to adjust your design to minimize it OR better yet adjust your design to take advantage of it. Stair stepping shows up obviously on flats, but over gentle curves it can enhance the lines like a topological map. Part of the Benchy's appeal are the print lines following the curvature of the hull.

You should definitely try the PLA. Different machines, filaments, and settings will give different results, so don't let your buddie's PLA experience influence yours. PLA is a very popular filament for general printing.

It is hard to say adjust this setting to this number, because it may not work for your machine and filament. I have no coast and wipe and 1mm of retraction,but I don't print ABS. If I did, I may find that I suddenly need some.

If you want a good starting place, rsilvers profiles are not bad. http://www.thingiverse.com/thing:806946

[Jules]

You probably won't need a 5mm wipe, that's pretty large and your little divots are pretty tiny. (Maybe try 0.5 mm first and if you need a little more you can try 1.0 mm.) It's really just an experimentation process until you find something you like.

Everyone here pretty much uses the eSun PETG - it's inexpensive and prints well. But start with the PLA, it's a lot easier to learn on. PETG requires a lot of finessing to get it to print correctly. (Once it does, it prints beautifully.)

I'm not sure what good retraction settings are for ABS, 1.0 mm is good for PLA. You need a little more for PETG. (1.4 mm.)

When you switch to a different filament, check out the Filaments sub-forum. Suggested starter settings are listed for just about everything there.

[NickN]

Thank you all. Very helpful feedback. PETG and PLA are on the shopping list

[Jules]

Don't forget to pick up some eSun Cleaner Filament to use before you switch to a different filament. (Keeps the nozzle from clogging.)

[NickN]

Thanks for the heads up. Amazon prime is my best friend these days...