3D Printing Guide/Tips/Tricks

With my team maybe picking up a 3D printer soon, I realized that no one really knows that much about 3D printing. Theres so many variables to a print like layer height, wall thickness etc which all vary depending on the part and material.
Hence, I ask you guys to post in this thread about what the different aspects are and what to change when etc. Especially with the increasing presence of 3D printing in FRC, I feel like this would make a good thread for future teams looking to get into 3D printing.
Thanks!

Which printer? (If you have not chosen which printer I highly recommend the prusa i3 mk3 I would say it is the best consumer 3d printer if you prefer to not spend ridiculous amounts of money)
For any printer, the most important thing is to spend time dialing in the settings. Whether that is bed leveling, bed temp, etc., make sure those basic settings are done well.
To strengthen parts, the most important setting to change is wall thickness and shells. If those are thicker, there is more material to bend, etc. It’s the same reason a thicker walled 2x1 is going to be stronger than a thinner walled 2x1. More infill is nice, but shells and wall thickness are more important.
One other thing that our team is gonna try out soon is a bigger nozzle, we bought .6mm and .8mm. Allows us to print quickly in the pits, I will update on how this goes.
Second to last thing: if printing with PLA, dont use them in places that might be taking shock loads. PLA is very brittle and doesn’t bend much, it breaks. We 3d printed sponsor panel holders that doubled as air tank mounts and if they ever got hit (they were close to the edge of our frame perimeter and we played heavy defense) they would just break. Those would work fine if we relocated them, but where they were they were bound to break. We use our printer most for camera mounts, electronics mounts, spacers (biggest one), and this year a cone for our hatch panel mech (it worked fine cause it was thick with probably too much infil and shells but better safe than sorry.
I know this is long, one last thing though, more in depth info can be found from this video from the citrus circuits workshop series.

What do shells do?

Adding onto the post above, look into different filaments you might want to use, since printers are often limited to one or a few filaments. PLA is the most common (and cheapest as far as I am aware). It cannot handle high heat or repeated impacts though. ABS is great with heat and impact, but it is very finicky to print (requires an enclosure and venting). PETG is a good alternative to ABS, and is easier to print.

There are many other filaments as well (Nylon, CF, etc.), but I don’t have any experience with those. Hopefully someone can enlighten us, because I hear of Nylon being used quite frequency.

Shell = layer of wall thickness. I never go under 3, and I’m more likely to run 6 if I think I can get away with it

If you’re running ABS, on the bottom surface of the part, add some short pegs, about the diameter of your print nozzle (0.4mm, or whatever your size is), and maybe half an inch long. That should get your part up out of the way of any warping, and the pegs will break off with the support. Ideally, of course, the part doesn’t warp, but ABS…

Also, filament supplier: Hatchbox, then everybody else, unless your printer needs specific filament. My work has had more issues with non-Hatchbox suppliers than with Hatchbox by a large margin. Cheaper isn’t always better…

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We tried to print with nylon this year. In theory good, but if left out it collects moisture and gets ruined very quickly. We had problems with bed adhesion and decided to abandon.

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Ok, so firstly, some general tips for 3D printing functional parts for FRC:

  • Layer Resolution: In general, I print most parts at 0.2mm layer resolution, this seems to be the most durable setting when using a 0.4mm nozzle (the most common default).

  • Infill: This varies a lot depending on the part, but I typically use between 20%-25% infill for functional parts using a Triangle infill pattern. Keep in mind, infill mostly affects the compression strength of a part.

  • Perimeters/Shells: 3 perimeters minimum, with 5 perimeters needed for stronger parts. Also, make sure your bottom and top solid layers are at least 1mm thick (I use 1.6mm on mine). Perimeters affect the rigidity and layer adhesion of a part.

  • Rafts: Avoid whenever possible, they tend to be a pain to remove cleanly, add a lot of time to your print, and are usually unnecessary if you designed your part right. The ONLY time I ever use rafts is if a part has limited surface contact on the build platform (typically happens with very small parts), but even then I use rafts only as a last resort (and usually after a print attempt or two).

  • Supports: Try to design parts so they don’t require supports, or if you can’t, at least try to design them so the supports don’t affect any critical geometry. In general, you can get away with overhang angles of up to 45 degrees before supports are required. Also, try to avoid designs that require internal supports (IE supports between layers of the parts themselves) as these tend to be difficult to remove.

  • Bed Adhesion: Heated glass build surfaces are the most preferable for printing using standard PLA. I also recommend applying “Elmer’s Washable School Glue Sticks” (the white ones, not the purple) prior to prints, it’s easy to apply and clean off and is by far the best easy way I’ve found to get parts to stick.

  • Material: Assuming you’re not doing anything crazy (like trying to print a gearbox or something), in general, standard PLA will work fine. I highly recommend Hatchbox PLA, which is readily available on Amazon with Prime shipping. Alternatively, if you’re looking for something a bit more durable, but just as easy to print, I’ve also had good luck with eSun PLA+ (the wheels on our drive system this year were printed with this material and it held up fine).

Now on to printer specs to look for:

  • Firstly, as I eluded to earlier, a heated glass print bed is preferable for part adhesion. An enclosure also helps quite a bit, but if a printer you’re looking at doesn’t come with one you can always build one out of polycarbonate.

  • Next, automatic bed leveling. While this seems like a simple feature, it’s a HUGE time saver. My first printer required manual leveling and it was a HUGE pain that took hours of constant tweaking. My current printer automatically levels itself before each print so I don’t have to touch a thing.

  • Avoid printers that require proprietary filament. The operating costs will come back to bite you if you don’t and it tends to limit your filament options.

  • A large build volume is always a plus. The printer I have can do parts up to 8"x9"x10", which is large enough for basically any FRC use.

  • Dual Extruders is a nice bonus if you can afford it (but beware, not all dual extruder printers are created equal). If you get a printer with this feature, make sure it also has automatic leveling AND that it levels each extruder head separately. The main benefit to having dual extruders is the ability to print dissolve-able support structures, which allows for far more complicated parts and cleaner final parts.

As for printers specifically, before all the Markforged shills show up in this thread, I have and recommend the Robo3D R1+ which I’ve gotten a TON of use out of and has been very low maintenance. It’s also fairly inexpensive (<$500), can handle a ton of different filament, has a large build volume, and works fast (I typically print parts at around 85mm/s). I’ve also had good experience with the Original Prusa i3 MK3 that my team has though we haven’t done nearly as much work with it. It does have a lot better support and a bunch of mods you can add to it to give it more functionality.

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Used a Prusa mk2s. We bought mostly PLA+ at microcenter. We tried ABS but burnt up the bed on a 20hr print, not sure how. We printed several CF20 PETG parts which worked well but hurt to pull off the bed.

Calibration was important to get right, adjusting the z-axis like shown in the manual. Also cleaning each time with a little IPA seemed to keep good adhesion. Also adding a raft to parts that you were concerned about it.

We are doing extensive printing - we actually working on printing the whole robot we also started a youtube channel

First if you get a printer and want to do some serious printing for robotics beyond small brackets you should get one that can handle NYLON, PETG, ABS/HIPS so that means full metal hotend, garolite build plate (if you do Nylon) and a heated bed that can reach at least 100c We currently have a Prusa clone which works fine and with the build area of 250x210x220 is barely big enough. If a sponsor comes through we are going to get a 2nd printer a CR10-S5 that we upgrade to a full metal hotend and a 750 W heated bed. Building yourself an enclosure is highly recommended for most materials.

NYLON - Tough, some is good for Gears and brakets (like 910) some is more flexible and not well suited for stuff that needs to be stiff but almost indistructible - will give a lot - Downside - expensive, tough to print

PETG good for brackets more durable than PLA, Stringy (parts don’t look as Nice as PLA. Sticks well to most things especially itself so not good for gears - Medium priced

ABS/HIPS - very Cheap more durable than PLA needs high heat on bed not as easy to print as PLA or PETG but did I say cheap.

PLA - Inexpensive about on the level of ABS/HIPS, Hard, good for low torque gears if lubricated - very brittle so don’t hit it with anything. We use it for size fitting and model gear boxes as its a decent even though brittle analogue for Nylon. And its easier to throw something away thats 12/kg than something that is 90. So most gear boxes are first made in pla and if everything fits and meshes well then they get printed in Nylon. We also make things like limit switch brackets and show pieces out of PLA.

When it comes to tuning in your printer maybe watch my video on volumetric extrusion. If you have any questions feel free to message me.

Fresh of the printer - not cleaned up yet - frame piece to hold Toughbox mini and 6 in wheel printed in yellow HIPS (was on sale )

currently on the Printer - 267mm long frame piece also HIPS (will be reinforced with 3/4 in al. square tube

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We also use Hatchbox pretty much exclusively, usually purchased on Amazon.

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As others have mentioned, I’ve had great luck with hatch box pla as well, but if you’re really wanting to get some cheaper filament I’ve also used Inland filament from Amazon and have had no issues with it. There are lots of videos on youtube testing different materials and ways to make them stronger which I’d highly recommend looking at even if just to see what factors affect the strength of the material you use.

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We bought and successfully printed close to 30kg worth of filament from Hobby King . Mostly HIPS ABS and PETG A little PLA for prototyping. Most the Nylon we used so far is Taulman but that might be as they sponsored quite a bit. Its great stuff even though maybe a little on the pricey side.

I have an Ender 3 Pro and have had good luck with Hatchbox and 3D Solutech filaments. PLA filament

if you want to import from Canada or someone from a Canadian team is reading this filaments.ca has some good deals like their econo fil pla if its in stock its $15 per kg and 125 cnd free shipping in Canada and in us its 150usd. they also have generally good deals on filament.

We’ve used 3D Solutech PLA, Inland PLA, and Hatchbox PLA/PETG and AmazonBasics PETG. No issues with any of them but Hatchbox is generally $3 to $7 more per kg.

I’ve been printing eSun PLA+/pro exclusively for almost the last year. At ~$20/kg, it’s not the cheapest out there, but it is notably stronger than normal PLA, particularly when it comes to impact resistance and flexibility.

For other things related to 3D printing… I basically run three distinct settings now. The way I describe this is # of perimeters - %infill. So the “fast” print is 2-10, for 2 perimeters, 10% infill. For durable parts, I typically do 4-40 or 4-80. All of these get a layer height of 0.35mm, as this is the max I can get on the Prusa without issues. I tend to prefer maximum layer height because it increases the strength of the part and speeds up print time (see: https://www.3dhubs.com/knowledge-base/impact-layer-height-3d-print). I can also pull out some papers if you’d like.

I’ve recently become a fan of using heat-set inserts. They’re very easy to use with a soldering iron, even without the “right” tip. I like to use the tapered inserts from McMaster. Special tip: make sure to look up the manufacturer suggested minimum boss and hole dimensions, and follow them well. Also, have a flat reference surface you can use to make sure the inserts are level with the surface of your part-- after you set the insert, flip it over quickly onto the reference surface and press it for a more consistent leveling.