3D Printing 3D printer plunge

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I have two here at work that I help maintain (MakerGear MkII & Fusion360 - we LOVE that one!!)

The purple glue stick. that's what came with the Fusion360. works well, too well almost! We tried a sheet of plexi on the MkII (no heat though!) and worked OK..

We run PLA at 215°C & a bed at 70°C. that's what our PLA manuf. recommends. So far, no issues.
 
My printer is a Lulzbot Mini. Great little machine. Pricey though. It's about as turnkey as printers get, but there's still a lot of fiddling to get some things to print well. They come with a PEI surface, which I found works well with most materials, though I prefer a thicker sheet I got from a third party vendor. The glue stick works well for some materials on it as well, nylon doesn't like to release from PEI, so the glue is nice there. Some of the flex materials are the same way. It's as much art as science to get good results from the things, but they are incredibly useful for a lot of things.
 
No fast and hard rules. But I do try to keep the number of threads per unit of length relatively low which gives the appearance of “large” threads. Given PLA I have found they just come out better since I print the thread with no support and given the tolerance of the printer.

See https://m.wikihow.com/Read-a-Screw-Thread-Callout for understanding the thread spec.

I tried a pretty coarse thread too, with ~45-degree angles on the top and bottom of the thread. I think part of my problem was tolerancing, not leaving enough gap between the male and female threads or between faces of bearings. It probably didn't help that the part was pretty small and the mechanism was turning the rotation 90 degrees.
 
I tried a pretty coarse thread too, with ~45-degree angles on the top and bottom of the thread. I think part of my problem was tolerancing, not leaving enough gap between the male and female threads or between faces of bearings. It probably didn't help that the part was pretty small and the mechanism was turning the rotation 90 degrees.

I’m a relative newbie to both CAD and 3D printing. I think the only reason I’ve had success with 3D printing threads is that the Fusion 360 software has a wonderful thread tool built in. It supports many standard thread specifications automagically.
 
Which type of filament is better in rocketry - ABS, PETG, or PLA?
 
PLA is the beginner filament its great to learn on, its very forgiving and for most part would do fine for what ever you need, biggest draw back is its weak and has a low glass temperature.
ABS is much harder to tame especially on larger prints smaller is not as bad, biggest draw back is warping, and smell
PETG is kind of best of both worlds strong yet flexible will bend rather then snap "usually" Biggest draw back is stringy during printing, wont look as pretty as PLA "typically" but with a little practice and fine tuning it will become your best friend in rocketry, Very high glass point, strong enough to do anything but be used as a motor mount. You will also need a decent printer with bed that will reach at least 80c and nozzle in the 220-240c range.

I now exclusively print in PET regardless if its for rocketry or not just so I can keep fine tuning my print quality. That being said most every 3d printed item for sale is made with PLA and will be just fine for you.

These are just my opinions I have been 3d printing for about 3 years.
 
I took the advice of a club member and attended a 3D printing class at a local maker-space to see if it's something I want to invest in. The "teacher" was a bit of an ass; but between his relentless bouts of self aggrandizement, I was able to ask some meaningful questions. I'm not sure I got meaningful answers though. After explaining my primary goal was rocketry, he showed actual interest, so I hope his advice is sound. PLA, as others have said, is a great training wheel- it's hard, but not terribly strong (these are from my scratched notes, so please elaborate/refute with real experience!); ABS is good, but temperamental. His suggestion for parts was NylonX, which is CF-doped Nylon. Sounds exciting and exotic, but after reading about it, has some very crucial limits- it's hygroscopic (not a big problem, we can work around), and the milled CF makes it abrasive on the printer parts (extruder nozzle, although there are upgrades (of course)).

So- flipping the cart for the horse, what sort of parts are you guys printing with the filaments you recommend?

It would also be helpful to note what impulse you're expecting these parts to survive...for those of us timidly sitting on the sidelines, of course!
 
My 4" NC has had about a dozen flight or so. Mach 1.4 is the highest so far, on an M1770 I think. Material is ABS. One recovery was 300kph to 30kph landing speed instantly and the NC banged a fin and cracked. A bit of acetone and it was glued back together and is still flying.

I have a transition on the same rocket that has had almost no problems, except for the above mentioned sub-optimal recovery. Broke it and had to hit "Print" again. Relatively painless ;).

I think the NC can push harder, but probably not to Mach 2. Transition would have no problem.
 
I've only printed in ABS. It doesn't seem to give me a problem, but I have enclosed printers that elevates the temperature a bit - that helps. I've printed some very sturdy fin cans and nose cones, but I have no flight experience with them. Right now I'm printing components for NARAM events - LPR only, and as lightweight as I can get. I wouldn't call the bits sturdy so I don't expect more than a few flights out of anything - it's just a fun experiment. We'll know in a week or two.
 
My 4" NC has had about a dozen flight or so. Mach 1.4 is the highest so far, on an M1770 I think. Material is ABS. One recovery was 300kph to 30kph landing speed instantly and the NC banged a fin and cracked. A bit of acetone and it was glued back together and is still flying.

I have a transition on the same rocket that has had almost no problems, except for the above mentioned sub-optimal recovery. Broke it and had to hit "Print" again. Relatively painless ;).

I think the NC can push harder, but probably not to Mach 2. Transition would have no problem.

Heck with a 3D printer, just print another.
 
PLA is the beginner filament its great to learn on, its very forgiving and for most part would do fine for what ever you need, biggest draw back is its weak and has a low glass temperature.
ABS is much harder to tame especially on larger prints smaller is not as bad, biggest draw back is warping, and smell
PETG is kind of best of both worlds strong yet flexible will bend rather then snap "usually" Biggest draw back is stringy during printing, wont look as pretty as PLA "typically" but with a little practice and fine tuning it will become your best friend in rocketry, Very high glass point, strong enough to do anything but be used as a motor mount. You will also need a decent printer with bed that will reach at least 80c and nozzle in the 220-240c range.

I now exclusively print in PET regardless if its for rocketry or not just so I can keep fine tuning my print quality. That being said most every 3d printed item for sale is made with PLA and will be just fine for you.

These are just my opinions I have been 3d printing for about 3 years.
https://airwolf3d.com/2017/07/24/strongest-3d-printer-filament/

PLA has a higher tensile strength than both ABS or PETG.

https://downloads.makerbot.com/legal/MakerBot_R__PLA_and_ABS_Strength_Data.pdf

ABS only really beats PLA in impact resistance. I’m sure PETG is even better in that regard, but I’m too lazy to find any data. I’ve printed a nose cone in PETG and managed to drive it a few feet in the ground with no damage. It’s pretty heavy, though.

PLA is a very good material if you work around it’s limitations. I’m enamoured with CF PLA. It’s easy to work with and holds a very tight tolerance. With proper settings I’m getting consistent prints within about 5 thousandths either way. I’ve never been able to get that with normal PLA on the same machine. Forget anything under about 15 thousandths with ABS. While it does have a low glass transition temp, I’ve used it on motor retainers and tail cones without issue. I’ve also left rockets in the garage on a hot day and the CF PLA didn’t warp, no idea what the actual temp was though. I still do try to keep the parts in more appropriate temperatures.

Really, if you take the time to mitigate the limitations of any of these materials they’ll probably all perform reasonably well. Using multiple materials on a project in the areas they’re best suited for will probably give the best results.
 
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Well the MK3 kit arrived and wasn’t that bad to put together at all. I didn’t even get through all the gummies. Calibration and setup was easy and on point. I did make a 30x30x30 cube with 2.5mm thick walls to print. With my digital calipers it came out 29.94x29.95x30.03 and walls at 2.53mm.

I’m ready to get rolling with some designs now.

IMG_5226.jpg

IMG_5228.jpg
 
Well the MK3 kit arrived and wasn’t that bad to put together at all. I didn’t even get through all the gummies. Calibration and setup was easy and on point. I did make a 30x30x30 cube with 2.5mm thick walls to print. With my digital calipers it came out 29.94x29.95x30.03 and walls at 2.53mm.

I’m ready to get rolling with some designs now.

Accurate to about 0.05 mm. That is spot on (when you design parts that have to fit tightly together, leave yourself a 0.05 mm gap in the prototyping stage...saves on sanding). Well done on the build, good luck and enjoy.

How do you like the spring metal detachable bed? The biggest pain with the mk2s is getting the parts off the bed.
 
How do you like the spring metal detachable bed? The biggest pain with the mk2s is getting the parts off the bed.

So far, it’s great. I printed a few items in PLA but now I’ve printed about 5 things (none larger than a ~60mmx~35mm footprint) in PET and they all just pop off when you bend the sheet slightly. You can tell they were pretty stuck to the textured sheet too. Seems to work great but n=1 here for me.

I’m building that enclosure from their website with the ikea tables so I’ll be printing those parts for next few days.
 
I bought a Prusa MK3 and haven't looked back. Put it together in parts of two evenings. First print and every one since is great. Kept it busy for a month 24x7 printing rocket parts. Printed a whole 54 mm 3in fin can and fins -- took 40 hours to print. I use onshape for CAD. Will be happy to share any designs - aerodynamic fins, NC, fin cans, altimeter bay parts, altimeter bay bulkheads and the like.

I would recommend staying away from PLA for rocketry. It is brittle and melts in the sun. Not good for rockets.

ABS can degrade in sunlight as well.

I use mostly PETG. Very strong and fairly easy to print.

I would also recommend using a liner - cardboard or blue tube between motor mounts and plastic 3d printed parts.
 
[QUOTE="Cl(VII)
How do you like the spring metal detachable bed? The biggest pain with the mk2s is getting the parts off the bed.[/QUOTE]

I’ve had my MK3 for about three weeks. The flexible heated bed is a great feature; particularly if you have a large part directly on the bed.
 
Got my printer together, but am struggling with calibration, so haven’t had a chance to print anything yet. Still fun to look at while I wait for a part from the vendor.

IMG_6182.jpg
 
How do you like the spring metal detachable bed? The biggest pain with the mk2s is getting the parts off the bed.

So far, it’s great. I printed a few items in PLA but now I’ve printed about 5 things (none larger than a ~60mmx~35mm footprint) in PET and they all just pop off when you bend the sheet slightly. You can tell they were pretty stuck to the textured sheet too. Seems to work great but n=1 here for me.

Same for me too, by far the easiest way to remove the parts that I've experienced yet. However, the adhesive PEI sheet (haven't used the powder coated version yet) can be susceptible to damage. I think not letting it cool down completely and PET parts with big surfaces on the sheet were contributing factors, but I haven't yet printed that much to be sure. The sheet can be replaced, but the procedure is neither fast nor funny. I will be more careful in the future.
The flexible sheet wont help much with very thin objects (eg. aborted prints after a layer). For this, I've found "prying tools" for smartphone repair quite useful. Basically, they are small Nylon sticks with a pointy and a chiseled end. The edge is sharp and robust enough to "shave" the piece away, yet soft enough to not damage the surface. They can be found on Ebay and cost about a Dollar for a pack of 10.

Reinhard
 
Unscented Aquanet hairspray is great for promoting adhesion to PEI sheets (rarely an issue), and also making parts release easier (almost always the issue with PETG). If I get a part that sticks too well, I temperature cycle the bed a couple times, and that usually helps.
 
Found this today, which is the most complete description of print settings in the Simplify3D slicer that I've seen. There should be corresponding settings in other slicers. The author is working with a Prusa MK3. https://www.breathflute.com/pdf/S3D_SettingsCG.pdf

Unfortunately, it doesn't cover the process features of S3D.

I don't think we've discussed slicers here yet. I've used S3D for quite a few years, and at one time it was pretty far ahead of everything else. Now it's due (overdue) for an update, and I think that Cura/Sclic3r have some features that it doesn't.
 
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Found this today, which is the most complete description of print settings in the Simplify3D slicer that I've seen. There should be corresponding settings in other slicers. The author is working with a Prusa MK3. https://www.breathflute.com/pdf/S3D_SettingsCG.pdf

Unfortunately, it doesn't cover the process features of S3D.

I don't think we've discussed slicers here yet. I've used S3D for quite a few years, and at one time it was pretty far ahead of everything else. Now it's due (overdue) for an update, and I think that Cura/Sclic3r have some features that it doesn't.
Working on EDM machines, I can tell you that more features isn’t always better in terms of usability and the quality of the product produced. If you look at any new mill, laser or EDM, there’s a ton of features that would slow down or add complexity to probably 90% of users’ workflows without providing benefit equivalent to the time/money lost implementing it. That said, a lot of the newer tech is definitely applicable to niche areas (and does very well) and some will probably become commonplace in the future. If it works for you and you’re happy, I’d stick with Simplify3D until you have a reason not to.

I’ve used Simplify3D for a while as well. It’s been good to me. No issues with print quality and it’s been very reliable. That said, most slicers out there are pretty good. I’d play with a few to see which feels best and go with that.
 
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