3D Printing Planes

[Joker 53150]

So this topic could go any number of places, but since this corner of the forum is devoted to 3D printing I figure it would best go here. Questions raised here would probably cover any of the printable plans currently offered.

Admittedly, I'm extremely new to 3D printing having just purchased the Anet A8. Currently I'm using Cura for my slicer. The one thing that finally gave me enough reason to buy was the printable planes from 3DLabPrint. Yeah, doing a plane with no printing experience is like throwing the Ferrari keys to a kid who just got his license, but I live dangerously...

I've downloaded the plans for the Stearman and printed both sections of the right horizontal stab, mainly as a test. I'm trying to follow the instructions online and in the manual as much as possible, but being new doesn't help. Either way, the first piece turned out pretty good, although that piece was re-started twice due to me forgetting certain changes to how it was going to print. The second print had some stringing along one side, which was odd since none of the settings were changed before printing.

There will be a lot of trial & error getting this figured out, but it should be a fun project.

If anybody has found a "secret sauce" in getting great prints on these super-thin walled prints, please share!

 

[GremlinRC]

Hi Joker, Yes definitely worthy of a thread of its own. I'm in a very similar situation to you, since I only have my printer 2 months. I downloaded the P-47 and have been experimenting. I had mixed success initially. but I found that dialling a few settings brings rewards.

This is what I was getting at first.



I found a number of causes.

Under retraction. Do you get little stringy bits at the ends of the inner structure? If so increase retraction gradually in 0.5mm increments until this stops. What I found was happening was the stringy bits were catching the flow on the thinwall perimiters. Hopefully the stearman has a little wingtip or something small to practice on. The p47 wingtip just takes 7 minutes so its a good part for practice runs.

The other thing I found was my spool holder was catching and jerking the z axis, and resolved with a new spool holder with free spinning bearings;



Gonna remake that wooden part in PLA soon. The other thing is just slow it all down. In my initial excitement all I wanted to do was print it all and get the glue out but alas it really does appear that patience is a virtue. So I slowed it down to 50mm/sec and with the other changes mentioned, I'm getting much more reliable results.



In that pic you can also see my little PLA oiler. Just a wad of cotton with a couple of drops of oil. Not sure how much use it is, but at least it cleans the PLA. You can actually see the crud build up on the cotton. Interested to hear about what you've had success with.

My printer is a Wanhao Duplicator i3 v2.1

Cheers

Dave.

 

[Joker 53150]

This was my first attempt at printing a part for the Stearman, part of the horizontal stabilizer. It's a little stringy inside, but not too bad overall. I don't recall what I had set the retraction to, as I made a huge mistake in making a bunch of changes all at once instead of doing a test-print between changes. The outside looks fairly decent and there are no thin spots. I'm also surprised at how the hinge pocket was nice and clean with no debris or stringing inside it to block proper use. Another couple pieces will need to be printed to make sure I'm happy with the quality before I start printing "for real".

It appears that the various components have different printer settings, as there are configuration settings for the tail, the wings, and the fuselage. I didn't look to see what the difference between them is yet. Thoughts?

For my Stearman I'm debating between the classic yellow/blue or going clear. Maybe a combination of both. I'm also taking delivery soon on translucent blue and translucent yellow which might make an interesting look. The engine will probably end up a combination of black, gray, and aluminum colors even if the rest of the plane is clear.

 

[AkimboGlueGuns]

That's a pretty good print for thin wall stuff. On par with what I've done with the 3DLP stuff. Keep an eye on the trailing edge of any wing/tail pieces as they tend to pull up off of the bed. You might want to try using skirt on the part to give it some more surface area to grip the bed.

 

[97tj-neil]

We just got an A8 for my son's birthday, and I have already purchased the files for the Stearman as well. We will be watching this thread with interest.

We have been doing a bunch of practice prints and made FT firewalls and a bunch of control horns after we printed several upgrades for the printer.

 

[GremlinRC]

Joker,

I agree that's a VERY decent start. See this bits where the layer gets like a sort of dashed line for a little bit at the start of the thinwall perimeter. I'm pretty sure that's the same as what I was seeing too. I've figured out that due to under retraction those inner structural elements are extruding slightly at the beginning and end. As a result when the perimiter runs around it hits that little but of over extrusion and either the head rides up over it or it causes a tiny judder which cause the next inch or so to sort of bounce.

I ramped up my [edit delete extrusion] [replace :retraction], and those pretty much went away. The way I did it was to print a small part, check for any loose bits or stringyness, then just kept upping the retraction until those went away. I am not seeing any more of that since.

Keegan: Good tip, definitely will keep that in mind. Keep 'em coming thanks.

I'm printing the P47 in black because I want to use a metallic silver paint job afterwards, silver always comes up better over gloss black. The yellow parts were just test pieces.

 

[Joker 53150]

That's a pretty good print for thin wall stuff. On par with what I've done with the 3DLP stuff. Keep an eye on the trailing edge of any wing/tail pieces as they tend to pull up off of the bed. You might want to try using skirt on the part to give it some more surface area to grip the bed.

I'm certainly not unhappy with it, for my first attempt. Plus it was the first print with the clear/natural filament and I wasn't sure about the extrusion and bed temps. It looks like 200/60 will work, although I don't know enough about it yet. The kit designers recommend 50 for the bed, but when I first printed at 50 even the skirt started to lift. Your dad suggested I do 60 and it's been all unicorns & puppies since then. He's been very good about answering some questions for me, which is substantially better than wading through the interwebz looking for a "correct" answer!

 

[GremlinRC]

BTW I'm VERY interested to hear from anyone who went from CURA to Simplify3d. Did it make a significant difference to thinwall printing?

 

[Joker 53150]

Here's a very useful trouble-shooting guide for stringing (and other print problems) from Simplify3D. I'm going to go back and play around with settings to see what happens.

 

[jhitesma]

As already covered in the other thread I've been experimenting with the 3dlabs prints sample parts on Thingiverse before committing to buy - but not having a lot of luck. I do plan on putting in the time to get cura playing nice so I can try it...but it's low priority for me so instead I've dug in on printing this plane:

http://www.thingiverse.com/thing:2044074

The designer of which also wrote an article here on FT so may even stop in the forum for all I know. But his design slices well in my prefered slicer - slic3r so I've been working on it the past few days.

Going to get a little photo heavy here and will probably have to split this into multiple posts...sorry if you're only interested in the much more visually impressive 3dlab prints planes I'm just looking to make something that can fly first...then I'll deal with a fancy plane

Anyway...here's my first test piece. I pretty much ignored the suggested settings and went for what I knew worked well for single walls on my machine:




This is one of the tallest prints I've done yet. And definitely the widest that's this tall. Got scary near the top, as the print head moved to the left the umbilical would drag my LCD left across the top rail...then as it moved back to the right the stepper would hit the knob and push it back to the right. Thankfully the LCD mount is pretty loose up there and the knob is pretty stiff so it didn't mess anything up. But I should probably temporarily relocate the LCD on these tall prints!



I printed it at my usual 60mm/s - twice as fast as the fastest recommended speed by the designer. I also printed it at 0.25mm since I know that's an optimal layer height with my mechanics and didn't want to bother checking if 0.20 (the suggested layer height) was. The print only took a bit over 2 hours which was way faster than I expected. I did turn off cooling as suggested which speeds things up quite a bit too. The initial print looks pretty good...but has some issues.



Hard to see in a photo but the area inside the spars is sagging a bit. This is with 0.48mm thick walls not the suggested 0.6 (see my discussion in the other thread about extrusion thickness) and while they printed well they're just not really substantial enough to support themselves.





And without cooling the bottom corners which have some overhang didn't print optimally. Still usable...but not as well as I get with cooling enabled. I could probably print this piece facing the other way...but the lack of cooling could cause bigger issues then.



I ended up destructively testing this first part...it was probably usable...but did break easier than I'd like, mostly delamination between layers but also across them so that's a good sign that it's not layer bonding just the thin walls that are the major weakness.



There were also a few areas where things were a bit thin or gappy after a retraction.

Based on that first test I decided to try a few other things. So...next post please!

 

[jhitesma]

So...next test. I picked the outer wing section since it was the smallest one. It immediately presented me with the issue of how to position it. The STL opens with the outer edge towards the build plate...but the outer edge is angled. It could probably be printed with that flat on the board - but I decided to invert it.

I also slowed things down to the recommended 30mm.s max.

And I enabled a 0.2mm compensation after retraction to make up for the weak areas.

I left cooling off as suggested - still against what my experience was telling me I should do.

I also set wall thickness to 0.6mm in the slicer though it didn't make much a difference since a single wall should still be 0.48mm with a 0.4mm nozzle...but what the heck, let's try it.

The results were stronger - I had to really work to break this test. And the thin areas were gone. There were still some issues due to the lack of cooling though and....



Can you see the big issue? Kind of hard to tell from this angle. How about this one:



The post-retraction compensation was too much even at 0.2mm There's now a blob anywhere it had done a retraction.

And with the angled end up having the top layer set to 0 meant that only the very top layer got excluded...all the other "top" layers as it worked up to that top got a single useless strand across them - not a huge deal and fairly easy to remove but...


What, what's that at the fart left?



Ugh. The very top came out horrible as I suspected it would with no cooling. Cooling doesn't just mean a fan...in slic3r it will also slow down the printer to give layers time to cool. These are the cooling settings I usually use:



So without those the print goes a lot quicker (this was still only a 3 hour print even with the lower speed and smaller layer height) but there's a definite loss in quality.

Ok, 3rd time's the charm. Let's dial that retraction compensation back out and do what I've been suspecting is needed from the start and enable cooling...fan and all.



The 3rd test is on the right. Yeah, printing different pieces isn't as rigorous of a testing regime as printing the same piece would be...but it's less boring and lets me see how things fit together overall. Thankfully these single wall prints don't use a lot of filament even if they do use a lot of time - so no worry about using up too much filament testing.

It's hard to see in the photo but the color is significantly different. The slower thinner layers are much darker. And this piece is even stronger. It doesn't have the sagging between struts and I can almost squeeze it enough for the top and bottom to touch without it breaking. It's not perfect...but it's good enough I'm probably going to use this piece without reprinting it.



The biggest problem is that the servo pocket didn't bridge very well. I probably need to turn up the bridging speed a bit since usually I get much better bridges and bridging usually seems to benefit from a bit more speed than normal printing. But that's not really functional so I can live with it, the parts that matter came out fine.



Also, with the retraction compensation dialed back the weak spots came back...but with the speed slowed down they're not nearly as bad and there are no actual gaps. I could probably dial retraction back a hair bit more still and get this just about perfect.

But it's good enough for me to move forward and I've got the 1st piece back on the printer tonight. With the new settings the piece that took a bit over 2.5 hours in my first test is now taking 5.5 hours - but it's looking a LOT better. Printer is about an inch away from where it starts hitting the LCD and I've got 30 minutes left on the print. So we'll see how it turns out.

One other thing I did differently is that test fitting all these together I learned that using a solid first layer, while great for bed adhesion, means you have to cut that layer out to assemble these parts. So this time I turned off the solid bottom layer and instead gave it a 4mm brim. That seems to have held it down (along with some elmers and my glass at 60c) so I'll probably stick with that. Brim's are usually fairly easy to remove (harder in PLA than ABS but not horrible) while cutting out the inside solid layer is kind of a pain. So this should make for easier final assembly.

And if it goes well...then maybe I'll start to experiment with cura some more to see if I can get the 3dlabs planes to print

Oh - this is Maker Geeks Crystal series translucent red that I got in their december maker box. It's not a full roll, instead of 2 full rolls they sent 3 rolls that were a bit more than 2 full rolls between them. This red, a matching green (since it was Christmas) and a clear PETG. I haven't opened the green yet but both this red and the clear PETG made for some nice Christmas light covers:





With clear/transparent filament thicker layer heights look best...but aren't as strong Those were printed at 0.45mm layer heights so there was very little squish. But looking at them under the microscope my daughter got for christmas I could see tiny air bubbles in the extrusion since I printed them at 60mm/s and spiral vase mode. Printing slower and with individual layers probably would have given even better results.

For the ultimate in clear prints:
https://twitter.com/DanielNoree/status/801453732189839360/photo/1

0.5mm layer heights and SUPER slow with colorfabb HT filament. The design in the middle is air

 

[Joker 53150]

VERY nice info, that gives me a lot to think about with my upcoming test-prints!

 

[jhitesma]

Last nights print looks good. Matches up just about perfect with the middle section:



Removing the brim was a little tricky, but still easier than removing a solid layer from the inside. With it removed the two sections fit together just right.

Retraction still isn't perfect:



But it's close enough that those are all solid, just a little thin. I can probably dial back retraction just a hair...right now I'm using 1mm at 70mm/s - which is really more than needed for PLA - but slic3r treats retraction as a setting for the extruder under printer settings not as a filament setting so it's hard for me to remember to change it for different filaments and since I usually print PETG where that much retraction is needed I tend to just leave it there.

Tonight I'll do the new outer section which should be me this full right wing. Debating if I want to do the whole plane in red, or mix it up with some green or white....we'll see how the red spool looks when I get this wing done

 

[Joker 53150]

After a little more research I think I'm going to update a few things before really getting into printing the plane parts. My concern is that I spend too much time chasing problems that aren't necessarily the fault of the print settings, but are instead problems with the printer hardware. One item I'm going to do is bolt the printer down to a solid base. The acrylic frame of the A8 is ok, but even with the printed frame braces installed it can still flex a little which could really show up on these thin prints. There are a couple other changes I need to print parts for and then I'll install them all at the same time so I'm not constantly taking it apart. One of those upgrades will be replacing the X and Y axis belts with better quality units and also installing tensioners at the same time. A little slop in the belt could really screw up a print and this should do away with that problem.

On a different note, I'm pleased to see how cheap the replacement parts can be for these printers. Nozzles, feed tubes, motors, etc are all fairly inexpensive, although they'll certainly add up in time!

 

[GremlinRC]

While printing some parts this evening it sort of struck me that with these 3d printed planes rely entirely on the layer adhesion for their structural integrity. So I took an abandoned part which I had to abort because I discovered that one of my Z barce screws was about to collide with the z axis bearing and tested it to destuction. Admittedly there was little in the way of internal structural support in this part, but I was a little shocked at how easy it pulled apart. In fairness, I gave it stood of to me gradually increasing the pressure while trying to pull it apart, however when I gave it a sudden shock pull it broke quite easily.



My flying club is in a public park with lots of people around so safety is of the utmost concern to us. I think I could live with epoxying in some thin carbon rod to ensure that it doesn't fail mid air.

....... Darn, darn darn. Just as I was typing that last sentence I hear a pop from my printer and looked over to see my almost finished 6 hour part popped off the glass bed. You know what, I never had this problem with the default mat that came with the printer. It's happened twice since I installed the glass even with hairspray. I think I'll go back to the mat as I have a new spare. I really have to stop trying to fix stuff that isn't broken. Sorry for the rant, just very frustrated right now!

 

[Joker 53150]

Odd... The wing section I torture-tested yesterday certainly didn't go without a fight. Plenty strong enough, especially considering it was just the end of a horizontal stab. The other piece I've got here is the same, good adhesion between layers. I wish I were knowledgeable enough to know if it needs more heat, less heat, slower print speed, etc.

 

[LitterBug]

OUCH GremlinRC, What brand/type of filament are you using? The parts I've tested have been very flexible and resilient. I have the EASYMAX001 and ran out of natural PLA just before starting the right wing half. Switched to black AssUMed it would print the same only to find it was underextruded with all sorts of dropouts in the print when I went to pull it off the printer the next morning. Went ahead and glued it together to practice assembly and test strength. Even with some massive gaps in places, there were only a few places where the adhesion was so bad that it broke and only with a bunch of force. Have those parts on my wall of shame at work. Will have to get some pictures of them.

Cheers!
LitterBug

EDIT: Flexibility example:
Single layer thrust tube squish test

 

[GremlinRC]

Hi Guys,

Sorry I can't tell you which brand my PLA is. It's supplied by a local supplier who must buy in bulk and rebadge and redistro under his own name. So not sure of the providence. It's good stuff, I haven't had any problems with it to-date. But just to be clear. The problem is not with squish testing or even pulling it apart with gradually increasing forces. The problem seems to be layer shear from sudden shock. If I start trying to pull apart I have to use far more force than an airframe will encounter in the air to make it give way. However if I give it a short sharp pull it can give way sometimes. I'm thinking of buffeting and heavy landings etc. That's why I'm thinking of adding a few CF rods just to be sure.

 

[jhitesma]

GremlinRC - you may want to do some small tests and try printing slower/hotter or at different layer heights. Have a look at the optimal print settings calculator here: https://nathan7.eu/stuff/RepRapCalculator/RepRapCalculator.html#PrintSetup

If your WOH is getting too small you can have weak layers like that. With a 0.4mm nozzle and 0.2mm layer height if you're getting 0.6mm wall thickness then you're running a WOH of 3 which should give very strong layers but lower resolution...so assuming that's what you're doing I'm guessing it could be print temperature or speed causing weak layer bonding.

 

[gowen]

I've built the 3dlabprint Spitfire XVI as it was the only one that would fit on my 220mm diameter Delta Printer. The first flights were a bit hairy as I didn't have any expo on elevator and orientation was a nightmare as I'd printed it mostly in natural PLA. It's now sporting some stripes to help me tell which way up it is.