How to get good bonding for pillars

[mhackney]

Hello all, I've been working on printing an item that I designed that has pillars attached to a base plate. Here's a photo:



The issue I'm having is that these pillars are not very we'll bonded to the base plate and break off easily. I've tried KISS and Slic3r with various infills from 100% to 50%, fill patterns, etc without success. Does anyone have any tricks or am I going to have to redesign this?

regards,
Michael

[dpmacri]

Hello all, I've been working on printing an item that I designed that has pillars attached to a base plate. Here's a photo:



The issue I'm having is that these pillars are not very we'll bonded to the base plate and break off easily. I've tried KISS and Slic3r with various infills from 100% to 50%, fill patterns, etc without success. Does anyone have any tricks or am I going to have to redesign this?

regards,
Michael

Just a guess, but perhaps you're printing a little too cool such that the layers aren't bonding well enough?

[mhackney]

Thanks, but I did think of that. I've printed this in PLA and ABS and tried to use higher temps in both cases. The pillars were still fragile. PLA is a bit better but still pretty weak.

[dpmacri]

You said you even printed at 100% infill and they're still weak? Looking at the picture, it's hard to tell, but the pillars themselves look pretty sturdy. I.e. is the problem *just* at the interface to the lower surface? Or do they break easily along their length as well? Since you designed this yourself, can you add a chamfer where the pillars attach to try to get more material/better adhesion?

[int2str]

Can you post the STL file?
I'd be willing to give it a try and see if it works for me.

What layer height did you use for this print?
Lower layer heights (0.2/0.1?) might be best to promote adhesion since the filament is more "squished" into the next layer.

Other than that, adding triangles at the bottom of the pillars would stabilize it.

[mhackney]

Thanks guys. .2mm layer height, printed at 15mm/s.

The pillars are weak just at the interface where they join to the disk/ring. The pillars themselves are quite sturdy! (at least). I am playing around with a chamfer now. Using Rhino. I can easily add a chamfer for the 3 small and 1 larger diameter round pillar bit for some reason the moon shaped pillar, although it is a single polysurface when I select it, is broken into 4 smaller polysurfaces and I can nobly select one, not all of them,. This results in a bad fillet. Hard to describe! I think this might be the best approach if I can figure it out.

I've attached the STL for the print posted above.

ReelBackPlate-Rev2.stl

(659.07 KiB) Downloaded 76 times

[Batteau62]

Hi Michael- good to have you back on the forum
I'm inspired that you are trying to print the fly reel. I haven't given up on mine either, just some set backs.
I visit the eclectic angler often, and I love the simplicity of your designs. Any one interested should visit- http://www.eclecticangler.com/
Fillets will probably help, but I think this problem may involve some re-design. Rather than uniform columns, how about some fin bosses(like a rocket) or a "web lattice" between the columns? This one is hard to explain. I'm thinking of a more solid enclosure like the old auto-wind reels were. Only not fully solid, just a frame around the opening. I'll try to find a pic.
I also think (and still trying to get my e3d mounted to try) that nylon might be a better material? Especially if post treated with Cope13's infiltrant epoxy. See this thread: viewtopic.php?f=36&t=3653&p=23112&hilit=epoxy#p23112
Just some thoughts, maybe it'll spark something? Looking forward to your solution

[mhackney]

Thanks or the props! I had a friend out in OR print this in ABS on a Stratysis 3D printer and it turned out spectacular! There will be a top ring to hold things together but the current print is really fragile. The moon shaped pillar is very strong. I think even a slightly moon shape for the other 3 smaller pillars would be good. The large spindle pillar is still problematic. But I can easily do a fillet on that.

I am doing my POCs in ABS and PLA but I do intend to print in Nylon or T-Glase. I do know what you mean about the old auto-wind reels and that would be an option.

I have one printing on the Max now using different slicing parameters. I'm thinking that maybe 3 perimeters and shells will add to strengthen it. I'll let you know!

cheers,
Michael

[neurascenic]

Michael,

Have you tried to NOT combine your shapes? That is in your design, keep your parts mechanically separate.
I have yet to print anything, but playing around with Cura, I wanted to see how it would slice objects that overlap, and it definitely prints a higher density at the intersections. Can't see exactly what it is doing though.

Of course, this is probably bad form, and I would prefer not to design in such a manner... the way animators often do.

If you want to try this, I would do it on a very simple piece, as it might just drag the head through an already extruded area.

Has anybody tried this?

[mhackney]

Interesting idea, I can try a test.

Meanwhile, I can tell from my 3 perimeter and shell print that these pillars should be strongly attached. I wonder if 2 perimeters on the pillars just weren't enough to get a good bond. The print is almost done so I can test but visually, I can see they are better bonded.

[mhackney]

Well, that did it. The perimeters have a "pad" that is printed on the disk. With <100% infill, there is not a lot of area to bond to the plate. 3 perimeters give lots of area for a good bond and everything is nice and tight.

[bubbasnow]

do the pillars have to be round? the shear on stuff like that always worries me. maybe do a peg/hole(doesnt have to be totally round) type print and print those things longways so its not a weak point? maybe that's not a bid deal with this print i dunno

[mhackney]

No they don't But, there will be another ring attached to the top that will protect them and make for a rigid structure as you can see in this photo:



Compare this to the photo in my avatar and you'll get the basic idea of what I'm making!

[TFMike]

Could triangular ribs/supports be added that go down to the floor without interfering with anything?

[mhackney]

I've solved the problem by using 3 perimeters. But, for the pillars around the perimeter ribs could be used. The larger diameter pillar in the middle will have a spool inserted on it so ribs won't work.

Actually, the 3 perimeters yields a very strong pillar, I'm quite pleased with it.

cheers,
Michael

[TFMike]

Post a picture of the results, interested to see how it turned out, been having a few problems with posts myself. Also, anyone know of any easy way to sand AROUND cylinder posts? Was think gluing some sand paper to the inside of an appropriately sized socket but there has to be a better way....

[mhackney]

I posted some photos in the What are YOU Making forum the other day. Here is one:



Funny you should ask about sanding posts, I literally just did this tonight. This part is ABS but I think PLA would work the same. I used 400 grit wet/dry paper. I cut a strip about 1/2" wider than the length of the post and long enough to wrap around it to form a "U" with about an inch on each side. Does that make sense? Then, under flowing water (sink) I simply pinched the two ends together with the post in between and rocked it back and forth around the post, say about 90-120° if possible. If you can go all the way around, even better. It is best to remove any blobs with a knife first - or use an emery board (the kind women use to shape their finger nails).

[Batteau62]

"(the kind women use to shape their finger nails)."

Taking a risk here the wife doesn't know I took this. It's laser etched with a pattern that cuts one direction and smooths the other. It's mean't to take the ridges off fingernails. It works fantastic for taking off very little material. I don't remember the brand? You can find them in almost any pharmacy.

[mhackney]

Excellent - "I" have the exact same one!

[RegB]

First guess was "too cool" - - second guess is that while the printer PLATE might be very HOT, the rim that the posts are in/on is a thick insulator and the point of failure is almost certainly a lot colder - so I'm stall at "too cool" (-:

Personally I would take the easy way out, i.e. leave bolt head cavities in the bottom face, have through holes for bolts, use aluminum tube for the posts.
A "less than PURELY printed part" but probably a much more cost effective assembly to make; print time, failure rate, finishing and assembling time, materials, etc.

[lightninjay]

Lol, I don't mean to burst your bubble RegB, but Michael has been printing these reels for some time now and resolved his "non-sticking" post issue by printing more perimeters.

[heathenx]

How about adding a small chamfer or radius where the shaft meets the flat surface.

[lightninjay]

*scratches head* People don't check posting dates and read through topics anymore?

[heathenx]

*scratches head* People don't check posting dates and read through topics anymore?

Ha! Sorry. My bad. That was more of a drive-by post from me.