Stringy Infill with Powerspec Pro

[guitartoys]

I have burned an entire day trying to get S3d printing a decent print. I manage a software company, so I know maybe a teenie bit about software. And I've been successfully printing with MakerBot for some months.

I'm printing with a Microcenter Powerspec pro, which is a dual head clone of a FlashForge Creator Pro.

I print this 20mm calibration box, and it looks great. http://www.thingiverse.com/thing:2064/#files

I print this bridge test http://www.thingiverse.com/thing:12925 and it looks great.

I end up with a setting of 1.72 for the filament, .85 for the extrusion multiplier, and 205 for the temp. I start layer 1 with 220 and then drop to 205 for the rest of the layers.

I then go to print this, and everything goes to hell. http://www.thingiverse.com/thing:28109

The infill (15%) is stringy, and most of the time doesn't span the space. On some of the interior boxes, the infill doesn't seem to be hitting the shell (standard 20% overlap) when I get to the top layers, the 1st layer on the top shell can't seem to span the gap, which is a fraction compared to the bridge from the bridge test.

I'm about to go back to MakerBot.

Can someone tell me why I get such good prints with the 1st two and then crap with the 3rd?

Thanks.

Michael

[guitartoys]

Dan mentioned that maybe I had a partially clogged nozzle, so I switched to the left nozzle, and get the same results.

It seems like the infill is moving too fast, I'm going to try keeping all infill layers in the same direction, rather than switching back and forth with the 45 and -45. (It seems there might be a patent issue with using both 45 and -45 in the same layer).

Anywho, The shells seem perfect, the bottom layer looks great. It's just the infill and top layer that is crappy.

And I'm using 3 layers for top and bottom, with 2 shells.

I'm loosing my mind here.

I'm now trying another back to the very original settings, but I am getting much better prints with MakerBot, and can see all the cool stuff that S3D has, and just can't get a decent print.

Any help would be appreciated. I'm really frustrated.

Thanks.

Michael

[laird]

A few suggestions:
- for infill, set the 'infill extrusion width' to 200%, which will make the infill lines twice as thick (and half as often, so same fill%).
- Use 45/-45 (or 0/90) for infill angles - they form a grid that's stronger than a single angle.
- make sure 'use random infill placement for each layer' is off. it's the worst option ever.
- for layers, set 'top solid layers' to 4, which gives several layers for the top over the infill to smooth out any issues.
- in 'other' there are some speed settings, for infill, outline, etc., that you can tweak. I ended up using defaults, YMMV.

[guitartoys]

Thanks.

I'm gonna give the infill 200% a try right now. That seems to be the biggest issue. But what is so friggin' weird is that the top layer is thin, even though I've got it at 3 layers.

The solid filled cube, and the bridge prints came out so well, and the moment I want to do a real print, it's terrible.

I'll keep at it.

Thanks.

Michael

[jimc]

I think s3d really screwed up by calling it infill extrusion width. It confuses people. Infill extrusion multiplier would be more appropriate. Laird is right on all points. Broken infill is a common thing and easily fixable. Its usually a sign the your extrusion width is too low for your nozzle dia. Be sure to have it on auto or higher width. A.4 nozzle should extrude .48 or above. Broken infill is also a sign the temp is too high for the plastic your using. If your still having issues then infill extrusion width will need to be bumped up. I have tried up to 200% and i thought 200 was just too much. I found i get completely solid infill at 140%. The higher you go with this value the higher your infill% will need to be to keep the same grid or mesh size. The outline overrlap needs to be bumped up the higher this is also. At 140 i have mine at 25%. When i was at 200 overlap needed to be 40%.

[ole_blue_moon]

I had the same issue especially with the top layer being rough. When the infill was at 20% or less it took 5 or 6 top layers to get the top reasonably smooth, could have used more for perfect. Rather than change the infill extrusion width I bumped the infill up to 30% and the top layers worked much better. Maybe changing the extrusion width is better but this worked for me. Does take longer to print I guess.

[guitartoys]

Thanks for the feedback.

It just seems that out of the box, the configuration is terrible for my printer.

It does seem that the overlap is way off. because in the one print, you could see that there was a gap between the interior boxes wall and the infill as well as the top layer. I am guessing that part of the issue is that MakerBot has their settings pretty well tuned by default, and that S3D, since it is supporting so many different printers, hasn't really perfected

It there also a setting that ensures that the top layers properly overlap internal structures. In printing this: http://www.thingiverse.com/thing:28109

The printer is printing the interior walls of the square holes. It looks like when the infill is getting printed, it is NOT initially touching that interior wall, and air printing, which looks like part of the problem.

Then when the top if printing, likely not doing well because of the infill air print, the top layer isn't touching the same interior wall of the square holes. So is there a setting to make a top layer better touch the interior wall? As I can watch that it prints the interior wall, and then the top layer, rather than just printing it all as a top layer.

[jimc]

its hard to tell but it looks like you have no infill in this part. if not then your bridging and you need to set up your bridging parameters. the infill cant be super low or non existent and expect the one layer we are looking at in the pic to come out perfect and solid. its printing over air. many times low or no infill on something like this will require alot of top layers to finally straighten out.

[JoeJ]

Hey Michael - so I have a FlashForge Creator Pro myself, and I have to say, the stock profiles in the software worked really well for me. Great prints with no settings changes, and I don't remember seeing anything like your pictures. However, there can be a good deal of variation in plastic, temperatures, etc, so little changes can make a big difference. It sounds like you already changed the stock temps and flow rates, so it's possible these changes may be affecting things. However, if your calibration box looks good, I don't know why this part would be any different.

That image you posted looks like the first layer of solid infill on top of some sparse infill perhaps? You might want to try jimc's suggestions too

[guitartoys]

Yeah, the default profile was only working mediocre for me. I was getting gaps in shells, and such.

But I went back to the default profile, and it really wasn't any better. I'm going to start over.

I think in part, before I was running too hot. And then I decreased the flow multiplier, and I probably need to turn them back up a bit. But I had been running 220 on Makerbot for the filament forever, and the S3D default is 230. And I only changed the multiplier from .90 down to .85

I increased the infill multiplication, and that made a huge difference, but its ugly now, obviously looks too thick, so I probably need to back it down.

But still, I can see where the filament for the infill and top layers aren't touching the interior shell for the square holes. I'm pretty sure that is a flow problem.

I'll just go back to Makerbot until I can spend another solid 12 hour day on this.

Thanks for the help

Michael