First Custom Print

Discussions on normal hardware operation, tips, etc.
darthviper107
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First Custom Print

Post#1 » Tue Oct 02, 2012 3:57 am

I really wanted to do a print of something I've had printed before to compare the quality. This is 50 microns XY 50 microns Z, took 7 hours 44 minutes at 20 second exposure.

On this a had a bunch of trouble getting it to stick, turned out I didn't have enough support on the model so it ended up coming off after a bit due to the vat movement.

A few things as far as improvement--I build the support material too close to the model and a lot of it got stuck on there, the plastic is pretty rigid so cutting it off caused quite a mess. I think I also did it wrong by putting the support material into the actual print model rather than using the B9 Editor program.

The B9 Editor program has a tool to create support structures in the slice viewer, it saves them separately from the object slices. I think when it prints the model the support structure gets projected at a lower intensity than the rest of the model so that it is not fully cured and can be more easily removed from the model. However, it's a bit difficult to create support structures from the editor so maybe it would be nice to have a feature where you could do 2 slice files, one would be just the model, and then the second could be the support structure, that way it can keep them separate and you can design the support the way you want. Of course this won't matter once the automatic support system gets added to the software.

The other thing there are the horizontal lines across the model. I think that's because of the threaded rod for the Z axis, maybe there's slight imperfections or a bit of resin maybe got onto the rod or the piece that attaches the build arm to the rod. This could be fixed though by figuring out the amount of distortion and distorting the model beforehand so that it would result in a correct model. We'll see, I'm guessing that type of distortion isn't the same for everyone's printer so it might just be something only I would need to do for my situation.

The other thing is that the Z resolution was off, looks like it was something like 40 micron layers rather than 50. I'm not sure what caused that. Originally I was thinking that when I calibrated the build table that I pushed it down too far, resulting in less room than it should have, but that would have only affected the first layer (which would be smaller than normal) It shouldn't have affected the whole print that way.

Overall I think that it's better quality than the professional printer, just have to fix those problems. And this was only at 50 micron layers, could be even better at 25. Though this took 7 hours to print.
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nick
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Post#2 » Tue Oct 02, 2012 5:02 am

Very nice! Congrats on being the first to share a custom print.(unless i'm missing someone =x)

pmwasson
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Post#3 » Tue Oct 02, 2012 5:44 am

Looks great. What are the dimensions of the part? I'd like to get an idea of scale.

UGUSILVA
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Post#4 » Tue Oct 02, 2012 6:24 am

cool cool ;) congrats!!! ( by the way, thanks for the tip... working perfect now :P )

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behold3d
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Post#5 » Tue Oct 02, 2012 6:28 am

it would be nice to be able to select two stls or a stl and a slc file and designate one as the model and the other as the support like the "tec" systems do.

i make my supports in another program and export them. otherwise i have to boolean them together and they become.. odd

darthviper107
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Post#6 » Tue Oct 02, 2012 6:54 am

Quote from pmwasson on October 2, 2012, 11:44
Looks great. What are the dimensions of the part? I'd like to get an idea of scale.


It's supposed to be like 57mm, that's what the old Polyjet print (the blue one) is at. This turned out like 47mm or so. I'm not sure what could cause it to do that. There's enough slices, perhaps the motor isn't calibrated properly.

UGUSILVA
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Post#7 » Tue Oct 02, 2012 7:13 am

try to print it horizontally instead of vertically, i think the build time would reduce a looooot... ( although you would have a bit of work creating the supports for it)

darthviper107
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Post#8 » Tue Oct 02, 2012 7:40 am

It's just a little bit too long to print horizontally. Plus I had done it that way since it would have needed less support material. Although I guess I could orient it diagonally. Still have to fix the lines though. I'm going to try and remove the Z rod and clean it along with the arm connector and see if that works.

UGUSILVA
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Post#9 » Tue Oct 02, 2012 11:21 am

I think the lines are due to the resin properties, shrinkage and flow during print (but that's just a guess coming from the metratron print), do your repair and then compare, might also be that...

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behold3d
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Post#10 » Tue Oct 02, 2012 3:45 pm

why did you decide to change the suggested exposure to 20? I am wondering out loud if at 50 microns if the exposure time should be adjusted down slightly instead of up.

Its also great to see a print like this. I can just imagine how proper calibration would make this amazing

darthviper107
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Post#11 » Tue Oct 02, 2012 4:13 pm

You would think so but I've had issues with the layers not sticking together.

I tried printing again in a horizontal position (diagonally) but the first attachment layers wouldn't stick to the build table. It's possible that there were a couple damage spots of the PDMS that stuck it to the vat, but I'm not sure how to fix that issue.

darthviper107
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Post#12 » Wed Oct 03, 2012 7:19 pm

New print test

This one is 25 microns Z 50 microns XY Orientation is horizontal

Intially I had issues with it not sticking to the build table, but it turns out I had the attachment layer exposure too high. So build settings for this was 20 seconds attachment layer exposure and 10 seconds regular layer exposure. There were 4 fill layers as attachment layers and then a bunch of support structure. I think the exposure was still too high, the supports were pretty well cured so I think I should have set it lower, like 7 or 6 seconds. Build time was about 1 hour. The quality is excellent, way better than the other professional printers I've used. The X and Y resolution is completely smooth, the Z resolution is only noticeable at the most subtle of angles for a surface. It looks much better than the photo.

1 issue though was the sweeper, since the table barely moves, after a few layers the suction keeps material from getting under the table properly, so it ended up with holes in the layers where material didn't get to, that caused like the tip of the gun not to come out right and caused those damage dots that you can see. Once I noticed I removed the sweeper and it worked just fine. I'll do another test later to confirm that's what caused those issues, but I'm pretty sure. The sweeper isn't strictly necessary so in these cases you need to remove it.

The other side is messed up though, I didn't put enough distance between the model and the attachment layers and so it ruined that side, the exposure time I'm sure also contributed to that.

One thing I learned was that if you are having issues where the layers aren't attaching to the build table then it might be that your exposure is too high, of course it's also possible that your exposure is too low, but this is just to confirm that you can indeed set it too high.

In my next test I'm also going to try at an even higher Z resolution, I'm pretty sure it can do something like 15, which would be fantastic.

I'm also pretty sure the squashing issue I had isn't here anymore, though I can see 1 faint line across it, that might be the same thing as the bumps I saw on the earlier print. I still don't know what that is, but if it's unavoidable I might be able to reduce it by pre-distorting the model so that it cancels it out. It wouldn't be noticeable on surfaces that aren't uniform.
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behold3d
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Post#13 » Thu Oct 04, 2012 1:07 am

great print. good job troubleshooting

Suijin
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Post#14 » Thu Oct 04, 2012 7:07 am

I did a metatron print at 50x50 XY and 100 micron Z resolution with 20 seconds exposure. If you are only doing 25 micron Z then you should probably be more around 4 seconds expose.

darthviper107
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Post#15 » Thu Oct 04, 2012 7:24 am

Yeah, I think it should have been much lower. On the opposite side of the model there's a lot of extra material that cured due to the light shining through, plus again it was pretty well cured. I'm going to do another test again later once I get home, try to get it to 15 microns.

UGUSILVA
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Post#16 » Fri Oct 05, 2012 1:19 pm

super nice... and thanks for the tips... that troubleshooting is quite handy...

Keep UP! ;)

Leonardo Meccia
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Post#17 » Fri Oct 05, 2012 2:25 pm

hi to all, especially to the great Mike, I was wondering what is the exposure time to solidify the resin to 50 microns? if i increase the brightness of the projector over 50 the exposure time decreases? if yes, how can I increase it before making all a "brick"? please respond with the number!
sorry for the crappy English but I do not know!
thanks!

darthviper107
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Post#18 » Fri Oct 05, 2012 2:51 pm

I did it at 10 but it should probably be at 5 or 6. At 10 the supports were cured more than they should have been, plus the light traveled through the back to cure additional resin on the opposite side.

I have to wait until I can replace the PDMS layer, but if I were to test again I would do 4 attachment layers at 20 seconds (4 solid layers) and then do the regular exposure time at 5 seconds.

For 25 micron prints you'll have to remove the sweeper after the the first few layers, like after the attachment layers. The sweeper pushes the resin back but the suction of the build table prevents the resin from flowing back under between the table and the vat. You can keep it on there initially so you can see the bottom of the vat and make sure the resin isn't sticking to the vat, but after that take it off otherwise you'll lose parts of your print.

dragnink
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Post#19 » Fri Oct 05, 2012 3:30 pm

Awesome results, I swear I can see wood grain on the handle of the gun on the latest one. Is that a model that's downloadable somewhere? I'm going to start playing with ideas for support structures over the next week and report back with my results, it would be great if the support structures could come to a point at the tops and still provide a good bed for the model to sit on, maybe make for easier removal with less blemishes on the print surface too? I was looking at Formlabs approach, the only shame is that on some prints.. it almost looks like as much resin is used for the support structures as the print itself. :)

darthviper107
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First Custom Print

Post#20 » Fri Oct 05, 2012 5:02 pm

That wood grain effect is actually the Z print layers, you can't feel them, and even if you run something across it you can't feel it. It's due to that the difference in angles is extremely low on that part of the surface which is why it shows up there. There's no visible layers anywhere else, even the X and Y resolution has no visible layers.

The model is one I created, I haven't put it up, it's still something that I'm working on improving.

The thing about the support material is that I'm pretty sure the support is separated so that it can be projected at a gray color, thereby reducing the amount of exposure for the supports and making them softer so they are easier to remove. It would be easiest to model the supports by hand to ensure proper placement and you could do things like you mentioned, I think a support with a rounded top that ends right below the print object would be ideal, and that could be easily modeled, but you wouldn't be able to set it up so that the supports would be printed as gray.

Really as far as the quality goes, it's far better than the Objet or Projet printers, the only issue is the support system and the build size. For me it's OK, since the stuff I want to print is small and super detailed, but it might happen someday that I want to print something bigger. The project I have planned is actually a pretty good size, but I'm pretty sure that I could break it down into logical pieces that would fit into the 50 micron build size and then assemble them afterwards.

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