So John can I buy a replacement window should that become necessary?
hey, so I was looking at my model this morning and low and behold, those floating entities ARE in it!.. I just didnt notice them because of the way I had the part oriented and the level of zoom I had GAH! feeling silly at this point…Ill be correcting this soon, not sure if ill get a print going today but we shall see. Ive taken you mold advise to heart and im going to go back over my design as it clearly needs work and reconsideration.
im also looking at the split master idea itll take me a bit to digest all the details, but i get the general concept.
thank you for your help and advise.
ill let ya know what i come up with.
As @Ike wrote the issue is most likely with the galvo mirrors, which you have to access by removing the printer’s shroud (Formlabs has a PDF manual for cleaning these small mirrors). I wouldn’t worry about the optical window if it looks fine. I think Formlabs will sell you a new one though, but I have never had the need so not sure.
yeah ive not seen a parts list of what they are willing to sell, but i havent reall looked either.
again- if you look at the second model I posted- its a split master version of the half of the mold you posted- except I corrected the bad 1 and eliminated the fugitive geometry.
You can pour a silicone rubber on a print of that tool, and then the next day pour another- and then another.
The silicone molds will stand up to the chemical attack and exotherm of casting resins much better- and because the split master presents the die as a positive surface with engrave numerals, it will be much easier to polish the surfaces of the master… and that would result in every silicone mold you take off of it having a polished surface- and every part coming out with a polished surface.
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hey there
so i found and identified those weird “floaties” you pointed out…they were there all along I REALLY just missed them…
So I fixed that part of the model and removed those flaws “i found 2” I wasnt able to see what i will call the scratch…
I reprinted the fixed model and it still produced the same effect as before.
time to move on to split master i guess
Wait a minute-
Did you try printing the Corrected file I posted you a link to?
Or one you tried to correct?
If the file I fixed is not printing clean, and IKE was able to get your original file to print clean- then the fault is in your printer somewhere-
If the file you tried to print was the file you yourself tried to correct… then you may not have been able to fully correct the file.
Incoherent geometry can create all kinds of spurious data and clearly there is an issue exporting data from your modeling app.
It might be worth printing the Split master- though you will have to make the matching split master for the other side of the mold, too. But if the machine is still part of the problem, as IKE suggests, then you might not get the results you hope for.
The file that you just printed… was it the STL I provided? Which I know was flawless? Or the the version you tried to fix when you found the fugitive geometry in it?
one I tried to correct.
im totally going to try the split master… now that i go it downloaded, i can easily model that.
i wanted to try my file one more time just to see if it was ONLY the floating part of the file causing the issue or if there was more to it…this issue was has become a useful learing experince for me at this point.
Try printing the D20 corrected one I posted a link to.
Its a verified solid- without any fugitive geometry.
How well it prints might help Formlabs Support identify your printer’s issue.
The one thing about the split master is- because you will use it to produce rubber molds, the undercuts of the numerals do not matter.
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thats a good point about the undercuts… thanks… ill probably try it tomorrow. at this point im more interested in eliminating the possibility of any printer issues.
hey there, did you take this file off drop box? I got the split master file, but I cant seem to get the corrects d20.
last night i re tried printing my “corrected” file set to .05mm res…it was very close to what I wanted “numeral issues aside” the print itself was ok but not what i would call functional.
In an attpemt to determine if there are any further issues with the printer, i wanted to prnt your corrected d20 file in the interum im goin to try the split master file.
its really amazing how unseen spurious data creeps into a file like this. When i fixed the floating anamolies which I caused during a cut uperation and flat out missed in the final model I had hoped thisgs would work out. but I guess that other flaw you pointed out is still having an effect., from what I can see it looks perfect now. but clearly something else is wrong… the split master should be finished by late morning… will update with results.
Yeah, I figured you had downloaded it already…
here’s a new link
ok so here is the split master print! looks pretty much perfect…thanks allot for fixing the model!. this reassures me that its NOT my printer. I also attached what I printed last night to for comparrison purposes.
Now ill need to figure out how to detect those flaws you found “not the ones i left by mistake”
The print i did last night of the mold i made where i removed the floaters DID make a difference, but clearly there are still problems.
Any further suggestion on how to find these flaws would be appreciated.
thanks
The flaws can be impossible to find without a proper diagnostic software analysis.
The floaters were not the primary flaw- they were the render-able geometry left behind by a boolean or trim/stitch operation that resulted in non-solid geometry.
This might have resulted in duplicate points or polygons or line segments that perfectly coincide with other points, polygons or line segments.
Some of these bits of unconnected geometry or topology might be internal to the model… And most of these kinds of error will occur when you convert the file from a surface model to an STL model on export.
Something as silly as modeling in a space with a resolution of 0.0001 mm - but converting to or importing into a model space with a resolution of 0.001 mm can result in points in the modeling space being “Averaged” to the exact same coordinates… giving you two points in the same location, connected by line segments of zero length- either of which can give printers conniptions trying to figure out the shape of the object.
Just one polygon in a model that has its defining points connected in reverse direction creates a “hole” in a model that renders as a solid, but as far as the printer is concerned is a soap bubble with a wall thickness of zero.
Most of these errors are due to bad procedures or set up of a modeling space by modelers who do not understand solidity in 3D modeling, and therefore do not realize the kinds of things they might do that will violate solidity.
People who model in surface modeling apps like Solidworks, Maya, Rhino, or SubD apps like zBrush and Modo are far more prone to bad modeling technique, because the Apps themselves are designed to represent surfaces only and do not warn you when your model is not a solid. And so there is no pressure to learn what solid modeling is.
I can’t tell you how many jobs I’ve gotten where some really brilliant artist modeled a ZBrush figure with oodles of delicious detail… and the file gets handed to me because the artist did not make a model that could be realized as a solid object. ( a LOT of digital modeling if for CGI animation… or games… and does not NEED to be a solid- it just has to render nicely.)
Apps Like Meshmixer were largely originated as a tool for resolving the many different kinds of meshes produced by the many different types of modeling apps out there.
Preform itself has an import function meant to detect and correct many kinds of non-solid geometry- but it can not handle every possible combination of errors that modeling apps can produce…
And even though I run an app that ONLY can produce a perfect STL solid… Preform often claims that a model I import is broken… even though it is a perfect qualified solid.
The easiest solution is to spend the money to buy an app that models in voxels and can not export an STL that is not perfect… Like Freeform or its less costly cousin Sculpt from 3D Systems.
Failing that, the second best option is to use a modeling app that has solid modeling features, diagnostics and repair features such as Form Z.
And, of course, its better to read up on how Topology differs from Geometry and how the two have to be configured to achieve solid geometry.
For example- Imagine 8 points in space in the configuration of the apexes of a Cube.
That is the geometry of the model.
But HOW are those 8 points connected to each other? If each is connected in straight line segments defining the vertices of a cube- then you have a solid model of a cube.
However, if one of those corner points is connected to the diagonal opposite corner point thru the center of the cube… that can not describe a cube… can it? Those specific order of connections are the Topology of the model, and they must be in a very specific order for the computer to be able to understand the geometry as a solid cube.
In subD modelers you use 4 point geometry- meaning every polygon is supposed to have four points.
However- if One of those 4 points gets moved out of plane to the other three… then that polygon is NOT a flat plane anymore… and it will often render with a triangular ‘hole’ in the polygon. This violates solidity…
and, of course, STL conversion seeks to bisect every 4 point polygon into two triangular polygons because 3 points ALWAYS define a flat plane.
Yet- if one of those triangles is connect in the reverse direction to all the others, then its a hole into the model and it can not be a solid.
Some of these simple things Preform can correct for. Sometimes, in trying to correct bad geometry, Preform itself can create unprintable geometry… without being able to ‘recognize’ that the model its is displaying is a Ghost the Form 2 can not print.
3D modeling has become popularized… lots of folks get into it with no real training or background in how it works- they rely on software engineers to come out with apps that correct their mistakes without their even having to be aware there was one. And so those modelers do not improve in their technique.
There is no substitute for competence. And in the world of 3D printing… for every failed print that is the fault of the printer or its materials… there are 50 that are the fault of bad geometry in the model.
PS- you will note that in that split master print one of your separation planes is really ripply.
That is an artifact of that plane being very close to parallel to the build platform.
You will get a much better result if you angle the model such that the separation plane is inclined to the platform by at least 45 degrees. ( in the direction the angled faces are running so that ALL the separation planes are at around 45 degrees )
Because this is a split master- you do not need to use the costly high temp resin, and would be better served by an opaque resin like the grey- or the dental model resin so that you can better ‘read’ the surface of the model for finishing prior to pulling silicone molds from it.
Ideally- you want to orient the split master to maximize accuracy of the separation plane- you are less concerned with printing artifacts on the facets of the die.
the reason is because the separation planes of both sides of a split master need to Match and so you want to avoid at all costs having to retouch or alter the separation planes in any way. The surface of the model, however, you intend to polish and refine anyway…
so the printing angle that gets you the most accurate separation plane may well leave ripples or other artifacts on some of the angled planes of the die- but those are surface you plan to refinish anyway.
Ideally- You should create the opposite split master for the other half- and create some additional registration feature on your existing separation plane because the plane you modeled registers to two halves in ONE direction… but they can still slide relative to each other in the direction those angles run.
You will need to keep the CAVITY lined up in both X and Y and the existing planes only give you X.
And one last thing. I made that model as a demonstration from the file you provided. In addition to adding another registration feature… You can eliminate the Ejector port and have that face in the model.
And you should re-position your Gates ( the entry point of the resin you will be casting ) so that you introduce resin at the lowest point in the cavity-( As the mold will stand during casting ) with vents at the highest points… when you are not using an injection press, you need to consider that you are Not filling an empty mold with resin, you are pouring resin into a mold that is Already Filled, with Air.
Plan for the resin you pour or syringe into the mold to flow into the cavity at the bottom, and sweep the air up and out of the cavity ahead of the resin. This will result in better and more consistent castings.
Thanks for all the advise, I’ll need to reread this afew times to pick out all the details. I mainly work in solid works “because it’s what I have for machine design, solid modeling is clearly a side function” you make a strong case for some solid modeling software. Incidentally, for fun I ran that corrupted stl file through meshlab and freecad just to see what it would find. Both did find correctable errors, but they didn’t dlfind that “scratch” flaw in the face. I’m printing that corrected geometry mold.file just to see the results, I’ll have to redraw the whole thing to fix the numeral spacing. Thanks again. I’ll update when I have more results
Hi
Had some interesting results today, this pic is of the print I did last night from corrected geometry model you sent me.
It definatly came out better that anything Ive made, but still isnt useable, perhaps there are still some issues with the printer?
well that is not good. It should have printed perfectly… and again- the flaw is confined to the interior of the faceted cavity.
This is clear evidence that something is awry with your printer- Or it might be positional… that is, you appear to have the narrow hole at the top- closest to the build platform- so the facets are angling out as each layer is added. This might be resin clinging to the underside of these angled facets and getting cured by a laser spot that is not tightly focused due to some issue with optics.
If you haven’t opened a ticket with support, Do so and send them this and other pictures of the flaw.
I would tend to orient a model like this at a steeper angle… but this is a really strange and persistent flaw.
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It sure is persistent, I’m in a bit of a pickle as far as angle orientation. If I set it too steep I end up with supports either in the mold cavity or the pin channel “even if I abandon this design, I think it should be printable”. So it’s a balance. I did open a ticket a while back and NEVER heard anything from form labs, we never purchased the pro service plan, I guess you get what you pay for. I had allot of success printing this design in flexible resin, the only real difference is the hole in the mold. I gave some thought about workspace setup and it occurred to me that I did all my designs at home on an older version of solid works than what I use at work where I print the molds. I did some work on the design at work “on my lunch break” using the new version of SW on the same file, AND I never checked to see if the files tolerance settings were the same… I would think they should be but I don’t know for sure. I’ll have to look into that as well. Do you have any opinions on meshmixer and it’s stl/ solid model analysis tools? I plan on getting sculpt or freeform but meshmixer is an interim step.