3D Printed Models vs Itero Models

[Chad W Congo]

I am encountering a problem with itero. The 3D printed models come out different from the models from itero. We have angry doctors and now we just found out that itero is delaying sending out models 5-7 business days. Who can wait that long? We need a quick solution, but are really struggling. I've seen mention of something called GOM software, but have no understanding, unfortunately, of what that is or how it would solve my problem. I did google it, but I'm afraid that didn't help me much. I've been in the industry 30+ years and this is messing me up!

 

[Wainwright]

Are iTero models still being milled? I always thought that was super interesting.

Are you 3D printing iTeros model output or taking the raw scans and building them in 3Shape or ExoCAD?

GOM is just a surface analysis tool for comparing 3d geometry. Is accuracy the problem, the construction, or worse perception of the doc from iTero to 3D printed models...

 

[CoolHandLuke]

you'd use GOM to overlay two scans together, so you can visualize the difference between them. useful for seeing consistent patterns in wrong data - like seeing the contacts are tighter on one model than the other. or seeing deviations in curing.

visualizing the problem can be instrumental in communicating the problem to relevant parties.

 

[Wainwright]

Yeah. So you load the .stl file you printed (manufacturing file),scan the 3D printed model in your desktop scanner, load that file in and compare the two. Its pretty easy once you get the hang of it. If you get those two files I'd be happy to do it for you quickly and send you a report. If you'd like to try it send the files to wainwright(at)formlabs.com (didn't use @ because of the bots, those darn bots)

 

[Wainwright]

Did the analysis for @Chad W Congo . Very interesting... I'll let him share if he'd like to.

Small spoiler, its likely a bad print or printer...

 

[zero_zero]

Small spoiler, its likely a bad print or printer...

What else could it be

 

[Wainwright]

What else could it be

Model builder, perception of going from a milled to printed model, wrong case sent, incorrect shade taken so blames it on the model for remake. I could prob think of a few more : )

 

[LuthorCorp]

Having been going through multiple printers and testing it usually is an issue with the printer, for whatever reason getting consistency in prints for removeable dies ESPECIALLY is a nightmare. We have had prints come out flawlessly and literally do a carbon copy reprint, changing nothing and its a failure (Too loose, too tight... etc).

It baffles me.

 

[Wainwright]

Having been going through multiple printers and testing it usually is an issue with the printer, for whatever reason getting consistency in prints for removeable dies ESPECIALLY is a nightmare. We have had prints come out flawlessly and literally do a carbon copy reprint, changing nothing and its a failure (Too loose, too tight... etc).

It baffles me.

While there are many reasons one of the biggest is workflow consistency, which is why I made recently a restorative model guide that is absolutely step-by-step. I'm still working on the next version of it which will include implant models. Honestly some of the steps and best practices within can be applied to any 3D printer. If anyone is curious the downloadable PDF guide can be found here. Warning... its over a 100 pages.

 

[LuthorCorp]

While there are many reasons one of the biggest is workflow consistency, which is why I made recently a restorative model guide that is absolutely step-by-step. I'm still working on the next version of it which will include implant models. Honestly some of the steps and best practices within can be applied to any 3D printer. If anyone is curious the downloadable PDF guide can be found here. Warning... its over a 100 pages.

While I agree workflow consistency is an issue, what really grinds my gears is when I setup a print with the parameters I prefer, the print finishes and I test the model, looks good. Then I don't change a thing, I reprint from printer memory and boom failure. Ill print multiple of the same models are the build platform and get different results (This is more acceptable due to pixelization and build plate consistency).

Direct reprints should produce replicable results, as the only thing that changes could at the most drastic end of scenarios be environmental, but these are being operated on level surfaces in a lab not on a fishing boat during a storm.

 

[Wainwright]

While I agree workflow consistency is an issue, what really grinds my gears is when I setup a print with the parameters I prefer, the print finishes and I test the model, looks good. Then I don't change a thing, I reprint from printer memory and boom failure. Ill print multiple of the same models are the build platform and get different results (This is more acceptable due to pixelization and build plate consistency).

Direct reprints should produce replicable results, as the only thing that changes could at the most drastic end of scenarios be environmental, but these are being operated on level surfaces in a lab not on a fishing boat during a storm.

Well the failure makes no sense, that's a optics or tank problem.

My test block and the amazing "super lube" reallyyyy help make removable dies more consistent. Its in the guide, last section.

What kind of printer do you have?

 

[LuthorCorp]

Well the failure makes no sense, that's a optics or tank problem.

My test block and the amazing "super lube" reallyyyy help make removable dies more consistent. Its in the guide, last section.

What kind of printer do you have?

We are making the rounds, Eden, Form 2, Rapid Shape. We get close results and at this point I have taken apart these printers enough that I can become a service tech. I have made a few of my own calibration checks and objects, we get consistent enough results however as soon as we hit model and die it falls apart.

At this point I blame exocad because as a 3Shape user I must and our models are being made with that, but its the only link left that could be a reason.

We just make static models now instead with an extra die and a cutback model. works fine haha.

 

[Wainwright]

We are making the rounds, Eden, Form 2, Rapid Shape. We get close results and at this point I have taken apart these printers enough that I can become a service tech. I have made a few of my own calibration checks and objects, we get consistent enough results however as soon as we hit model and die it falls apart.

At this point I blame exocad because as a 3Shape user I must and our models are being made with that, but its the only link left that could be a reason.

We just make static models now instead with an extra die and a cutback model. works fine haha.

Its because fitment of dies with change with a variability of 20 to 40 microns. Its extremely difficult to nail. Honestly ExoCAD and 3Shape model builder could be so much better for 3D printing and reducing those variables. Two HUGE reasons why 3Shape is still superior to ExoCAD, while far from perfect, is consistent friction bar offset independent of die size (ExoCAD has friction in the socket holistically) and it has the ability to change offsets based on size of the abutment and angulation. We pretty much have that figured out but it is SO unintuitive its crazy.

Anyway, good chatting. I must close this tab to finish this weeks work up. THANKS @RileyS : ) : )

 

[JMN]

I wonder if the on board processing on each file by the printer has a baesian, monte carlo or other non-linear filter to decide whether to light a voxel or not and it is producing inconsistancies.

 

[JMN]

[...]

Anyway, good chatting. I must close this tab to finish this weeks work up. THANKS @RileyS : ) : )

I wish for days wehre the last task is 'closing a tab'.

 

[Wainwright]

I wonder if the on board processing on each file by the printer has a baesian, monte carlo or other non-linear filter to decide whether to light a voxel or not and it is producing inconsistancies.

How smart would it be if the nesting software go automatically understand the object and snap the appropriate pixel position? OKAY, really I need to stop

 

[Wainwright]

I wish for days wehre the last task is 'closing a tab'.

I just need to concentrate for another hour or two! haha

 

[LuthorCorp]

I wonder if the on board processing on each file by the printer has a baesian, monte carlo or other non-linear filter to decide whether to light a voxel or not and it is producing inconsistancies.

Who knows, the native software of the printer when constructing the build file could for some reason be holding on and tracking the laser differently from build to build. Or it could be some other weird thing that is proprietary to the machine and we cant figure out by testing.


I will say I think 3Shape square pin with friction bars is the way to go. FRICTION BARS. How does ExoCad not have this? Its so simple and it solves a lot of inconsistency just by erring on the side of slightly looser and adding friction bars. Its not a perfect solution but its close and at least workable.

 

[JMN]

How smart would it be if the nesting software go automatically understand the object and snap the appropriate pixel position? OKAY, really I need to stop

Let the printer position the object on voxel boundaries instead of where the tech puts it unless an override is slapped as we *want* a certina place for a specific reason.

Yours have a different issue though, one mitigated partiall on the 3 by using a gantry for one axis.

 

[bigj1972]

So much for "Going Digital"......where's my plaster knife?