Exocad and undercuts

karabear

karabear

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I looked it up ExoWiki:

"Understanding the difference between output for milling and selective laser melting (SLM)

If your constructions are to be produced using selective laser melting (SLM, often incorrectly referred to as "laser sintering“),the output data must be a "watertight“ mesh with certain specific characteristics:
No holes or open edges; completely interconnected mesh; No inner surfaces or self-intersections

SLM.jpg SLM2.jpg

The figure above shows a sectional view of the junction between connector and pontic, with SLM optimization (left) and without SLM optimization (right).

For milling, it is not mandatory that these special requirements are met. The post-processing for SLM involves time-consuming calculations, which is why the SLM optimizations
slm3.JPG
(controlled by checkbox [5]) are only performed by default when a laser-melted material is selected in the DentalDB module.
If checkbox [5] is unchecked, resulting bridges cannot be produced using selective laser melting
If checkbox [5] is checked, the resulting output is still suitable for milling

*Even if not using laser melting for production, it is helpful to enable the optimization for laser melting, if you plan to perform additional freeforming on the finished construction. To switch on SLM optimization once you already have saved output files for milling, click "Remove existing merged parts“ [4], then "Restart Merging“ [2].
SLM.jpg SLM2.jpg slm3.JPG
 
NicelyMKV

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Exactly Kara;) if you try to manipulate your design after regular merging, you will notice the connectors are independent to the Pontic and copings within a bridge. The calculation for SLM takes about 5 seconds more on average with my system. Keeps from having any oddities within the design. For me anyway;)
 
DMC

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OK, I think we were saving the CAD scene, or something else like that then?

It was a long day and I did not have time to play. I was just thinking out loud, as if I were expecting a perfect file to print.

In a perfect world, it would also be flattened to 0 Z axis, with minimal overall height to reduce printing times.

We have tried saving stls a few different ways in exo and found a difference for sure. One or more ways changes the rotation of the file.

Maybe it exports in the original axis of the initial model, or something?? I'll find out....
 
karabear

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My results were no different with the latest software update. As someone previously suggested, I may have to set the angularity of the block-out. The default setting of blocking out undercuts with a 0 angularity seems to be tantamount to no block-out at all. (I was able to remove the undercut with a severe insertion axis, but it goes without saying that that's not a result of the "block-out" feature.)
this worked.png undercut gone.jpg
this worked.png undercut gone.jpg
 
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Himanshu Sheth

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I have noticed the same thing. My setting is also "0" by default, and I am getting undercuts. What setting did you decide upon?

View attachment 4662 View attachment 4661
View attachment 4661 View attachment 4662


Hi guys, I am new to this forum and late to Exocad as well.

This is an old thread and a rather late reply.


Option 1:

In Valleta, you can click expert mode and then right click on the tooth with a bubble in the poured cast, or an undercut and select "Free-Form Scan Data".

You can now use a set of tools to block out on the models or trim away a missed saliva streak. Tools identical to Free-Form pattern tool. Add/Remove and Smoothen.

Option 2:

As far as blocking out undercuts is concerned, using an angle of 6 to 7 degrees worked well for me. I print my patterns to press into Emax or cast in NiCr.
As a dentist we are taught to have a minimum taper angle of 6 degrees for a successful drawing of a pattern. I applied that parameter and it does help.


Set "Dont Blockout Zone near Prepline" to "0" to reduce postprocessing.

Option 1 is more predictable


I generally prefer to make adjustments to the resin patterns (adjust undercut areas) before investing.

Hope it helps.
 
Mike2

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I have a question as to how the smile creator works vs using the provisional module to create a Diagnostic presentation model for patient approval? We used to mock up a white plaster model and get it perfect with white wax. Do u have to have a picture for smile creator, or can u use a diagnostic set of models(preop),then modify and print? Thanks in advance!
 
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SuperTan

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Is there a way to measure how deep the undercuts are?
 

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