Dentmill sprue issues

[karabear]

When I place sprues in Dentmill, sometimes, despite their appropraite appearance in the graphics, the result is a sprue that extends down the entirety of the tooth's axial wall. So instead of having a sprue of normal diameter, I have to remove and redefine the entire side of a tooth.
Anyone know what I am doing wrong?

 

[Dentaleng]

Check horizon shading while defining the pins. Mark pins at the intersection of the two colours. This shading helps you identify the areas accessable by your milling tool from the occlusion and cervical side of your coping. Hence the pins should be marked at the horizon.

 

[Dentaleng]

If the horizon ends at the margin, try to mark the pins at some other area or mark it as low as possible near the margin.

 

[DMC]

You are using the wrong CAM. LOL

That's what you are doing wrong.

 

[CoolHandLuke]

this occurs with my Laserdenta CAM too. but i do not find anything actually wrong, because this helps keep some marginal integrity to thin coping walls and thin margin designs. i'm happy with it and i'd never want it to change.

 

[Dentaleng]

This happens to all, and its not CAM related and if you follow the method I have explained earlier, you would avoid it or minimise it. This method should be followed in all CAM unless you are doing 5 axis milling, which I believe no body would do.

 

[DMC]

Kara, can you post a screen shot of your spruing of some teeth.

I have no idea what horizon the Denteng is talking about.

I would imagine you are using tools with at least 16mm reach, and no matter where you place sprues, you should be able to mill up to and down to the sprues.

Kara has a 5-axis Roland BTW. Maybe she does use 5-axis on the external of crown? How do we know?

Never happened to me, with both the standard 3M CAM from OpenMind, or SUM3d.

 

[Dentaleng]

Scott, do you use 5axis on the external??

Design a cone with say 10 deg taper. Place the pin in the center of the cone and create the tool path. Check your tool path below and above the pin. Below the pin you will see a very vertical tool path and not following the cone design.
Horizon, in case of the said cone would be at the bottom edge of the cone.

 

[karabear]

Kara, can you post a screen shot of your spruing of some teeth.

I have no idea what horizon the Denteng is talking about.

I would imagine you are using tools with at least 16mm reach, and no matter where you place sprues, you should be able to mill up to and down to the sprues.

Kara has a 5-axis Roland BTW. Maybe she does use 5-axis on the external of crown? How do we know?

Never happened to me, with both the standard 3M CAM from OpenMind, or SUM3d.

As you wish...

 

[JohnWilson]

As you wish...

I see Kara's hairy palm, didn't your Mom tell you that would happen

 

[Dentaleng]

Kara, I think you got what I wanted to suggest.

 

[CoolHandLuke]

lol hairy palm...

if you are finding this kind of sprue to be a pain there is a simpler method than moving the sprue all the way to the margin.

try and tilt the crown or puck or holder, so that the facial (if you indeed must sprue it) contour sort of bows around. place the connector at the peak of the bow to have very minimal creation of those "under-sprues"

but i have found i cannot make that trick work for copings. only full contour.

 

[Dentaleng]

lol hairy palm...

if you are finding this kind of sprue to be a pain there is a simpler method than moving the sprue all the way to the margin.

try and tilt the crown or puck or holder, so that the facial (if you indeed must sprue it) contour sort of bows around. place the connector at the peak of the bow to have very minimal creation of those "under-sprues"

but i have found i cannot make that trick work for copings. only full contour.

Usually in copings, the margin area would have the largest perimeter than rest of the copings. Similar to a cone. Hence it will block access of the tool below the margin.
Horizon shading (you may call accessability shading) shows you the areas that can be accessed by a tool from the occlusion side as well as from the cervical side, so it acts as a guide on where to place the pins.
This shading changes as you tilt the part.

 

[karabear]

Kara, I think you got what I wanted to suggest.

Yes, thanks a lot! It worked great. (There is nothing about this in the manual except "turn on shading"....and?)

 

[karabear]

Looking forward to trying the new "Dentmill for Roland" update.

 

[Dentaleng]

It's great. You will love it.

 

[DMC]

"Height of Contour", I believe is the most common Dental term you guys are searching for.

I call it the "Equator" in laymans terms.

Kara, you want to sprue there....almost always.

Most substructures are going to have that at the lower 1/3 of unit. Full contour more towards the middle.

Never sprue Anteriors at the top-half of unit. It casts an un-millable "shadow" under it. (As you found out quickly)

 

[DMC]

Usually in copings, the margin area would have the largest perimeter than rest of the copings. Similar to a cone. Hence it will block access of the tool below the margin.
Horizon shading (you may call accessability shading) shows you the areas that can be accessed by a tool from the occlusion side as well as from the cervical side, so it acts as a guide on where to place the pins.
This shading changes as you tilt the part.

Why would the shading change as you tilt the part? Does the tool axis not also change when you tumble a part? The Roland uses the 4th/5th axis to reposition the part to tool, so now you are just in the exact same situation again, no? Otherwise, the tool would not be able to enagage areas inside and outside due to too many undercuts, right?

 

[Glenn Kennedy]

Looking forward to trying the new "Dentmill for Roland" update.

Roland DGA is hosting a webinar for the new DentMill for Roland CAM software this month. Click here to register online.

 

[Delcam Dental]

Looking forward to trying the new "Dentmill for Roland" update.

Hi Kara,

If have any questions about using DentMILL that you would like us to help out with please email us at:

[email protected]

or call

1-877-Delcam1

One of our engineers will be more than happy to assist you

Thanks

****en