Wax patterns with open margins

[Hary]

Hi,
lately i started outsourcing my stl files to be milled in wax, I am getting open margins on the wax patterns but when I ask them to mill in PMMA the fit are perfect.
I know the milling center is using Roland to mill the wax is there something to be done to avoid this open margins.Thanks.

 

[pinkwilson]

I have waxed for years and sealing margins is critical. If the milling machine can go all the way to "perfect" margins in wax, wouldn't they be vulnerable to distortion during shipping? I think you would want to seal them yourself. If you are sending stl for bridges to avoid wax distortion, I think the PMMA would be a more suitable choice for shipped units. If you end up having to build up the margins, I think it would be too much work finishing it in metal. That's just my thought.

 

[Gru]

Parameters for different materials may be set differently. Have the milling center check them and adjust as needed.

 

[CoolHandLuke]

specifically the value "cement spacer" (if using 3shape)

this value is from the margin and up, yes, but it is also how high off the margin you go.

set it down to .01 or if using wax fully 0.000

 

[Hary]

Parameters for different materials may be set differently. Have the milling center check them and adjust as needed.

I don't know if its parameters problem its more like distortion problem. Do you think the speed of the spindle has to be lower for wax so it want distort?
Thanks Gru for your reply.

 

[Hary]

specifically the value "cement spacer" (if using 3shape)

this value is from the margin and up, yes, but it is also how high off the margin you go.

set it down to .01 or if using wax fully 0.000

I will try that. Thanks CoolHandLuke.

 

[Gru]

Maybe spindle speed matters, but I would still bet parameters. My pmma mills a bit tighter on my vhf mill, but my wax is dead on. to coolhand.

 

[CoolHandLuke]

well pmma naturally shrinks a bit, it doesnt surprise me that pmma fits tight.

however giving your design a zero tolerance margin needs a bit of explanation. no machine will be able to reproduce it unless it is a wide shoulder and large radius. any printed pattern will be instantly too tight. for printing its a whole other animal.

there are 3 curves at work here; let me show you from the settings themselves. in order to do that i need to take some screenshots from my terminal at work, so they will have to wait until tomorrow.