New Snowflake

[KAS]

So I wanted to test out a different Onyx mounting platform in hopes to reduce the warping when heating. Cut out of a HDPE cutting board from Wal-Mart. Added 6 threaded nutserts to the outside and 5 in the middle ring for a total of 17 with 12 binder clips spaced evenly.


How well does it work? It sits extremely flat and provides for a very equal mounting depth. but overall about the same as normal in regards to flexing during heatup. Wish the Onyx had mounting holes towards the center, maybe that would help?

[img]http://i482.photobucket.com/albums/rr18 ... 143902.jpg[/img]

[img]http://i482.photobucket.com/albums/rr18 ... 173924.jpg[/img]

[img]http://i482.photobucket.com/albums/rr18 ... 174512.jpg[/img]

[img]http://i482.photobucket.com/albums/rr18 ... 113146.jpg[/img]

[Jimustanguitar]

You can drill your own holes in the Onyx, as long as you're careful to stay away from the circuit traces. I drilled a new hole in mine that's off center for the thermistor. You could do that, and use the center hole for your center mounting point.

Looks like a nice mill/router setup. What is it?

[KAS]

Think it has enough space to countersink the screws? edit: I see what you saying, use the center hole for mounting. Was thinking drilling 5 holes about 5" from center, but I hate to mess it up.


It's a Shapeoko 3, spark fun edition.
[img]http://i482.photobucket.com/albums/rr18 ... 134220.jpg[/img]

[JFettig]

I'm planning on making a 3/8" build plate that mounts to my printer, rather than the snowflake mounting to the printer. I'll still use the snowflake as an insulator, but it shouldn't flex at all that way.

[KAS]

I'm planning on making a 3/8" build plate that mounts to my printer, rather than the snowflake mounting to the printer. I'll still use the snowflake as an insulator, but it shouldn't flex at all that way.

So you'll force the glass down over the Onyx? Will the Onyx float or still use the mounting screws?

My melamine snowflake was wrapped noticeably, was really hoping the new one mounted at multiple points would help.
It's a little better but still seeing .003-4" lift on the initial heat, but it only appears to be in the center.


I'm designing a new one that will hold the Onyx without the screws. Planning on using the clips to sandwich the onyx between the glass and snowflake. I'm thinking that will allow the PCB to expand without bowing.

[JFettig]

No glass, aluminum. Aluminum plate will mount to the base, onyx will bolt to it.

[mhackney]

If you want the plate to have even a remote chance to stay flat when heated [url=https://www.physicsforums.com/threads/t ... st-4460438

Reference https://www.physicsforums.com/threads/t ... sc.703648/]you must not over constrain mounting it at 6 locations[/url]! Where can the expansion/contraction go other than bowing the Onyx. The correct way to deal with it (and this is what I have done for several years without a problem) is mount at 3 locations with slots that allow for a little movement oriented towards the center of the plate. The hold down screws can apply enough force to keep the plate held down but loose enough to allow movement.

On my new MetalMax I'll be using 1/4" MIC6 with PEI and no glass. It will be mounted at 3 points wit the slots cut (and countersunk) in the MIC6 before the PEI is adhered so the top surface will be unbroken.