Big Epoxy Granite machine, Which frame is better ?

[JAZZCNC]

Personally I think a structural skeleton with the intention of adding strength is wasted money as it could have negative effects long term and interfere with resonances which is the main reason for epoxy granite. If the skeleton is to hold mounting plates etc and was a minimal wireframe affair then that's slightly different.

Where I think most go wrong with Epoxy builds is not putting enough effort into the molds, I would Save the money for laser cut steel and put it into a better quality and strong mold which would hold mounting fixtures, etc and allow for good vibrating. This is how the Big boys do it.!

Regards the Moving gantry or fixed then from the 2 you show then I'd say the Moving is the better stronger option. The fixed Gantry model has too much overhang on the table and when cutting at the outer edges you'll get vibrations.

If you support the table better along its full width then the fixed Gantry is by far the stronger choice but not how you have it drawn.!

[EZELab]

Hi EZELab
Welcome to the forum.
I would like to point you to John McNamara's epoxy build( https://www.model-engineer.co.uk/for....asp?th=139042)

Thank you (:
I checked it a couple of days ago, It's a great build, and learned a lot from him
Actually, I searched the forum for any "epoxy granite" related topic and checked what others did with their builds


Seems like the word "Skeleton" made some miss understanding here.
I am not talking about a big chunk of steel inside, It will be a waste of money.
I meant by skeleton is like any other EG build, some steel embedded inside the pour to provide some stiffness and mounting plates for stuff will be bolted on. Nothing more.
Here's a quick sketch for what in my mind.


Something like this, a thick 10mm steel on front for mounting rails & other stuff, And some 4 mm steel support inside the pour.
Am I on the right track or not?

And about the overall process, It will be not easy, I Know!
I'll do my best in molding. My plan is cnc'ing the mold out of Melamine wood And lay them on an epoxy leveled flat floor.
I don't have any hopes to get the Mounting plates flat after pouring on a big size like this. The base will go to a big milling machine to get everything flat & Parallel. Which will be another challenge since the estimated weight of this base around 600~700 KG

I think I'll go with the fixed gantry design, I'll make the process easier than the other design

If you support the table better along its full width then the fixed Gantry is by far the stronger choice but not how you have it drawn.!

This was a fast drawing, And sure I'll make the table much more stable, Thank you.

If anyone has any more suggestions, tips, Please share it (:

Thank you All for helping