What is your recomendation for gantry sides

[masinecc]

So what should i use as selection for gantry top and gantry side in your calculator if i use 2 spaced 5mm plates and i use the welded frame(650mm lenght,160mm height) from steel profiles 40x20x3mm?

[routercnc]

The stiffness spreadsheet calculator is only for simple shapes. It will not calculate 2 spaced plates or a complex gantry shape. If you really want to do that then you will need to purchase some finite element analysis (FEA) software. In general this is not cheap.

In the spreadsheet all you can do is make some approximations:
Gantry sides - model an RHS section with 5mm wall thickness and the same overall outside dimensions as your gantry sides. Your design will be a little bit less stiff than this analysis because you have posts and gaps instead of continuous walls on the front and rear faces.

Gantry top - Run one analysis on a single RHS profile of 40x20x3, write down the numbers. Run another analysis on a single RHS profile of 160x20x3, write down the numbers. Your design will be somewhere between the 2 analysis results.

Do you actually want to explore theoretical designs, or do you just want guidance on proven designs? If you want to just get on with something which works then post up what you want to cut and you will get feedback and design improvements from the forum members.

Thanks

[masinecc]

For what cutting speed are the results i get with your calculator?

[routercnc]

The deflections are only based on generic cutting forces for each material, not any particular feed rate. Doing it this way allows you to make simple comparisons and see relative performance from different designs, and that is all the spreadsheet was design to do.

There is lots of information on the internet relating to feedrate, number of flutes, depth of cut and chip load but this was not the objective of the spreadsheet as chip load is a topic in itself.