calibration for the design and initial leveling

[RonVais]

Think I've told you this in another thread but those tube thickness's are not a good choice, esp the 1.5mm.

Regards methods of leveling then if you don't have any way to check the rail plane then you'll be better using the epoxy method as it gives the best accuracy for a large machine without needing a reference surface.

However, If this is your first machine build then I suggest you exercise caution and research much more than you have already. Many people think it can't be anymore difficult to build a large machine as it would be a small machine but in practise this isn't the case. Every little error is magnified and if you haven't learnt the gotcha's on a small machine then they will bite you hard on a larger machine, many first time builders fail when they try to build large.

Hey JAZZCNC
Thanks for your replays it realy helps me yo get in the right direction with the build
As i wrote in the original post i want to do a simulation of that and realy understand the problem (may be i could dampen some spots and it will be enough?) But as you can see im still learning how to use fusion360 and havent yet made a normal model to simulate

As for deflections - as i wrote i tryed to use the calculator i mentioned above and in the ideal world the total deflation should be ok as far as i understand the results of the calculator

I assume by 50 you actually mean 5 mm (wall thickness)?
The calculator is correct for ideal conditions, perfect joints, and does not include vibration. So it is just a guide and great for comparing relative performance but real deflection will be a bit higher due to factors not included in the calculations.

Hey routercnc
I have been following you build and some posts you wrote and it taught me a lot !
Acutaly i meant 100mm hight and 50 width of the rectangular profile with wall of 3.2
That would be the largest stock profile that the stores around here hold

I was the guy who wrote up the "AVOR" design as mentioned earlier - which has proven to do a decent job for me even if it looks like a disaster area.

However, one of the main things I would change if I were doing it again (and I don't have plans to do that anytime soon) is to go up from 3mm wall thickness steel box to 5mm. When cutting harder materials especially there is a certain amount of resonance/vibration that you can feel as a buzz through the whole machine. May not be needed for strenght but just simple mass. There's a reason why commercial milling machines are made of cast iron - yes, rigidity is one reason but simple vibration damping is another.

I can only think that 1.5mm is going to ring like a bell!

Hey Neale
Thank for the replay !
As i wrote to CNCJAZZ i want to try and simulate everything and may be dampen the effect with
As far as i understand it should be a factor of beams length - or may be i could use soft connections at certain points

[JAZZCNC]

Hey JAZZCNC
Thanks for your replays it realy helps me yo get in the right direction with the build
As i wrote in the original post i want to do a simulation of that and realy understand the problem (may be i could dampen some spots and it will be enough?) But as you can see im still learning how to use fusion360 and havent yet made a normal model to simulate

As for deflections - as i wrote i tryed to use the calculator i mentioned above and in the ideal world the total deflation should be ok as far as i understand the results of the calculator

Ok then, I'll revise my last post and add this to it.!

If your building for the first time using only Simulation data and choose to ignore experienced advice then your SCREWED!!

You can't possibly simulate all the variables involved in building a machine even a small machine, ask anyone on here who's tried and gone to the trouble to simulate deflections, etc, they never work out as the model predicts. Multiple this x10 for a large machine then add a little more for safety and you might get some idea.

Then understand that getting anywhere near the predictions of the model requires every detail to be exactly like the model, just a small percentage change on any one will affect the result. Then, the finished result will be MASSIVELY influenced by the builder and His/Her Skills, mechanical experience, and ability with specialized measuring equipment and machinery.

Sorry to be so blunt in this next bit but I say this to save you BIG disappointment and Expense.!

You have NO experience, NO Machinery, NO Specialised measuring equipment and because of a lack of these things I'll assume limited skills in using any of them and seemingly choosing to ignore advice from experienced builders.!! . . . . Do I need to say more.!

Read my Tag line, it's very true.!