CNC building decision

[JAZZCNC]

I think you could get away with 1610 on the X axis as it is only 1500mm long (my X is 1600mm with slaved nema 23's) ..Clive

Not worth the risk IMO Clive as the performance difference is so little but the risk of Whip is greater. Actual difference in Screw Cost is minimal so why take risk of whip.!

Dinus take Boyan up on his Phone offer as it's much easier to build a Machine if you have a guiding hand from an experienced builder.
Boyan will learn you more in 30mins on Phone than months of searching the internet could. I do this all the time for people in UK and they all say the same thing that the call learnt them more than months searching forums and lifted much of the Mystery and Fog that affects new builders.

[Clive S]

I agree Dean it's not worth the risk for the small cost involved. ..Clive

[Dinius]

Hi, thanks for the replies...

Im going to call Silyavski this afternoon (Which I thank for the offer). Ill try to get much of the "Mystery and Fog" off my head and Ill give you feedback on my conclusions and "see" what you all think about them...

Cheers

[Boyan Silyavski]

Hi,
we spoke a couple of times with Javi and i promised to help the design. Instead of pointing the following in private email, i will say it here, so all should know to avoid making the same mistake / buying materials for frame without having the model.

Ok, so from the last email seems that the already bought material is the following, some is in Spanish but is clear that is the aluminum extrusion.:



Gecko G540


Hiwin:


- 2 HGR20 1500 mm (Link para archivo Cad)

- 2 HGR20 de 1076,2 mm

- 2 HGR20 de 400 mm

- 8 HGW20CA (Link para archivo Cad)

- 4 HGH20CA (Link para archivo Cad)

Perfiles: 2 x Perfil 45x90 Pesado tipo-B ran. 10 Mecanizado:2xM12 / 2xM12 Longitud:1500 mm 2 x Perfil 45x90 Pesado tipo-B ran. 10 Mecanizado:2xM12 / 2xM12 Longitud:1076.2 mm 3 x Perfil 45x45 Pesado tipo-B ran. 10 Longitud: 917m 12 x Escuadras de union para perfil 45.

So i sat down and made a sketch. Once i started drawing i saw what would happen at the end, but let me show the steps why.:




As its seen the 2x 45x90 1076mm profiles that were meant for gantry are not strong enough for a gantry, so one solution is to cut them to size and together with the 45x45 profile to form the table. Angle plates are not shown.

Now about that 45x45 profile extrusion = totally useless for a cnc build. I cant seem to find a use for them , not strong enough even for middle of the table, the only thing i see as possibility is to buy 6 meters of cheap steel 60x10mm and use that to reinforce all as shown in the photo below.




Now about the 45x90 aluminum extrusion and linear rails and ball screws. Lets do it the compact way. rails aside and ballscrews below. Grrrrrrr, not possible. not enough wide for both. So what. Linear rail up and ball screw aside, noooooo, it would eat the size of table and so travel will be limited...






So whats the conclusion. From all that aluminum extrusion a table can not be formed for the desired size and linear rails bought before.
Not a big deal cause i have other design in mind where the extrusion will serve for reinforcement and so, but not for the base structure.

I am working on my first more commercial cnc so i could change a bit the design and implement the extrusion. will soon show drawing where i do that to the exact size of his rails
Here is the general design. Thats the development from the other thread where i started designing small cnc that would be cheap and fast to put together. All is 20mm aluminum plate. So some of the plates could be exchanged for the existing profile.

[Jon.]

Hi There, I'm new here but ive just finished building a machine using 90x90 heavy profiles. You may find the pic helpful for inspiration.



https://youtu.be/txquIxeCVQY