Requesting some feedback on steel frame design.

[Misc]

Hello everyone

I have been lurking here for more than a year and have finally decided it's time to start designing a machine of my own.
The machine is intended mostly for hobby use, cutting aluminium but also wood and maybe even a very slowly cut steel part. That being said I try not to have
any unrealistic expectations about accuracy or speed, but i do want to do the best i can within my means.

The machine is designed with these constrains in mind -

• My shop space is very small 5m² (54ft²), so a 100x70cm (40x28 inches) footprint in a corner is all I can reserve.
• In such a confined space dust and chips must be kept to a minimum, so an enclosure is a must.
• The x-axis must run along the short (70cm) axis or access to the machine will be too hindered. So the gantry
  will span be across the 100cm axis which is not desirable but sadly seems unavoidable.
• The shop has neighbors close by so noise should be kept down as much as possible - via enclosure.

This is a rough sketch of the frame. I decided that feedback was needed before moving on.




The tubing is 50x50mm 5mm wall thickness. I am contemplating 60x60x4mm or 70x70x3mm since I remember reading that deflection is related to cross section. Also a NEMA23 stepper motor is around 55mm wide and with a larger pipe it will sit "inside". To keep weight managable I lower the wall thickness as i increase crosssection.
The plates on the back and sides are there to add structural strength and to act as splashguard and enclosure. I have dimensioned this to a thickness of 4mm at the moment in hopes that this will make it less likely to bow and induce deflections in the tube when it is welded. I have not added bracing yet at i was hoping these plates would make up for it, but is this a reasonable thought?

On a whole i know that welding is going to distort everything, but i do feel that the strength is needed for my purposes.
I have not drawn the linear rails yet, but they go on top and will be leveled using the epoxy method.


Any feedback is appreciated.

/Misc