a Steel Box Section Build with SBR20 & Ballscrews Plus a few questions

[grain_r]

Thank you very much for the replies, I have been adding to the design of how I have made the frame, although I still have the horizontal cross members to put together.





Also wondering if anyone has used Fred from BST Automations own Linear rails ? or is Hiwin the way to go,

Thank you

[JAZZCNC]

Also wondering if anyone has used Fred from BST Automations own Linear rails ? or is Hiwin the way to go,

Yes, I use lots of them and they are good for the money, but they are not as good as Hi-win so don't expect Hi-win quality. That said they more than good enough for a serious Hobby level Router and if maintained properly will last for years and they are nearly half the price of Hi-wins so no one should expect them to match Hi-wins really.

If you're wanting the best Stiffness and working the machine hard in a production environment 10-12hrs per day 6 days a week then you should go with the Hi-wins.

Re the frames It's still a little weak on the bracing IMO, because the sides are so tall the short end diagonals don't extend far enough across the beam, same down the sides, this will allow the cross beams to flex as the sides apply a bending motion to them. You would be better with another lower cross beam with diagonal braces between them.
My first machine was built similar to this design but with short sides and it flexed at this point, I later braced it up as mentioned above and it was much stiffer.

If you don't need to pass material thru the machine I would also fit triangle plates to the ends to brace the sides. Those tall sides with spindly tubes are a massive weak link in this design, why such tall sides with such a short Z-axis.?