'Otter'. Build log.

[Blazing Black Beard]

The 'Otter' CNC machine I am building is based on rigidity for harder materials for smaller jobs and versatility for larger jobs with softer materials.

I have collected a small amount of essential parts to build my machine. I will continue to post images as I progress the 3D design, procure more items for the build and as I make parts for the machine.

I am a beginner as the last workshop I was actively part of was about 25 years ago and plenty of skills have been lost over time since then. :-(

So here goes, any criticism is welcome to help improve my build.

Current parts list:

8x 100x50x3x1250 cold finished hollow section Strongbox 235 EN 10219:2006 grade S235JRH BSEN10204 2.2CERT

4x NEMA 23 3Nm 3Amp stepper motors

[s] 6x TB6600 micro-stepping drivers (2x redundant spares)[/s] Amazon lost them before delivery

Still to buy:

Bed plate
Linear rails and bearings
Ballscrews
Cable tray and chain
Stepper motor drivers
VFD
Motion control unit
Power supply unit
Workpiece coolant mister system
Cooling pump for spindle
ATC spindle
Vaccuum and compressed air cleaning system

Future upgrades:
Auto tool changer built with above Otter CNC

I'm currently researching Hiwin linear rails and bearings but they are hellishly expensive on the web sites I have found. I don't want to cheap-out on rails and bearings as I need a fair amount of accuracy and would like to machine harder materials, minimising vibration. Any help finding cheaper but still good quality linear rails and bearings would be welcome.

[s]I'm also not sure about the TB6600 stepper motor drivers as they seem fairly cheap and I have absolutely no idea what would be required of a more capable machine. They seem to cover the requirements of the NEMA 23 motors, with micro-stepping and current limiting. Are there any problems with these and if so are there better alternatives?[/s] Amazon failed to deliver and there are much better alternatives.

I've been messing around with GRBL but have not settled with a motion control solution yet. I am not familiar with GRBL's capabilities and could quite easily be encouraged to research a more established standard of motion control, as long as it's reasonably economical to implement. This appears to be the smallest challenge considering that the physical build will be much more demanding as far as calibration and physical tweaking are concerned.

I will be starting to build a frame for the table with the steel box section next weekend. I have zero welding skills so I'm considering drilling precision holes and using substantial bolts to fit brackets that will secure the frame both outside and inside. This should be just as good, if not better, than any weld for rigidity.

That's about it for now. Any comments and suggestions would be appreciated.

BBB