There are too many cool things I’d like to build. A sand table is on that list.
Basically a XY mechanism with a controller, steppers, etc. But mounted under the bed… and with a magnet that drags a heavy ball-bearing about in a layer of sand.
Quite a few people have made them, I came across this a few years back:
The curious thing is that this is a single-path machine, the ‘tool’ cannot be ‘lifted’, conventional cnc path generators will generate bad results.
And so; there is a ‘NC’ path tool for sand-tables, Sandify.
It has been a fun project to work on. Bob Carmichael (bobnik) has been driving development recently. He deserves all the credit for the image imports.
Sand tables are one of those immediately recognizably interesting machines. I love how the art ends up so beautiful, and then gets completely destroyed. Like automated performance art, almost.
The tables Mark Rehort has made are incredible. They move super fast.
His might also be the biggest. But there is a new one from Sisyphus at University of Texas in Austin that might win:
If anyone is on the fence about building one, go for it. I bring mine to RMRRF and it is a crowd pleaser, for sure. Ryan from V1 brings his to Open Sauce and there were a few machines there, including a smaller DIY version from Crunch Labs.
Servomotors are the way to go if you have the budget for them. They are much smoother and quieter than steppers and can go a LOT faster if you want. I run most patterns at a relatively slow 100-300 mm/sec to preserve detail, and edge motion at 500-1000 mm/sec. That’s accomplished by running a post processer on pattern files that adds speed values to each line of the pattern file. It differentiates between edge motion and drawing motion and sets speeds accordingly.
Ill have to see if the new changes to Sandify have broken my dual speed post processor and update it if needed.
