I originally had this over in the "look what I made" subforum, but since it's corexy, it is probably of more interest over here.
I am working on a sand table project for the Milwaukee MakerFaire that will be held at the end of September. The table will be 1.9m x 1m so that's how big this mechanism is. I decided to use cables because I haven't done it before and this is a relatively forgiving application. Also using cables allowed me to maximize printed content (yes, me!) in the mechanism. I designed, printed, and tested a set of parts, didn't like the way it worked, so I redesigned it. It seems to be acceptable now, though I am still testing, and have yet to test it with any sand.
The mechanism consists of 2x motor mounts, 2x Y axis pulley blocks, 2x corner pulley blocks, and a magnet carriage. The X axis is a piece of 16 mm square aluminum tubing, and the Y axis uses the t-slots in the frame for guidance to avoid the expense of linear guides, etc.
Motor mount rev 2 (the first rev was the problem with the original design):
![motor%2Bmount%2Brev%2B2.jpg]( "motor%2Bmount%2Brev%2B2.jpg")
The original design used a simple drive pulley that the cable walked up and down and overlapped itself, making plinking noises as it moved and probably interfering with smooth motion, too. The rev 2 version in the photo uses outboard steering pulleys to guide the cable and prevent it from walking up and down the drive pulley and overlapping itself. No more plinking noises, but now the noises from the cheesy steel pulleys are bothering me.
Y axis pulley block:
![y%2Baxis%2Bbearing%2Bblock%2Brev%2B2.jpg]( "y%2Baxis%2Bbearing%2Bblock%2Brev%2B2.jpg")
The white piece is UHMW PE used as a bearing. It is cut to fit in the 10mm wide slot in the frame.
Corner pulley block:
![corner%2Bpulley%2Bblock%2Brev%2B2.jpg]( "corner%2Bpulley%2Bblock%2Brev%2B2.jpg")
The corner pulley blocks are mirror images of each other. I generated two stl files in CAD using the CAD mirror function, but you can use the mirror function in Cura to print the second block, too.
Magnet carriage:
![magnet%2Bcarriage%2Brev%2B2.jpg]( "magnet%2Bcarriage%2Brev%2B2.jpg")
The cable is 90 lb test dyneema fishing line, the magnet is 1" cube N52 neodymium (crazy strong), and the steel ball will probably be 15 mm in diameter, possibly larger.
I connected it to the smoothieboard I recently pulled from UMMD, added a couple homing switches, and ran some tests at much higher speeds than I will be able to use when the ball is pushing sand around.
Video here: [vimeo.com]
I am working on a sand table project for the Milwaukee MakerFaire that will be held at the end of September. The table will be 1.9m x 1m so that's how big this mechanism is. I decided to use cables because I haven't done it before and this is a relatively forgiving application. Also using cables allowed me to maximize printed content (yes, me!) in the mechanism. I designed, printed, and tested a set of parts, didn't like the way it worked, so I redesigned it. It seems to be acceptable now, though I am still testing, and have yet to test it with any sand.
The mechanism consists of 2x motor mounts, 2x Y axis pulley blocks, 2x corner pulley blocks, and a magnet carriage. The X axis is a piece of 16 mm square aluminum tubing, and the Y axis uses the t-slots in the frame for guidance to avoid the expense of linear guides, etc.
Motor mount rev 2 (the first rev was the problem with the original design):
The original design used a simple drive pulley that the cable walked up and down and overlapped itself, making plinking noises as it moved and probably interfering with smooth motion, too. The rev 2 version in the photo uses outboard steering pulleys to guide the cable and prevent it from walking up and down the drive pulley and overlapping itself. No more plinking noises, but now the noises from the cheesy steel pulleys are bothering me.
Y axis pulley block:
The white piece is UHMW PE used as a bearing. It is cut to fit in the 10mm wide slot in the frame.
Corner pulley block:
The corner pulley blocks are mirror images of each other. I generated two stl files in CAD using the CAD mirror function, but you can use the mirror function in Cura to print the second block, too.
Magnet carriage:
The cable is 90 lb test dyneema fishing line, the magnet is 1" cube N52 neodymium (crazy strong), and the steel ball will probably be 15 mm in diameter, possibly larger.
I connected it to the smoothieboard I recently pulled from UMMD, added a couple homing switches, and ran some tests at much higher speeds than I will be able to use when the ball is pushing sand around.
Video here: [vimeo.com]