View Full Version : Design check needed

10-13-2010, 02:35 PM
As stated in the topic, I just need a quick design check for the gear mesh system that I am planning on using for my Y axis sled. The image shows the intended air cylinders and the intended motion path for the meshing of the output pinion gear to the rack. The question is do you think this will work ok or would you recommend using a pivot type mesh system with only one air cylinder?

The reason for two air cylinders is that there isnít much room for one air cylinder and the needed pivot travel without changing (widening) the sled which I would prefer not to do just yet.

This machine is intended to be dual purpose, performing both CNC mill and CNC plasma operations. I understand that the required force for meshing the gears doesnít need to be too extreme for plasma however CNC milling will requires much more as the intended milling material will be 100% aluminum.

Any advice or recommendations based on experience are welcome.

I am still playing around with the design and considering other options as well regarding the Y axis. I plan in using rack and pinion for the X as it is 12í long. I have designed in a pivoting mesh gear for the X axis using a slightly larger air cylinder. For the Y axis I am also considering going with a ball screw but I am concerned about whip/vibration at higher speeds (looking for 250-300 ipm max) The Z axis will be a ball screw as it will only have 12Ē max travel.


10-15-2010, 05:58 PM
Interesting design, why are you using "air cylinders" to provide the pressure on the pinion?

Wouldn't a pair 35lb springs attached as shown accomplish this without the air cylinder option?

10-15-2010, 06:26 PM
If springs work, you could also use springs to "push" the same way that your air cylinders would. Also you could adjust the pressure on the springs by using a nut to increase the pressure. Good call on the spring idea.

10-16-2010, 08:42 PM
Springs would defiantly work and are still and option. As stated both a compression or tension springs could work in this app. I may play with the compression spring idea with and adjustment screw. One advantage of the air cylinders is the ability to increase and decrease the force of the cylinder thus increasing/decreasing the mesh pressure. Right now the mesh force needed is an unknown.

Thanks for the input! Keep is coming.