need some help with sinusoidal movement of axis

I am trying to build a paddle to create waves in a water tank. I have built a linear drive with ballscrew and plastic nut, stainless steel bearing driven with a hybrid stepper and HSS86 leadshine type drive. Currently the max I can drive the motor is approx 4000 rpm with a UC300eth and bob. My original idea was to drive the one axis from the bob, using a circular G2 command sending the other axis not connected through the bob. I could maybe use a formula or vb code but not that savvy on these commands. Basically want to oscillate the axis or table around a zero position and have feedrate control and be able to cycle this in the smoothest possible manner for different radius. Any suggestions for the best method?

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Originally Posted by donkeyot

I am trying to build a paddle to create waves in a water tank. I have built a linear drive with ballscrew and plastic nut, stainless steel bearing driven with a hybrid stepper and HSS86 leadshine type drive. Currently the max I can drive the motor is approx 4000 rpm with a UC300eth and bob. My original idea was to drive the one axis from the bob, using a circular G2 command sending the other axis not connected through the bob. I could maybe use a formula or vb code but not that savvy on these commands. Basically want to oscillate the axis or table around a zero position and have feedrate control and be able to cycle this in the smoothest possible manner for different radius. Any suggestions for the best method?

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This sounds overcomplicated to me or I don't understand what you are trying to do. Why not just use a simple ordinary motor to do this? The motor shaft should drive the paddle up and down creating the waves. A speed regulator could be used to adjust the speed of the motor. I don't understand why use a stepper and a UC300ETH for this project, or how you plan driving the motor. The UC300ETH requires some software as well, like the Mach3 or UCCNC. With those you can write and run a macro, or run G code in a loop to do it, but it seems very complicated for this simple task.

A Scotch Yoke with the drive pin mounting point adjustable for radius, a variable speed drive for the motor, tachometer on the shaft of the Scotch Yoke.

That gives you variable amplitude from zero to the size limitation of the Scotch Yoke you build, with variable speeds from zero to things you could only dream of with steppers ;-)

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Originally Posted by magicniner

A Scotch Yoke with the drive pin mounting point adjustable for radius, a variable speed drive for the motor, tachometer on the shaft of the Scotch Yoke.

That gives you variable amplitude from zero to the size limitation of the Scotch Yoke you build, with variable speeds from zero to things you could only dream of with steppers ;-)

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Thanks for the replys I have tried the scotch yoke with pwm, and the mechanism was reasonable but couldn't cope with the rebound wave as it was stalling the motor. I wasn't strong enough to do it without stalling, and it was a seriously geared motor. I have a cnc and run mach3, the uc300eth was an upgrade for my setup and allows me to do a tidy setup, and run the hybrid stepper through the Bob. Quite impressed with the hybrid stepper and motor Nema 34.8Nm HSS86 getting 4500 rpm before it stalls. 2005 ballscrew with machined split nut made out of UHMWPE as chlorine won't affect it. Still see if it works if not I will have to try something else. More interested in Gcode options to drive it, as fast and smooth with cycles atm.

G code options -

There's a good list of CAM options here - http://www.machsupport.com/software/...-ons-for-mill/

Fusion 360 will do what you want and can be free but I'm not an Autodesk user.