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General Mach Discussion / Re: What's your fastest feed rate for your mill/parallel port.
« on: January 12, 2012, 06:05:40 PM »
Mike,
You are missing basic concepts of motion (the motion profile in tuning) which is used by the controlling software to provide pulses to dowstream devices. Changing the Kernel Speed allows Mach to assume some pulsing is possible in Motor Tuning. The driver test confrims if the selected Kernel speed is usable.
Thus, higher is of no value if the axis "system" is not capable of using the pulses. Note that an axis is made up of both electronic and mechanical items and all of them are relative to each other.
Velocity is calculated or tested by trial to find the max velocity. It is a user defined input value in motor tuning. If calculated then one assumes a safety factor. If tested one again provides a safety factor. The value can be restricted if the steps per unit are high, but if the axis can provide for a great velocity
and the computer train output is proper, then usable velocity can be varied over some range. Since velocity is constant speed in time, the tuning will show you the IPM avialable based on input velocity and steps per unit. Just because the controller indicates a high IPM dosen't mean you can use it.
So velocity is related to other inputs. What velocity can be acquired by a axis system is based on the motor characteristics to provide power / rpm / speed to overcome the forces acting on the motion of the axis. The mechanical aspects can be used to change the rotational to linear motion to provide for a different end use velocity. So how fast you can constantly go is dependant on a number of related items.
Acceleration is different than velocity since it is defined as a time rate of change of velocity. It also can be calculated, tested to find, and is a user defined input value. What determines the acceleration is again defined by available power to overcome the forces acting on the axis. The forces are different in that greater power / force is required to accelerate to some velocity. You need to overcome the inertia ....resistance to a change in motion.
Same goes for decelerating.
What motion is available by others is totally irrelevant to YOUR machine unless you are comparing "apples to apples".
Just because you have changed the computer and increased only one part of a number of interelated factors may not necessarily give you a great
feed rate. It's all related and usually will require a compromise.
RICH
You are missing basic concepts of motion (the motion profile in tuning) which is used by the controlling software to provide pulses to dowstream devices. Changing the Kernel Speed allows Mach to assume some pulsing is possible in Motor Tuning. The driver test confrims if the selected Kernel speed is usable.
Thus, higher is of no value if the axis "system" is not capable of using the pulses. Note that an axis is made up of both electronic and mechanical items and all of them are relative to each other.
Velocity is calculated or tested by trial to find the max velocity. It is a user defined input value in motor tuning. If calculated then one assumes a safety factor. If tested one again provides a safety factor. The value can be restricted if the steps per unit are high, but if the axis can provide for a great velocity
and the computer train output is proper, then usable velocity can be varied over some range. Since velocity is constant speed in time, the tuning will show you the IPM avialable based on input velocity and steps per unit. Just because the controller indicates a high IPM dosen't mean you can use it.
So velocity is related to other inputs. What velocity can be acquired by a axis system is based on the motor characteristics to provide power / rpm / speed to overcome the forces acting on the motion of the axis. The mechanical aspects can be used to change the rotational to linear motion to provide for a different end use velocity. So how fast you can constantly go is dependant on a number of related items.
Acceleration is different than velocity since it is defined as a time rate of change of velocity. It also can be calculated, tested to find, and is a user defined input value. What determines the acceleration is again defined by available power to overcome the forces acting on the axis. The forces are different in that greater power / force is required to accelerate to some velocity. You need to overcome the inertia ....resistance to a change in motion.
Same goes for decelerating.
What motion is available by others is totally irrelevant to YOUR machine unless you are comparing "apples to apples".
Just because you have changed the computer and increased only one part of a number of interelated factors may not necessarily give you a great
feed rate. It's all related and usually will require a compromise.
RICH