ATC module for ER20 spindles

I have done some more digging and since it is a DC motor, you will have completely different torque curve, with some significant torque available from the start. Theoretically many times higher to what I can get on my 2.2kw spindle at very low RPM, assuming your spindle DC power supply can handle it, it might actually work!

You would need to sort out the manual speed control and the reverse operation, but other than that, it should work.

Thanks for the extra information Daz. If the motor could generate the torque it would need a very different controller, the current one is KBE thermistor type. Something that would generate stall current at low volts would be needed, and anyway as it's a PM motor it might be field limited. Also the height would severely restrict me and my table is only 125mm wide! Shame it's a very nice concept.

That's as cool as a Hippy Penguin's Jesus Sandals!

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Originally Posted by JohnHaine

Thanks for the extra information Daz. If the motor could generate the torque it would need a very different controller, the current one is KBE thermistor type. Something that would generate stall current at low volts would be needed, and anyway as it's a PM motor it might be field limited. Also the height would severely restrict me and my table is only 125mm wide! Shame it's a very nice concept.

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The whole point of an Impact Driver Mechanism is that it isn't reliant on motor torque, it releases the drive in response to pre-settable torque demand, allowing the spindle to accelerate, it then uses spindle system angular momentum against a braking mass to apply the required torque, repeatedly.

Very cool!

Cant wait to see your first cassette of tooling in play and in production :thumsup:

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Originally Posted by Lee Roberts

Very cool!

Cant wait to see your first cassette of tooling in play and in production :thumsup:

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Here is my first job using the ATC modules. The cover needs some improvements to keep the collets clean.

https://youtu.be/FH3Ue6h8MHE?si=oE4Sxmk5fvD7b8i3

That is Totally Ace!

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Originally Posted by magicniner

The whole point of an Impact Driver Mechanism is that it isn't reliant on motor torque, it releases the drive in response to pre-settable torque demand, allowing the spindle to accelerate, it then uses spindle system angular momentum against a braking mass to apply the required torque, repeatedly.

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That's true when tightening but loosening is a different matter as the spindle will be stationary.

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Originally Posted by JohnHaine

That's true when tightening but loosening is a different matter as the spindle will be stationary.

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It is the same for tightening and loosening. The operating principle doesn't change. The average torque required to spin the module is low, but the impact torque resulting from the hammer hitting the anvil is high. The impact happens two times every full revolution. The impact torque depends mostly on the spindle RPM.

The main difference between tightening and loosening is that for loosening, the spindle needs to overcome the initial module resistance from the standstill. The resistance comes from the need to overcome the hammer return sprint in order to depres the hammer. Once the hammer is depressed, the anvil (top of the module) can slide over it and make the rotation.

Aha! Right, I didn't spot that in the video.