Hello Misan,
What is the advantage of using a brushless DC motor instead of a stepper? Is it a cost reduction aim that you are looking for? Or is it size?
I have some time ago ordered a number of various hall chips to try and do what you do, so I am really interested in your work. My aim is size reduction and absolute position.
I would like to make a printer (coreXY type) but with only the hotend moving up and down in Z direction. I only need to move ~50 mm up and down. For this purpose I need a small, light and powerful motor with high step resolution and with absolute position because I need to compensates for the non-linearities in it's movement.
You can see a picture of my early design here:
[lh3.googleusercontent.com]
Actually my plan these days is to use it for a laser instead of a hotend at first. For this reason I really need high precision because the focal distance needs to be perfect to get smallest burn spot.
Unfortunately I have so far made zero progress besides buying some SS543-AT chips - For test and verification a 600 pulse optical encoder for calibration and test purpose. No motor selected yet.
About calibration - One solution is to use a lot of gears and let the motor run fast. The idea is that as long as we get the RPM right it does not matter if our sensor is reporting 10% too much or too little at some given degree in between because the error will be flattened out with the gears. We can also use cheap plastic gears running a shaft where we mount the magnet so that one rotation on the motor (running directly the printer) gives 10 rotation on our shaft with the magnet - Thus also flattening out the error.
What is the advantage of using a brushless DC motor instead of a stepper? Is it a cost reduction aim that you are looking for? Or is it size?
I have some time ago ordered a number of various hall chips to try and do what you do, so I am really interested in your work. My aim is size reduction and absolute position.
I would like to make a printer (coreXY type) but with only the hotend moving up and down in Z direction. I only need to move ~50 mm up and down. For this purpose I need a small, light and powerful motor with high step resolution and with absolute position because I need to compensates for the non-linearities in it's movement.
You can see a picture of my early design here:
[lh3.googleusercontent.com]
Actually my plan these days is to use it for a laser instead of a hotend at first. For this reason I really need high precision because the focal distance needs to be perfect to get smallest burn spot.
Unfortunately I have so far made zero progress besides buying some SS543-AT chips - For test and verification a 600 pulse optical encoder for calibration and test purpose. No motor selected yet.
About calibration - One solution is to use a lot of gears and let the motor run fast. The idea is that as long as we get the RPM right it does not matter if our sensor is reporting 10% too much or too little at some given degree in between because the error will be flattened out with the gears. We can also use cheap plastic gears running a shaft where we mount the magnet so that one rotation on the motor (running directly the printer) gives 10 rotation on our shaft with the magnet - Thus also flattening out the error.