You are not logged in. Please login or register.
SoliForum - 3D Printing Community → XYZ Printing Hacks & Mods → Anybody heard of the mechaduino?
As the xyz 3D boxes are known for step skipping what about these?
The first application listed is for 3D printers.
The Kickstarter has closed (with multiple project goal surpassed), but they will put up a shopping site soon.
http://tropical-labs.com/index.php/mechaduino
The y motor's back is clear, but the most useful x axis motor is v close to the right side cartridge end part.
@pricecg44 - correct me if I'm wrong but none of the XYZ printers are using servos to drive filament or any of the axis (actually I don't know any FDM printer which utilises servos in that way)
This is very nice concept though if you need servos. But effectively it's a stepper controller to run regular widely available nema17/23 stepper motors as servos.
The mechaduino would attach on the end of the stepper motor. You remove the phase wires from the stepper and plug them into the mechaduino, from which wires go to the stepper.
You glue a magnet onto the end of the rotor. The mechaduino thus could read the stepper position and immediately correct any missed steps.
Thus we have an error correcting servo mechanism on the steppers, so you now have a printer that should stay true to the movement commands given. Current printers just are issue and hope. I see the posts, and experienced skipped steps being a problem with the smallish steppers and whatever driving circuits of the xyz boxes.
We have to wait for the guys to get setup and delivering their products via their linked website.
Correct me if I am wrong about this add on. I should query the guys on this possibility.
@pricecg44 - concept sounds great but...
Let's say your stepper skipped few steps and now it's 1/4 further then it suppose to be therefore didn't pushed enough filament through, let's say imaginative number 10mm.
So next step - compensation will kick in.
To compensate those 10mm of un-extruded filament we need to push those 10mm of filament forward, so rotate 1/4 of the revolution. Sounds right?
But... Servo compensation will work other way round. It'll detect that it is 1/4 further then it suppose to be and will compensate that by rotating 1/4 backwards so it is in the spot where it suppose to be.
That will result with 10mm filament retraction. So effectively this solution would make it even worse.
Instead of misextruded 10mm we now have 20mm.
I do hope all this makes sense.
Also, when extruder skipping happens that's not stepper motor skipping steps, hob bolt doesn't have a good grip etc so in theory there's nothin wrong with the stepper.
I'd swap XYZ extruder to any other aftermarket reliable extruder. Or if for some reason stepper itself is misbehaving, just get a decent motor and you are all good.
Yes for extruder, but I'm referring to Xy positioning were say 5hz of position gcode commands are actioned. So we are trying to do closed loop stepper step checking.
Whether this mechaduino pub motor rotor closed loop can be an add on, or needs to be integrated with the controller motherboard is my concern. I have posted to the tropical labs this guestion.
The z axis has always been ok. Y axis I don't know, but x axis seems to be the dimension that acts up.
So if hopefully, mechaduino is plug into the stepper phase wires. I will first put it on the y axis motor and see if it works, as in works as normal. When if ok, I need to figure out how it would fit onto the y axis slider cartridge, as the motor back end is up close to it. Likely we need to extend that end part.
SoliForum - 3D Printing Community → XYZ Printing Hacks & Mods → Anybody heard of the mechaduino?
Powered by PunBB, supported by Informer Technologies, Inc.
