Quick engineering question for a project I'm working on. I've spent at least 20 hours trying to figure this out on my own but I'm more confused than ever. I have a new respect for engineers now
I am building something that moves a component over an area 80 cm x 100 cm (pic related).
This is the belt (longer followed by shorter):
.080" (MXL) Pitch, 488 Teeth, 3/8" Wide Single Sided Neoprene Belt with Fiberglass Cords
.080" (MXL) Pitch, 390 Teeth, 3/8" Wide Single Sided Neoprene Belt with Fiberglass Cords
This is the pulley:
2.03 mm (MXL) Pitch,18 Teeth, 4mm Bore, 2 Flanges/With Hub, Aluminum Alloy Timing Pulley for 9.5mm Wide Belt
If I want ±0.1 mm accuracy, would a 0.72° resolution stepper motor suffice? 1.8°?
How much should I tension the belt?
>>8097323
Also... do those parts work? Or did I fuck that up also?
>>8097323
Shit, forgot to mention:
First belt is 39.04 inchs (pitch diameter)
second is 31.20 inches
>>8097323
pls provide links to documentation, I can't access any page
>>8097339
Of course
Larger belt:
http://shop.sdp-si.com/catalog/product/?id=A_6Z16-488037
Smaller belt:
http://shop.sdp-si.com/catalog/product/?id=A_6Z16-390037
Pulley:
http://shop.sdp-si.com/catalog/product/?id=A_6A16M018DF9504
Sorry if the pitch diameters are insufficient; I didn't know how much tension would play into it.
I am no engineer, but from what I can see using the simple perimeter formula s=r*theta, if you want a 0.1mm resolution, then 0.1 =(2.03+0.02)*theta, meaning you would need a 8.51e-4º resolution. You can probably use gears to change that, so you put a smaller gear in the motor connected to a bigger gear to reduce the angle made by it.
>>8097350
ok sorry I don't know any english terminology about belts, so I'll just explain to you what you need to know: a step of your motor will determine how your accuracy as you know.
Now what matters is the distance between the center of the motor and the exterior of the belt.
if the grooves of the belt (I think that's the name? or the teeth or whatever) are very deep, the distance between the motor and the exterior of the belt gets larger. Likewise, if your stepper motor has large teeth, the distance increases.
I think you can choose what to attach to your motor, so you can adapt it.
so if the distance between the center of the motor and the belt's exterior is R, and the motor has a step of [math] \Delta \theta [/math], and your wanted accuracy is [math]\Delta l [/math], then you need [math] \Delta \theta < \Delta l / R [/math]
If can get R = 1 cm, and you want an accuracy of 0.1mm, that would give you a step of 0.01rad, or 0.57°, and that's not accounting for a lot of stuff.
Keep in mind that you can always add a reduction if need be, with a loss of power of course. Don't forget that you are limited by your thickest belt if you use the same motor/reduction for both belts.
>>8097384
Ah, wonderful answer. Thank you very much.
Yes I was afraid I would have to use a reduction. But this makes things a lot clearer
Are you a mechanical engineer by chance?
>>8097395
not exactly, but I've had the opportunity to work with robots and even build one
>>8097402
That's actually even better.
Look, to be honest I'm behind on this project and I could use the help selecting parts. I'd be willing to compensate you for your time (with PayPal, or something similar).
Here's a temporary email I just made, if you're interested: [email protected]
>>8097423
kek
sorry I'm behind as well on some projects, I'm cramming right now
good luck anon, building a fucking autonomous robot was the hardest thing I did in my life.
>>8097432
Lol thanks man
Yeah I haven't even really started and it's getting... intense, let's just say
>>8097473
http://sdp-si.com/estore/centerdistancedesigner
Accuracy depends on how small each motor step can be. Once you know that, then you can convert that to linear distance on the edge of your pully.
Keep in mind you'll have to keep the belt tensioned and that will cause your shaft to deflect and your beatings will get loose over time. Going reverse will also has it challenges. I am assuming you are using an open control loops and verify the position of your component.
>>8097674
I may try to look at this when i am not on a mobile device.
>>8097323
what are you building? 3d printer or laser cutter?
