MrB Posted October 19, 2017 Posted October 19, 2017 I've long since come to realize that i really shouldn't try some things for my self.At this point, i'm trying to pull things together for a star roller. I managed to get my "dream" roller barrel. It's probably going to end up being to small in the end, but i'm going to pretend not to be aware of that, and go for it regardless. It's a stainless steel cutie. Made from two IKEA bowls, welded to one and other, and then a shaft stuck to the one pole, and a hole taken up in the other. I still need to smooth over the "lip" IKEA puts on it to make sure people don't cut them self, planing on using some "liquid metal" for this. Anyway, the bowl is "blanda, blank" (Blanda means mix, and blank, sort of means shiny, i wont link it, since IKEA seems to keep defaulting back to swedish when i try to brows the site.) putting it at about 28cm along the welded seem.Something like 50-55 rpm's. I want it adjustable, so something like a motor controller, or a frequency convertor (Industrial Inverter?) coupled with a suitable motor, seems prudent. I could go with anything from direct drive, to gear reductions, and probably the cheapest alternative, belt drive solutions. This last part is easily enough sorted, it's "just" mechanics", but... i have NO idea what sort of power i need from the motor, not sure if i should go DC, or AC, and what to use as a speed controller. Since a few people around here build at least stuff with static rpm's there is clearly more knowledge here then i have, hence the question.Since i'm intending to buy stuff, it's pretty much a free for all, with suggestions, but i'm not going to use washing, drying, or windscreen wiper motors.Security demands a sealed unit, i suppose ideally a... TEFC, TENV, TEAO,(?) type unit.Similar requirements would be placed on the "motor control unit" what ever it turns out to be. Ideally that thing has something like a knob to turn, or up / down buttons, to control speed. Also, since i'm in Sweden, my wall voltage is 230v. I got 400v 3 phase in the workshop, but i'd rather stick to 230v single phase. It lets me be more free to select where to use the darn thing when i'm done. Admittedly, since i still haven't been able to get the budget for a Rebel 17, i do sort of hope to learn enough to be able to make similar choices later on, if i decide to build a new ball mill.At this point... Any suggestions would be appreciated.Thank you for your time and effort.
XMax Posted October 21, 2017 Posted October 21, 2017 I don't know what budget you got, or maybe I missed it, but I'm using a wiper motor witch is cloesed and work well for a long-time run. Cost about 70 kr at the junkyard.
Col Posted October 21, 2017 Posted October 21, 2017 Hi BIf it wasnt for the dream barrel, i`d suggest building a heavy duty mill base unit (TEFC motor etc) and just throwing a car tyre on it for rolling stars. I tailored the gearing to run the mill at 55rpm. The tyre runs on the same gearing at 24rpm (30.15 inch/sec) which is about the same as the 28cm dream barrel at 55rpm (31.75 inch/sec).
MrB Posted October 22, 2017 Author Posted October 22, 2017 I don't know what budget you got, or maybe I missed it, but I'm using a wiper motor witch is cloesed and work well for a long-time run. Cost about 70 kr at the junkyard. Not really an option i want to go with. I've burnt out a number of these at this point. Probably just bad luck, but these things hate me. Hi BIf it wasnt for the dream barrel, i`d suggest building a heavy duty mill base unit (TEFC motor etc) and just throwing a car tyre on it for rolling stars. I tailored the gearing to run the mill at 55rpm. The tyre runs on the same gearing at 24rpm (30.15 inch/sec) which is about the same as the 28cm dream barrel at 55rpm (31.75 inch/sec). That solution has advantages, and drawbacks. I've been using it, but i want the steel container to stop the "bouncing" action, and see if i cant turn out rounder stars. Not sure if it is the fact that the tyre isn't smooth inside, or if it is the "springiness" of the rubber that makes things bounce somewhat. Anyway, i'm hell bent on making something out of this welded thing, and see if i can make it work. Just need to figure out how to control the RPM of a reasonable motor. Gearing it to get the motor in to the right range isn't a problem, but controlling it at all, seams to be a rather large issue.Might end up trying something with brushless, sensorless motors, and a RC controller. But it cant be a "RC" motor, they aren't exactly made for continual use, so, not sure about that one either. Wheelchair motors, or mobility scooters perhaps?
chuckufarley Posted October 22, 2017 Posted October 22, 2017 Most of those wheelchair motors are brushed dc motors. You might find some brushless ones around but I don't know of any off hand. Alot of new cordless drills/drivers ate going brushless now days, maybe you can find a damaged one of those for the motor?
MrB Posted October 22, 2017 Author Posted October 22, 2017 Alot of new cordless drills/drivers ate going brushless now days, maybe you can find a damaged one of those for the motor? While these probably can be found, with reasonably good quality, they are not really rated for continual use. They could be an alternative, but...And as you said, a quick search on eBay turned up a lot of brushed wheelchair motors. They might still be an alternative, but brushless would be my first choice. Mobility scooters turned up a bit more brushless stuff, but i think i need to refine my searches more... 12v 60w, @ 170rpm, seems... a bit to much weak sauce. I think.
chuckufarley Posted October 22, 2017 Posted October 22, 2017 (edited) What about using a stepper motor? They are very easily controlled using an arduino, or similar controller. Not sure what kind of duty cycle theyre rated for, but might be something else to look into. Edited October 22, 2017 by chuckufarley
Col Posted October 22, 2017 Posted October 22, 2017 (edited) B, I use a brushed wheelchair motor (24v) on the tape slitter, its worm geared and virtually unstoppable. I use a Hankook brand tyre for rolling, its pretty smooth on the inside. I use Dunlop for milling Edited October 22, 2017 by Col
MrB Posted October 25, 2017 Author Posted October 25, 2017 Pretty much looks like i'll be giving up on brushless, and will be going with a brushed wheelchair, or mobility scooter motor.I might end up having to get a 24v PSU for it, but to start of, i intend to at least try running it on 12v, since it's a bit over the top for both torque, and rpm. 0.5-1HP at 3000rpm.Anyway, i decided to pick up something stupid simple, a PWM DC motor controller of eBay.Not my first choice, but these motors are at least made to last, even if they are brushed.The amount of rotating mass & gearing should make sure it has a smooth rotation, even if it is PWM...
chuckufarley Posted October 26, 2017 Posted October 26, 2017 Good luck B! If you can try and isolate the motor from any possible dust, keep it as clean as possible between runs. Let us know how it works out for you!
MrB Posted October 26, 2017 Author Posted October 26, 2017 At least these motors generally are "weather resistant", so pretty much anywhere from IP63 to IP66 rated. The main issue would be that most motors are "used" at best, (due to price restrictions, of course) and brushed motors have a tendency to, well, consume brushes in the long run. While they are rated for "continual use", they are typically not run for hours on end, and the heat tends to make the brushes wear faster.As a bonus, the load is lighter, which i suppose will offset it somewhat. I just wish i could find affordable 200'ish watt TEFC brushless motors, that wasn't originally designed for high-speed, short term operations, and needed the worlds fanciest speed controller.Oh well.
chuckufarley Posted October 27, 2017 Posted October 27, 2017 MrB, just suggestion, but maybe talk to Lloyd about rolling stars. I remember him posting numerous times about needing only to adjust the angle of the roller, and not the speed(assuming it within a certain range). I may be wrong but a constant speed with a variable drum angle might be a more viable, and simpler option.
Col Posted October 27, 2017 Posted October 27, 2017 B, If you go for the wheelchair motor/gearbox i`d look for a cheapish 0-30v, 0-5A variable bench power supply.
MrB Posted October 27, 2017 Author Posted October 27, 2017 B, If you go for the wheelchair motor/gearbox i`d look for a cheapish 0-30v, 0-5A variable bench power supply. I went with something like what i linked above, a PWM motor controller, and will (at least try to) power if of a PC PSU. If that doesn't work, i have a freaking huge 24v transformer (not a switched powersupply) i'll try, and only after that, would i try buying something dedicated as a bench supply. Mostly since i don't think 0-5A would manage the motors. I might be wrong. Being able to change the voltage rather then PWM the current, should make the motor run smoother, so it has advantages.
Col Posted October 27, 2017 Posted October 27, 2017 I think you`ll have plenty, mine only draws a couple of amps at best.
ExplosiveCoek Posted October 28, 2017 Posted October 28, 2017 Please take into account that the grip of these bowls is terrible. I have the same for my star roller drum. You'll need very large batches, or 'mass' of stars to get friction/rolling going on in these bowls. Therefore I always start with a smaller bucket inside the bowls . If the stars don't fit anymore in the bucket, I put the stars in the roller.It is ideal for making MCRH though. Those work like a charm. Impossible for making cores though. I already tried sanding, grinding and even pounding dents in there to create more friction. But nothing works.. Keep this in mind please, saves you some headaches. Even used 10# sand paper combined with 100# to finish it off. I made the star roller with changeable angle combined with frequency controller for the speed. Normally I have it roughly at 50 RPM from what I recall. Have to check though.
MrB Posted October 29, 2017 Author Posted October 29, 2017 Please take into account that the grip of these bowls is terrible. I have the same for my star roller drum. I've sort of been cheating, and sticking it in an household appliance, (kitchen aid, Ankarsrum N23) just to be able to make test runs, to figure out what sort of RPM's i need, what angles i want to be able to use, and so on. I haven't really had issues with low friction, but i think this might be due to the way i "smoothed out" the inside. I have a mate who does pretty much nothing but welds stainless... No, that isn't true. I have a friend who does pretty much nothing but walks the floor, while the paid slave labor welds stainless, and when he gets bored enough with that, he welds a bit him self. Anyway, i managed to persuade him to weld the bowls together, add a shaft on one end, and make a hole in the other. Ideally he was going to cut out the folded over lip on the inside, but he determined that the bowls were so thin he wanted the extra material when he welded it. Well, that is his story, i think he just forgot about removing the lip. So, now i had a lip on the inside, pretty much right where i expect the stars to roll. So i used a 2 component chemical metal, which i suspect to be pretty much an epoxy, and aluminum powder, filled the ridges between the lips, and outside them, and then set it to spin, and went at it with a lamel (?) sanding wheel. Took down most of the lips, and most of the chemical metal stuff, and perhaps most importantly, it made a lot of very fine scratches that are 90 degrees of from the welded seam. It might be what gives me traction, but denies you. If not, no idea.
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