DIY vibration tumbler fan keeps failing - Page 1
Forum section: electronics / projects

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: August 16, 2019, 12:43:33 pm
content: So I've followed this YouTube tutorial to build a vibration tumbler:It works great until I have to replace the fan after a week or so of constant use. It's a slow process to remove rust from small parts but the intense vibration either causes the fans to burn, break a blade or come right offI've decided to forgo the usage of a fan and was looking for some kind of purpose built vibration motor that can withstands the stresses and forces the poor fans had to endure.Any ideas what I would need for this project? By trying not to spend 200$ on an actual vibration tumbler, I am finding myself getting closer in budget to what it would have cost me originally to just buy a real machine

author: ledtester
author_rank: Super Contributor
timestamp: August 16, 2019, 12:57:14 pm
content: As it happens I've just been watching videos on DIY vibration tumblers!Here's an idea which uses a DC motor with an offset weight - like how a pager vibrator works:https://youtu.be/lXknqxaYgPYDon't know what the longevity of such a design is... but at least you have more leeway in choosing your motor.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: August 16, 2019, 01:31:32 pm
content: That's a terrible design. Do it like the video above, but I'd use a more robust motor. Look at shooters brass "tumblers". We used to have a big expensive Sweeco vibratory at work and they provided a special grease to lube the bearings and a strict schedule on doing it. We didn't and that was the end of it. Pay attention to the location of the offset weight, the pivot point (the springs, sort of) and the mass to be vibrated. The less vibrating the motor does, the better, but the motor bearings always have to take the load.

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: August 16, 2019, 01:53:54 pm
content: Quote from: Conrad Hoffman on August 16, 2019, 01:31:32 pmI also think a heavy duty motor with a counterweight is a better way to go. Only issue is how big should I get it? Also, what RPM/torque specifications should I be looking for?

author: ledtester
author_rank: Super Contributor
timestamp: August 16, 2019, 03:14:58 pm
content: Here's an implementation using a vacuum cleaner motor:https://youtu.be/AJ6JOfOPQTQand one using a foot massager:https://youtu.be/Vm2n8Py2qLc

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: August 16, 2019, 05:38:40 pm
content: We had a small brass tumbler at work and the motor was 115 VAC, 60 Hz, 1/30 HP, 3000 RPM. Manufacturer was Fasco, p/n 71215777 with sealed ball bearings. The offset weight was steel, 15.8 mm diameter, 38.8 mm long, with the shaft hole drilled about 8.3 mm from the end. I think this was a 8 or 10 inch diameter bowl. That should give you a start.

author: james_s
author_rank: Super Contributor
timestamp: August 16, 2019, 07:53:55 pm
content: I made a vibrator for the hopper of my sandblasting cabinet after I had trouble keeping the sand flowing down into the bottom. I used a shaded pole motor salvaged from a junk microwave oven and attached an eccentric weight to the shaft. I've been using it for years without a problem.

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 17, 2019, 02:18:22 am
content: The industrial version uses a steel ball propelled around a track using compressed air. Not very efficient but hard to beat the durability.

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: August 17, 2019, 09:51:55 am
content: Quote from: NiHaoMike on August 17, 2019, 02:18:22 amSurely this would be the ideal solution except for having to run my air compressor 24/7. Imagine the noise and electrical consumption not to mention the wear on my poor machine.

author: TERRA Operative
author_rank: Super Contributor
timestamp: August 17, 2019, 01:45:26 pm
content: Quote from: drummerdimitri on August 16, 2019, 12:43:33 pmAre you using fans with ball bearings or sintered bushings? The bushings will fail quick smart when used like this...

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: August 17, 2019, 02:02:53 pm
content: Quote from: TERRA Operative on August 17, 2019, 01:45:26 pmThis is the fan I used last:https://www.aliexpress.com/item/32844553484.html?spm=a2g0s.12269583.0.0.775829e97C9mATHave spent around 40$ already on failed fans. This one is dual ball bearing how much better can it get?

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 17, 2019, 02:08:45 pm
content: Quote from: drummerdimitri on August 17, 2019, 09:51:55 amMaybe it could be possible to make the ball move using a magnet spun by a BLDC motor? It would decouple the motor bearings from the moving weight. Or perhaps the way to go would be an offset weight held by skateboard bearings with a flexible coupling or belt connecting it to a BLDC motor.Now I wonder if that ball could be moved with water or oil instead of air. Liquids compress by a negligible amount so no compression losses that make compressed air inefficient. And small pumps for water or oil are pretty cheap and don't need much power.I suppose a bass shaker might be another solution, not sure how much they would be needed to be derated to run 24/7. Cheapest might be a junk speaker with a little concrete or something to weigh it down.

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 17, 2019, 02:14:17 pm
content: It seems pretty obvious a fan with bearings and a motor designed for very low highly consistent loading isn't going to last when loaded irregularly with high peaks. It's about the worst motor to pick for this. The problem with these Youtube tutorials is that a large proportion are prototype builds done by people who have no idea what they're doing and who haven't tested or researched anything.