[mazinkaiser]

where are you guys getting the microbrite media ???
it it the same as ceramic balls ?

[Unabiker]

After over a year of shaking and learning, I've developed some ideas for improvement on my vibratory finisher. When the drive pulley on my axle came apart a week ago, I decided now was the time for some upgrades.
I would often use a ratchet strap to restrict the movement of one side of the tube to help get the media to move in a cylindrical tumbling fashion. With this in mind, I got rid of the springs along one side and replaced them with an axle and bearing setup.



I think this setup offers several advantages over the old style in that it gets rid of the guides (and the noise they created) that were used to keep the tub centered over the base, it makes emptying the media from the tub very easy, and it allows for easy access to the drive axle and weights.
On the original design, the drive axle was located just off of center on the bottom of the tub. I moved the drive axle further outboard to increase the effect that the spinning weights will have in creating up and down motion, and to create a bit more space for my drain upgrade. I also shifted the drive pulley over a bit, and relocated the motor, again to make space for the drain. The motor was relocated closer to the tub pivot axles in order to decrease the side loads on the motor created by the tub's up and down movement.



For drains in the original version, I had been using 3 brass fittings that are threaded on one end with barbs on the other with 1/2" ID vinyl tube running to the puke tub. When the media is new, these worked ok. But as the media wears and gets smaller, it would get down into the fittings and plug up the drains. Then you would have to remove the drain lines and unplug the drains with a punch. As you can see in the pics, this makes quite a mess.
To improve this, I switched to a bath tub style drain. This drain has a metal plate with lots of tiny holes that should prevent the line being clogged by media. The larger diameter of the tubing also helps keep things moving along nicely.



My original barrel had started wearing away at the contact points and I wanted to change the drains. Instead of patching the old one, I splurged and spent $15 on a new barrel. A lot of the noise on the old design came from various parts of the rack smacking into the barrel. To help this area, I cut several strips of 3/8" plywood to act as shims between the rack and the barrel. The strips were slid into place, with a bead of liquid nails securing each strip to the next. The barrel is bolted to the rack using stainless steel hardware. I lucked out and found some oak trim pieces that were just the right shape to act as spacers between the rack and barrel at the bolting areas.
Here she is sitting in the sound resistant box ready for action.



The above changes all have helped increase the effeciency of the machine, as well as reduce the noise output by half. The cycle time is 20-30 minutes, depending on the shape of the objects. This load had 8 pieces and ran for 30 minutes. The number of parts varies depending on the shape of the parts. Some of my larger guards can only be run 4 at a time. I make a lot of 5" long x 7/16" rods and run them through hundreds at a time.



I'm in the process of trying different size pulleys on the motor to vary the speed of the axle. I've done one change so far, and it tells me faster is better.
I need to take some shots of my stuff before and after finishing, and after they come back from anodizing so you'll have an idea of the finish quality I'm getting.

[zoeper]

Bloody hell Unabiker, those are some serious counterweights you've got there. If you're getting any decent speed out of that motor your tub must just about be taking off! Then again, if it works and it works wel, way to go man!
What would you say your shaking frequency is at present?

[Unabiker]

The motor I'm using claims 1740 rpms at full boogie. Right now, I've got a 2.5" pulley on the motor and a 5.5" pulley on the axle. That should give me about 790 rpm at the axle shaft. Using the 3" pulley on the motor gives me about 950 rpm.
If it weren't securely bolted to the floor, it would walk around the shop at a fairly brisk pace.

[zoeper]

Unabiker
What is the amplitude of your vibrations, say at the non-hinged end of the drum? I am busy working on plans for my model and had fairly small amplitude but high Hz (more like 2 KHz+) in mind. Is there anyone out there who have one of these on a varispeed drive and took it all the way up in the speed range?

[Unabiker]

Currently, the amplitude is about .200". You can affect the amplitude by changing the speed of the axle or by playing with the weights on the axle.
More RPM's on the axle will result in a smaller amplitude at higher frequency. Increasing the weight on the axle will increase amplitude....it will also put more stress on the machine.

[ManuelMP]

Unabiker,
can you indicate to me as you are due to calculate the power of the means

excuse my English

Thanks

[Unabiker]

Unabiker,
can you indicate to me as you are due to calculate the power of the means

excuse my English

Thanks

I think you are asking how I calculated the size of the motor used. That was easy, as I used a surplus motor that I had laying around my shop.
The power requirement could be easily figured if you knew how much the tub and media weighed, the size of the desired amplitude, and the frequency of the shake. Using the amplitude and frequency, you can figure the amount of accleration of the tub. Multiplying that by the mass of the tub and media would give you a required force.

[ManuelMP]

I mean how I cancalculate the spring

Thanks

[Unabiker]

First, you need to esimate the weight of everything that will be supported by the springs. In my case, I needed to support aproximately 400lbs. My local hardware store had a variety of springs availabe with a 1" diameter, so that seemed like a good place to start. The softer springs had a rate of 40lbs/inch and the stiffer springs had a rate of 150lbs/inch. Using lower rate springs would yeild a larger amplitude, and the higher rate springs made for a smaller amplitude. I played around with it a little bit, and seemed to get better results using the higher rate springs coupled with a faster speed on the axle.

[Ted383]

Hello all. I own a small sheet metal shop in NC. I have used various vibratory tumblers over the years when I was punching a time clock.
The time has come to make one for my shop. I have secured two junk gas cylinders (free) from the local gas co. A 100# and 150#, one of these will be the tub. The 100#er is pictured below.
http://www.mantank.com/products/stee...ane/50-100.htm

A buddy will be giving me a 3HP 220V motor. I believe 1 HP would be fine but the 3 is free. I'll make the frame. The only thing I haven't sorted is the tub lining. One place I worked many yrs ago "painted" on some sort of urethane. I have not been able to find anything like that yet.

Nice work Unabiker. Thanks for sharing all the info.

BTW. Did you say your axle is 1"? Looks bigger. -ted


.

[mxtras]

The only thing I haven't sorted is the tub lining. One place I worked many yrs ago "painted" on some sort of urethane. I have not been able to find anything like that yet.

A spray in bed liner would be an effective option.

Scott

[mxtras]

I need to take some shots of my stuff before and after finishing, and after they come back from anodizing so you'll have an idea of the finish quality I'm getting.

Yes, you do!

Got any?

Scott

[Unabiker]

Finaly, here are some pics.....
This is a batch of radiator guards ready to come off of the machine. I'm cutting using an Onsrud single flute cutter at 17,500 rpm traveling at 85 ipm, using a water-based Cool Mist mister.



This is one of the pieces after bending. Edge finish is not terrible, but it does need some de-burring.



After about 30 minutes of swimming in the shaker. My goal is for an even finish with no harsh edges. With a full load of media in the tub, I do 6 of these pieces at a time.



Here is what they look like after anodizing.




Here are a couple shots of the guards mounted up on bikes, ready for crashing...





You can see all the different stuff I make at www.Unabiker.com

[mxtras]

Very nice products!

Scott

[buckie555]

excellent work - very impressive. I was wondering how you hold your parts down. It looks like double sided adhesive on chipboard or mdf. We do something similar with our sheet metal parts but find it a little time consuming and tricky to release them without bending the parts. Any tips? Also from your experience have you any recommendations as to which grades of aluminium anodise well?

Cheers,

Neil

[Unabiker]

My hold-down technique has evolved over the years.
In the beginning, I was spraying down the back side of the aluminum with 3M Super 77 adhesive and gluing it to the sacrificial board. Once everything was cut, I would heat up the aluminum with a torch, which would cause the spray adhesive to release. Then everything had to go into a parts washer. The results were acceptable, but the process was a pain in the ass, and it made my shop smell like a meth lab.
My current method involves no glue. I have a 3/4" MDF sacrificial board on the top of the machine held in place by 18 countersunk 1/4" bolts. This board gets surfaced as needed to maintain a +/- .007" flatness. I have to do this once or twice a week, depending on humidity fluctuations and the amount of stuff I'm running. This board gets replaced about every 3 or 4 months.
For the actual hold-down technique, first, I put 8 holes in the scrap areas in each 4'x4' section. After that, I run 3/4" drywall screws through those holes. These screws serve to keep the aluminum from moving around while cutting. I made a system that has (2) 2" steel tubes attached to the gantry that roll on either side of the cutting bit. These tubes are spring loaded to provide downward pressure on the aluminum. All of the parts are connected to the sheet by 3 or 4 .020" thick tabs per part. After each run, the parts are clipped off of the sheet with a pair of tin snips and the tabs are buzzed off on with a disk sander. All scrap, both sheet chunk scraps and chips are collected once a month and sold to a local metal recycling company. The proceeds normaly cover a month's worth of race entry fees and an occasional set of tires for the bike.
As far as aluminum that anodizes well...I cut all my parts from 6061-T4 and make my rods from 6061-T6. I think the grade of aluminum doesn't really matter much...it all anodizes fairly well, as long as it is not cast aluminum. For cast aluminum, powdercoating is the way to go.

[buckie555]

Thanks for the tips regarding the grades of aluminium. The roller idea to prevent the sheet from lifting while machining is interesting. Looking at the before and after anodizing photos the two finished ones look to have an even and flawless finish. Close up is the finish as good as it looks in the photos after just 30 mins of duburring? I ask because my application is a cosmetic one and I require as close to a flawless finish as possible. I'm seriously considering building something similar. At the moment we outsource to a vibratory polishing shop but the batch costs are quite high and it's a process I'd be happy to bring in house for quality control. They're also a vibratory machines and consumables supplier so I shouldn't have too much trouble obtaining media. Would it be possible for you to take a close up of the finished anodized part that shows the surface finish, if convenient of course.

Thanks once again,

Neil

[Ted383]

A spray in bed liner would be an effective option.

Scott

The purpose of the liner is to suppress noise and keep the parts from banging into the tub. I think bed liner would be too hard. Plus the inside of a tumbler is a pretty hash environment, I doubt it would hold up. -ted

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[300sniper]

interesting read!