DiY 50 bucks simplest balancing machine

[flyover1974]

Hi Guys,

here i will show you a very simple Balancing machine that balance at 5/1000 grams exactly.
This is a modified machine of what they use in germany to balance model turbine rotors that spins over 200.000 rpm and need accuracy balancing.
The building cost is from 0 to 50$, depending of what you have at home.
You need 2 aluminium pieces with min 8mm thickness and 25x25 cm side lenght. You can use steel as well.
Than 1 piece of 40x25cm for the ground plate.
You need 1 old/used/new 12" metal hand saw blade,
1 piezo buzzer,
1 steel rod 2-3mm
2 prismas (selfmade work well)
1 piece of teflon min 2mm thick and 8mm large and 16cm long or 4 pieces min 4 cm long,
1 small 12v motor that turns min. 1000rpm or/and a variable power supply to regulate turns.
1 long o ring diameter min. 10cm or out of old cassette recorder.
With the prisma and 2 pieces of the saw blade you build a swing.
The 25x25cm pieces you cut out a piece in the middle to form a U, 1-2cm larger than the prisma with saw blade.
Drill holes in both insides at top of U and with 2 pins hang in the swing.
At the bottom drill a hole in one side from the side and put in a spring out of a pen. At the opposite side drill a 3-4mm hole (depends of rod size you choose) and slide in the rod with 15 cm lenght.
Take a heavy piece of somewhat (old lead acid battery or a metal piece) in front of the rod and glue the piezo buzzer on it. The center of buzzer needs to point on the rod.
Inside of v from prismas glue or screw the teflon pieces to build a easy slide for the crank bearing. FIx the 12v motor right under a free piece of the crank shaftand put the O ring on it.
Connect a digital multimeter at the buzzer and set sensibility at 1 or 2 Volt.
When you now start the motor spinning the crank over the O ring, the unbalanced crank will make small side pressures on the prisma swing and the rod transmit this movements to the piezo buzzer. This one generate an electrical dc that you see on the multimeter. Somethimes it helps to invert the cables from buzzer due the electronic inside. This leads in more accuracy.
To find the point to add weight, you need to try.

For the next step that shows you where is the unbalance, you need a infrared reflex sensor that focus somwhere at 5-10mm and a oszilloscope with trigger possiblities.
Set a mark at the shaft and put the sensor over the shaft where is the mark.
The sensor holder base needs to be outside of the construkt but on zhe same base alinged with the spinning center. See picture 2.

Edit:
The spinning velocity is good from 300 to 1000 rpm

[flyover1974]

some changes:
you can use 3 pieces for the U if simpler for you and fo the ground plate you don`t need an aluminum plate. it can be some other material but not too light and soft.

i hope the building instructions are not too confused. if you need any help please let me know.
Hermann

[scottiniowa]

what is a long O ring?

[flyover1974]

Sorry , i meant a large O ring about 4 inch in diameter but i think its easier use a larger one because the motor to spin the crank its too close to the crank.
Found a nice german YouTube video that shows a very similar machine and the internet site of them it shows how to compute the oscillating and rotating weights to add at the crank for correct balancing results:


Edit:
This guy says, its enough to balance only with the additional rotating masses, dont need the oscillating as well.
Above in the start picture of the video you see very good the additional rotating mass at the rod bearing and the half moon oscillating mass  at the...dont remember the word.

[scottiniowa]

Hi Guys,

here i will show you a very simple Balancing machine that balance at 5/1000 grams exactly.
This is a modified machine of what they use in germany to balance model turbine rotors that spins over 200.000 rpm and need accuracy balancing.
The building cost is from 0 to 50$, depending of what you have at home.
 

For the next step that shows you where is the unbalance, you need a infrared reflex sensor that focus somwhere at 5-10mm and a oszilloscope with trigger possiblities.
Set a mark at the shaft and put the sensor over the shaft where is the mark.
The sensor holder base needs to be outside of the construkt but on zhe same base alinged with the spinning center. See picture 2.

Edit:
The spinning velocity is good from 300 to 1000 rpm

so maybe the O-ring is a V-belt?  
and to make use of the spinning part for $50, all you need is a infrared reflex sensor (focussing one) and a oszilloscope  that has trigger possibilities!  what do these things cost? 

[flyover1974]

Hello Mr. Scott,
The O ring is a small rubber belt.
For the whole balancing machine i mean the simple one without a oszilloscope for 50$.
But probably if some piece of build materials are in your work shop you can built is complete with oszi for 50$.
The infrared reflex sensor cny70 cost about 1$.
A oszilloscope from china like dso138 cost about 20$.
But in the simple version you dont need this 2 things.
Than the balancing machine dont show you where is the unbalance and you need to try to add somwhere weight and see if its better or not.
When its better, add more and see whats happening. When you find the right one, you remove this ammount on the opposite side.
This needs longer time to balance but the result is the same as with oszi and infrared trigger.

[macca]

would love a step by step instructions plus drawings and component placing on this   and a video on all of the construction every one of us here need to know how to do this even if it cost a hundred dollars to build how worthwhile would it be knowing your power plant runs as smooth as you can get it just not relying on a shop saying yep its good to go i am not electronic savvy but can build most things if i know how too ...checked out these parts mentioned on ebay and not a lot of money for the bits ..thank you for the post it has only wanted me want for more
Macca

[scottiniowa]

would love a step by step instructions plus drawings and component placing on this   and a video on all of the construction every one of us here need to know how to do this even if it cost a hundred dollars to build how worthwhile would it be knowing your power plant runs as smooth as you can get it just not relying on a shop saying yep its good to go i am not electronic savvy but can build most things if i know how too ...checked out these parts mentioned on ebay and not a lot of money for the bits ..thank you for the post it has only wanted me want for more
Macca

  I would draw this out in clear format, if I had some details.       Started to,  but  couldn’t figure out the jig-saw puzzle well enough to know if I was right or wrong on guessing how things would go together… Perhaps I was just getting lost in the translation…  So if details get cleared up more, I will draw and post these.

[macca]

Thanks Scott,
Thank also for your excellent  contributions to the forum, a lot of time is spent from yourself and all so many others as well to keep the information coming, time is so precious thank you very much for looking at this, And Flyover 1974 what a great bit of ingenuity you have provided us here on the forum please keep up the great work, bravo!  
Macca 
toofubartooften

[flyover1974]

Hi Guys,
It was a busy time and had no time to look at the forum.
First i need to say, its not my idea but a german guy invented it for balancing complete turbine rotors for model turbines. They spin from 20.000 rpm ro 250.000 rpm and a very accurate balancing is a must.
Here the link to the original site:
http://www.technik-tuefteler.de/motor/turbine/turbineauswuchten.htm
At the bottom there are links to pictures and function principles.
Scott,
Maybe that helps you to understand the principles.
To use that machine for our cranks,
It needs only to scale it bigger.
Btw. I ordered the 20$ oszilloscope, was a hundred pieces to solder, the resistances was the smallest one before smd types and impossible to read the ring codes, so it needs for every resistance to check it with a multimeter. But i was done in 3 hours and it worked at first power on
the piezo buzzer was of a electronic birthday wishes card and works great.

Now im in holidays for 2-3 weeks and probably can not make a video before.

Hermann