3dprintforums logo


Page 2 of 3 FirstFirst 123 LastLast
Results 13 to 24 of 32

Thread: balancing machine for turbine shaft!!!

  1. #13
    Registered
    Join Date
    Jan 2008
    Location
    USA
    Posts
    27
    Downloads
    0
    Uploads
    0
    I didn't think it was this simple. I hear quotes for 400 dollars to balance turbos but from the looks of this project I might try making my own. I usually just put a scribe on the nut and the compressor wheel and just cross my fingers and try to line it up.
    Wish that guy threw up some dimensions but the electronics are probably what I'd have more trouble with than anything, at least he put up a schematic.

    Edit: Insert Foot A into Mouth B. I found the drawings on the very next link I clicked.


    --Steve



  2. #14
    Registered
    Join Date
    Nov 2007
    Location
    SOUTH AFRICA
    Posts
    37
    Downloads
    0
    Uploads
    0
    Quote Originally Posted by fz1 View Post
    I see this guy made a balancer just for what you are wanting to do. I hope this might be of some help.

    http://www.technologie-entwicklung.d...cing_tool.html
    old thread but just in case someone is looking for those parts on that site. I have cnc machined 2 sets a long time ago so if anyone is in CT and interested just pm me, u can have them for free just come & collect.



  3. #15
    Registered
    Join Date
    Jan 2008
    Location
    USA
    Posts
    27
    Downloads
    0
    Uploads
    0
    What a coincidence! I am in CT!
    We are talking Connecticut, right? I see your location in your details reads South Africa.


    --Steve



  4. #16
    Registered
    Join Date
    Nov 2007
    Location
    SOUTH AFRICA
    Posts
    37
    Downloads
    0
    Uploads
    0
    Quote Originally Posted by Paraquat View Post
    What a coincidence! I am in CT!
    We are talking Connecticut, right? I see your location in your details reads South Africa.


    --Steve
    Hi Steve

    sorry no - I live in Cape Town (CT) South Africa.

    regards
    anilam



  5. #17
    Registered Khalid's Avatar
    Join Date
    Apr 2006
    Location
    Pakistan
    Posts
    3183
    Downloads
    0
    Uploads
    0
    Hi very interesting thread
    I am still in search of DIY solution to balancing.. But i will go with the Keyphasor and proximity tranducers way... If their is any body who can tell me what type of electronics following guys are using?
    www.precibalance.com/
    http://www.balancemaster.com/

    Regards

    http://free3dscans.blogspot.com/ http://my-woodcarving.blogspot.com/
    http://my-diysolarwind.blogspot.com/


  6. #18
    Registered Khalid's Avatar
    Join Date
    Apr 2006
    Location
    Pakistan
    Posts
    3183
    Downloads
    0
    Uploads
    0
    Hi Neil,
    I am really impressed to know you are expert in balancing.. Can you guide me making a 2-plane balancing machine... Actually we have CEMB Model WA-3000 that we want to convert into Digital balancing..
    Is it possible we can make a DIY arrangement?

    http://free3dscans.blogspot.com/ http://my-woodcarving.blogspot.com/
    http://my-diysolarwind.blogspot.com/


  7. #19
    Registered neilw20's Avatar
    Join Date
    Jun 2007
    Location
    Australia
    Posts
    3659
    Downloads
    0
    Uploads
    0

    Just get back to basics.

    Understand the principals.

    http://en.wikipedia.org/wiki/Balancing_machine

    The tricky part is is learning how to process low frequency signals with precision, and interpreting them.
    As for the balancing planes, it is a just like balancing CW and CCW moments on a beam, around the planes where the pickups are.
    You add the correct proportions of each signal, with each other to resolve plane(s) inside and/or outside the pickups, but all done with AC signals, just to make life a little more difficult.

    If you already have a machine, you are already a long way to making a digital machine. A PC is more than powerful enough, in real time to get excellent results, but this is not a trivial exercise. Search the web....

    Digitally there are quite a few techniques, and on the web you will find most of them.

    As for me, I wish I had the time to do some balancing programming, but that's another year. This one and the next is full.

    Neil

    Super X3. 3600rpm. Sheridan 6"x24" Lathe + more. Three ways to fix things: The right way, the other way, and maybe your way, which is possibly a faster wrong way.


  8. #20
    Registered Khalid's Avatar
    Join Date
    Apr 2006
    Location
    Pakistan
    Posts
    3183
    Downloads
    0
    Uploads
    0
    Hi Neil,
    Last year i have attended the course on "Machinery Diagnostics" conducted by GE energy at Florence. The practice session was carried out on SYSTEM1 of Bentley. I have studied a lot about vibration and balancing ... Single plane, Two planes and Multiple planes balancing----

    But the Bentley system is tremendously expensive, because it do much more than balancing ...

    So just came through BalanceMaster and saw their simple hardware and software specific to balancing... and... It really attracted me..but again the cost is high not for us the hobbiest

    Currently, for my own, i want to make a DIY simple system for balancing..This is to get more experience at my home..a kind of R &D..

    I have seen some applications that can get PHASE as well as 1X vibration using SOUND-CARD.. You can google "Virtual Oscilloscope using Sound-card" and you will find some free applications.

    Programming is not difficult for me... but i need to see some DIY stuff on balancing to make the reliable BASE

    http://free3dscans.blogspot.com/ http://my-woodcarving.blogspot.com/
    http://my-diysolarwind.blogspot.com/


  9. #21
    Registered
    Join Date
    Jun 2008
    Location
    Netherlands
    Posts
    2
    Downloads
    0
    Uploads
    0
    Hey guys,

    Let me first introduce myself. I'm Rik Hermsen, 22 y.o. student Elektrotechnics at university of Eindhoven (Holland). For the hobby I am building a MW54 turbine turboprop engine. To balance the shaft i build a balancer tool, and developped electronics for it. This last part, i'm still working on that. Here in Holland there are also serveral builders that were interested in the electronics.

    I have a website (in dutch, i'm sorry about that) were i post photo's of recent projects were i am working/worked on.

    You can find the website here!

    My way of balancing (at least i hope to do so) is by driving the shaft with a motor and an elastic cord. Then the electronics (microcontroller) measures the speed and regulates the shaft to a constant speed at frequency of the band pass filter. I am still working out the desing, so it's not finished yet. The hardware (i.e. balancer mechanics) is finished and has all sensors needed.

    On my website you cay also find pictures of the MW54 i'm building, as well as the building planns on that same page.

    Cheers,

    Rik



  10. #22
    Registered
    Join Date
    Jan 2006
    Location
    Australia
    Posts
    481
    Downloads
    0
    Uploads
    0
    would be nice to have one of these machines $$$$$$$$ High-speed turbo balancing machine [nomedia="http://www.youtube.com/watch?v=TMA5RFpGRbg"]YouTube - High-speed turbo balancing machine[/nomedia]



    Amazing with all that technology they still remove metal filings of rotating assembles being balanced and it mixes with the return oil lubrication system while the shaft assembly is being spun to operating speeds to be filtered.



  11. #23
    Registered neilw20's Avatar
    Join Date
    Jun 2007
    Location
    Australia
    Posts
    3659
    Downloads
    0
    Uploads
    0

    Cool It is now a digital world.

    Rik.

    Most of the noise comes from the drive system.
    The old analogue bandpass filter suffers a large phase shift for a small change in frequency. The phase gives you the position which once the Q is high enough to get rid of the noise, the angular error is significant.
    A small angular position, once the balance becomes finer becomes an error at close 90 degrees.

    Don't worry about speed regulation.
    Just spin it fast, release the drive belt and process on the spin down.

    You can use a Kalmen filter http://en.wikipedia.org/wiki/Kalman_filter to resolve signals at 0 and 90 degrees, say, call them X and Y.

    I reality you simply multiply the signal by plus/minus 1 at the correct times for 0 and 90 degrees, and save them, along with the current speed.

    sqrt(X^2 + Y^2) gives you the vector for each measuring plane.
    Multiply X and Y by 1/(speed squared), to get rid of the speed problem.

    Stuff all the vectors in and array for discrete speed steps, and process as percentiles, and throw out the wild values caused by silly resonances.
    You need 0 and 90 degrees signals optically from the shaft, and the signals for each measuring plane.


    For this to work it needs to be a high tune system where you measure the unbalance FORCES. Not deflection.
    Piezoelectric transducers against a large mass, work well.
    You can resolve the vector to the balancing plane(s) from the measuring planes by simple moments about the measuring points treating the shaft as a beam.

    Super X3. 3600rpm. Sheridan 6"x24" Lathe + more. Three ways to fix things: The right way, the other way, and maybe your way, which is possibly a faster wrong way.


  12. #24
    Registered
    Join Date
    Jun 2008
    Location
    Netherlands
    Posts
    2
    Downloads
    0
    Uploads
    0
    Hi Neil,

    Tnx for your reply.

    I tried to do build it in digital environment, but it introduced even more phase lag. The idea was to use a DSP, and implement a 100th order low pass FIR filter in it, convoluted with a delta pulse ( in order to get a band pass) and then multiply the samples with that filter. In this system the phase shift was not constant, so that was the big issue, and the reason why I got back to analog domain.

    The first thing I did was making the signals visible, so i can see all the frequencies present:

    picture1

    and then zoom in on the frequency of interest:
    picture2


    I measured the signal with an usb Handyscope, and plotted the signals with Matlab. This is the FFT at 7800rpm, where i got the best result.

    Then, i made a simulation of a band pass filter in LTspice
    picture
    I took as example a LT1363, and made a band pass filter with it at 130 Hz (i.e. 7800rpm). The red line is 1st order, de green one 2nd.

    Some people here in holland drive the shaft first with a compressor. Disadvantage is that u will always need a compressor. So that's why I thought to hold the turns stable, and make a band pass filter on that stable frequency.

    The method you described we here know as the least squares method, where you draw an optimal line trough points (correct?). The question i'd now like to ask is why you use this theory/method. Can you show some measurements and analysis you did? It looks very interesting, but also quite complex(). Do you have pictures of set-ups? I wonder why you use such a complex method, and what the information is you get (because that's not quite clear to me).

    Please let me know what u think, i could use some help

    Cheers,

    Rik

    p.s. turbinecrazy: If u like me to start me a new topic, please let me know. i don't want to "steal" your topic or something like that.

    Last edited by Rikkepic; 09-28-2010 at 06:26 PM.


Page 2 of 3 FirstFirst 123 LastLast

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


About CNCzone.com

    We are the largest and most active discussion forum from DIY CNC Machines to the Cad/Cam software to run them. The site is 100% free to join and use, so join today!

Follow us on

Facebook Dribbble RSS Feed