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  1. #21
    Member deadlykitten's Avatar
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    Default Re: Diagonal Hobbing

    hello, i have looked over your code this is where X movements can be implemented :

    Code:
    (CUT PASS)
    OCUT
    SB=SRPM M14
    X=HSIF             ( X=X_start )
    G01 Z=ZSTA+ZCL1 F=FAPR G94
    G01 Y=YPOS*[[PIND/2]+[CUTD/2]-DDEP] F=FAPR G94
    G95
    F=FEED
    G01 Z=ZEND-ZCL2    ( X=X_end )
    G00 Y=YPOS*[[PIND/2]+[CUTD/2]+YAPR]
           Z=ZSTA+ZAPR ( X0 )
    M164
    M01
    RTS

    please, what is the purpose of this comment : (INTERRUPT SUBROUTINE) + (ACTIVATED BY YELLOW BUTTON) ?


    also there are many unnecessary movements that can be eliminated, etc, but i consider the ratio problem more important; once the ratio will be fixed, maybe i will rewrite that code ( for posterity's sake, etc )


    please excuse me for repeating : the ratio key is inside the tapered hob ( thus measuring it should provide an idea ); also these guys, i think, can provide an answer : M.T. S.r.l. – Produzione moduli rotanti

    kindly

    we are merely at the start of " Internet of Things / Industrial Revolution 4.0 " era : a mix of AI, plastics, human estrangement, powerful non-state actors ...


  2. #22
    Member deadlykitten's Avatar
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    Default Re: Diagonal Hobbing

    MS sync methods :
    ... flat turn : master spindle = S
    ... M556 : master spindle = M

    we are merely at the start of " Internet of Things / Industrial Revolution 4.0 " era : a mix of AI, plastics, human estrangement, powerful non-state actors ...


  3. #23
    Member deadlykitten's Avatar
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    Default Re: Diagonal Hobbing

    [ sugestion for measuring the hob taper angle ]

    hobe taper angle is represented in image 1 with blue lines; i need this value ( or data that can lead to this value ), so to provide a ratio, which i hope it will work i am not sure, but i think it will work ...

    the hobe itsself is a part; if we consider removing from it the geometry marked with yellow, the result is a conical end mill, capable only for side machining, and not for face machining

    i made the analogy between hob and end-mill so to make it easier to locate the needed geometry, etc ...



    image 2, drawing 1 : lets consider the hob slided on an arbor, until it hits a shoulder; this arbor is rotated directly by the M spindle ( i guess this is your real setup, or maybe close to it )

    image 2, drawing 2 :
    ... remove the hob from the arbor, without removing the arbor from the spindle
    ... check arbor tirr in 2 places, so to have an idea
    ... also make sure that the arbor axis is paralel to X axis ( adjust B head to be paralel with X axis )
    ... by B head, i mean that horse head that is inside the multus

    image 2, drawing 3 :
    ... when arbor is checked to be paralel to X axis, and arbor tirr is good, put the hob on the arbor
    ... the play between the arbor and the hob should be something arround tolerance=0.02; so to make it is possible to put in ( or take out ) the hob by hand, with normal effort, and without putting stress on the B head; the arbor should have a thread at the end, so after the hob is slided, just use a nut ( or a screw ) to secure it, not to fall down; this nut ( or screw ) should be torqued very light, only to secure the hob not to fall, thus there should not be used high torque, like when securing the tool against cutting forces; in this stage is not required to be used that thing that goes inside the zone marked in image 2b; in this stage the assamble should be tighten soft, with a gentle hand, not to be secured for cutting forces, but only enough not to fall apart when measuring
    ... check the tirr on the hob, just like on the arbor; the [ hob tirr ] should be close to [ arbor tirr ] + [ less than the play between arbor and hob ]

    image 2, drawing 4 :
    ... take a dial indicator with a magnetic base
    ... magnetic base on the chuck and dial on the hob
    ... in this stage it is important to avoid extra precision when using the dial, otherwise precious time will be lost
    ... please use this tips :
    ...... the angle between dial axis and a horizontal ( or Z axis ) can be 10 .. 15 degrees without worries
    ...... the dial axis is not required to be contained inside [ ZX ] plane; it can make 20 degress without worries
    ...... the dial axis is not required to intersect the hob centerline
    ...... the dial axis is not required to be perpendicular on the hob taper
    ......... in other words, is enough to make contact and just have a position which is subject to common sense
    ... for best results, from now on :
    ...... always rotate the hob in same sense; do not reverse sense
    ...... always feed the X axis from top to bottom, or viceversa; do not revere sense
    ......... sense reversing will lead to extra forces on the dial indicator, making it to lose precision
    ...... always make sure that the dial is armed at same value; i would recomand 0.3 - 0.5; if, for example, 0.43 is chosen, than never go over 0.43; if somehow 0.47 is reached, go back to 0.2, and after that back again towards 0.43 ( thus no dial reversing )
    ... rotate the hub to make sure that the heighest point is reached ( shown in image 3 )

    measure like this, along the taper, 4..6 points; dial should always show same value

    take a photo of the cnc screen, coresponding to each measurement, and send them to me if you wish, you may use a program that records axis position from the cnc and saves them to a file

    kindly

    we are merely at the start of " Internet of Things / Industrial Revolution 4.0 " era : a mix of AI, plastics, human estrangement, powerful non-state actors ...


  4. #24

    Default Re: Diagonal Hobbing

    You're on the right track and that is my hob/arbor setup, except that it is reversed... large end of hob is toward "top" of machine. the cutter will start into workpiece at full depth first then fade away in x positve and z negative movements. Mainly so the b horse head is moving up and away from chuck (other than z- move). i have to make this a safe dummy proof setup so i dont make things too hard on myself when i train the next operator on this job! But im years from that now... it will take some time to get your requested info. This machine hasn't sit idle since we got it in april. Thanks for the help and im amazed by the fast response! I think the hob angle u want is on the cutter but it doesn't hurt to double check i suppose.



  5. #25
    Member deadlykitten's Avatar
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    Default Re: Diagonal Hobbing

    large end of hob is toward "top" of machine
    hello corey cutting forces are :
    ... getting bigger ( or lower ) during the cutting, or
    ... are constant ( because depth decreases while cutting edge length increases )

    in all these cases, i think that is better to have the hob with the smaller diameter near the M spindle, so to have increased rigidity when finishing

    as i have seen from the program, the hob is under the part; if you wish to flip the hob on the arbor, than the hob must be above the part when cutting simply replace in your program YPOS=-1 with YPOS=+1 should work of course, real trials are required so to take a decision about hob orientation

    it will take some time to get your requested info. This machine hasn't sit idle since we got it in april
    15minutes should be more than enough time for measuring the hob inside the cnc i proposed this variant, because it provides data from the clamping position, thus measuring the tool where it will be used

    of course, tool may be measured also externally the cnc

    is good, from time to time, to run trials on the cnc / so to die smarter

    I think the hob angle u want is on the cutter but it doesn't hurt to double check i suppose
    i need the taper of the cutting edges; edges are disposed on a cone; the conicity of the tool

    in image 1 i represented the segments for 2 rows of teeth; each row of teeth has the cutting edges colinear, among a generator; all these generators are intersecting right at the top of the cone ( image 2 )

    i need the cone angle ( 2*alfa from image 3 )

    you may measure it inside another cnc, or just ask for this value from the tool provider ( hoping that is not a resseler, but the manufacturer of the tool )

    again : what i am doing with this hob story is not something that i have done before, so i hope it will work

    we are merely at the start of " Internet of Things / Industrial Revolution 4.0 " era : a mix of AI, plastics, human estrangement, powerful non-state actors ...


  6. #26

    Default Re: Diagonal Hobbing

    Quote Originally Posted by deadlykitten View Post

    please, what is the purpose of this comment : (INTERRUPT SUBROUTINE) + (ACTIVATED BY YELLOW BUTTON) ?
    It's for the big yellow Emergency Return button right above the "e-stop" button.... it makes the tool escape out of the cut if the operator doesnt like how something looks or sounds. But the "feed hold" button does the same thing during the hobbing cycle.


    Okuma made contact this morning so hopefully help is on the way.

    BTW, How can i tell if i have the flat turning option?



  7. #27
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    Default Re: Diagonal Hobbing

    hi, maybe your Okuma rep has a good application guy but diagonal hobbing is not common ...

    flat turning allows only this ratios : 1:n, where n=1,2,3...6; this function realizes the sync between S&M axis, but you allready have the M556 that is designed for hobing so ...

    however, if you are really interested to see if you have it, simply run a specific flat turning code, and, if you dont have it, an alarm about specs will occur / kindly

    we are merely at the start of " Internet of Things / Industrial Revolution 4.0 " era : a mix of AI, plastics, human estrangement, powerful non-state actors ...


  8. #28

    Default Re: Diagonal Hobbing

    It's been almost a full revolution around the sun and i have another order of these bastard parts coming up real soon... okuma was no help on this at all so im back doing more research and getting mentally prepared for frustration, anxiety and finally a victory when i present a good part to my boss. Has everyone brushed up on diagonal hobbing in the past year??



  9. #29
    Member deadlykitten's Avatar
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    Default Re: Diagonal Hobbing

    ooo, happy birthday corey far as i remember, there was a missing piece in that puzzle, which involved the tool angle ( cone angle )

    did you delivered those parts ? if so, simply run that program again ...

    otherwise, pls share drawing and tool photo, and i will try to help best as i can / kindly


    ps : 1year ? time is flying don't worry, i have never done diagonal hobbing; i imagine the required movements, try to calculate the ratios and code it ....

    we are merely at the start of " Internet of Things / Industrial Revolution 4.0 " era : a mix of AI, plastics, human estrangement, powerful non-state actors ...


  10. #30
    Member deadlykitten's Avatar
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    Default Re: Diagonal Hobbing

    hello i have been thinking about this : is required to "sync the rpms" and to "find the ratio for Y&Z axis"

    - syncing the rpms :
    ... n1 = live tool ( hob ) rpm
    ... n2 = part ( spindle ) rpm
    ...... n1 / n2 = hob_nr_of_teeth / part_nr_of_teeth ( should be something pretty close to this )

    - finding the ratio between Y&Z :
    ... if y is not moved, you should end up with a straigth gear
    ... inside the machine, you may measure a few points :
    ...... among the blue line in image 1 ( maybe for 2-3 different C angles ); from those points you may check how close you are to the value from image 2
    ...... among the yellow line in image 1, thus to compare the simetry of the right & left flank

    even if you measure the hob, in the end, you still have to measure the part, so maybe is better to measure only the part

    to shorten the trials time, don't cut the full gear from 1st time, thus don't cut until z2.484 is reached, but a smaller distance : on this smaller distance, measure, adjust, and recut





    one more thing : be sure that there is no play inside the live tool transmission, thus that the hob is cutting at constant rpm; if there is play, it may be possible to detect it by checking the rpm displayed inside "axis data menu - this menu has a higher display refresh rate" ( also a discontinuous sound may be there, etc ); if part does not has a nice surface rugosity, it may be because of the play : consider a light-finish final cut same for trials : light passes, so to end up with a nice smooth part, that should be easier to measure; if you go hard, and there is play and/or rigidity issues that are not taken into consideration, downtime & wtf moments will appear


    i would start easy, smooth, and when measurements are ok, i would increase the specs, or maybe rough+finish increasing the specs should deliver a part with increased surface rugosity, but all should be ok if dimensions are inside given tolerances, or part functionality is acceptable

    kindly

    ps : i am still woking on my teleport tower-sledge, otherwise i would be santa-claus, helping you find a good-part on monday morning; i am also digging tunels deep underground, but i have no clue where they end up ...

    we are merely at the start of " Internet of Things / Industrial Revolution 4.0 " era : a mix of AI, plastics, human estrangement, powerful non-state actors ...


  11. #31
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    Default Re: Diagonal Hobbing

    Very interesting! Who manufactured the hob & what information came with it? Seems like you'd need to know exactly where the hob needs to be positioned (along its length) when it's centered over the beginning of the spline. You'd also need to know exactly how far the hob needs to shift over as it cuts the length of the spline. Once you have that information you should be able to figure out how much to adjust the RPM of the work piece to get straight teeth.



  12. #32
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    Default Re: Diagonal Hobbing

    You'd also need to know exactly how far the hob needs to shift over as it cuts the length of the spline
    hi technical ted measuring the cone among the blue line, in image 1 from my previous post, will show how close is the angle to the desired 3*16'44"

    measuring the flanks ( yellow line ) will show how good the ZYsync is, because a wrong shift will destroy / damage the flanks

    all these measurements can be done inside the machine, with the part in the spindle ( i guess light cuts are recomended, for a good surface finish )

    i believe that finding the good ZYsync is a priority, and i would run trials to achieve the middle of all flanks among a straight line, or pretty close to this ( at this point the tapered root angle should be pretty close to hob taper )

    Seems like you'd need to know exactly where the hob needs to be positioned (along its length) when it's centered over the beginning of the spline
    if ZYsync is known, then simply lower / raise the start position of the hob, until the "circular tooth thickness=6.239-0.05( image 2 )" is achieved at "pitch_dia=56( image 2 )", at a position where root_dia=52.77(image 1a)=tool_base_diameter(image 3)

    this can be measured inside the machine, with a 3d taster ( with minimal tir and a palpator with a ball_dia=2.5mm; at this size, there is still 0.362 clearance until the tapered root - image 1c )



    well, so far so good, but the tool has a different taper then the required value from the drawing; tool has 3*11'55"=3.199* ( image 3 ) while the technical drawing shows 3*16'44"=3.279* ( image 2 previous post )

    i would run some trials until i would obtain the taper from the tool 3.279*, and after that i would target the taper from the drawing 3.199*, and compare results : at this point i should be pretty close to something; ( well, close but no cigar )

    kindly

    we are merely at the start of " Internet of Things / Industrial Revolution 4.0 " era : a mix of AI, plastics, human estrangement, powerful non-state actors ...


  13. #33

    Default Re: Diagonal Hobbing

    Good morning guys and thanks for the response. It will be at least a week, maybe longer before i begin setup on these so i can't do any trials or testing until then. However, i am running a straight tooth spline now that i may be able to play with as the job winds down. Same principle would apply to traverse the tool diagonally, but also would take the taper out of the equation... but this job is running so well i hate to mess with it! Probably best just to solve original problem first, then apply it to other parts later as to get full use of the hob with least amount of wear..

    Anyways to answer a few questions. Sync of z and y? Should be whatever its supposed to be i guess? Machine is 18 months old and luckily no hard crashes. A few bumps that required a turret alignment but nothing major. Nobody else ever runs this machine. I do not understand how the spindles are synced, the machine gear software does this for you when u plug in values for no. of teeth on cutter and no of teeth on part etc.

    P.S. the tapered root spline part in question has an angular tolerance of -+ 2 degrees!!!
    Gleason made the tool, it has alot of info on it and pictures are in some previous posts toward beginning of thread.
    Last order of these parts that i did, well lets just say we had to bend over and take it from an outside source... 4-5k on a 44 pc. order and it took them 3-4 weeks

    Last edited by coreywadeadams; 09-12-2018 at 10:09 AM.


  14. #34
    Member deadlykitten's Avatar
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    Default Re: Diagonal Hobbing

    this job is running so well i hate to mess with it!
    hey corey if you wanna mess with it, but still be safe, target small changes, thus to be sure that the tool won't fail

    i guess there is no problem if the part is a failure, but tool has to be protected

    Sync of z and y? Should be whatever its supposed to be i guess?
    aha ... that's it

    Machine is 18 months old and luckily no hard crashes. A few bumps that required a turret alignment but nothing major
    i have custom load-monitor code, that is designed to increase safety, more precise to reduce the force that trigers motors-shutdown

    it may save the day, may lower the turret deviation, or stop before turret goes missaligned, or stop before a tool is broken

    [ protection during positioning ] : find the "torque value" parameter, and lower it as much as possible; should be inside "system parameters"
    [ protection during cutting ] : use a general load monitor address, for all axis : for example, at the begining of the program, i load 80%limit into all axis : XZCYM; no limit in S

    so far it saved me at least 4 times

    I do not understand how the spindles are synced, the machine gear software does this for you when u plug in values for no. of teeth on cutter and no of teeth on part etc
    i remember that you have that fancy software ... it outputs G-code, and it would be nice to understand that code, so to adjust it faster

    Gleason made the tool
    maybe you can run some trials with a representative from Gleason he may tell you to input 0.2 somewhere, and like this, you will get the part in no-time

    however, he may tell you to change a parameter that is not available as input directly into the software interface / kindly

    we are merely at the start of " Internet of Things / Industrial Revolution 4.0 " era : a mix of AI, plastics, human estrangement, powerful non-state actors ...


  15. #35
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    Default Re: Diagonal Hobbing

    Hi Corey – 1st thing I would do is try to contact the person who posted the video that Deadly linked in post #11.

    Here’s what I think you will have to do:
    1) Calculate how far the hob must shift to get the full depth root diameter and taper to zero depth.
    2) Let’s say the above dimension is 2.473695. Divide that by .494739 (circular pitch). That equals 5.
    3) So the workpiece would have to rotate 5/14 more (or will it be less) to compensate for the hob shift.
    Does this make sense to anyone else? I’ll work on some of the math & we can compare results.



  16. #36
    Member deadlykitten's Avatar
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    Default Re: Diagonal Hobbing

    Calculate how far the hob must shift to get the full depth root diameter and taper to zero depth
    hello technical ted, you are right ... there is an image at post #20, which shows the part/material and the tool/hob in contact; the taper on the part depends on the taper of the tool, and in that moment i suggested that is a good idea to measure the tool, so to calculate Z_travel & Y_shift with a precision of few tenths

    after that, rpms has to be calculated; tool_rpm/part_rpm=tool_nr_of_teeth/part_nr_of_teeth ( i guess ) / kindly

    we are merely at the start of " Internet of Things / Industrial Revolution 4.0 " era : a mix of AI, plastics, human estrangement, powerful non-state actors ...


  17. #37

    Default

    Quote Originally Posted by Technical Ted View Post
    Hi Corey – 1st thing I would do is try to contact the person who posted the video that Deadly linked in post #11.

    Here’s what I think you will have to do:
    1) Calculate how far the hob must shift to get the full depth root diameter and taper to zero depth.
    2) Let’s say the above dimension is 2.473695. Divide that by .494739 (circular pitch). That equals 5.
    3) So the workpiece would have to rotate 5/14 more (or will it be less) to compensate for the hob shift.
    Does this make sense to anyone else? I’ll work on some of the math & we can compare results.
    Thanks for the response Ted, in doing some research and reading i remember something about adding 1 tooth to the index ratio but I can't find that article again. I'm not sure if I add the tooth to the part or the tool... Anyways, 2.484" is length of hob travel in z axis and to move cutter in x axis from full depth to no contact will be 2.6" I don't think the y axis will be any trouble to fine tune once I get some straight teeth cut deadly kitten... Any other info u need feel free to ask. I'm just now getting started on setup. One thing I noticed is that the software calculates the mill spindle rpm as 130.26327... I'm guessing that string of numbers to the right of decimal has something to do with index ratio? Going to post some random pics of what I'm actually working with.

    Last edited by coreywadeadams; 10-01-2018 at 12:52 PM.


  18. #38

    Default

    Some pics...

    Attached Thumbnails Attached Thumbnails Diagonal Hobbing-img_20181001_140232-jpg   Diagonal Hobbing-img_20181001_140132-jpg  


  19. #39
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    Default Re: Diagonal Hobbing

    Dear Sir,
    If CNC Hobbing machine used for daigonal hobbing cutting
    what programme used with details send me.
    for fanuc control machine
    data is same as erlier your taper_spline.txt


    Before DATA of Taper_spline.txt[/B]
    what is meaning of
    BA=86.18360
    RDIS=0.39365
    DDEP=0.14280



  20. #40

    Default

    Quote Originally Posted by bpg View Post
    Dear Sir,
    If CNC Hobbing machine used for daigonal hobbing cutting
    what programme used with details send me.
    for fanuc control machine
    data is same as erlier your taper_spline.txt


    Before DATA of Taper_spline.txt[/B]
    what is meaning of
    BA=86.18360
    RDIS=0.39365
    DDEP=0.14280
    It's not a "real" hobbing machine but it does have all the axes. Hobbing software was an option at purchase of the Multus u4000 with osp-p300sa control. BA= tilt of head calculated by helix angle of hob cutter. RDIS= retract distance if slide hold is pressed. DDEP= tooth depth



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