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  1. #73
    Gold Member handlewanker's Avatar
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    Default Re: X axis spring back on vice squaring ?

    On the return to China topic.....no I did not contemplate a send back option as that would probably be a return as the same as before fix.....it needs a different approach.

    The unit that was fitted to the machine was rated at 24 volts and the rectified voltage of the transformer was up at 36 volts.....this was probably a ploy to get more current flow for a short while as the down thrust was only a 3 sec move duration.

    It firstl burned through the wire to the brushes and after fixing that it melted the brush carrier itself.

    I could fix that too but it might go on to burn out the armature itself.....a redesign was the best option in my opinion......when I get a round tooit

    Back to the thread......do you still consider that more preload is needed?.....Taiwan will not be pleased to honour a warranty claim on that score.......they did specifically state NOT to mess with the dang thing......adding more preload above the manufacturer's recommendation will not cure backlash........especially if backlash is only really a problem on the finishing cut when the drive train is lightly loaded.

    BTW....so far all I've seen is a test to determine that backlash is present when the drive train is not under a load.

    Heaven forbid that it will get worse once the spindle is working and a cutter is engaged.........that tells me the thrust housing are totally inferior and not up to the task of resisting the cutter loading.

    Before they get opened I would suggest a return to sender for a refund and a buy in option with another supplier for better quality.

    Too bad if the supplier tests them and can find no fault with their preload settings......quite frankly I think you're barking up the wrong tree.

    How about an acid test........put a piece of aluminium in the vice....about 70mm X 70mm x 20mm...... and do some hand coding to make a cut across one end face and then the other end about 5mm deep to a specific length dimension.

    This will test the accuracy of the X axis balls crew.....do a cut on the other 2 faces to test the Y axis ball screw too........this will also test the X and Y axes for squareness.

    With a known cutter diam, If you get the sizes right on both dimensions you have no backlash in the X or Y ball screws.

    CNC is all about accuracy built into the machine via the ball screw pitches.....and their attachment points too.
    Ian.



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    Default Re: X axis spring back on vice squaring ?

    Quote Originally Posted by handlewanker View Post
    Back to the thread......do you still consider that more preload is needed?.....Taiwan will not be pleased to honour a warranty claim on that score.......they did specifically state NOT to mess with the dang thing......adding more preload above the manufacturer's recommendation will not cure backlash........especially if backlash is only really a problem on the finishing cut when the drive train is lightly loaded....
    You must be in a dream, of some kind, if you think there is any kind of warranty


    Quote Originally Posted by handlewanker View Post
    Before they get opened I would suggest a return to sender for a refund and a buy in option with another supplier for better quality...
    You must of missed the part about sending something back for a replacement, it would cost the OP more than the part cost to send it back, there is nothing wrong with the Housing, the Bearings just need adjusting, they are only P5 grade Bearings, and are not a matched set, so it is expected to have to make some adjustment's, if needed, even the supplier says adjustment may be needed


    Quote Originally Posted by handlewanker View Post
    CNC is all about accuracy built into the machine via the ball screw pitches.....and their attachment points too..
    You have a lot to learn, you are not even close


    Another good Rant though with no substance, your acid test method would not show if there was any backlash, your uneducated approach would be fruitless

    Mactec54


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    Default Re: X axis spring back on vice squaring ?

    I have sent an email to the supplier of the bearing housings and they said the preload is adjusted by tightening the nut on the ballscrew to press the angular contacts together. Only i dont see how that can be possible with the bearings face to face as in there picture of them ? Unless they are not the same as in the picture and are actually back to back. I shall have to ask them. They do seem like they are interested in helping out though requesting pictures of my setup and how i am measuring backlash. They also said "the shaft couplers are pre-loaded, they dont have backlash" when i asked them if the backlash could be there.

    They also said "it could be that you have 0 backlash.but are seeing stickslip. that is more difficult to solve."

    I did the steps-per setup in Mach3 again this time with backlash comp turned off. Restarted Mach3. And things do seem better. Then i adjusted gibs and measured backlash again and got some better numbers. 0.016mm X axis, 0.025mm Y axis, 0.03mm Z axis. Popped those numbers into Mach3 backlash comp and set 50% acceleration setting. Restarted Mach3. And it looks to be working normally from my dial gauge readings.

    Sometimes Mach3 dose something funny as when i set it to step in 0.01mm amounts the first step from 0 will be 0.0075mm on the DRO and the table will hardly move. Then the second step will be 0.0175mm and the table will move 0.02mm. All other steps will be in 0.01 from then on till it gets back to 0 on the DRO then the first step from 0 will be back to 0.0075.

    So i think you are correct in Mach3 is also playing a part in my backlash problem making things difficult.



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    Default Re: X axis spring back on vice squaring ?

    Quote Originally Posted by ti5m View Post
    I have sent an email to the supplier of the bearing housings and they said the preload is adjusted by tightening the nut on the ballscrew to press the angular contacts together. Only i dont see how that can be possible with the bearings face to face as in there picture of them ? Unless they are not the same as in the picture and are actually back to back. I shall have to ask them. They do seem like they are interested in helping out though requesting pictures of my setup and how i am measuring backlash. They also said "the shaft couplers are pre-loaded, they dont have backlash" when i asked them if the backlash could be there.

    They also said "it could be that you have 0 backlash.but are seeing stickslip. that is more difficult to solve."

    I did the steps-per setup in Mach3 again this time with backlash comp turned off. Restarted Mach3. And things do seem better. Then i adjusted gibs and measured backlash again and got some better numbers. 0.016mm X axis, 0.025mm Y axis, 0.03mm Z axis. Popped those numbers into Mach3 backlash comp and set 50% acceleration setting. Restarted Mach3. And it looks to be working normally from my dial gauge readings.

    Sometimes Mach3 dose something funny as when i set it to step in 0.01mm amounts the first step from 0 will be 0.0075mm on the DRO and the table will hardly move. Then the second step will be 0.0175mm and the table will move 0.02mm. All other steps will be in 0.01 from then on till it gets back to 0 on the DRO then the first step from 0 will be back to 0.0075.

    So I think you are correct in Mach3 is also playing a part in my backlash problem making things difficult.
    Yes that is the normal problem that you see with Mach3 Backlash comp, and when 2 axes change direction it will do it all over again

    You have this figured out quite well, the Ballscrew locking nut can only do so much with the bearings being Face to Face, so you are correct with that, and they are not, they don't know what they are selling, as well, the Bearings for a Ballscrew like this should be assembled Back to Back, Face to Face can work for a machine like yours, but what I have been saying will have to be done to correct any Backlash with your Bearing assembles, once the Ballscrew lock nut is locked then the adjustment would be with the front clamping plate, this would need a shim in front of it as I showed, if this is not enough, then you would need the shim in between the 2 inner Bearing Faces

    Stick Slip is a normal component of all solid way machines, this does not cause backlash, this is just there uneducated excuse, which is a poor one, your small light machine would see very little Stick Slip

    Mactec54


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    Default Re: X axis spring back on vice squaring ?

    Quote Originally Posted by mactec54 View Post
    You must be in a dream, of some kind, if you think there is any kind of warranty




    You must of missed the part about sending something back for a replacement, it would cost the OP more than the part cost to send it back, there is nothing wrong with the Housing, the Bearings just need adjusting, they are only P5 grade Bearings, and are not a matched set, so it is expected to have to make some adjustment's, if needed, even the supplier says adjustment may be needed




    You have a lot to learn, you are not even close


    Another good Rant though with no substance, your acid test method would not show if there was any backlash, your uneducated approach would be fruitless
    Well Mac....if you have backlash (or stick slip) you WON'T get any accurate sizes like I suggested....that is interpreted as lost motion on the reversal of the screw(s)......something you have no control over as it's purely mechanical and guesstimating how much compensation is needed is a shot in the dark.

    ADJUSTING the nut on the ball screw to take up the slack is a lot different to just adding more preload......adjustment is a definite action......preloading is a guesstimation of what you think a cutter will exert on the ball screw and the counter force required to resist it.

    BTW....if you tighten the dovetail gibs more to attempt to reduce slide wander, you WILL get lots of stick slip, of that you can be sure.......this will also impact on the ball nut and thrust bearings.

    AND Mac, in your infinite wisdom..... which I doubt..... pray do tell us what results you would get if you applied the acid test I suggested......ranting and disputing the method is not a valid answer.

    As you "probably" know, once you hit the green button to start the wheels turning you are in the lap of the gods until the job is finished.......the G code values will determine where the cutter starts and stops .....not you.

    If the outcome is not as expected due to backlash, then you won't get accurate results......preloading will not give you an accurate outcome.if it's not the cause of the problem....otherwise the test I suggested will come out good if the preload is sufficient for the needs.
    Ian.



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    Default Re: X axis spring back on vice squaring ?

    Quote Originally Posted by handlewanker View Post
    ADJUSTING the nut on the ball screw to take up the slack is a lot different to just adding more preload......adjustment is a definite action......preloading is a guesstimation of what you think a cutter will exert on the ball screw and the counter force required to resist it. .
    It does not matter what he does with the Nut on the Ballscrew, it won't help with any of the Backlash he has, so why are you even talking about it, you have no idea or concept of what is happening with his Face to Face Bearing configuration


    Quote Originally Posted by handlewanker View Post
    As you "probably" know, once you hit the green button to start the wheels turning you are in the lap of the gods until the job is finished.......the G code values will determine where the cutter starts and stops .....not you. Ian.
    Your Rants get more and more of the same all the time, it just shows your inexperience, and lack of education with CNC machines and there building, just remember you have never run a CNC machine to make anything, and never built one either, but you can tell someone how it should be done

    When you get experienced, if ever, you will find you can make changes after you have press the green start button, you can make any offset changes you want on the fly, while the machine is running, changing the part being machined

    The proof will be when he adds a shim and removes the backlash he has

    Mactec54


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    Default Re: X axis spring back on vice squaring ?

    LOL.....oh Mac, you are so uptight with your thinking......once you have run a program and the part is finished it is.....FINISHED.......what part of that don't you understand?.......if, due to lost motion, your part is undersize it is.....SCRAP......metal taken off can't be put back on, unless you have an inbuilt putting on machine....LOL

    Of course, if you have to keep stopping the machine in the middle of a run and have to constantly measure the work piece because you have the fear that the outcome will not be to your liking...........that's a manual mode, and I would be doing that on my manual mill not messing with the vagueries of a CNC mill that is unreliable.

    It gets worse......if you are running with a CAM program.....at what part of the program do you butt in and do a measurement?

    It has been said many times that once you close the door the part is made in there not with your God like hand hovering over the throttle.......and pray, do tell me where you would make an offset change when you find that a hole is oval instead of round?.....on the next part after you scrap the first one?

    I think you should desist from insisting that anything anyone says is contrary to how you would like it......go with the flow.......by all means offer your advice, it can be valuable occasionally, but keep your hands in your pockets.

    I will state definitely that you are raving and don't remember what you are saying.....in post # 78 you DID state that............"it does not matter what he does with the nut on the balls crew, it won't help with any backlash he has"'

    Strange, I thought the whole point of the exercise was about the supposed possible backlash from loose bearings in the thrust housing and the method of possibly fitting a shim and tightening the nut was the whole solution to curing the backlash effect.

    Tightening the nut with the shim fitted....if it's really needed....... DOES give you the reduction in backlash by preloading the bearings....... PROVIDED it isn't caused from some other area.

    BTW...CNC machines are only machines, made by Man, not Heavenly bodies that you worship reverently.....and they do have feet of clay.....they cannot think for themselves and even I with my small knowledge can make one sing.
    Ian.



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    Default Re: X axis spring back on vice squaring ?

    Quote Originally Posted by handlewanker View Post
    LOL.....oh Mac, you are so uptight with your thinking......once you have run a program and the part is finished it is.....FINISHED.......what part of that don't you understand?.......if, due to lost motion, your part is undersize it is.....SCRAP......metal taken off can't be put back on, unless you have an inbuilt putting on machine....LOL

    Of course, if you have to keep stopping the machine in the middle of a run and have to constantly measure the work piece because you have the fear that the outcome will not be to your liking...........that's a manual mode, and I would be doing that on my manual mill not messing with the vagueries of a CNC mill that is unreliable.

    It gets worse......if you are running with a CAM program.....at what part of the program do you butt in and do a measurement?

    It has been said many times that once you close the door the part is made in there not with your God like hand hovering over the throttle.......and pray, do tell me where you would make an offset change when you find that a hole is oval instead of round?.....on the next part after you scrap the first one?

    I think you should desist from insisting that anything anyone says is contrary to how you would like it......go with the flow.......by all means offer your advice, it can be valuable occasionally, but keep your hands in your pockets.

    I will state definitely that you are raving and don't remember what you are saying.....in post # 78 you DID state that............"it does not matter what he does with the nut on the balls crew, it won't help with any backlash he has"'

    Strange, I thought the whole point of the exercise was about the supposed possible backlash from loose bearings in the thrust housing and the method of possibly fitting a shim and tightening the nut was the whole solution to curing the backlash effect.

    Tightening the nut with the shim fitted....if it's really needed....... DOES give you the reduction in backlash by preloading the bearings....... PROVIDED it isn't caused from some other area.

    BTW...CNC machines are only machines, made by Man, not Heavenly bodies that you worship reverently.....and they do have feet of clay.....they cannot think for themselves and even I with my small knowledge can make one sing.
    Ian.
    I don't think you have had enough sleep, your Rants are getting worse, and if I said that back in post #78 and you are repeating it that is correct, it does not matter how much he tightens the clamping nut on the Ballscrew it won't help anything, the OP already knows this, as I said you have no concept how this works, with a bearing arrangement like this

    You are sounding like a broken record, once you have had a few years running a CNC you will lean about changing tool offsets and tool wear comp on the fly, it has nothing to do with if you have a machine that machines an oval hole, if you want a perfect hole you would be boring it even on a CNC

    Mactec54


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    Gold Member handlewanker's Avatar
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    Default Re: X axis spring back on vice squaring ?

    Mac............sigh.....I suppose that cuts out machining a large diam raised circle on a job too if it ends up oval.

    On the innuendo of the lack of knowledge of fitting bearings....... I've fitted more bearings than you've had hot breakfasts,........so we'll have to agree to disagree and let it rest at that.

    Nobody really wants to keep reading about your constant criticism AND PERSONAL REMARKS ....it's boring.....so for the thread's sake let it go....no more to be said.......PERIOD.
    Ian.



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    Default Re: X axis spring back on vice squaring ?

    Quote Originally Posted by handlewanker View Post
    On the innuendo of the lack of knowledge of fitting bearings....... I've fitted more bearings than you've had hot breakfasts,........so we'll have to agree to disagree and let it rest at that..
    That statement could be correct, as I eat heathy and don't have hot breakfasts very often

    I doubt that would be possible, even with me not having a hot breakfast, you would not come close, I was contracted by SKF to manufacture special Bearing assemblies for a number of years, how many precision Bearing sets do you have in stock, I should take a photo of my Bearing cabinet, have you ever made a Bearing, I mean a complete Bearing assembly, meaning rough machine, heat treat grind micro polish, make the cage and measure for the correct ball size then assemble, I would love to see the out come, you could only dream, I have been making machine spindles and assembles like this for 30 years, I even built a Hobby spindle for a Zone member, that is here on the Zone, you should check it out, you might learn something

    Quote Originally Posted by handlewanker View Post
    Nobody really wants to keep reading about your constant criticism AND PERSONAL REMARKS ....it's boring.....so for the thread's sake let it go....no more to be said.......PERIOD.
    Ian.
    You need to practice what you preach, go back through the post, and it was you and only you that started off with the personal remarks, and I will continue as long as you do, you can't post uneducated, non related rubbish, and not expect to get some criticism, if you can't handle it then don't post none related pie in the sky wild uneducated dreams

    Study the Bearing assembly Post #58 that was posted by the OP and you will see that it can not be adjusted by the Nut that clamps the Ballscrew and Housing together, not with that Bearing arrangement anyway, now if the Bearings where Back to Back that would be the first part to check

    Mactec54


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    Default Re: X axis spring back on vice squaring ?

    Yeah Yeah........blah blah....whatever..........nobody's disputing your expertise............I've always been supplied with bearings as the occasion fits......PERIOD. ..........old last word Mac.
    Ian.



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X axis spring back on vice squaring ?
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