Machsupport Forum
Third party software and hardware support forums. => SmoothStepper USB => Topic started by: RIBBIT on January 24, 2012, 05:08:04 PM
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Hello. I came across this forum trying to figure out the problem im having with my smooth stepper. Im setting up a taig micro mill dsls 3000 unit for a customer to rework some parts on site.
I got everything working except one little issue. When first started up i go to run the program and i get a smooth stepper error (see image below). This only occurs on the first attempt to
run the program. Once the alarms are cleared it will run without hiccup. Problem for me is when this happens the machine seems to jump causing the x and y zero to be off for my fixture offset.
Its not a big deal to redo the zeros but the customer is not gonna want to have to do that. I tried with the machine turned all the way off and same result just running in mach.
error message says possibly change the timeout setting but was hoping for a little help before i try that. Hopefully i explained the problem i am having well.
(http://i1199.photobucket.com/albums/aa462/coronado35/314aa2e5.jpg)
(http://i1199.photobucket.com/albums/aa462/coronado35/401069c8.jpg)
thanks in advance
mike
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It sounds like your configuration might not be quite right.
First take a look at: http://www.soigeneris.com/Document/Installing_and_Configuring_the_SmoothStepper.pdf (http://www.soigeneris.com/Document/Installing_and_Configuring_the_SmoothStepper.pdf)
If you have a large file it might also be a tool path display issue, see: http://www.machsupport.com/forum/index.php/topic,20588.0.html (http://www.machsupport.com/forum/index.php/topic,20588.0.html).
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Thanks ill check it out
mike
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hello guys,
i have some problem about smoothstepper in threading. my threading stop while running for 1 or 2 second therefore threading pitch shift.
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hello guys,
i have some problem about smoothstepper in threading. my threading stop while running for 1 or 2 second therefore threading pitch shift.
Attach your xml and I will check your config to see if I can find the problem.
Hood
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thanks hood.
i attached xml here. please check it and give me the solution it would be helpfull.
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You have the Index pulse set to Port 1 pin 13 but you also have the MPG set to the same port and pin. That is likely your problem.
Hood
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hi hood,
thanks for replying me.
it was correct what you said that index pin & and port, MPG port & pin was same.
i have changed mpg pin &port number. and another thing is that, i m not using MPG.
after changing pin&port my problem still not solved.
another problem is that RPM not showing correctly. its actual RPM 229 but it shows some time 2200, 564783930 like this for 0.5 second. and i m not using spindle servo motor. i m using 2 hp ordinary 3 phase spindle motor which is use in manuallathe machine . actually i converted manual lathe into CNC with two axis X& Z. i can turn easily by using smooth stepper. but when i start thread in first depth of cut its stop for1 second.thats why i loss my pitch. i can thread up to 150 mm properly by using parrallel port. now i have require ment for 400 mm thread that is why i purchased smooth stepper. but i can do properely thread please give solution.it would be helpfull.
for every depth of cut it is happening same like first depth of cut
thanks
santosh
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I also noticed you had the Index Debounce set to 10, try setting it to 0 and see if that helps.
If not can you tell me a bit about theIndex pulse you are using.
Hood
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i have set it to 0 but i could not see any changes in RM value it shows same.
in general configation i saw there 8 bit one stop for serial output.
i dont know exact where i can find a bit about index pulse?
can u please guide me?
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have set it to 0 but i could not see any changes in RM value it shows same.
in general configation i saw there 8 bit one stop for serial output.
i dont know exact where i can find a bit about index pulse?
can u please guide me?
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I am asking what hardware you are using for the index pulse, ie is it a slotted disc with an optical sensor?
Hood
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i m using proximetry sensor
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Does the spindle speed show correctly in Mach when you have it running?
Ok another question, in your PM you said you want to thread 500m but I am not sure what you mean, are you meaning a length of 500mm or?
Hood
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when i use parrallel port that time spindle RPM shows correctly i told you i can thread 150 mm long length for longitudnal 6 mm pitch.
on parrallel port i cant do thread up to 500mm length and 5mm pitch. because after 150 mm length thread pitch shift. so i prefered to use SS.
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Does the RPM show correctly with the SS?
Hood
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yes it shows correct RPM
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Ok I am needing to understand a bit more about what your problem actually is. I realise English is not your native language so it is not so easy for you but likewise it is not so easy for me to understand what is actually happening.
You say
"my threading stop while running for 1 or 2 second therefore threading pitch shift." Do you mean the SmoothStepper faults or does the threading just stop and stand still?
Are there any error messages?
Does the SS lock up?
Hood
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no there is no any fault in smooth stepper.threading stop for one second in first depth of cut and continue withine second same cycle because of that our threading pitch shift in second depth of cut of cycle. this kind of thing happen every depth of cut. i changed ss board but same problem also. as well as i replaced ram of pc 1GB to 2Gb
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What RPM are you threading at?
Hood
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232 revolution per minutes
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hi hood,
Generation of Index Pulse in our board,
We are using the proximity switch which is fixed near the spindle and on spindle one steel material is fixed in such way that it comes near the proximity switch once in one rotation and proximity switch generates one pulse for one rotation. On time of pulse is 10% as compare of OFF time of pulse. further these pulses are optically isolated and feed to MACH3 to measure the Speed of spindle rotations.
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Please answer the question I asked earlier, what RPM are you threading at?
Hood
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hi
i m threading at 229 RPM.
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Ok, is your motor powerful enough? 6mm pitch will take a lot of Kw.
Does it cut OK if you just cut air rather than having the part in the chuck?
Open the SS Diags when you run the thread and see if there are any clues in there.
The SS is perfectly capable of doing that length of thread, I have done 800mm long threads for my pipe bending machine and they were perfect.
Hood
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First time i checked with part in chuck.
after that i checked in air.
ok now i will thread in air.
but where in ss diags i will have to search clues?
can you any example?
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The SS Diagnostice is from the Plugin Control menu.
I see you are only using a 250Hz controller frequency for the SS, have you tried faster, maybe 2KHz? Also I would recommend that you set the Y, A, B, C and Spindle to 32KHz in the SS Setup.
Hood
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One other thing I am not quite clear about. Does this happen exactly the same with the PP?
Hood
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not yet i tried 1khz and for y ,a,b,c,x and spindle 256khz.
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i have done that changes what you said but problem is still happening.
and i dint understand about pp?
please tell me long form of pp.
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PP = Parallel Port.
Hood
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santos,
I am having difficulty due the translations so bear with me.
You need to have the index working properly to do threading. When working properly the displayed RPM is accurate. There can be some change in the rpm and Mach will adjust the threading cycles based on the rpm.
If the rpm drops too much, say 50%, the threading cycle "may" recover. If the actual threading stops then probably the thread is ruined. Have a read of the Threading on The Lathe write up in Members Docs (page 4) .
From your replies you say using a proximetry sensor, 2hp motor, and trying to do a 5mm pitch x 500 length thread at 229 rpm. So will comment on the above:
- proximetry sensor- don't care what you use as long as the displayed rpm is correct AND can provide an accurate consistant index pulse for the feedrate you are using during threading. If you use the threading wizard to generate the code it will provide the feedrate and required accel based on RPM and pitch.
-500 length - like Hood said, he has no problem cutting long threads. You should scribe test and see what you can do. Have a look at the Threading wirte up on what to do. Also eliminates motor slow down as a factor when testing.
- 5mm pitch & 2hp motor - pitch is the distance between same points along the thread parallel to the axis.
So 5mm ( approx .197" imperial) between points. How much hp you need to cut that kind of thread will depend on type of thread and depth of cut and how it is being cut. So 2hp may or may not be adequate.
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threading stop for one second in first depth of cut and continue withine second same cycle because of that our threading pitch shift in second depth of cut of cycle.
Are you meaning ......during the actual cutting of the thread the spindle rpm drops a lot / almost comes to a halt.
If that is the case, then Mach "may" try to fix the thread. Any "fixing" would be applied to the next threading cycle. Chances are, the thread will not be correct. You may want to consider doing the thread using alterante
flank infeed method ( see page 44) in the wirte up on how to set.
RICH
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How about posting the code you are using to do the threading? Maybe it is just a GCode problem?
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Hi Hood,
I have some help to write my posts as English is not my first
language. I hope that my communication is clearer from now onwards.
I have checked my index pulses using an oscilloscope and they are clean.
The RPM display previously showed some momentary variation. After
changing the noise filtering value from 0 to 0.75 in the smooth
stepper configuration, this variation has gone away and the RPM
display is now solid.
This has changed the behaviour during threading and there is no more
stopping of the Z axis for 1-2 seconds as it used to previously during
threading. All the cutting is smooth for all the passes.
I still have the problem of pitch variation. After 130mm the
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i still have the problem of pitch variation.After 130 mm the length of job.
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santosh,
Can you define the amount of pitch variation?
Does the pitch increase or decrease?
How accurate is the pitch from the Z=0 to 50, 100, 150 distance?
The pitch will only be as accurate as YOUR lathes mechanical "system". If the spindle maintains an accurate rpm then the axis must move at a defined feedrate. The pitch accuracy is the result of the feedrate. Feedrate in terms of linear motion is the result of steps per unit, thus over a long distance if the steps per unit are not exact then the pitch will suffer and all other movements can also affect the pitch ie; backlash, acceleration, and quality of axis components, including the actual cutting action of the thread by the tool.
RICH
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I think your issue may well be your spindle motor is too small for 6mm pitch threads but it may be worth connecting your index pulse to Port 3 on the SmoothStepper.
Hood
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Hi hood/Rich
Now i am using 5 hp spindle motor, 115 RPM , 9 inch centre hight of lathe machine (Heavy Duty Lathe).
Pitch Variation= 0.4 mm
Pitch is increasing.
pitch accurate distance= 0 to 110mm distance is getting accurate.
I am using new spindle motor.
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Did you try the index in on port 3?
Does this happen on the first pass, in other words if you take a very light first pass and then stop the thread do you see the pitch varying?
Hood
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yes i tried the index pulse on port 3 but i dint get any difference.
In first pass my pitch getting correct.
from second pass it start shifting after 110 mm .
And i have taken scribe test according to rich manual.
And i have taken very light first pass also.
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Try with a M49 before the threading code and see if that makes a difference.
Hood
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hi Hood
i tried with M49 before the threading code but it shown up to 1mm pitch shifting.
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Ok so if its worse with FRO locked out you have some serious issues somewhere.
Where is the hard bit to determine. As this happens with both PP and SS then it has to be a hardware issue.
You mentioned you had to filter the index so I am wondering if that could be the issue, maybe a better index pulse device would help.
Not going to go back and read to see whether you mentioned it or not but are you using steppers or servos? If servos it could well be your servo tuning is not good. If steppers it could be they are not powerful enough.
Do you have ballscrew or just acme lead screw?
Hood
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i am using servo motors for x &z axes as well as using rolled ballscrew C7 grade.
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What type and make of servos and drives?
Hood
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I am using panasonic servo drives and servo motor. (2.4 Nm)
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You should be able to monitor the following error in the drive software, what errors do you get and what count encoders do you have?
Hood
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Because of that things, i tried with schnider motors and drives also but the pitch variation is showing same.
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I dont know what to suggest then, only things I can see that could be wrong are your index is not good, some mechanical parts are moving/slipping or you have poorly tuned servos.
Hood
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Hi
Hood, Actually i re tuned motors again but i got same result.
Is there any changes in ss config? so i can change?
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I cant think of anything in cofig that could affect threading in the way you are describing but if you attach your latest xml I will have a check through it. Also attach the code you are using.
Hood
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Hi Experts,
I also have been facing the same problem of pitch variations in threading with SS. Strangely I am not able to find any clear guidelines about interfacing encoder for threading with SS Manual. I am not clear how the encoder should be connected to SS card. Should all A B and Z be connected in port3 which has encoder input. Should only A or B be connected and configured as Index or timer input.
I have connected 'A' phase of 1000 PPR encoder to port 2 input of SS and configured it as index. I get a steady RPM indication at 348 RPM. But when tried to thread with wizard code for rod dia of 28 mm and thread length of 60 mm, depth of thread as 2 mm, I get a 20 pass code. When the program is run, threads are not matching and instead of a clean thread of 2 mm depth, I get a roughly turned part due to overlapped threads.
I am attaching my XML and Prog files. Please advise.
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Mach expects one single pulse per revolution of the spindle, which is what the SmoothStepper also expects. You can try just using the Z from your encoder (which provides 1 pulse per revolution.)
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Jeff,
Thanks for the reply.
I understand that SS gives much better performance in threading just because Mach with PP sees the index just once a revolution and hence slow to respond with spindle speed variations, while SS can take index as encoder inputs and hence quick to respond and gives accurate threads.
Also I get RPM indications very well accurate. I also get started well with the pitch but as the passed increase, threads get overlapped.
And I fail to understand the use of encoder at spindle if you are supposed to use just Z phase instead of total PPR. Please clarify. I am a lot confused.
Also there is given a parameter as Encoder index multiplier up to 4098 pulses in the SS configuration menu. I have set this as 1000 because my encoder is 1000 PPR and it gives me fairly accurate RPM on the DRO.
Please clarify. Someone using encoder practically may respond.
M Vyas
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The Smoothstepper only uses an index pulse the same as Mach, the difference is the Smoothstepper controls threading external to Mach and thus the index and threading are all in the hardware so theoretically should be much more stable.
I would suggest you try the Index input on Port 3 if you are using the USB Smoothstepper. If your encoder has differential Index signals then use one of the differential Inputs on port 3 for it.
Also reduce filtering in the SS plugin for all functions to as low as you can, 0 is preferable but if you need some filtering then start with the 1.43 (smallest increment)
Hood
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Hood,
Thanks for the reply. But I fail to understand that while using Encoder with SS, there are three phased available A /B /Z . While A and B give pulses 1000 Times a revolution for a 1000 PPR encoder like mine while Z gives only one per revolution. Now, if I am supposed to use only Z, for one PPR, why go for encoder and not go for simple sensor fitted over spindle like Inductive Proximity Sensor?
Also it is strange that while it has a dedicated encoder port available all the A/B /Z inputs, it just takes Z as index. This will surely not give best result as compared to if done with 1000 PPR Phase A or B.
So,if it is confirmed that I have use only one pulse per revolution, then what is meaning of the SS setup parameter Encoder Multiplier or something like that..
M Vyas
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The benefit may be twofold. First is if you are using a servo for the spindle it will have an encoder on it so there is no need to fit an additional signal to feed the Index input. Second is the encoder is likely to have high quality electronics and thus will likely have a cleaner Index pulse and thirdly Encoders are often differential so you have less problems with noise that a single ended input could have.
I dont think I have that setting in the plugin, I still use an older plugin as newer ones had issues so I went back to the old one and have not bothered updating since.
Hood
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Hi archcomp,
Mach needs a index pulse that is at least 50% wider than the other pulses. Mach is watching that pulse to start the threading.
I guess your encoder don't provide that wider pulse.
just a thought.
Alex
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Mach when using the parallel port does not use the Timing input now so it should not be set up.
With the SmoothStepper I dont think it ever did use the Timing input so again it should not be used.
The only input needed for threading is the Index and that is what you should use.
There was talk a long time ago that Greg was going to use an encoder to fully sync Z to spindle but 2 or more years passed and it was not done so I suspect that is still the case and that it will not be done. Whether that is for hardware/software reasons or commercial reasons I cant say.
Hood
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Hood,
Thanks for the clarity. I will try the setup tomorrow and post it here after confimation.
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Arch, I forgot that the newest SmoothStepper plug-in included the ability to use a standard encoder for the spindle. So using the A or B channel should work fine. Encoder signals can get swamped with noise from the spindle motor. I had this happen when I added a VFD and three phase motor to a piece of test equipment that was previously working fine. The noise from the motor/VFD was enough to confuse the National Instruments controller. The solution was to fit a differential encoder which was powered by an isolated power supply.
If you have access to an oscilloscope you can check the quality of the signal getting to the SmoothStepper. This will let you know if noise is an issue.
The other things to look for are how stable your spindle speed is and how much you are trying to cut in a single pass. You can start up the spindle and watch the RPM display in Mach while you apply some load. Is it easy to slow the spindle down? Then take a really light threading pass, just enough to scratch the surface. Does the pitch stay consistent?
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Jeff,
Thanks for the information.
Strangely I get pretty stable RPM on DRO at 348 RPM +/- 1 . Also there is almost no change in RPM while cutting. Cutting depth is about just 0.1 MM per pass so that should not be a problem. As I have pointed, I have set my Encoder input with " Spindle Index Prescale" =1000 as shown in SS Plugin setup. But when I undertake multipass threads, the pitch drifts and at the end of several passes say 20, it is hard to find clear threads..
I have a VFD connected to spindle running at full RPM. I will try to see if noice is my issue. But in that case, I should not be getting a stable RPM on DRO. Suggestions are requested.
M Vyas.
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A few stray pulses from a VFD will not effect the RPM reading much but could effect the threading timing. You can try adding some noise filtering to the index pulse in the SS config screen. You might also want to post this on the Warp9 forum so Greg from Warp9 will be sure to see it.
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Jeff do you know if the newest plugin resolves the Step/dir spindle issues that have been present since the start?
I looked at the site but no changelog on the plugin page so no idea what has been done in them.
Hood
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I'm not sure about that Hood. I'll be talking to Greg today so I'll ask him :)
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Ok thanks. Last time Greg skyped me he said he was going on holiday and would try and get it sorted but never heard back from him again so just presumed he didnt/couldnt. Maybe he did manage after all.
Hood