Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: pointcloud on August 13, 2007, 06:14:04 PM
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Hey Fellas,
I have a freind whom has just completed his benchtop mill. He outfitted it with camtronics. What we have is a bad "HUM" on Z and X. Y then seems to have a plus "HUM". We have the caculations of the steps correct, and have attempted to tune from the lowest extreme to the highest useing Mach3 Volicty and Accel..
His caculations are 30,000 on X and Y and the Z is 60,000. We have the step Dir at 1 and 5.
The kernal is 25,000, which I trtied 35k and 45k. No change. (the processor speed on the pc is 1.6ghz)
Our best setting on X and Y were 46.5 and 12.5. Z is 22.4 and 6.2.
The encoders are 500s.
He has .200 ballscrews geared 4:1 on X and Y. Z has a worm to Rack to 4:1 belt.
Y has a very little backlash which he is working out to be null. Other than that there are absolutly no mehanical problem that would cause the motors to hum.
Ok... I know that there is a galil plug in, can we tune camtronics/mach3 with the galil wsdk? I just think that the tuning method in mach3 is less detailed, but I may not totally understand the differance between the 2 different tuning methods..
I am 10000% sure that the motor should not be humming as I have an identical motor hooked to a low-cost-retro system, and it does not hum.
Thanks for the help in ADVANCE..
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I'm the friend. Pointcloud is helping tune the servos. Only correction is that reduction is 3:1 instead of 4:1.
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You can only use the Galil tuning software if you have galil card... I am thinking that you have G320's ... They will make a hum when they are running... the Teknix drives seem to be smoother but they do cost more :( Having said that I have run a machine in the past for a few years that has G320's and it worked well.. the problem is that it is not the best sounding servo system but they are a very good price! Have you tuned the drive with the pots on the back?? there are instructions that tell you how to do this from Gecko.
Thanks
Brian
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Not really an operational issue, just did not think it should make noise... It's a sign that tunning is off, true? No on the Gecko tuning, but I will look into it.. Thanks for the reply...
Marc
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I have found that they will make a grown from time to time when they are setting there doing noting :(
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It's a pretty consistant hum... On Y and Z, and the pulse is on X.. It holds position and has no poblems with rapid moves. I am going to look into tuning the drives. I may be over reacting but it seems loud..
Marc
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I had gecko 320 servos on a machine and they growled like mad. I tuned until I was sick of it. I finally solved the problem by switching to steppers. Now dead quiet, and the machine runs 75ipm rapids instead of the 100ipm I got with servos. I'm happy.
Ive still got servos on my router, they growl like mad, but the router makes so much noise I can't hear the servos :-)
I don't think gecko servos will ever be quiet, tuning may make them a bit less noisy.
ron ginger
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Sounds like with the 320's and servos that its a "live with it" situation. Is this common with other users? Like to hear if or how you solved problem.
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The CNC Teknix amps sound nice.. I helped put them on a lathe and they are very happy with them..
But in the end the G320's are half the price!
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I have to say that I have a system from here http://www.lowcostcncretrofits.com/ and there are geckos inside, I am not sure what the numbers are 320 340 but I have 2-600oz servos, and 1-1200 and NONE of the HUM.. It is true that you will not hear them while running but I feel like this will result in a fault at some point in time. I have the geckos and a galil 18x2 all withservos and my servos do not HUM. It took a little while to tune the Galil but while tuneing them I found that the slightest HUM would soon result in a fault. There may be a little hum allowed with geckos but it realy shound not be very loud, or there is a problem...
A servo with a bad hum is poor tuneing, or loose motion, or poor amp tuneing, or an encoder problem.
At this time we have only tried motor tuneing and checked for mechanical slack, and both are ok.
We have not tried amp tuneing at this time, but will I am sure.
I am pretty sure that the encoder is ok, as it would have faulted out the drives during his testing.
Ok, for a minute I will go along with the crowd and say humming is ok. BUT I just can't.
Does everybodies HUM? dgoddard's is 3 axis and two different hums(z,y same and x is a bouncing hum), so if there going to hum I am sure that they would do it consistantly?
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I have had my Camtronics controller with gecko 320's on a 4 axis Technoisel machine, for about a year. There is a brief hum every few seconds but it's nothing I would be concerned about. I have run my machine for hour's at a time and never had problems with accuracy or stalling of any sort. I have a 3 year old Maxnc mill that has a stepper motor and drive, let me tell you, it literally is a constant scream from the controller. Works fine but if you have to listen to that for hours you would go mad.
In the day time I program industrial CNC routers and the high end servo motors(Fanuc, Yaskawa, bosch-rexroth) have a hum as well.
If you have backlash or play in your system it will be more pronounced from my experience. Especially when the head or axis moves to position rapidly and stops or changes direction. I'm sure you could build a completely silent system, but the cost would be substantially greater.