Noisy X and Y (M)oves

[dhunt]

After having our new non-Alpha PRT-96 Shopbot up and running for a week or so,
I'm still worried about noisy X and Y (M)oves.
I can (J)og the X and Y cars in either/any direction, they sound beautifully smooth, the way they should, but (M)oving them via the (K)eyboard function, both X and Y sound like hell! - not quite "grind-y", but certainly noisier than they should be, and with a certain degree of fine vibration that we can both feel!

Running the X-car with just one motor (per side) results in clarifying nothing,
all we notice is the expected wobble from trying to move a 5ft.wide car with motor on one side only.
We have applied pressure here and there to X and Y cars over their rails,during these (M)oves, but that proved/aleviated nothing.

We've greased the racks and the cogs, with the Lithium grease supplied
(most of it gets squished out the sides, but that's how it works).

2 yrs. experience with another (2001) PRT tells me what are acceptable noises or not, so I'm not exactly a virgin,here.

What's wrong? Are we out a cog on the X rails?
And if so, why too does the Y car make just as unseemly a (M)ove noise(in both directions, like X does)?

I couldn't say with certainty that this worrying noise is occurring during true commanded (M)oves, since I notice it while (K)eyboarding the tool into position: we've done just two simple 8-inch-square cuts to verify the machine's accuracy, which seems to be reasonably okay
(it appeared to be out by around 1 mm.,which we can work on)

(We're using SB control software 3.4.25,recently downloaded,
via a 733 MHz. Celeron box
Ramp settings were left at default values = .4 )

Help?

[richards]

What are your move (keyboard) speeds? Slow moves are often louder than faster moves. At certain speeds stepper motors can be really loud because of resonance and harmonics. No harm is done to the motors at those slower speeds, but they sound terrible.

[dhunt]

I'm not at the machine right now, but just today I reduced (M)ove speeds from 1.2 ins. per sec.
to 1.0 ins. per sec.
When I go to (K)eyboard function, it uses pre-set (M)ove speeds, doesn't it?

Regardless.. even at 1.5 and 1.2 ips it was making the not-quite-right sounds.
Maybe I should temporarily jack the (M)ove speeds up to 2 ips.
and see if that quiets the machine any..

How might Ramp speeds/settings affect this?
What are your "average" Ramp settings?
Are default Ramp settings 'ball-park' ??

[bob_reda]

I don't know if this would pertain to this situation or not. i had a very noisy xaxis, found a couple wires in the Wago connector loose

[dhunt]

This is a brand new machine, two weeks old..
Wago connectors at the motor end are shrink-wrapped by Shopbot
(can't even see what's going on in there).

IF it's loose wires it would have to be loose on both X motors
and on the Y motor too, all at the Control Box end.
Unlikely, but thanks anyway for the suggestion.

[mikejohn]

I posted a message similar to this when I first ran my new style PRT last year.
The response I got back was that the noise differences were normal.
It still sounds like a sewing machine in jog, like my wife snoring in move

It cuts and works fine though.

......................Mike

[dhunt]

What I find a bit troubling is that it sounds *Absolutely Perfect* at Jog speeds, and yet this kinda 'cheap-coffee-grinder' sound at Move speeds!
It's the difference that's worrying.

AND I have another Shopbot just a few miles away for comparison,
a machine I've worked on/with over the last few years,
so I have basis for comparison, and that other machine never sounded like this brand new one.
Hopefully this new machine will settle down and sound better as it goes along.

The other thing that surprises me is the lack of response I've had to this 'problem'
Maybe it's not a problem,
or maybe everyone's gone away on Summer Holidays...I dunno

[patricktoomey]

David, is there a difference in the motors, gearbox ratios and/or pinion sizes between the two machines? Mine is loud at move speeds and quiet at job speeds. I've also been told that this is normal. I've seen another machine that was quite but they had a different pinion size and different motors than mine so I'm thinking that's the difference.

[jerryp]

I had a problem with my y motor that sounded like bad gear noise at move speeds and at jog speeds it sounded good. It turned out to be a bad driver. Just an Idea.

[dhunt]

Patrick,
I think you may have hit the right spot.
Yes, the two machines are difrnt in gear sizes.
The older(2001) machine I'm familiar with has smaller 'cog-wheels' on its motor-shafts,
while this newer(2006) machine had noticeably larger cogwheels on its motor-shafts,
and that could very well be the reason!
Glad you pointed this out, becoz I may have been comparing apples and oranges.
Thanks: I think you have a point!

Jerry,
We blew our drivers(or was it diodes?) already.
Bin there, Done that!
Sent the brand-new Controller-board back to Shopbot,
and it is now fixed/replaced, as is our entire Grounding/Earthing circuitry!
(see another post about THAT problem!)
..so it's v.unlikely to be that (I know what a dud channel sounds and feels like,
on both new and older style controller box boards) but thanks for the input.

[Towersonline]

David, Do you still have access to the other bot?
If so why not try its controll box and see if the noise is reduced. I just finished rebuliding a ShopBot, late model control box and new gantrys, its much noisier than my old PR machine. Especially at slower move speeds.

Good to hear you have resolved the grounding problems.

Bill Thorpe

[dhunt]

Hmm.. good suggestion about trying alternative control boxes on the same machine, to see if it's signal quality that's the problem - thanks.

- or just order in a fancy Ascension 1000 box which is guaranteed to send superior signal quality to your tool

[mikek]

David I am getting a brand new Benchtop up and running and I had an intermittant Z axis problem where the Z would go into an uncontrolled speed and direction mode. Stop was the only thing it would understand. It turned out to be three wires pulled out of the motor side of the Wago connector that was tiewrapped and heatshrunk. Had to cut off heatshrink and cable tie and reinsert wires. Make sure power is off

[dhunt]

That's not good.
I wonder how that happened, and where.

Surely Shopbot quality control during assembly and shrink wrapping is better than that.
Do you think maybe it's you that may have yanked the wires,somehow?

Thanks for your input:
yours is now the 2nd. or 3rd. input related to loose Wago connector wires.

[richards]

I've not used Wago connectors in my former life in the process control computer arena, but I've put together lots of Molex connectors. Those plastic connectors can sometimes fool you. When you've used enough force to seat the two ends together, sometimes they're not seated. On more than one occassion, I've had a connector pull apart when I was certain that I'd fully seated the two halves. Changing to a Molex with locking tabs eliminated that problem. The same situation has happened when inserting the pins, even though the pins have locking 'tabs' built in. There have been times when the wire/pin was deformed just enough that something other than the tab caught in the tab slot - meaning that the wire/pin was not seated.

A good quality control department will still have trouble finding those kinds of errors because everything looks and feels correct.

[gordon]

David,

Is your machine a PRT or PRTalpha? The PRTalpha uses a Molex style connector on the motor and cables that locks and is heat shrunk to prevent the disconnection of the connector while energized, as well as, prevent debris from getting into the terminals. The pins in these connectors are fairly delicate and aren't designed to take a major pull on the cable without possibly unseating the pins.

A PRT will have WAGO connectors on the motors and cables that are heat shrunk and locks as well. They use cage clamps to hold the wires instead of crimped pins. Using the WAGO tool included with the tool or a small screwdriver inserted into the square hole in the back of the connector the wires can be put back into the connector. It takes a good bit of force to pull the wires from a WAGO without damaging something else. Before these motors ship they're tested on the control box that goes with the tool and run in to make sure the connections aren't intermittent.

Let us know which one you have and we will help get you back together. Either email me or support at support@shopbottools.com (mailto:support@shopbottools.com) or give us a call.

[odulfst]

almost 6 years and only 12 posts???

we need more of your input Gordon Bergfors, ShopBot Tools.

[dhunt]

Our new 2006 PRT is non-Alpha.
The dk.grey heat shrunk connectors at the motor ends of our cables are not standard Wago sized affairs, they are noticeably less broad!
I am familiar with Wago connectors, via my previous experience with an older(2001) SB-PRT-96 already on the island, which I helped assemble and then run.
The motor-end connectors we have here are NOT yer regular Wago thingy at all.

Is it possible we were incorrectly supplied with Alpha cabling,somehow?
- and would this matter?

The machine runs okay, it's just that (M)oves in either direction, up or down, X or Y, sound undesireable, especially compared to (J)ogs in similar directions.
Given Patrick Toomey's comments about the differences between the dia.size of older 'cogs' versus the newer,larger cogs, I had resigned myself to accepting the slow-(M)oving sounds..
but now you describe Alpha connectors, I'm wondering all over again.

I won't be near the machine until tomorrow, so can't answer any detail-questions you might ask,
but we'll be in touch,I'm sure.

Thanks for your comments.

[mikek]

David, I can assure you that I didn't pull on the wires. I have been in the electronics end of the world since 1964. Someone probably carried the motor by the cable and pulled them out not knowing any better. The Z axis was in the box and had the cable tie wrapped to the motor. It was very well protected from me. It was definately done way before shipment. Frank from the factory encouraged me to inspect the other cables, which showed me one more loose but making contact wire on the Y axis motor. Ted had the entire factory re-inspected afterwards to make sure no more would escape.

[dhunt]

Thanks for the input: I'll see what I can do to simply push them together a bit
(if there's any slack)
- I REALLY don't want to remove that sexy SB-supplied shrink-wrapping!

And by the way, I took photos, sent them to Gordon B. at ShopBot,
in the hope he'd come back to clarify whether we have the right motors and cabling connectors(his post implied a measure of suspicion)
but GB doesn't post too often,so I'm still in the dark,there..

[mikek]

David, I couldn't see the problem until after I had cut away the heatshrink. I knew I had a problem when I accidently brushed against the cable while I was trimming out cable runs and heard a motor sound. Wiggling the connector showed me there was a problem inside. I shut the controller off, and held my breath until I had fixed it and powered back up and nothing was broke (electronics). Even with the connector tightly tiewrapped the wires were pulled out from the back of the connector. The connector was mated very permanently with the tie wrap and heatshrink. It is mated just fine without it too, and works much more reliably now. Best regards. Have a good weekend.

[dhunt]

Have you replaced the heat-shrink with some other kinda anti-dust covering?
Hope you aren't running it bare.
- that's why they're there..guys were having problems with deep-seated dust way down in the connectors, mainly from blowing off their machines with compressed air, and in the process blowing dust down into the connectors!
Thus today's cool heat-shrink...there for a reason.

[mikek]

Then why don't the X and Y axies have the heatshrink? Farther away from the router? It is easy enough to add.

[dhunt]

Had an interesting incident today,
which seems to have 'cured' the noisy X and Y (M)oves problem!

While experimenting in Relative Mode, I gave instructions to Nudge the Y axis (never used Nudge before)
and must have sumbitted the wrong data or hit the wrong button or something, but the X gantry charged back to the very end of the table's rails, banging incessantly against the aluminium stop-blocks.
I leaped for the Space Bar(panic button) whacking it several times,
but for some odd reason this normally-useful method had no effect at all,
and so I then leaped for the big Red Panic Button supplied with the machine, some feet away!
- that did work to stop all motion.

Once my feathers were smoothed again(and still in Relative Mode)
I did a few (K)eyboard moves and Eureka! lo and behold the previously noisy X and Y (M)oves are completely gone,
and are now sounding civilized,smooth as silk, just like (J)og sounds!

Obviously, all the two gantries needed were a bloody good shaking-up to solve the noise that seemed worse than ever this morning, incidentally!

Sure, this is a most unusual "solution" to the problem,
and we're not quite sure just what happened to cause the erroneous movement in X,
or how the banging for 5-6 secs. vastly improved the signal to both the X and Y motors:
maybe someone could give it a shot?

[mikejohn]

David
You frightened the hell out of the poor thing, thats why!
I am considering reporting you to the RSPCSB


...............Mike

[harryball]

Just reading through this thread the first time... it's not the first time I've seen a good wailing fix a peice of equipment.

Loose connectors or a cold solder joint comes to mind. Years ago, I had a large steel industrial control box with a safety interlock system I built in it. There was a 386 motherboard (old PC now but state of the art at the time) and the system locked up anytime I closed the door to the box. Nothing but NOTHING made sense. When I closed the door, locked up. I felt sure it must be something I had built causing the problem. To make a long story short, after several hours I kind of lost my cool and slammed the door with extreme prejudice. The system began working!

Weeks later it failed again, this time one of my professors (this was part of my college project with the Georgia Tech Research Corp) told me what he thought was wrong. The motherboard had either a cold solder joint or separated layers. When I closed the door to the unit the RF inside the cabinet was sealed in and was disrupting the signal path. The sudden jar given earlier had stressed the board enough to hold the path closed reducing the capacitance. Alas, the problem recurred after sometime. Theory being right or wrong... replacing the motherboard solved the problem.

When I first starting reading the post I wondered if the gear teeth from one side to the other could be out of alignment.

Robert

[dhunt]

Turns out the primary problem seems to have been nothing more than a corrupt ini file to be found deep in the bowels of My Computer >> C: >>Program Files >> ShopBot >> somewhere,
where Support sent us looking for a small file with an icon that included a gold-coloured sprocket!
Dead easy to find once you're there,of course.
We threw it out, and the next time we restarted SB v.3.4.19 control software,
it asked us if we wanted to reinstall the appropriate whatever for our model of SB, which we did,
and Voila! quiet machine.

Since that simple and miraclulous solution,
any time we have any sort of machine screw-ups,
we dump said Golden Sprocket ini file,
and often enjoy a smoother machine,thereafter!

Another thing that seemed to have been manifesting itself as software probs. turned out to be a failing 733 MHz computer running the SB Control box,
which has now been replaced with a 450 MHz. machine which(incredibly)
runs the danged rig as smooth as silk!

so you can neverrrr tell just what it is..
that's up your SB's nose!