Is this whining noise a setting, or a hardware fault?

[jay_t (Jay)]

I’m new to Ruida controllers and LB software.
The problem I’m having sounds a somewhat similar to: GWEIKE LC1390N Z-axis grinding noise

To be clear, this AccTek laser has 2 control panels; main 1 is for XY control the 2nd is for the Z-axis which has an automatic height-following head.

When I start any laser job, the head normally moves down to just above the metal surface (we could call this a ‘punch’ movement?) and self-adjusts to keep that height right for the whole job. Holding the height works fine but there seems to be a problem with the initial ‘punch’ motion. View video clip here:
https://www.canva.com/design/DAGDF3hd1As/19WFuJ2ZuUvEhZeO61Evww/watch?utm_content=DAGDF3hd1As&utm_campaign=designshare&utm_medium=link&utm_source=editor
You can see it is possible to push on the whining head to help it downwards and then it will carry on just fine.

[jkwilborn (Jack Wilborn)]

That sounds like you’re loading the focus motor. Did it just start this noise?

[jay_t (Jay)]

I guess the focus motor is a better name for it. It started about a month ago but we haven’t been able to get a lot of help from the supplier…language barrier, etc…
My most recent research suggests the settings for this up-down function are not accessible from within the software, but this may be incorrect

[jkwilborn (Jack Wilborn)]

Russ Sadler did a video on problems with interpreting what the Ruida wants for auto focus…

I have never had an autofocus on my machine, so I can’t really make much of a suggestion. It sounds like it’s working OK, but I don’t know.

Here are a couple of videos that I watched a few years back and a newer one I haven’t. Might be worth a watch…

RDWorks Learning Lab 167 Auto Focus Frustration

RDWorks Learning Lab 169 Auto Focus Practical Alternative

RDWorks Learning Lab 249 Auto Focus for New Laser Users

Good luck

[ednisley]

@jay_t

push on the whining head to help it downwards

That suggests the focus switch is not tripping when the laser head reaches the bottom of its travel, where additional hand pressure moves it another itsy.

Given how fancy the machine appears and that it’s intended for metalwork, the head is probably an inductive sensor rather than a mechanical clicky switch.

The RDC6332 manual shows the controller console has a Diagnose button that displays the state of the axis switches. Get enough air under the laser head to hand-hold a chunk of steel and see where it must be to trip the switch; you may need an assistant to trigger the Read button on that display.

Then figure out where / what the switch is on the laser head and if it has an LED indicating when it’s active. If it does, you can watch to verify it’s not tripping at the bottom of the head travel until you give the head a shove. If the switch doesn’t have an indicator or you can’t see it, tape a stick to the side of the head to show where your chunk of steel trips the head, then eyeball the clearance under the stick during the focus cycle.

The switch may have shifted position upward (maybe it got bashed?) and can be moved just slightly downward so it trips properly.

Or the head moves on linear bearings that have collected enough crud to jam just above the lower end of travel, so the switch is fine and the bearings need cleaning.

Or all the tubes / wires / gimcrackery hanging off the head snag on something inconspicuous and prevent the head from moving freely all the way down.

Plenty of possible causes: stick a couple of eyeballs in there and look around …

[jay_t (Jay)]

Thanks, I will have a look at those videos for clues.

@jkwilborn

It sounds like it’s working OK, but I don’t know.

You mean the noise? No, not OK; that part normally runs very quietly. I notice it has no problem going up, only down.

[jkwilborn (Jack Wilborn)]

@jay_t

No, not OK

I assumed it made that noise … from you clarification, I’d follow @ednisley lead

[jay_t (Jay)]

@ednisley

the head is probably an inductive sensor rather than a mechanical clicky switch.

Correct Ed, it’s inductive, responds to touching it with metal or fingers.

@ednisley

laser head reaches the bottom of its travel

No, it isn’t anywhere near the top or bottom of it’s travel. It does have limit switches for this (which are working normally)

@ednisley

Or the head moves on linear bearings

The head moves up & down by the ‘screw’ beside the lens tube. The screw thread looks clean but I’ll see if I can find the bearings.

[ednisley]

@jay_t

• it isn’t anywhere near the top or bottom of it’s travel
• find the bearings

In that case, I’d expect to find the leadscrew between a pair (or more) of rods with bearings guiding the head.

@jay_t

limit switches for this

Does the laser head home upward / downward / not at all when you turn the machine on?

I assumed the Ruida was handling the Z axis downward punch-to-focus as part of its homing or focus ritual, but if the problem is in the sensor for the height following controller, then I’d suspect the sensor is misbehaving.

[jay_t (Jay)]

Problem partially solved and it seems it was a hardware issue: I’ve reduced the speed & acceleration that the head may lift up & down. This lets it run happily but causes a different problem of it not adjusting to the proper focus height fast enough. Some fine-tuning may fix it otherwise I may have to run some jobs in 2 parts, one being slower and at fixed focus height.
Anyway, thank you for all your valuable input!