Shopbot vibrations and sounds

[Unckdecamp]

Hello all,

So I am testing out our new PRStandard machine and I noticed that when we do an outline of a Z, the machine makes a weird noise and starts vibrating a little bit while cutting the diagnol part of the Z.

Is this the X motors being out of sink, or was it just too small of an increment for them to move while sliding the Y car?

I have no clue what is going on?

Please help!

Thanks!

[Unckdecamp]

Also,

We are going to be cutting 1/4" PVC board, so does anyone have any starting suggestions as to how fast to move while cutting and RPMs and router bits, etc...

(We haven't tried cutting anything yet)

Thanks in advance!

[Gary Campbell]

Mark...
Some combinations of X & Y moves produce resonance from the steppers. This does sound like a growling noise and is more prevalent in the standard machines. This is normal. It usually occurs when the move in one axis is much longer than than the other.

I assume you mean the extruded pvc foam usually for signs, we cut letters at 2-4ips, 10K rpm with a .125 or .185 single upshear O flute. You would need to adjust for your machine and router/spindle capabilities.

[dlcw]

Mark,

My PRSAlpha growls a lot when I move at high speed (15-18 IPS) along the Y axis. It doesn't do this along the X or Z axis though. I sent a video with audio to Shopbot and they said it was a normal resonance noise from the motors. Guess it's the luck of the draw with the stepper motors ShopBot puts in to a particular machine.

[scottbot]

I get that too and it's been driving me crazy.
I've adjusted the cam rollers and checked the pinion more times than I care to count. I thought for sure it was something I had adjusted wrong but nothing ever appeared to incorrectly adjusted yet it still made that seriously unhappy sound.
I'm glad to hear that it's normal and I can quit worrying about it.

Scott

[Unckdecamp]

Thanks for the replies everyone!

I am glad to know that this is normal. I still want to run a test when I actually cut a letter Z to see if the slant part of the Z has a ton of ridges.

And the material is a sintra board.

http://www.sintrapvc.com/

Thanks again for the help!

-Mark

[jerry_stanek]

I use a 1/4 inch gerber P80368A and cut at 4.5 IPS I do a lot of cutting in 25 mm sintra

[bleeth]

This has always been a feature of Bots at certain speeds. On PRT's it was so predictable that Bill Young defined it down to notes on a scale and had them playing Happy Birthday!

[dhunt]

This has always been a feature of Bots at certain speeds. ===> Our 10-yr-old PRT96 does it.

On PRT's it was so predictable that Bill Young defined it down to notes on a scale
and had them playing Happy Birthday!Maybe it was him who did "Joy to the World" this past Christmas?

http://www.youtube.com/watch?v=7kcmkOaBguA

[bleeth]

All posted by Seaside-Yep-That's our Bill! The PRS is more subtle in its Octave range than the PRT!!