Buddy prsalpha movement chatter

[mryan]

Hi just setting up my new buddy prsalpha and I am experiencing some serious chatter in the x and y axis. Any settings above 6"/sec in the move parameters lead to serious chatter when moving in just that direction. When I use the jog command I have no chatter all the way up to 30"/sec. Also tried the spiral sample file and had problems even at 6"/sec setting.
Will be calling tech support at the earliest opportunity but in the mean time any suggestions would be appreciated.

Mryan:confused:

[Brady Watson]

Slow it all down...You are cutting WAY too fast. Start cutting at 2,1 and see how that works. Then gradually feed in more speed until your cut degrades (or your hold down fails).

It is A) Not possible to go 30 IPS on your tool and B) Not recommended to set the JS to 30 IPS. It is physically impossible for the tool go go 30 IPS in any direction within the confines of a BT (powerstick maybe...but not advised).

Picture the fastest car you can think of trying to go 200 mph in the 7-11 parking lot. Ain't happening. Even though the software will allow the tool to jog @ 30 IPS (on larger tools it can do it), the gearboxes are only rated to about 22 IPS max if you calculate what OM advises.

Aim for quality over speed...and grease your gear racks right now before you forget. Also, you should NEVER cut anything using Jog moves. All cuts should be made using M commands, up to 12 IPS.

Close SB3 can goto the Diagnostic folder in C\ProgramFiles\ShopBot\ShopBot3 & run SpeedTest.exe - Find out what your transmission efficiency is. You SHOULD have plugged that USB 2.0 hub into the back of your computer & the SB USB cable into that - Did you? What are your speeds with & without the hub? The condition you mention is pointing to low COM speeds, causing the motors to choke. This is not a problem when Jogging because the motors full step under jog conditions & microstep under move/cut conditions. The demand for communication is 10x greater during an M move that they are with a J move...which is why you see the difference.

Oh - welcome to the SB forum!

-B

[mryan]

Wow thanks for the welcome and the info. Was not even trying to cut yet just getting familiar with the machine and controls. I appreciate your recommendations about starting slow and agree entirely but was just getting familiar with the machines limits. I am familar with operating a larger SCM machine in our shop and understand the importance of going slow and keeping things well lubed. I did not use the USB hub and from your description this sounds like it could be my problem though I do not understand how the hub speeds things up. I will fix this on monday when I'm next in and run the test you suggest. Again thanks for the great response.

M ryan

[gerryv]

Welcome aboard Mark. You're off to a good start; you just got advise from the best.

[mryan]

I have done some further research on this forum on the importance of good communication between the control computer and the CNC machine and here are some comments.

1) It is clear from previous posts that this is a common problem that has been experienced by many.
2)The solution has been clearly articulated by the extremely knowledgeable and helpful forum members and shop bot staff.
3)Some members of this forum are getting a little frustrated dealing with the problem and explaining the solution.

Here is my addition to the topic and I am not trying to bash anyone just trying to be helpful.
The specifications in my manual for my controller computer says the following
"You need a pc with an available USB port that is running windows xp/7..."
No mention of the USB hub.
I read a post by a member I believe to be from shop bot that said
"There has been a hub provided for you by ShopBot tools. Its use has been specified in your instructions"
I have read the 2 instruction manuals that came with my machine and neither specifies to use the USB hub with the standard cable. Specifically it says
"plug the USB cable from the control box into a USB port on your computer"
The only time it suggests the use of a hub is if you are going use a cable longer than the 10' one provided with the machine. And here it says to not use a powered hub were I have read on this forum that a powered hub might help.
The advice it gives about USB communication problems is the following
"IF you should have a USB communication problem from electrical noise of the spindle or router, try shortening the cable" again no mention of the USB hub.

Again not trying to deride anyone but just trying to point out that if the HUB is as important as I am learning it is it would be beneficial to all if this could be clearly explained in the current manuals that come with the at least the Buddy machine I received.
Also the fact that this forum exists with its first class members justifies my decision to choose the ShopBot tool. I know that every piece of new equipment (especially something as complicated and capable as a CNC) will have setup and use learning curve. So the support provided by this forum and ShopBot is critical to a good customer experience.

Mryan

[Brady Watson]

Mark,
Please send a copy of your post to SB Support. In case you are not aware, it is a rare occurance that anyone from SB Support even checks this forum - Support, per se, is not the purpose of this forum. If there are discrepancies and inconsistencies in the manual, ShopBot should be made aware of it as soon as possible.


I've been running a ShopBot for a long time & there have been many different model variations over the years. The manuals seem to take some time to get updated from when a new tool is released. There are at least 3 different variations of the BT tools (since their inception) and this requires a change in the manual for each change.

Page 76 of the latest User Manual (via ZIP DL) (http://www.shopbottools.com/files/SBDocs/SBG00344OwnerManual100106.zip) towards the bottom states:

The Computer must have a USB (USB2 capable preferred) port that can be dedicated to running ShopBot. A hub and USB cable is included for connection between the computer and control box.

If you have a more efficient way of getting the USB thing noticed, please by all means make a suggestion to ShopBot. They are VERY GOOD at listening to customer suggestions on how to make things easier. As you can imagine, a seasoned user takes a lot of things for granted because they have done certain things so many times before that it becomes 2nd nature.

-B

[mryan]

Thanks Brady I will pass this on to support. My suggestion will be to place the the statement in appropriate and prominent location's (not at the end of a long technical manual). I am sure i am like most people and will not read the entire manual before I Start up my machine.
cheers

Mryan

[mryan]

Just received a reply from ShopBot immediately after sending them a email Wow on a Saturday even. They are currently updating their manuals and will make this point clearer. They said they will probably post a link at some stage for this forums input. Clearly ShopBot was the right purchase decision.
Cheers
Mryan

[myxpykalix]

"Instructions...we don't need no stinking instructions!":eek:

The best thing for you to do is to come back here and ask your questions if you get stuck and need help. We all were new at one time and we all came here for help.
Besides some of us like to show you how smart we are by answering your questions:D

[garyc]

Mark...
As Brady says, the hub may make the difference on many computers an whether the SB controller is installed on an enhanced port. This is required to have both reliable and full speed communication with the machine.

[gerryv]

I'm sure this has been stated a number of times before by the guru's we all lean so heavily on but I just can't recall or discover if a hub is recognized as an enhanced port (good thing) if it is not plugged into a wall wart. Sorry if the answer has been made obvious before :o

[mryan]

"Instructions...we don't need no stinking instructions!"

Yeah well I tried that on a $100,000+ Italian CNC with English instructions converted from Italian and virtually 0 tech support. Very steep learning curve(picture a cliff).
Lol
mryan

[garyc]

Gerry...
Putting a USB2.0 hub in a USB port forces an enhanced (USB2.0 480 mb/s) port. A standard port (USB1.1 12mb/s) will not allow full speed comm with a ShopBot and the machine will run jerky as a result of data choking.

About 10-15% of the computers out there (most of mine) dont require a hub. This can be verified by using the SpeedTest.exe and the USBView programs included with the SB3 software. If the ShopBot Controller is shown on an enhanced port and has an equal or higher comm rate without the hub, then it most likely is not needed.

[Brady Watson]

I'm sure this has been stated a number of times before by the guru's we all lean so heavily on...

Gerry...It takes being a 'guru' to fully realize just how much of a load of **** 'being a guru' really is...Same goes for 'expert'...:rolleyes:

:D

-B

[beacon14]

I heard somewhere that the definition of an "expert" is "someone who knows a little more about a subject than you do".