Newbie Question - Sudden z rate change

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asever
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Newbie Question - Sudden z rate change

Post by asever »

I am trying to engrave on a sheet of brass. I am using a .007 engraving bit with a cnc Shark (Bosch Colt router). It started working fine, but then all of a sudden plunged into the piece (reading the G code it looks like .2362 inches) I can't figure out why.

I have uploaded the first snippet of the *.tap file as the file itself exceeds the size allowed by forum software. The crv file is way too big to uplaod (I could ftp it to server I maintain and link to it if that would help).

Any help would be greatly appreciated. I am learning...just slowly!

Thanks.

Andy
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glenn
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Re: Newbie Question - Sudden z rate change

Post by glenn »

Hi Andy, and welcome to the forum!
When you select your tool, make sure that the pass depth is set very small, so vcarve cannot generate a path that exceeds a safe limit.
Also, set the flat depth on the toolpath flyout on the right.
I hope this helps... keep us informed if you still have troubles,
Glenn

asever
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Re: Newbie Question - Sudden z rate change

Post by asever »

Thanks for the quick reply. Currently the pass depth is set for .003 inches and the flat depth is set for .005 inches.

Andy

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glenn
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Re: Newbie Question - Sudden z rate change

Post by glenn »

do you use Mach?
If so, is there a chance that your z axis needs to be reversed?
Can you use jog buttons to raise z and lower z?

asever
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Re: Newbie Question - Sudden z rate change

Post by asever »

Thanks again for the help Glen. I am pretty sure the Z axis is correct as I have cut 20+ items, and I have successfully cut several 3d items from 3d Vector (although this is not the first time I have had odd tool movement - I was cutting a 3d gavel and it was almost done with all of a sudden the router cut into the gavel).

I think the cnc machine is operating per spec because the G code shows the sudden plunge

G01 X-0.0805 Y-0.2457 Z-0.0050
G01 X-0.0704 Y-0.2457 Z-0.0050
G01 X-0.0716 Y-0.2440 Z-0.0050
G01 X-0.0725 Y-0.2391 Z-0.0050
G01 X-0.0728 Y-0.2009 Z-0.0050
G01 X-0.0715 Y-0.1978 Z-0.0050
G00 X-0.0715 Y-0.1978 Z0.2362
G00 X-0.0756 Y-0.2418 Z0.2362

G01 X-0.0756 Y-0.2418 Z-0.0050

I am not sure what you mean by using Mach.

Thanks again I sure appreciate the help.
Andy

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glenn
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Re: Newbie Question - Sudden z rate change

Post by glenn »

Andy,
Sorry...you have me stumped! (doesn't take much),
Mach is a cam program, by the way. Did vcarve generate the g code? The reason I ask is on my version it always includes the line number on each line of g-code.
Hope someone else can jump in and help you, I'm curious about your strange z plunge!
Glenn

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Re: Newbie Question - Sudden z rate change

Post by gravirozo »

hello andy


the part you have posted, it shows your router lifting up, and the two line of red shows moving to a point (actually an inner island) and start to work there...

this code looks normal... the G00 shows rapid movement on Z because the X and Y equally with previous point.... the second shows the movement "to" ... and the next line has same X Y position so only Z moving with feedrate downward to the -0.005 level... G01 interpolated movement with predefined feedrate...

but, shark has some habit, on the forum a few member use it.... mezalick got some extensive experience of shark routers...

type in the searc on the forum, "shark" and you will get a lot posts... you might find answer you asking for...


thanks
viktor


G01 X-0.0805 Y-0.2457 Z-0.0050
G01 X-0.0704 Y-0.2457 Z-0.0050
G01 X-0.0716 Y-0.2440 Z-0.0050
G01 X-0.0725 Y-0.2391 Z-0.0050
G01 X-0.0728 Y-0.2009 Z-0.0050
G01 X-0.0715 Y-0.1978 Z-0.0050 moving with feed to this point
G00 X-0.0715 Y-0.1978 Z0.2362 same x and y moving z with RAPID
G00 X-0.0756 Y-0.2418 Z0.2362 rapid to next x and y with same z
G01 X-0.0756 Y-0.2418 Z-0.0050 same x and y moving z with feed

no sudden drop

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Re: Newbie Question - Sudden z rate change

Post by metalworkz »

Hello Andy,
It sounds like the controller is losing control of the machine to me. This sort of thing happens with Mach3 being used as a controller if the screen saver or other applications are allowed to interrupt the system. I am not familiar with the CNC Shark and how the controller works, so I am not sure if this can be a problem with that controller.
Also I think there have been some posts here of similar problems where the activation of the controller software was not current so it was reverting to the trial version with a limited number of lines in the gcode. You may want to check the status of the software license to make sure it is not running in a limited state.
Best regards,
Wes
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mezalick
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Re: Newbie Question - Sudden z rate change

Post by mezalick »

My suggestion is to make sure you don't have any unwanted nodes .
Check your design closely.
It may be a glich in the program. I had a similar issue when I was cutting an item that was sliced.
Michael
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Re: Newbie Question - Sudden z rate change

Post by BrianM »

asever wrote:Thanks again for the help Glen. I am pretty sure the Z axis is correct as I have cut 20+ items, and I have successfully cut several 3d items from 3d Vector (although this is not the first time I have had odd tool movement - I was cutting a 3d gavel and it was almost done with all of a sudden the router cut into the gavel).

I think the cnc machine is operating per spec because the G code shows the sudden plunge

G01 X-0.0805 Y-0.2457 Z-0.0050
G01 X-0.0704 Y-0.2457 Z-0.0050
G01 X-0.0716 Y-0.2440 Z-0.0050
G01 X-0.0725 Y-0.2391 Z-0.0050
G01 X-0.0728 Y-0.2009 Z-0.0050
G01 X-0.0715 Y-0.1978 Z-0.0050
G00 X-0.0715 Y-0.1978 Z0.2362
G00 X-0.0756 Y-0.2418 Z0.2362

G01 X-0.0756 Y-0.2418 Z-0.0050

I am not sure what you mean by using Mach.

Thanks again I sure appreciate the help.
Andy
As has been said above, the moves you have highlighted in red are NOT plunges but retracts to the safe z / clearance height. The snippet of g-code you have posted looks fine.

Brian

asever
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Re: Newbie Question - Sudden z rate change

Post by asever »

Thank you for all the replies and help. The more I think about it the more I think it is hardware/driver related.

It is scary how fast a machine can drive a bit through a table.

Andy

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Re: Newbie Question - Sudden z rate change

Post by mezalick »

If you think it's a hardware problem, try slowing down the spped rate of the machine.
I run mine at about 70%

asever wrote:Thank you for all the replies and help. The more I think about it the more I think it is hardware/driver related.

It is scary how fast a machine can drive a bit through a table.

Andy
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