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Five paths to cut a square? #eagle #gcode


Martin Rowe
 

Setup: OS OpenSUSE 15.2, Eagle 9.6.2, PCB-GCODE 3.6.2.4

Workflow: New Eagle Project with a single component with a single 2.00x1.00mm SMD pad centred at 20x10mm on board.
Run the pcb-gcode ULP and remove all the "generate" options except Stencil (I'm working towards a laser cut solder stencii - hopefully!l).
I have attached the resultant gcode file.

My question is this: Why is the tool path making 5 passes to cut a 4-sided square? Should it be doing this?

Regards, M


John Johnson
 

Maybe I’m misunderstanding.
In the file you attached, I only see that it is cutting out the square with a single pass.


On Mar 23, 2021, at 4:09 AM, mprowe@... wrote:

Setup: OS OpenSUSE 15.2, Eagle 9.6.2, PCB-GCODE 3.6.2.4

Workflow: New Eagle Project with a single component with a single 2.00x1.00mm SMD pad centred at 20x10mm on board.
Run the pcb-gcode ULP and remove all the "generate" options except Stencil (I'm working towards a laser cut solder stencii - hopefully!l).
I have attached the resultant gcode file.

My question is this: Why is the tool path making 5 passes to cut a 4-sided square? Should it be doing this?

Regards, M
<dimensions.top.stencil.gcode>


Martin Rowe
 

... or maybe I'm using the wrong word with "path"? Let me try again...

Line 32 "G00 X19.0000 Y10.5000 " gets the tool to the North-West corner of the square.
Line 34 "G01 X21.0000 Y10.5000 F360.00 " moves the tool to the North_East corner
Line 35 "G01 X21.0000 Y9.5000 " moves the the South-East corner
Line 36 "X19.0000" moves to the South-West corner (modal - G01 still in effect)
and Line 37 "Y10.5000" completes the 4th side of the square by moving back to the North-West corner.

So why is Line 38 "X21.0000" moving the tool to the North-East again?

Regards, M


John Johnson
 

Ah, I see. 

I’m not sure why that happens. Pcb-gcode just processes the line segments that Eagle gives to it, so it looks like Eagle saw the need to pass that extra line segment. 

Regards,
JJ


On Mar 23, 2021, at 7:50 AM, mprowe@... wrote:

... or maybe I'm using the wrong word with "path"? Let me try again...

Line 32 "G00 X19.0000 Y10.5000 " gets the tool to the North-West corner of the square.
Line 34 "G01 X21.0000 Y10.5000 F360.00 " moves the tool to the North_East corner
Line 35 "G01 X21.0000 Y9.5000 " moves the the South-East corner
Line 36 "X19.0000" moves to the South-West corner (modal - G01 still in effect)
and Line 37 "Y10.5000" completes the 4th side of the square by moving back to the North-West corner.

So why is Line 38 "X21.0000" moving the tool to the North-East again?

Regards, M


Martin Rowe
 

Thank you JJ,

Can you also clarify another puzzle for me? Again in the Solder Stencil Making area.
From limited testing, it seems that whatever shape the Eagle PCB pad is (Rectangle, Octagonal, Round or Oval), the pcb-gcode "top stencil" output results in a bounding square? Is this correct?

Additionally, which Eagle layer is pcb-gcode reading to generate its stencil output? As an experiment, I placed a polygon on layer 21 - Top Cream and the pcb-gcode output is effectively empty?

Regards, M


John Johnson
 

Hi M,

Pcb-gcode only uses the top, bottom, mill, and text layers. This might be why you're seeing a bounding square - it's actually on one of the other layers.
Is it possible you're using someone's fork of pcb-gcode that processes other layers?

Regards,
JJ

On Mar 23, 2021, at 11:52 AM, mprowe@... wrote:

Thank you JJ,

Can you also clarify another puzzle for me? Again in the Solder Stencil Making area.
From limited testing, it seems that whatever shape the Eagle PCB pad is (Rectangle, Octagonal, Round or Oval), the pcb-gcode "top stencil" output results in a bounding square? Is this correct?

Additionally, which Eagle layer is pcb-gcode reading to generate its stencil output? As an experiment, I placed a polygon on layer 21 - Top Cream and the pcb-gcode output is effectively empty?

Regards, M


Martin Rowe
 

Hi JJ,

Ever more questions - sorry.

On 01/04/2021 15:36, John Johnson wrote:
Hi M,

Pcb-gcode only uses the top, bottom, mill, and text layers.
Does that imply that the stencil output is deduced from the copper layers?
This might be why you're seeing a bounding square - it's actually on one of the other layers.
Sorry. What is "on one of the other layers"?
Is it possible you're using someone's fork of pcb-gcode that processes other layers?
It looks like yours? From https://groups.io/g/pcbgcode/files/2Software.

Regards,
JJ

On Mar 23, 2021, at 11:52 AM, mprowe@... wrote:

Thank you JJ,

Can you also clarify another puzzle for me? Again in the Solder Stencil Making area.
From limited testing, it seems that whatever shape the Eagle PCB pad is (Rectangle, Octagonal, Round or Oval), the pcb-gcode "top stencil" output results in a bounding square? Is this correct?

Additionally, which Eagle layer is pcb-gcode reading to generate its stencil output? As an experiment, I placed a polygon on layer 21 - Top Cream and the pcb-gcode output is effectively empty?

Regards, M



--
mprowe


John Johnson
 

Hi Martin,

I believe that is a modified version, but haven't been able to figure out who did it. I've search my drives, and don't see any version of the code or pertinent files that mention 'stencil'.

It looks like in source/pcb-gcode.h the variable PH_TOP_STENCIL is defined as layer 5, and the bottom as layer 10, if that's any help to you.

There are quite a few messages on the groups.io about 'stencil', which might be of some help to you.

Regards,
JJ

On Apr 1, 2021, at 1:20 PM, Martin Rowe <mprowe@...> wrote:

Hi JJ,

Ever more questions - sorry.

On 01/04/2021 15:36, John Johnson wrote:
Hi M,

Pcb-gcode only uses the top, bottom, mill, and text layers. 
Does that imply that the stencil output is deduced from the copper layers?
This might be why you're seeing a bounding square - it's actually on one of the other layers.
Sorry. What is "on one of the other layers"?
Is it possible you're using someone's fork of pcb-gcode that processes other layers?
It looks like yours? From https://groups.io/g/pcbgcode/files/2Software.
<pjehlnllhdlhpebp.png>

Regards,
JJ

On Mar 23, 2021, at 11:52 AM, mprowe@... wrote:

Thank you JJ,

Can you also clarify another puzzle for me? Again in the Solder Stencil Making area.
From limited testing, it seems that whatever shape the Eagle PCB pad is (Rectangle, Octagonal, Round or Oval), the pcb-gcode "top stencil" output results in a bounding square? Is this correct?

Additionally, which Eagle layer is pcb-gcode reading to generate its stencil output? As an experiment, I placed a polygon on layer 21 - Top Cream and the pcb-gcode output is effectively empty? 

Regards, M



-- 
mprowe