# My CNC mill did exactly what I programmed it to do



## dansawyer

The good news is my Bridgport BOSS 3 mill is back on line and working. I have learned to write simple G code, load it, and run the program. All good. It was facinating to watch the machine work through the program and create a part.
The bad news is I created an offset to account for the mill tool diameter - but added instead of subtracting the correction. The result is the part is too large.
I am fortunate to have linuxcnc loaded and operational. It provides a clean interface, visual representation, and DRO based on steps.


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## mmcmdl

You can get a smaller part out of too large part . ( unless this is a inside bore or feature ) . The opposite is not so easy . Only possible if you own an add-on end mill .


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## BGHansen

Controllers have come a LONG way over 40 years.  My Bridgeport has an Anilam Crusader 2 circa around 1983.  No preview screen or nothing.  Strictly conversational only programming.  It's a 2-axis controller which allows for very easy cutting in air above my project.  I prove out routines a couple of ways.  Sometimes make a pass into particle board.  I'll also do a light skim pass of 0.005" on the actual project if the air pass looks okay.

My Tormach has a screen shot of the complete tool paths before running the routine.  It also allows for virtual cutting.  Don't quote me on it, others with more experience will chime in, but I believe there are CNC simulators out there that will virtually execute your tool paths.  Might be worth a look.  Nothing breaks a tool faster than a G0 when you thought you entered G1!

I'm still a G-code guy too and am still learning.  G40/G41/G42 cutter path compensation is fantastic.  One lesson I learned this past year was to get off the part before issuing a G40 (turn compensation off).  My "assumption" was the tool wouldn't move when G40 was issued.  I'd cut to the corner of a rectangle (for example) and do a G40.  The cutter kept gouging the part.  Tormach's PathPilot allows the user to execute the program one step at a time, then pause.  I discovered that if I was using a 1/2" end mill with G41 or G42, issuing G40 moved the tool a 1/4" to a new position.  PathPilot's preview screen showed me what was going on with the completed part and the step-by-step pointed me to the offending code.  Now I do a G0 Zx to get off the part before issuing a G40.  A CNC simulator should give you the same tool.

Bruce


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## mmcmdl

Full graphics have been here for 25 years .  The Makinos I use to run had them and they saved my butt while learning Fanucs quite a few times . Canned cycle starting points were the main issue , other than learning that the machine will always return to that point , I found the conversational programming very easy and very quick .


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## talvare

BGHansen said:


> Controllers have come a LONG way over 40 years.  My Bridgeport has an Anilam Crusader 2 circa around 1983.  No preview screen or nothing.  Strictly conversational only programming.  It's a 2-axis controller which allows for very easy cutting in air above my project.  I prove out routines a couple of ways.  Sometimes make a pass into particle board.  I'll also do a light skim pass of 0.005" on the actual project if the air pass looks okay.
> Bruce


I have a Bridgeport EZ Trak 2-axis mill which works fine for what I do, but compared to today's CNC machines, it's a dinosaur. I use the same methods that you do for proving a program before I start cutting the actual part, but one of the most useful methods I use is to simply chuck a pencil in a collet and let the machine draw out the part. It sure helps to see those little unexpected moves that are just part of the Bridgeport canned program but don't show up as a line of code on the display. It has saved me from breaking a lot of tools.
Ted


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## Mtnmac

mmcmdl said:


> You can get a smaller part out of too large part . ( unless this is a inside bore or feature ) . The opposite is not so easy . Only possible if you own an add-on end mill .


We always wanted an "undo" button on the control.


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## dansawyer

Yes. I have the chips in the vaccum, however I did not number them when they came out. .
All is all it was a great experience. I am used to failing to make consistent parts because I fail to account for backlash or don't have the full design layed out. It will be an experience to design a part, create a jig and then make parts the same.


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## Shotgun

BGHansen said:


> Controllers have come a LONG way over 40 years.  My Bridgeport has an Anilam Crusader 2 circa around 1983.  No preview screen or nothing.  Strictly conversational only programming.  It's a 2-axis controller which allows for very easy cutting in air above my project.  I prove out routines a couple of ways.  Sometimes make a pass into particle board.  I'll also do a light skim pass of 0.005" on the actual project if the air pass looks okay.
> 
> My Tormach has a screen shot of the complete tool paths before running the routine.  It also allows for virtual cutting.  Don't quote me on it, others with more experience will chime in, but I believe there are CNC simulators out there that will virtually execute your tool paths.  Might be worth a look.  Nothing breaks a tool faster than a G0 when you thought you entered G1!
> 
> I'm still a G-code guy too and am still learning.  G40/G41/G42 cutter path compensation is fantastic.  One lesson I learned this past year was to get off the part before issuing a G40 (turn compensation off).  My "assumption" was the tool wouldn't move when G40 was issued.  I'd cut to the corner of a rectangle (for example) and do a G40.  The cutter kept gouging the part.  Tormach's PathPilot allows the user to execute the program one step at a time, then pause.  I discovered that if I was using a 1/2" end mill with G41 or G42, issuing G40 moved the tool a 1/4" to a new position.  PathPilot's preview screen showed me what was going on with the completed part and the step-by-step pointed me to the offending code.  Now I do a G0 Zx to get off the part before issuing a G40.  A CNC simulator should give you the same tool.
> 
> Bruce


You could try installing linuxcnc in a VM*.  Then you could use its AXIS program to visualize your GCode.

*For the unitiated, a VM is software that will run another operating system on your computer.  A virtual computer inside your computer, so to speak.


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