# Still breaking things :(   - I hope I am learning :)



## dansawyer (Nov 15, 2021)

I found a Bridgeport BOSS CNC 'project' and have managed to bring it back on line. The mill itself is in great condtion, the ways are chromed and the motors / ball screws are smooth and accurate. All very good and unfortunately still way above my pay grade. 
I am trying to make parts but am stuck writing g-code directly. This weekend I:
1. Forgot to raise the z axis before I repositioned the x axis and ran the edge finder into a vise, scratch one edge finder - minus 4 points. I was able to figure out how the edge finder worked + 1 point. 
2. Ditto above error on a #30 drill in a piece of work. Minus 4 points on the error and minus 2 points for making the same mistake over again. 
3. Similar error: At the far end of aa x axis travel I issued a combined x, y command to return to home. The y movement took the drill edge into the vise face and acted like a mill cutter. Minus 4 points + minus 4 more for making a similar error. 
4. The last straw: I had a piece of bar stock down in a vise. I was using a centering bit to mark drill locations and forgot to notice the top of the centering bit would run into the vise face as I move along the x axis. The bit took off a good piece of the vise face. Beyond grading, kind of like driving a car into a cement lamp post. 
The good news: I was able to make initial interchangeable parts. They fit together and the design idea was solid. 
I need to find a good CAD/CAM tutorial to get started. I have to believe it would help with some of the above errors. All in all today is a new day. 
Thanks for reading, Dan


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## mmcmdl (Nov 15, 2021)

I tried to keep up with the points count but got lost . CNCs are fun .


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## DAT510 (Nov 15, 2021)

I know your pain!  I've used this Gcode simulator to test out my gcode before hitting start on my machine.  It helps me with the big goofs. 









						NC Viewer // GCode Viewer and Machine Simulator
					

Powerful online GCode Viewer to simulate GCode files. NC Viewer is the best free gcode editor for verifying CNC and 3D printer files.




					ncviewer.com


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## RJSakowski (Nov 15, 2021)

I have a broken edge finder from performing the same maneuver.  I have also run tools into a dowel pin and a clamp.   My CAM processor defines a safe plane for each tool and exclusion zones to prevent collisions but occasionally, the collisions still happen.  Writing your own G code will definitely increase the probability of operator error.  On a new program, I will set my z zero 1" higher than the actual zero and cur air.  I also single step my program for the approach to the work to verify that my tool offset is correct.

The original controller on my Tormach mill was Mach 3 and would reference the z axis before the x and y.  The current controller is Path Pilot and references the axes individually so I immediately developed the habit of referencing the z axis first.  PathPilot has an andditional feature which allows table feeds and rapids to be slowed down a crawl whuch gives you sufficient time to hit the e Stop when a collision is imminent.  Useful on a first run of a new program.


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## Larry$ (Nov 15, 2021)

XXit happens. Had an employee leave a decimal place off a parameter setting. Z-axis down 7 instead of .7 expensive! Direct g coding is risky.


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## ericc (Nov 15, 2021)

A simulator would not have caught these errors.  They are outside the narrow use envelope.  The only way the simulator would help is to only run the machine under gcode control, and model all the workholding.  Typically, both of these are violated to some degree.


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## mmcmdl (Nov 15, 2021)

Can you run a dry run or does the machine have graphics ? I remember all of our machines I could do either to test out programs not written by myself .


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## Just for fun (Nov 15, 2021)

Oh heck Dan,   that sounds like quite a day!


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## Bob Korves (Nov 15, 2021)

This is why I stick with manual machines.  They are cheaper and let me work my brain to keep the cuts to where they need to be.  My old brain needs the exercise, and I like to do the work with as little written down stuff as possible.  Have a well thought out plan, and measure as you go along... 
OLD SCHOOL!


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## RJSakowski (Nov 15, 2021)

Bob Korves said:


> This is why I stick with manual machines.  They are cheaper and let me work my brain to keep the cuts to where they need to be.  My old brain needs the exercise, and I like to do the work with as little written down stuff as possible.  Have a well thought out plan, and measure as you go along...
> OLD SCHOOL!


I like running manually, and most of what I do on the CNC mill is manual but there are some things that can't be done on a manual machine.


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## Reddinr (Nov 15, 2021)

I almost always "cut air" above the part for the first run.  I've saved many end mills that way and avoided many clamp/vise hits.  I usually run with a laser pointer mounted and I can watch the path better.  It does not help with:

Migrating parallels that get zonked half way through the run.
Missed that there were hardened set-screws inside a part.
Improperly tightened vise.
End mill slowly pulled out.
The XY table that grazed a part that fell over and knocked over the computer that ran the show.

Ask me how I know.


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## RJSakowski (Nov 15, 2021)

I have used a piece of 1/4" Delrin rod set about .5" high when I air cut.  The Delrin will deflect if it runs into an immovable object.


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## dansawyer (Nov 16, 2021)

RJSakowski said:


> I have used a piece of 1/4" Delrin rod set about .5" high when I air cut.  The Delrin will deflect if it runs into an immovable object.


Thank you all. Very interesting. I am glad to know there are combinations I have not tried yet.


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