Weird behavior and crashes...

Hello!

I am experiencing some odd behavior during simulation and code output. I have attached the file that has an example of the behavior. Basically the file is some letters and an appropriate bridge to hold them during machining. The end mill is a 3/16" HSS ball nose. The stock is 3.5" x 3" for the CAM but in truth it is a 3" x 1/2" x 12" 6061-T6 flat bar. I use a curve to limit the machining to a smaller area of the stock.

When you run the simulation it collides with the sides just above the bridges after a few passes. It also manifests in the generated g-code as the cutter would collide with a very high face and possible break the end mill. I apparently had another edit that produced a collision earlier. I heard it but didn't see when it happen. The resulting gouge on either side of the stock above the bridges was small that time so I just thought my gibs had come loose. Now this attempt has a much more pronounced jog out side of the curve defining the boundary to cut within.

Also, when I forget to stop the simulation before I close the window I crash Rhino.

Thanks for the help!

OK, so here it is again!

If you are looking at the letters JB the bridge to the left has the anomaly. Basically about half way down the end mill sudden starts doing a spiral which half of the spiral is entering the face of the stock. My end mill would break at this point because it cannot handle the depth of the entry which is rough 0.25" deep, even in a spiral motion.

This is a TIALN 3/16 4 Flute end mill, BTW.

I stopped MadCAM from doing the swirl by adding an object to the right and left and made it part of the model for the tool path calculations. Then MadCAM found the face of the stock and left out the spiral entry at the bridges.

Now this roughing pass is really a mess! At first look I thought I had stopped the collision with the sides but in truth it goes nuts at the bottom. The simulation shows the cut goes fine at first but then it basically machines away the very model it was working on! Yikes!

Unfortunately I have no time until the weekend, but then I can have a look at your model.

Cool! Thanks, probably pilot error anyways.

Take your time, I'm down with hardware issues until next week.

Can you post a screen shot of your parameters? Step-over, step-down etc. Also, can you attach the tool? It will have a .ctr extension, and most likely will be found in C:\Programdata\5XCNC\MadCAM\5.0\Cutters. If it's not there, then you most likely have your own custom place for it (as do I). I'm asking for this because I (and much of the rest of the world) work in metric so having the actual tool you used will be beneficial.

FYI... I changed the units to millimeters in Rhino, let Rhino scale the model up 25.4, and tried with my Ø4mm endmill (Ø.157"). I didn't see any problems. It worked well. I think to truly test what you are seeing, I need to do it in inches with your tool and parameters.

Thanks,

Dan

Further on this subject...

I tried with a Ø5mm endmill (Ø.197") and it's looking okay too.

Dan


Attachment 232706

As far as parameters I accept the defaults set by madCAM... with the exception of making the bottom stock a little lower than the actual stock so that the end mill will make a clean edge on exit out the bottom. Otherwise, I ended up with a curved out slope at the bottom of the letter where they should have been straight and I didn't want to change tools on my tool changer-less X3 mill.

Here are my cutters, I am using the TIALN 3/16 4 Flute the most.

Thanks. I will take a look in the morning.

Dan

Have you changed the mesh properties for your model?
Don't forget, they are per file and not global.

I loaded your tool and recalculated the toolpath using your exact settings and it worked well. I took a look at the mesh properties and it was set at the default "Jagged and faster". As Sven mentioned, you need to be conscious of your mesh settings when working in madCAM. There is a couple of ways you can do this. The least efficient way is to memorize the settings and change them every time. I wouldn't do it that way. You can set the properties and then save a template that you use every time you use madCAM. I don't do it that way, because I've got way too many templates already. What I did was add another button to the madCAM toolbar, right at the beginning, that sets the mesh settings and also creates some layer organization. That button runs a simple Rhinoscript (soon to be converted to Python) that takes care of this. So all I do when I need to make some cutter paths is to pick that button first, then activate my part. If you're interested, I can share that script.

Back to your problem. In this case, setting the tolerances correctly wasn't a factor in cleaning up the toolpath. Honestly, I'm not sure what is the cause. What are your system specs? Maybe we should start there. Are you running the latest madCAM in Win7 64-bit? Are you using Rhino 5 64-bit or 32-bit? Is your Rhino at SR8?

Attachment 232924

Version 5 SR8 64-bit
(5.8.40305.11495, 3/5/2014)
Commercial

Latest version of MadCAM (5.0.2014.304)


I am using Windows 8 Professional, 12 cores, 36 GB RAM so its not running out of memory.

Weird but it kind of taught me to always run the simulations before cutting.


Thanks for looking into this for me.

The only difference I see between your specs and mine is the OS (and a lot more RAM). I don't have Win8 to test on, so someone else might need to give this a try. I've tried it a few different times, and it works as it should every time for me. That's good, but not very helpful to solve your issue.

Quote:

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Originally Posted by Dan B

What I did was add another button to the madCAM toolbar, right at the beginning, that sets the mesh settings and also creates some layer organization. That button runs a simple Rhinoscript (soon to be converted to Python) that takes care of this. So all I do when I need to make some cutter paths is to pick that button first, then activate my part. If you're interested, I can share that script.

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Hey Dan,

Is this posted anywhere that I can get it? Would love to check it out.

Thanks,

Jason

Contact me off-line and I will provide the script. It's a Rhinoscript (not Python) so hopefully that's not a problem. Re-writing it in Python is on my to-do list, but I haven't gotten to it yet.

[email protected]