Author Topic: New MOP  (Read 413 times)

Offline nivagc

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New MOP
« on: August 09, 2020, 13:42:42 pm »
I was very interested to read this, it was posted back in 2012.
This is something I think would be very usefull as it's been a workaround issue for me for sometime having to produce sevaral different 3D drawings to be able to accomplish Engrave in all three dimensions.

I have tried to.
Import .STL files
Edit, Surface, Edge Detect
Clean up unwanted lines ect
Then Offset the 3D line.
Problem being is Cambam offsets the lines in the X and Y direction BUT levels out all of the Z dimensions to 0.

It will be interesting what you guys think out there, if there is an easier workaround and or plugin of some sort.

Best Regards Gavin


I already warned Andy I was going to be interested in this, so I'll just push it onto the stack to be popped out later.

When one creates a "3D" outline - say, a closed polyline projected onto a sloped surface - it is only possible to machine that outline in all three dimensions using an Engrave MOp.

Of course I don't see clearly enough to know why, but in my mind, I don't see why any pocketing or profile MOp couldn't do the same.  It would be delightful to have a MOp capable of that, or to make the existing ones do it.

Yesterday, Andy helped me solve a problem by reminding me that an engraving MOp would follow the 3D outline.  But I had to "hand build" a special outline inside my 'real' one in order to use an engraving MOp with an endmill cutter that has (obviously) a greater diameter than an engraving bit.

It worked a treat, but it would be great if a profile or pocket could do all its tool diameter offset magic AND follow in three dimensions.

LLoyd


Offline Dragonfly

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Re: New MOP
« Reply #1 on: August 09, 2020, 15:24:12 pm »
It's quite logical. Who can tell where the dept is under an offset-ed line?
But nothing stops you to project the new line back onto the surface.

Offline nivagc

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Re: New MOP
« Reply #2 on: August 10, 2020, 06:25:26 am »
Hey Dragonfly, Thanks for your reply.

I understand that I can project the lines back to the surface. This with a profile or pocket MOP would not be needed as Cambam only sees the lines from a X/Y prespective.

This is not the idea I have in mind.

The Engrave MOP has the ability to follow a route regardless of its position in space, its not just limited to the X/Y plane. However is limited to the centre of the line.

What would be nice is if you could put in a mill diameter or a roughing clearance so the mill would run along side of the line sooner than along the centre of the line.


Offline EddyCurrent

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Re: New MOP
« Reply #3 on: August 10, 2020, 19:26:45 pm »
Use, Edit->Offset, to make your new line
« Last Edit: August 10, 2020, 19:29:46 pm by EddyCurrent »
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Offline lloydsp

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Re: New MOP
« Reply #4 on: August 10, 2020, 19:35:38 pm »
Eddy, yes... that works.  That's how I did it back then.

But that's not his point.  He's asking for a profile MOp that will follow 3D lines, or, alternatively, an engrave MOp that will allow a tool offset based upon tool diameter.

There are all sorts of 'trap doors' in that first.  But the second should be easy, and it would be up to the user to deal with 'undercuts', etc.

Lloyd
« Last Edit: August 10, 2020, 19:37:24 pm by lloydsp »
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Offline EddyCurrent

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Re: New MOP
« Reply #5 on: August 10, 2020, 19:47:59 pm »
It makes little sense because as Dragonfly said the terrain under an offset could be nothing like the terrain under the original engraving line. It could work in some cases but not in others.

At least if you make an offset line and project that to the surface you know where it's going to cut.
« Last Edit: August 10, 2020, 19:50:15 pm by EddyCurrent »
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Offline Bubba

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Re: New MOP
« Reply #6 on: August 10, 2020, 23:34:56 pm »
if you make an offset line and project that to the surface you know where it's going to cut.
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Offline nivagc

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Re: New MOP
« Reply #7 on: August 11, 2020, 06:35:41 am »
Hey Guys, Thanks for your replies.

Lloydsp you've hit the nail on the head, that is just the ticket.
Yes i understand there could be issues with undercuts etc.
The main reason I need this is because the job in hand requires me to run a deep profile towards one end of the work.
Yes I could do several profiles starting in different places, but this is a big workaround.
What I tend to do is off-set the mill size in the original drawing then import/edit/detect edges then run the engrave.

Attached is the part I'm currently working on which are about 90% finished (I have 5 to do). It's a suspension link arm for a race bike.

Offline nivagc

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Re: New MOP
« Reply #8 on: August 12, 2020, 17:49:02 pm »
Hey Everybody,

I've added the .cb file for you all to digest! I've had to delete the .STL file as it was all to big to post! That was in the previous post.

As you will see I've achieved the offsets I required in my CAD package then moved over to Cambam, again edit, surface, detect edges. Then removed all unwanted lines etc.
Dropped it into place and added the engrave MOP.

I have Disabled the "Outside Profile NOT INUSE" but if you enable you will see how much "air" cutting is required to complete this work. You will also notice the end/slot mill would need at least 75mm of flute, in my experience you tend to get a lot of chatter when milling with long cutters.

By using the engrave MOP this way I can use a shorter end/slot mill with less "air" cuts.

Has anyone got any ideas on how this could move forward with this idea?

Regards Gavin

Offline dave benson

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Re: New MOP
« Reply #9 on: August 15, 2020, 04:13:01 am »
Gavin
I had a look at the stl, and most of it is fairly beefy (there's no stress reliving radii on the model)
so I'm assuming that you are going for the 5 mm radii from the endmill.
the model looks a bit light on in this area in the pic, I did try to import into Freecad and run the
FEM analysis but even after using Feecad to repair the model I couldn't get to run.
I'm very busy with my grinder project now, but when I get time I'll try again.

Dave

Offline nivagc

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Re: New MOP
« Reply #10 on: August 16, 2020, 15:46:13 pm »
Hey Dave,

Yes all stress reliving on the model is being done with a 10mm ball nose.
I'll be interested in the out come of the FEM analysis.
I'm not familiar Freecad as I use 3D Systems Cubify Design but will look into it.

Thanks for your input.

Regards Gavin