History....correct terminology?

[turmite]

I know that in some cad systems, there is a feature called history or history tree. I have seen mention of it in cam systems, but I don't know what it is called. Would someone knowledgable in the use of such a system enlighten me as to how they work....and what they're called?

What I'm looking for is an answer to the following question.

If you create a toolpath with say .500" ball nose and you have all the parameters set up but have yet to post the code, then realise a .459" ballnose would be better, can I simply change the parameters for the cutter, hit a button and the software update the toolpath? No other input require other than the one change?

Mike

[turmite]

Anyone?

[Cammotion]

Originally Posted by turmite I know that in some cad systems, there is a feature called history or history tree. I have seen mention of it in cam systems, but I don't know what it is called. Would someone knowledgable in the use of such a system enlighten me as to how they work....and what they're called? What I'm looking for is an answer to the following question. If you create a toolpath with say .500" ball nose and you have all the parameters set up but have yet to post the code, then realise a .459" ballnose would be better, can I simply change the parameters for the cutter, hit a button and the software update the toolpath? No other input require other than the one change? Mike

History tree is a good term. They are a wonderful thing in my opinion. This is called "parametric modeling". Each step you do in building your model shows up as an event in the "tree". As a simplified example, let's say you want to build a rectangular part with some holes through it. You create a sketch on on of the planes, give the rectangle a length and width dimension and close the sketch. The sketch shows up in your history tree. Now you want to make a solid with some thickness, so you go to the "extrude" command and select the sketch geometry and give the extrude a height. Now you have a solid body. Now, for the holes, you make another sketch on the top of the block, give them a size and some dimensions from the edges, close the sketch and do another extrude, only this time, you tell the software to do an "subtract" to some depth, or all the way through. Boom, holes! Now here's the beauty of the tree: The boss comes by and tells you there's been a change, and he needs to have the hole moved and re-sized. Go up the tree to the hole sketch, edit it, change the dimensions to what the boss asked for, and as soon as you close the sketch, the model updates!

Now for the cam part. Yes, you can edit the size of the endmill and re-generate, and the toolpath will update without any other input.

These analogies are very simple, and softwares will have their differences, but that's the general concept. Hope this helps

[ger21]

Originally Posted by turmite If you create a toolpath with say .500" ball nose and you have all the parameters set up but have yet to post the code, then realise a .459" ballnose would be better, can I simply change the parameters for the cutter, hit a button and the software update the toolpath? No other input require other than the one change? Mike

I guess it depends on the CAM software. I use MeshCAM, and it doesn't have a history tree. But all the settings remain set, so that it is possible to just change the tool diameter and recalculate the toolpaths? Or are you asking if you can change the tool diameter and the toolpaths are automatically recalculated, sort of like changing a dimension in a parametric modeler?

[turmite]

Thanks cammotion and Ger,

Ger your question is what I want to know. cam got close, but I want to know if there is a history tree in cam where, as you ask, change a parameter and the result is all the following information is updated.

Let me get to the crux of my questioning. Joakim from Madcam is going to put some sort of history tree within Madcam and he ask me which would be better to start the tree with.....the cutter selection or the toolpath (not his idea). I assumed that most everyone who does cam, opens the model then selects the cutter of choice, sets the tolerences etc. until the tool path is created. It seemed quite backwards to me to start with the last step, but since I have never used a tree.....I thought I had better ask!

Since you are a mod, can I do a poll to ask questions about how this should be done and get the reasoning behind the thoughts?

Mike

[Cammotion]

I use Unigraphics NX 5, so this might be a scenario:

Note: In NX, the list of operations in the tree will have green checkmarks next to them if they've been posted. If you change a parameter in an operation, a red circle with a slash through it will appear, meaning you have to hit the "re-generate" button. Once you re-generate, it will have a yellow "exclamation point" next to it, meaning it needs to be re-posted.

Let's say I have a program for a part that consists of roughing, semi-finishing and finishing a tapered pocket. The pocket corners have 1/4" radii, and were finished with a 1/2" endmill, causing the cutter to change direction abruptly in the corners, so I want to use a 3/8" cutter to make the corners a sweeping motion. In the finishing op, I make the cutter change, and this will turn that op red, so I hit re-generate to re-calculate the toolpath, and re-post.

So, in my case, the program doesn't automatically update throughout without some clicking as described above, but it is pretty quick and easy to make modifications. (There are other ways to make changes in NX, but I'll save it for a different discussion.)

I'm sure that most softwares work in a similar fashion.

[ger21]

Originally Posted by turmite but I want to know if there is a history tree in cam where, as you ask, change a parameter and the result is all the following information is updated.

Sounds like a bad idea to me, if eveytime you change a setting, the toolpaths are automatically recalculated. What if you want to change a few different things? Do you need to wait for the recalculations every time? Seems like that would get old real quick.

Feel free to start a poll, but I think that you might only get useful info from those that have actually used madCAM, and know the way it works.

[turmite]

Ger I'm not sure if you meant Madcam has this feature now or not, but if so, no it doesn't. Anyone should be able to give input since what I am asking is not tied to any specific program, but a concept. I want to know what people think would be a good way to implement this, or something akin to it.

BTW I already have your input! With that said, and assuming you knew ahead of time the different changes you wanted to make, they could all be updated at once. On the other hand, if you discovered a needed change after making one, then the time would be no different anyway.....least wise the way I see it.

Mike