Problems with contour finishing

[justCNCit]

Hey, been successfully using this CAM package for years but the latest email to MadCAM seems to have gone ignored.

Basically I am doing an 8 foot sign, in about 2 foot long sections (its 1 foot wide). Running a 1/4 ball mill with .010" step over at depths of up to .75".

The older versions of madcam didn't have a contour option just parallel x or y. Contour looks like a new feature but seems to have a memory capacity issue or something. Does anyone know a work around?

it won't take the whole thing at once. The most it will calculate is about 6 x 6 inches of the part, or the whole part at .125" step over. Obviously the contour toolpath is much higher quality, anyone know what to do please let me know. Thanks

[IMG][/IMG]

[mcphill]

How much RAM does you PC have? That may be your limitation.

[justCNCit]

It won't be my system, since the toolpath is the same size for x and y parallels.

but it is a gaming pc with 4 gigs of RAM and a newer AMD cpu. windows 7

[svenakela]

I wouldn't say that Contour gives a better result by default, it totally depends what the work piece looks like and it can still leave traces - as any pattern. And of course it totally depends on the step etc. 0.010" is fine grained and the contour strategy is a lot more complex than ZigZag. On the other hand on a large work piece with a lot of details Contour is usually faster while milling because it avoids a lot of extra Z movements.

I did a test with a work piece that's similar to yours, and yes it takes very (and I really mean very) long time. Normally I don't use contouring, I think it's very useful when a mould with deep pockets is milled. I usually mill big surfaces and use either the ZigZag directions or some of my special "home made" strategies that are very nice for bent shapes.
The reason why it takes such a long time in a piece like yours is the calculation of the regions that can be contoured.

I say go for the X/Y path instead of contouring. You're not milling in steel anyway, right?

[justCNCit]

there are odd shapes involved in the machining of this part.

XY is ok but leaves ridges in one or the other direction. Contouring adjusts the toolpath so that it mills around bosses and cavities rather than ignoring the geometry of the feature.

fyi I did machine this part over the weekend and it turned out like crap. I have done contouring vs. xy and the difference is big.

i have no pictures on hand at this time unfortunately to illustrate this.

What were your system specs, pics of the part, and how big was it exactly?

computation time doesn't matter to me, so long as it is doable. Thanks for your help too.

[svenakela]

I did a workpiece with the same size as yours, one by two feet. I then added "leaves" on top randomly placed to have a scenario that looks like the image in your first post. I just quickly made the test on a laptop with pretty crapy performance, it took very long time but it did finalize the piece. The CPU was loaded as long as the contouring computation was ongoing so yes, there are heavy calculations happening.

I'm curious what your strategy is and what went bad during the weekend run. It shouldn't end up like crap just because you use the XY direction instead of contouring. Did you try XY and a pencil trace? I assume you have a higher license level as you have contouring, and then you also should have pencil. And if you don't have pencil trace, there are still work arounds...
Did you generate all the 3D-paths (roughing, Z-level) or did you go directly to facing?


I think we can sort out a working strategy even without the contouring. But as I mentioned my contour did run fine but the generation was time consuming.

[justCNCit]

well I did a simulation of pencil trace, and it isn't what I want, since it does Z-levelling at .010" steps.

the countour is actually a x-y finish, but the toolpath tends to flow around the features

it's not a higher level license either, its the newest version of MadCAM which I downloaded recently. Pencil trace is probably used in the contour algorithm for planar finish in the new version, which is what I am trying to use.

I'll post pics soon of how it turned out, the contour makes a world of difference, but my cutters wore out anyways and since its been 6 months since I worked on a part, I crashed the machine on it too :/

in any case nothing really went right from the start.

[Dan B]

Contour remachining should be making an appearance in the next service release of madCAM. This may be exactly what you need.

Dan

[svenakela]

I'm still missing information. What tool paths did you generate before the pencil trace? Contouring is just one piece of a whole strategy, I've been milling mould tools for a long time without contouring and still I have perfect results.
Did you read the 3D-tutorial, any ideas from that?

It might that Dan B's assumption is correct. I still think we can get this piece nice for you before that.

[Toolrunner]

So, what's the latest? this is an interesting thread. And what's the story with the new service release - any further details?
T

[svenakela]

I didn't get more info from the O.P. but I know that the service release includes contour remachining as a new option and a redesigned contouring that calculates much faster.
I think that the service release will be out before the Euromold fair (beginning of december).

Regards,
Sven

[Dan B]

I recall Joakim mentioning that material removal in the simulation will now support different colours (perhaps driven by the layer colour??)

This will be great for comparing what is cut from tool to tool.

Dan