Tool Selection?

Here's the place for discussion related to CAM/CNC and the development of the Path module.
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JoshM
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Re: Tool Selection?

Postby JoshM » Sat Oct 07, 2017 5:26 pm

Thanks Gene. I updated Freecad yesterday--will keep updated frequently going forward.

I'm unclear on pocketing if you mean clearing the hole, or the different behavior in two identical pockets. In latter case, the cut is incorrect. I do get that though I say identical, the two pockets might differ from a 3D model standpoint--construction layer constraints might differ for example... if you meant clearing around holes being traditional, what's the workaround traditionally applied to remove that remainder?

Regards,
Josh
GeneFC
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Re: Tool Selection?

Postby GeneFC » Sat Oct 07, 2017 11:38 pm

Josh,

I may not fully understand what you are trying to show. The only picture I see shows two pockets that look the same. The small residue around the holes is due to tolerances, and perhaps due to a somewhat flexible material.

The newly named "3D pocket" does indeed clear out the entire pocket area. I am a bit confused, since I believe this is supposed to be the old-style pocket, and the new pocket operation is the one that should have the flexibility to clear more than just the exact bottom face.

Perhaps mlampert or sliptonic can explain better.

Gene
mlampert
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Re: Tool Selection?

Postby mlampert » Sun Oct 08, 2017 1:19 am

GeneFC wrote:
Sat Oct 07, 2017 11:38 pm
The newly named "3D pocket" does indeed clear out the entire pocket area. I am a bit confused, since I believe this is supposed to be the old-style pocket, and the new pocket operation is the one that should have the flexibility to clear more than just the exact bottom face.
That is correct - except that the "3D Pocket" operation is the old pocket operation, and the "Pocket Shape" operation is the new one. What Pocket Shape brings back is the way the original Pocket operation from several months ago operated before we switched to using Path.Area.

I struggle a bit to clarify with all the "new" and "old". From a timeline perspective it looks like this:
* a long time ago we had "Pocket" which just milled everything above all the selected faces
* along came Path.Area which made a lot of functionality accessible
* all operations got moved over to use Path.Area
- during this process the behaviour of Pocket changed silently because it used the actual shape of the model as input for the operation, the two most noticeable consequences were:
- FinalDepth could no longer get manually modified
- Anything surrounded by the selected faces got pocketed as well
* while Pocket now worked nicely like a 3D roughing operation it caused issues where one wanted controlled pocketing
* we renamed Pocket to '3D Pocket' and moved it into a '3D Tools' group, together with '3D Surface' - and also gave it a new icon
* we created a new op called 'Pocket Shape' which only generates paths for the actually selected faces

I guess one of the potential confusions I absolutely underestimated was the creation of a new operation in the same place as the old operation with the same icon as the old operation - but still keep the old operation accessible at a different location in the toolbar with a new icon. The rational was that most would want the behaviour of the new operation so using the old icon and location in the toolbar would cause the least amount of "surprises".
GeneFC
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Re: Tool Selection?

Postby GeneFC » Sun Oct 08, 2017 3:25 am

Thanks for the explanation. I mistakenly thought the "3D Pocket" was the ancient version, not the recent version from the past several months.

Now it makes sense to me.

Gene
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JoshM
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Re: Tool Selection?

Postby JoshM » Sun Oct 08, 2017 3:33 am

Thanks for the help. I'll reread this carefully Monday, but sounds like you've provided options for the pocketing operation, so I may need to redefine my job--to cut over holes, verses clearing around them...

Gene--on that picture, there are two pockets in white delrin, faced at 12mm. Each of two pockets performed in two cuts at 9mm and finally at 6mm. Sorry for poor contrast, but note top-side of the bottom/closest pocket, and you can see final cut at 6mm differs from cut at 9mm. This is not true for the other pocket--both passes were identical and correct. The error is approximately a bit diameter--3/16" (4.6mm), so not an insignificant error.

Best regards,
Josh
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Re: Tool Selection?

Postby GeneFC » Sun Oct 08, 2017 3:43 pm

OK. I now see the step in the closer pocket.

When I tried pocketing your model I got error messages about b-splines, so it is hard to say what might have caused the step to occur. Errors can cause strange, seemingly unrelated effects.

I see that mlampert has just made a fix for the b-splines. New Windows versions should be available soon.

Gene
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Re: Tool Selection?

Postby mlampert » Sun Oct 08, 2017 6:01 pm

As it turns out I made a mess out of that fix - be prepared to get some errors. As with the original error there shouldn't be a functional impact. I submitted a fix and hopefully this time tested it properly to catch all cases - sorry about that :oops:
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JoshM
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Re: Tool Selection?

Postby JoshM » Sun Oct 08, 2017 10:17 pm

I'm really excited by the response here. I see impressive progress, and I'm looking forward to actively working with Path-Workbench. Although I'm not a developer, I will do my best to contribute feedback to hopefully help with evaluating software fixes/improvements. My coworker, Scott, has begun working with Freecad/Path-WB, which has helped--I've taught him enough to get going and have already been rewarded with learning things I had missed.

1--On Pocketing-Operation(s)--I believe both the ability to explicitly choose to mill OVER sub-cavities or, AROUND them is important. In the job I attempted Friday, the 6mm holes were small compared to the overall pocket, and beyond leaving a less perfect result, it created more work for Freecad and the CNC.

But, consider a simple 100mm square pocket, 5mm deep, with a centered parallel 90mm square pocket, 5mm deep(er). Selecting the 5mm "shelf" for milling might well not benefit from milling over the 90mm square. It might, but that's a strategy I'd prefer to have explicit control over. It sounds like the current FC-Path has that, but one choice is the obvious icon, the other is available but buried--if I followed Mlampert on that...

2--Early FC frustrated me when issues came up, but it's tremendously more stable now. Occasionally though, I will get some element(s) marked in error. Is there a strategy I should employ to fix those when they occasionally occur?

3--I want to minimize the number of unnecessary questions I post, and I'm aware most forums have some expectation that members make a good faith effort to search and read. Because development here is so active, it's not clear to me how best to navigate since a response from mere weeks to months might be outdated and counter productive. Mlampert's response with timeline for pocket operation highlights this. Any thoughts on what developers anticipate users to know/learn to become proficient at "driving" FC-Path?

4--If it hasn't been suggested before, I notice that toggling visibility of Operations grays them out on the Combo-View panel, but the lines still show on the 3D model. Is there a way to toggle the Green-Cut lines of operations On/Off that I'm not understanding correctly? The reason I have wanted to do this is that with multiple operations, the 3D view gets very "busy" with green lines, and inspecting a particular operation gets more difficult if unable to isolate it. On same note, changing the cut-pass colors for the same operation when multiple passes are used might better differentiate them.

5--I've had a chance to play with the G-Code output/Post-Processor use, and now see what you guys were driving at before: if I invoke the Post-Process icon, then the G-Code output has the Spindle gets turned on, etc... I was confused since this behaves differently than with the Export-Gcode, but is what I need, and is correct, so bravo and thanks!

Best Regard,
Josh
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JoshM
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Re: Tool Selection?

Postby JoshM » Mon Oct 09, 2017 4:19 pm

I modified my FC operations to use the Pocket_3D operation, and that did what I needed for pocketing the two areas, leaving clean results where the two holes exist in the pocket floors. Thanks for clarifying those operations mlampert!

I added pocketing for the Pickout I will need to insert into the mold, which I hadn't attempted before, and used the Pocket_Shape operation. It behaved correctly for that operation, although it highlighted a complexity that I'm not sure how to resolve. It's not a Bug, just a complexity.

Where there is material that must remain, I need to perform an "interior" pocket. Where the edge overhangs empty space, the ideal cut would occur at about a bit-radius to leave clean edges. The resulting cut for example can be seen to approximate the sharp edges of the 30 degree angles where the surface ends, and empty space begins. Ideally, I would like to cut there. I also have a remainder--likely the backlash amount of my machine--where the two pockets meet (similar edge at external) of about 0.025-0.050 mm... What FC-Path outputs is exactly CORRECT. I'm just not sure how to address the exception to allow me to have my CNC machine make cuts that are best for my job, but result from FC modeling and FC-Path strategies.

Dog-Bone options almost fix this, but are not quite able. For the short term, to accomplish this cut, I ended up having to generate a 3D model that was a subset of my final model--but only the Pickout Pocket, in an oversized Body, allowing me to generate a separate Fix-up file... I believe what I need to do either already exists and I'm not clued in to using it, or it will exist soon because this is a limit to useful machining otherwise...

Any suggestions are greatly appreciated.

Best Regards,
Josh
Attachments
Goniometer_Mold_Fixup.FCStd
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Pickout_Area..jpg
Pickout_Area..jpg (86.08 KiB) Viewed 562 times
2nd_Pass_Machining.JPG
2nd_Pass_Machining.JPG (276.56 KiB) Viewed 562 times
Goniometer_Mold_200.FCStd
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