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Messages - Tool-n-Around

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1
Scripts and Plugins / Re: Drag-Knife Plugin
« on: April 18, 2024, 22:54:51 pm »
I was also wondering about this observation commented in my post.

Quote
As aside, on the attached file, if I examine the DK profile polylines, I expected to see a different Z-heights at the lead out moves driven by the retract depth and angles selected, and the engrave MOP would follow accordingly, but all Z coordinates are at the depth of cut. Why?

I noticed the same was true in the amended file.

Maybe I'm misinterpreting the meaning of the drag knife settings in the documentation for retract height and angle, but isn't the retract height supposed to establish the depth at which the knife point is initially engaged in the stock and the angle dictates the ramp at which it climbs out through the (re)positioning curl? If so, shouldn't that portion of the drag knife paths have changing z height for the engrave MOP to follow?

I suppose being able to place these knife positioning moves in the waste stock makes this less important since it is inconsequential if the waste stock is scarred by the move.

Best,
Kelly

2
Scripts and Plugins / Re: Drag-Knife Plugin
« on: April 18, 2024, 20:26:23 pm »
Hello kelly, Look at the picture ; is this what you want ?

Yes!!

To get this result ; for each polyline circle, I rotate them 180° around Z, so the first point of the polyline is at is left side instead right side. (a circle always has it start point at 3h00)

Ah-hah! Very clever. Also I didnt know that circles always start at 3 O'Clock. Thank you.

for the external shape, I add a new point to the polyline, at the right, them I define this point as the polyline start point. the pink points show where the polyline start points are.

use Eddy's Cbbule plugin to check where is the start point.

http://www.atelier-des-fougeres.fr/Cambam/Aide/Plugins/CBubble.html

I'll go away and play with this a bit to make sure I understand it.

Seems that the positioning arc is always done at the right side of the polyline start point.

This along with the rest of your reply should give me what I need. Still trying to get my head around if that preserves the proper starting position of the blade but looks like indeed it does.

Thank you,

Best,
Kelly

3
Scripts and Plugins / Re: Drag-Knife Plugin
« on: April 18, 2024, 19:45:40 pm »
However, I have made clean, unburred holes in gasket material with my CNC.  You do 'drill' them, at a very low rpm, using a hollow hole punch, not a drill or a mill. 

They come out perfectly smooth and sharp-edged, if you use the sort of punch tapered on the inside, rather than on the outside. (In other words, a "hole" punch, not a "disc" punch.) Lloyd

Good suggestion Lloyd. I do have the outside tapered disc punches, but as you say, they will break out an ear if not punched before the profile is cut. I could easily make myself some hole punches/cutters in several sizes, but I dont have a low spindle speed option. Still, they might come in handy as a manual punch. They are surprisingly hard to find.

Small holes do cut very well with spiral flute router bits with a spiral lead in, and also the type of drill bit similar to a brad point with the raised outer cutting edge. If the need arises for small holes in thicker stock, those may be the my only options. They all do create vacuum leaks in the hold down table. The knifed hole interiors stay put (most of the time).

For now, I'm trying to get by without tool change so I can cut many (nested) features in an unattended fashion and without secondary OPs.

The old school production method was steel rule dies and presses. Remember those?

Best,
Kelly

4
Scripts and Plugins / Re: Drag-Knife Plugin
« on: April 18, 2024, 16:25:12 pm »
Hi Everyone,

Me again. I’ve been using the drag knife plugin with good results but still learning and refining. I re-read this entire thread again and have a few questions. I’ll try to reference other posts in this thread that I think are relevant to my questions.

I’m cutting automotive gasket stock with thicknesses that range from .015”-.063”.  I was having trouble cutting smaller holes (~<.25”, but would like to cut as small as .125”), particularly on the thicker materials. Because of the material thickness, I am using the retract feature. My knives are fixed in their holders and not spring loaded.

Part of the problem with the smaller holes was the style and size of knife I was using. Dave Benson suggested I look at the small vinyl cutting knives. I purchased some of the “deep cut” variety and with their small offsets, made knife holders, and was able to cut the smaller holes with the paths generated by the drag knife plug in. I also was successful using the Profile MOP to do same as described by Dave earlier in the thread.

I realize I could mill or drill the small holes, but they collectively make for vacuum leak and loss of holding on the vacuum table, and optimally, I’d like to cut a large number of features and nested gaskets without a tool change. The use of a smaller knife and offset accomplished this for me.

My question is, how do I get the plug in to generate the knife repositioning move on the waste side of the material? On the attached file, they always land on the gasket side of the material not the waste stock.

If I could get the repositioning move to land on the waste side of the stock, I could use greater knife engagement in the stock to get more reliable lead out knife positioning without scarring the gasket.

Per post/reply #28 on page 2 of this thread, I thought the answer was through combination of polyline direction and starting point. But, on the attached file, if I change the polyline direction in the DK plugin dialogue box, it changes the direction of cut, but the lead out move still lands on the gasket not the waste stock side. Changing the direction of the original polyline used by the plugin to generate DK profiles has no affect, I presume because the plugin overrides direction per that selected in the dialogue box as remarked in post/reply #78 on page 6 of this thread.

I don’t know how to change the starting point. I see on the engrave MOP I can enter a new starting point, but hasn’t the DK plugin already pre-determined the required starting/ending point with the placement of the lead-out knife positioning move? Also, because the DK plugin generated tool paths are not closed, the direction is stated as unknown and is not able to be changed.

As aside, on the attached file, if I examine the DK profile polylines, I expected to see a different Z-heights at the lead out moves driven by the retract depth and angles selected, and the engrave MOP would follow accordingly, but all Z coordinates are at the depth of cut. Why?

I am using the latest revision of the plugin per the date of this post.

Here is a YT video I made of my learnings thus far using the drag knife.

https://youtu.be/FxsfDxR8CD4?si=tdivA4LVzXlxKlGZ

Best,
Kelly

5
Have a fairly complex part (modeled in CamBam) that I need two of........BTW it is just a straightforward 2D job ... several pockets and 2 profiles (one for each iteration of the part).

Any ideas will be appreciated.

No idea what caused the sizing anomaly but you'd likely be much better off just nesting the second copy instead of copying the model. That way any changes or optimization you make to the MOPs are automatically carried to the second nested copy.

I say likely because it's easier to nest if all the MOPs are contained within one machining "Part". If they aren't you must be careful with the nesting method to make sure the stock size and machine origins are consistent with the part geometry and MOPs.

Best,
Kelly

6
Hello

Quote
It's been so long I couldn't recall for sure so I went to the CB program file, checked properties and other than Verion 1.0 I'll be darned if I can identify whether its 32 or 64 bit. How do I identify that? There was a file in the CB folder fade2D_Win32_v120_Release.dll

Go to Help/about CamBam menu

In the info panel it will be named CamBam plus [1.0] x64 if this is the 64 bits version, and only CamBam plus [1.0] if this is the 32 bits version.

Of course, the 64 bits version can only be installed on a 64 bits version of Windows ;)

++
David

Must be 32 bit because only says CamBam plus [1.0].

Best,
Kelly

7
Kelly, Are you using the 64bit version of CamBam ?

It's been so long I couldn't recall for sure so I went to the CB program file, checked properties and other than Verion 1.0 I'll be darned if I can identify whether its 32 or 64 bit. How do I identify that? There was a file in the CB folder fade2D_Win32_v120_Release.dll

Best,
Kelly

8
Hello, I think (but not sure) that CB crash because your 3D model is too big and it ran in an "out of memory" error. Maybe you're using settings that gives an object with too much facets.

Are you using the 4GB patch to be able to use 4GB of RAM instead 2 ? (works only on 64 bits Windows) ; it solve most of the memory problems.

http://www.cambam.co.uk/forum/index.php?topic=4613.msg34067#msg34067

++
David

Does CB have a <100MB memory limitation? I ask because the original poster of this thread mentioned 100MB and I have a large (108MB) surface I wish to machine that fails because of the same memory exception. I originally thought the memory exception might have been my computer and I was going to install CB on another computer but having read this and the link to the patch, maybe not. I have experimented a bit with the mesh settings but it is a large surface (24" x 12" x 2") so even large mesh means a large amount of cells. If so I'll start another thread so as not to hijack this one.

Best,
Kelly


9
CamBam help (General usage) / Re: Problems Import/Export svg
« on: February 21, 2024, 15:31:21 pm »
.....If you can manage it, .dxf is the way to go, I believe you have issues with this as while you can use the geometry as a sketch you cannot modify it.

I think I have this sorted. I just need to immediately explode the dxf once imported to Alibre and then I can edit it, but if I don't clean it up and simplify it in CB, the sketch will have so many components I'll never get it fully defined and locked down in Alibre.

Just FYI, there are different versions of SVG files, and if you are having issues with importing for example a CB made SVG into Alibre

The funny thing is, I cant even open an Alibre created svg with Alibre. It seems like maybe it could be related to the operating system when the file is created. Both are windows based machine with ME Edge as the default application for viewing them. One computer has an older windows releaseand the other the newest but neither produces an SVG recognized as such by Alibre.

If you find yourself in a bind, you can load a CB SVG in Freecad  where the object comes in as wires and faces (meaning that they are fully editable) and can be turned into sketches if you need to and then exported to Alibre, Freecad has many file formats to choose from including Flattened SVG and both the WebGL formats, I know this is the long way round, but It's an option if you have a desperate need to, and cannot find any other solution.
Good Luck with the Guru's as this is where the solution should come from.

FreeCad would be useful for a lot of little tasks, mostly file conversion and compatibiliy for my other softwares. I'll eventually download it. Wish I was little more knowledgable in managing and maintaining my own IT affairs. I'm not. It comes from a lifetime in teh corporate world with IT departaments that did it all for me and had restrictive admin rights that prevented me from doing so even it I wanted to.

Thank again,
Kelly


10
CamBam help (General usage) / Re: Problems Import/Export svg
« on: February 18, 2024, 20:11:22 pm »
xml and html are both markup languages and hence look very similar. If I open the example svg circle file in Firefox it shows as a green circle in the browser window, any issue is not with the file but with your MS Edge.

Thanks Eddy, it's probably moot at this point since I can/should use dxf for my 2D transfers........until I actually do want an svg from a rastorized image or something similar. The CamBam generated svg files open and display just fine in MS Edge for me.

I dont know why Alibre doesn't recognize the svg exported from CamBam as a valid file format, but it also doesn't recognize an svg exported from Alibre as valid either. The computer I have Alibre installed on is a newer windows based platform also with MS Edge. SVG is supposed to be a supported input format by Alibre. I've posed that to the Alibre gurus.

-Until I need svg for some raeson, on to more pressing matters.

Best,
Kelly


11
CamBam help (General usage) / Re: Problems Import/Export svg
« on: February 18, 2024, 13:48:38 pm »
Ah ... the SVG format, it's an headache !! ........So I banned SVG from my life !! it is not designed for CAD works but for graphic design work !! ... the DXF IS the format to use for CAD works.

...and yah xml not html.....LoL!

As I mentioned earlier I wrote the SVG export plugin for use with my K40 laser.........The best format (for me) that does all of that is SVG.........For anything else I would most certainly use dxf

In the thread I originally asked about transfering 2D stuff, I was also working with (rastorizing?) images and somehow got it in my head that svg was the preferred 2D transfer file format. -I'll forget that.

I did switch and re-exported all the CB 2D stuff in DXF. The problem I was having with editing them was lack of familiarity with the Alibre 2D viewer and modeling screens. Almost everything (until now) I do in Alibre is 3D. Once I exploded them I could edit the dxf content fine, but it does pay to make sure the CB generated polylines are clean and simplified in construction, arc fit,...etc as possible so the explosion isn't such a mess. Depending on what I was using the dxf content for, most of the time it was better to leave it unexploded and just use the selected export of the dxf in the shapes needed for 3D modeling.

Once I figured that out I was able to quickly model this solid in Alibre from the CB dxf imports, then export it back to the original CB file as an stl. Then a quick sim in camotics with a simple scanline 3d MOP. I added some 2.5D features as well. It's an intake manifold lid and is approximately 24"x12"x2". After a number of years 2D modeling parts in CB, I have a pretty good library of parts and features made for other purposes that serve as the basis for many new similar designs, thus my interest in tossing the 2D files back and forth. I'm still getting use to the Alibre 2D viewer and commands for dxf stuff. My parts are all engine castings and machine parts so they need to be dimensionally accurate and precise.

Thanks for the help fellas.

Best,
Kelly

12
CamBam help (General usage) / Re: Problems Import/Export svg
« on: February 18, 2024, 02:25:56 am »
There's no problem with importing stl files to CB whether I have created them in Alibre or other. What I was trying to relate.......if I use the same Alibre sketch that will not export (import to CB) correctly scaled/positioned as an svg, to extrude a profile solid/surface then stl, that stl is is both correctly scaled and positioned when imported to CB.

When I export an svg from CB, It dsiplays as an MS Edge html file and Alibre wont recognize it as an svg, even though the properties of the file say it is an svg, so Alibre does not recognize it as a valid file format. However, I can re-import that same file to CB with the plugin svg loader.

The CB file in the previous post has all three examples as a simple circle.

Thanks for the tip on zip. See attached.

Best,
Kelly

13
CamBam help (General usage) / Problems Import/Export svg
« on: February 17, 2024, 18:08:22 pm »
I'm having some problems with the SVG plugin and trying to swap files between Alibre and CB.

When I export an Alibre sketch to svg, and import to CB, the sketch is about 100x larger than the size in the same units in Alibre and in the incorrect position. Alibre documentations says:

Quote
In a Part workspace, 2D Sketches can be easily exported to SVG file type either while within active sketch mode or when not in active sketch mode.  SVG export is generated at 96 DPI. Scaling to a 3rd party application’s expected DPI may be required within that secondary application for the sizing to be correct.

Boy, they can say that again....

If I make a thin extrusion with that same sketch in Alibre, export it as an stl, and then import the stl to CB, it is the correct size and position. There doesn't appear to be any setting available in Alibre for svg export. If I try to export more complex sketches from Alibre as svg, they are often a broken mess even though the are fully defined in Alibre. I've posted this one on the Alibre forum.

I cant read any svg file exported from CB in Alibre because Alibre declares it to be an unsupported file format. When I look at the file in windows explorer, it displays like an html file, well actually an MS Edge supported file. When I click properties it says it's an svg file. #2 below is an example. Is there a setting or step that I am missing in CB that would allow Alibre to recognize the file properly?

If I export a file from CB as a dxf, it imports into an Alibre sketch in the correct size and location, and even though I can use it as a sketch in solid modeling commands, I of course cannot edit that 2D geometry.

I'm really scratching my head here because I thought svg was supposed to be the universal format and I'd really like to be able to exchange and edit 2D geometry between CB and Alibre.

Attached are three one sample files.

1. Alibre SVG Export Test: A circle sketched in Alibre with 1 inch diameter located at X=1, Y=1.
2. CB SVG Export Test File: The same circle 2D sketched in CB and Exported as svg from CB (edit: the forum will not allow either of the svg files to be uploaded.....arghh!!)
3. CB Test File: Containing layers with the above two files and the and a CB sketch of the same circle used to create an svg of same originating from CB.

Best,
Kelly

14
Scripts and Plugins / Re: Drag-Knife Plugin
« on: February 15, 2024, 15:27:01 pm »
Thanks again Dave.

That's all pretty much as I suspected and had the same experience as you related above.

Since the last post,as a quick and dirty test, I just clamped a small razor knife balde in the slot of an ER16 collet and used the sprindle (router) bearings. It initially cut one great hole, then the fine tip on the blade broke, the blade was too flexible with much stick out, and the spindle bearings had too much drag to keep the knife properly positioned.

I'll make a small holder and grind my own blades......and I have an inexaustable supply of small tool steel and carbide. I'll see if I can cut the entire gasket with it, but if it requires a tool change to a larger knife so be it. I know I can cut those holes very nicely with a small end mill, and probably the hole gasket profle as well for that matter, but they expose the hole and with multiples cause vacuum loss on my vac platten. The knife cut holes seem to (mostly) stay in place.

.......I would show it to you but had a shop fire on the 23 dec and the demolition crew are coming around today to knock the rest of the building down.

That's terrible. So sorry to hear this. I hope you can recover quickly and build back better than before.

Best,
Kelly

15
Scripts and Plugins / Re: Drag-Knife Plugin
« on: February 13, 2024, 14:00:06 pm »
I battled with those little tear outs especially in thicker materials and smaller holes. So I set up an experiment watched the cut, and it turned out that the knife was not orientated normal to the cut, ie. The knife could have any angle and wasn't clocked to the impending motion around the cut. Industrial cutting machines can clock the knife angle.

Were you actually cutting stock or simulating? Either way, thanks for going the extra mile. In my sample cuts I did notice the little swivel move at the end of a cut didn't always get the knife reoriented properly, especially on thicker material. I played around with retract depth but wasn't much help.

What I tried then was a profile mop with the appropriate roughing clearance (to centre the knife) and used a spiral lead in, this worked well as the knife was gently orientated into the cut rather than simply plunging to full depth and then trying to orientate the blade possibly tearing out small pieces of material.

I actually had a fleeting thought about the profile MOP too, specifically for lead in function but didn't try it. I have a couple questions about the method you describe above.

1. I presume the knife still had offset. Is that so? If so, what was it?
2. Must have been a fairly shallow lead in angle. What was it?
3. Appropriate roughing clearance? How is that determined? Are you using the unaltered toolpath for the shape or the one generated by the drag knife plugin?

I also think using a smaller tipped blade possibly along with smaller offset could be helpful, because the various sources suggest drag knifes can cut radii comparable to but no smaller than the knife tip offset, so smaller would seem better for small holes?

Those utility blades oriented at 45 degrees have a lot of (straight edge) blade engagement/width in contact with the stock and I could see it was causing some tearing especially on the smaller holes and thicker materials,

I bought my drag knife because it was inexpensive and I already had to make the vacuum table. The popular hobby knifes are 1:1 with offset and depth of cut, but it doesn't have to be that way, and I'm not opposed to making what I need. It would be very easy to make a simple holder to test with a smaller blade.

The alure of being able to cut any gasket, or number of gaskets on a sheet, complete, without a tool change, is quite appealing to me. Plus, cutting and loading a sheet on the vacuum table is very fast and the cut cycle times are very short!......I'll get there.

Thanks again Dave.

Best,
Kelly

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