Sheetcam cut order and cut direction

I’ve been using sheetcam for nesting multiple cuts but it’s driving me crazy because I can’t get it to cut counter clockwise on inside cuts and clockwise outside. It also will cut the outsides first so on small parts they drop into the water table before the inside details can be cut. Where can I find these settings? Thanks!

On the lower left corner of the screen there are icons for the different operations (cutting, milking, etc). When you click on the plasma one (it’s the top icon on my stack) it opens a window where you define all the parameters for cutting. Sheetcam does it by layer - and by default all your lines are in one layer.

Before I do the cutting definition I put the lines on different layers so they can be different toolpaths. I almost always have these layers: outline cut, large holes, small holes and lines. I can order them as I want.

For lines I don’t have a lead-in or out or pierce pause. For small holes I also don’t use a lead-in/out. For large holes I have both. For the outline I move that to be last.

There is a path/line selector in the menubar - I don’t remember what the icon is but the hover help will say. I click or drag & lasso the pieces I want and right-click where the option to move it to a later (& create new layers) pops up. I turn off the layer in the layers section of the left panel on the screen. That way I can see what I’m moving as I do that.

Then when I go and define the cutting operations I pick the layer that I want the settings to apply to. I usually run the simulation and if it all looks good I post for Mach 3.

I currently create different layers for different cut profiles, I’ll have to pay more attention to which ones it’s processing first.

The problem I had the other day is I would create all of the layers for 1 part and nest the part where I wanted it, then create a new part, import a drawing, and establish the layers for that part. About 75% through the first part, the crossfire shifted to the 2nd part, cut the outside, then shifted back to the first and finished it. 2nd part was small so it fell right into the water :unamused:

With great power comes great responsibility :smiley:

The extra control over toolpaths is great but you’re right - gotta pay attention that it’s doing what you want in the order you want.

I’ll also sometimes break up cuts into subsets so it’s not doing a ton of cutting next to other cuts without giving the metal time to cool. In Fusion I have to setup separate paths. In Sheetcam you can just move the start points & order of each item in a toolpath.

The reverse cut direction is in the Operations tab. I’d bring your whole piece in. You select all your inside cuts first, create layer. Select outside cuts, create layer. Then in operations tab down in left corner, with that open you can select which layer you are programing. So I do inside first, set your feedrate, choose your preset tool (whats nice on this is you can select your tool right in operations and edit the pierce delay if needed etc, rather than going into a whole separate thing to edit your tool). You can set your cut direction, lead ins etc all within operations tab. Its really easy. Most times I have two layers. You can set rules also for small circles etc. I found all this out on youtube. Take a few tries to get use to all the symbols etc in sheetcam. I also like how you can select what pieces get cut first or last in each layer.

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That’s really handy to minimize warping of material. It takes a bit longer to cut the project that way but not running a production shop I don’t mind :slightly_smiling_face:

I realize this thread is exactly one year old, but the info is relevant to my question so…

I am building a job that is an indexed design requiring three sections over 66" (I have a 2x2 table, sorry). So, in Inkscape I sectioned my design into three different layers, each with it’s own color, and imported into SheetCam. I then ordered the Operations into three sets, each set belonging to each section. So far, so good.

Now, all of the contours are open lines since the contour stretches across sections. I defined the operations for each, checking Offset Open Paths and Leadins on Open Paths, with Contour Method as Outside Offset. Cool, SheetCam processed it all very nicely with good leadins and cut directions.

However, last night I realized it will be easier to align the indexed sheet IF the first cut of the next section is at the very end of a cut on the current section. So, ok, no problem, I started adjusting the Start Points in the second section and found something VERY confusing. If I tried to set a Start Point at the end of the previous section, the Inside/Outside relationship reversed. Without going into all the gory details, I discovered that I was being tripped up as to WHERE the ‘Start’ point was being flagged. When I edited a ‘Start’ point, I was really creating the ‘End’ point for the segment! Why? Well, again, long story short, for each operation I had Reverse Cut Direction checked (as advised for Plasma cutters) and, in so doing, the Start Point editor, on an open path, creates an End Point with the Start point at the other end of the line!

Not convinced? Try a simple open segment with a Leadin, no Leadout. Then highlighting the operation you’ll see that the ‘Starts’ are at the Leadout end, not the Leadin end of the segment and, if you edit them with the Start point editor, the start will only change if you click on the Leadin end and it will then become the Leadout end.

Now, I’m still ‘new’ to this so maybe the phenomenon is well known, but doing a quick search for info about this didn’t yield anything. Has anyone else observed this? Is it documented somewhere?

I got a reply from Lee on the SheetCam forum: https://forum.sheetcam.com/viewtopic.php?p=27377#p27374

Yes, this is expected behaviour even if it isn’t very intuitive. Open contours have no inside or outside so SheetCam doesn’t really know which side you want to cut. Instead it always cuts to the right of the start point. If you imagine you are stood on the start point looking down the line the cut will always be to your right. Now if you reverse the cut direction the only way to keep on the right is to start at the other end.
The alternative to this behaviour would be for reverse cut direction to also reverse the cut side but I decided it would be too easy to accidentally ruin your job if you change the cut direction in your operation and don’t notice it has swapped sides on open contours.

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