Cutting start point in a job?

[Allan Longson]

I am using a ULS VLS6.6 laser with Corel Draw X6. I have "enhance and sort" in the laser print attributes selected. I am cutting out rectangular shapes that have 2 rounded corners on them. I want the laser to start at a square corner for each rectangle and most of the time it does so but every now and then it starts at a rounded corner. Sometimes, when it starts and finishes the cut in a rounded corner, the cuts do not line up exactly and I have to rework the job. Yes, it will be helped when I replace the X and Y axis belts but that is in the future when the parts arrive.
I have tried lead in lines but the laser just ignores them. I have tried various options in the sort and enhance field but that doesn't seem to make any difference other than the laser cutting random lines all over the place when everything is deselected.
Can anyone give any advice as to how to make the laser start a cut at a particular point in a job? Does the order or layers of objects on the page make any difference?

[Scott Shepherd]

In CorelDraw, and I'm doing this from memory until I can get in front of a computer, click on the node edited pointer, the one under the select arrow on the toolbar. Left click on the corner node you want to start at, then I think it's under "arrange", click that and then "break apart". You should see a little triangle node jump to that node. That's the starting point.

Try that.

[Mike Lassiter]

turn off or deselect sort in driver. The order of how they objects will be processed is from the bottom going up in the object manager. Something I have found is if you are vector cutting like a scroll saw type pattern and have many cuts that ramble around and lines that are open and also ramble about you will speedup laser time by node editing and looking at the direct the triangles point on the lines. Many times say you have several lines close together but the first one starts at the right side moving toward the left. Then the next one also will start on the right side and move toward the left. If you run this, the laser will go from the right to left, then have to travel back across to the start of the next cut to the right without cutting. If you right click on the node on the second line at the left side you can reverse direction of the starting point of the line so that now you cut the first line and instead of the carriage moving back across from the end of the first line back to the right to start cutting the second it will only have to move to the left side of the next line and cut as it travels back right.
This can take a good deal of time to optimize if there are many objects. I have done this for files that I have planned to cut many times and reduced cutting time by over 1/3 on one file. It isn't something worth investing the time in on many projects. ULS told me I would always see the best results by selecting sort and enhanced but I didn't find this to be the case. Laser Buzz files with the hundreds of small dashes to simulate the rope effect was the source of this for me. Started running them at 12 and rather than proceed around the diameter one dash then the next in a continious path the laser jumped all over the place doing one or two in one spot then across the circle and repeat. More time spent moving for here to there than cutting. A 1/3 time reduction for one part amounts to much more output if you have several items. It took me hours to go thru the hundreds of objects and place then in order in the object manager and reverse paths so the laser carriage moved maybe 1/8" between objects instead of 1/2" (times hundreds of objects). Sort is a great idea, but my experience has been it doesn't work that well. And in fairness if the nodes of lines determine the direction of the path then perhaps sort cannot over ride that and make the driver process then in what could be the truly best way.

[Allan Longson]

Thanks guys, I'll try these suggestions tomorrow and see how it goes.

[Richard Rumancik]

When you select a closed shape with the pick tool, you will see some nodes highlighted. The node with the larger rectangle is the start point. So you will know right away where Corel would start (unless the laser overrides somehow.) If you click on the shape tool while the shape is selected you will see the direction of the vector (arrow).

You can easily reverse direction of the cut, but I don't know of a command to re-assign the start/end point. Probably because CorelDraw is a drawing program, not a manufacturing program. To elaborate on what Steve said, if you have a closed chape, you can break it at a point (shape tool -> right-click node -> break apart) and then it will re-assign the start/stop. But usually I like to have my shapes closed. In this case, you could re-close the shape by dragging a shape window over the two nodes (start and end nodes) and selecting "join two nodes". Then the shape is closed again. Maybe a macro could be made to do this. Maybe there is an easier way but I don't see it in X4.

[Scott Shepherd]

To elaborate on what Steve said, if you have a closed chape, you can break it at a point (shape tool -> right-click node -> break apart) and then it will re-assign the start/stop. But usually I like to have my shapes closed. In this case, you could re-close the shape by dragging a shape window over the two nodes (start and end nodes) and selecting "join two nodes". Then the shape is closed again. Maybe a macro could be made to do this. Maybe there is an easier way but I don't see it in X4.

Richard, I've never seen any issues with the method I mentioned causing it to jump around, or treat anything like it's not one object. My experiences with doing that has been nothing other than it moves the starting point. I've never seen it change the vector order where it now sees that object as multiple objects and jumps around. It just moves the start point and that's it, from my perspective. Where it's closed or not, the start and end point are the same spot, so I'm not sure why that would matter.

[Allan Longson]

Scott, I tried your suggestion (I did leave the ULS driver "enhance and sort" option on) and it made no difference. The laser assigns it's own start points. Looks like I will have to try this in combination with enhance and sort off and ordering everything (thanks Mike) so it prints in the quickest manner. Sigh, pita, was hoping for something logical that could work other than hours slaving over Corels object manager....

[Kev Williams]

My Chinese Triumph starts wherever it damwell pleases, but my ULS and LS900's start where I tell them to start. My 'enhance and sort' option has always been OFF...

That said-- do you have room around what you're cutting to incorporate a tangential entry & exit? Example:
http://www.engraver1.com/erase2/tangential.jpg

This is a common practice when cutting vinyl, as the knife will cross the common point and cut it, rather than leaving a snick of vinyl un-cut.

This works great for laser cutting too. Each graphic is open rather than closed, with the start and end points outside the graphic. The cutting MUST start on one of those points. And, this way the beam PASSES the common point rather than stopping and starting at it, which can overburn.

The trick is finding some software that will create this. My ancient Casmate is how I do it...

In your case, since you're just cutting out simple rectangles, you can just hand-draw your own entry/exit in Corel.

A lot of the 1/8" thick plastic plates I engrave that I saw to size require rounded corners. I just have the laser do the rounding, but I have the edges 'tail off' to prevent the stop & start burn marks.

http://www.engraver1.com/erase2/rads.gif

[Scott Shepherd]

Scott, I tried your suggestion (I did leave the ULS driver "enhance and sort" option on) and it made no difference. The laser assigns it's own start points. Looks like I will have to try this in combination with enhance and sort off and ordering everything (thanks Mike) so it prints in the quickest manner. Sigh, pita, was hoping for something logical that could work other than hours slaving over Corels object manager....

Pick "Sort" and turn "Enhance" off.

[Mike Lassiter]

I do the opposite of what Scott suggested, I use enhanced and deselect sort.

From the ULS manual:

Vector Optimizer

The four available selections apply to vectors and

affect how vectors are grouped and in what order they

are executed. Vectors are grouped by pen color first

and will always execute in the color order listed in the color table, but all vectors of a given color will be

grouped and executed based on which of the following controls is selected:

None

This selection does no sorting or enhancing and prints in the original order in which they were passed to

the printer driver by the graphics program you used to create them. This is usually a random order.

Remember, however, that they will always be grouped by color.

Enhance Only

The ENHANCE function looks for all vectors that are connected in the graphic being printed and makes

them into a continuous path.

Sort Only

The SORT function will sort vectors so they are executed in the following order:


All open path vectors are output first, beginning with the end point of the vector path that is

closest to the current position of the focus carriage. All subsequent open vector paths are output

using the same “nearest neighbor” starting point method.


Once open paths are completed, closed paths will follow in a nested order, beginning with closed

paths that are contained within other closed paths, with the innermost closed path executed first

and ending with the outermost closed path.

Enhance and Sort

Enhance and Sort turns on both features simultaneously.

[Kev Williams]

as an addendum to my post, a simple way to create a start/stop overlap with any object with square corners
is to disconnect one corner, then move the nodes. In this case, the bottom-most/left node will always
be the starting point, cutting clockwise.
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