corel draw tabs or bridges for laser cutting

[paul j campbell]

HI everyone

does anyone know of a plugin or system for corel draw or Autocad for the automatic creation of bridges
or TAB as some people call them in CNC

the idea is to cut kits that the parts are held into the sheet by tiny bridges

this is common in CNC toolpaths becuase you need to hold the parts in the work to stop them flying off the table

but is achieved in the toolpath not the drawing.
for laser it you need the bridges in the actual drawing
so i was hoping there was some software out there that handles this automatically or with minimal data entry i guess what i am looking for is a similar system to vectrics Tabbing function but as perhaps a plugin to autocad or preferably corel draw

the reason i am looking is i would like to cut kits of our propducts but need the parts to stay in the sheet...i have hundreds to do so i am looking for a fast solution

in vectrics software you can move the tabs around by dragging them and they also have a few other features
if it is not already out there it would make a great plugin for Corel and Autocad for laser users

thanks in advance for any help

[Scott Shepherd]

I would start by going into the "Outline" dialogue box and on the outline, click on "Edit Style". There you can make your own outline style and save it. Then it's just a matter of selecting it. If that doesn't work for you, you could easily create your own brush stroke with the space in it and use that for the outline.

[Scott Challoner]

You can also turn your ppi down to perforate the material. I do this quite often and it works very well. Do some experiments at different ppi settings to adjust how much force you need to break the parts out.

[Joe Hillmann]

If the items you are cutting are closed objects in corel you can draw a very narrow rectangle (the width of your bridge) over the part and then do "back minus front".

Select everything on the page and convert it to curves, Then you have to click on each spot where you want to put in a bridge, add a node, click break apart then drag the nodes apart.

Both method are time consuming the rectangle method works good if you have everything laid out then combine them before adding the rectangles but if you want to rearrange the layout afterwords it takes some creative thinking. The other method works best if you do it as you are designing the parts rather than at the end. So far I haven't found an easier way.

[Richard Rumancik]

Paul, I don't know if there is an automated method but I would be leery of it if there was one, for my applications. I usually want to decide myself where the bridge should go. What material are you cutting? Do a search on "tabs" or "tabs on cutouts" and you will find an old thread or two.

People suggest perforating and using special broken lines but I don't think those solutions will be the answer for you.

I haven't changed my mind on this since the old thread of 2010. Unless you can find a plug-in you like, I think you should use the eraser tool, and do it manually. It won't take that long - give it a try on a simple shape and see what you think. You can find my suggested procedure in that thread.

Always keep a copy of the master drawing and make a new version with the bridges for production.

[Joe Hillmann]

I never knew that the eraser tool worked with vectors in corel, I just gave it a try and sure enough. Thanks Richard.

[Steven Cox]

Another way you could do it is to draw the shape you want for the tab and colour it to a colour not used in the file, Set Snap to object, then position the object a few times around the path, just use the + key to duplicate each time. After you've placed all the "Tabs" where you want them use the find by colour to select all the "Tabs", then weld them all to the path and you're good to go. if you use a semetrical shape eg a perfect circle then Snap to Object will make the circle snap dead in the middle of the outline.

[Richard Rumancik]

Joe, to refresh my memory I just opened Corel and played around with a few curved shapes. It worked fine, but I was a bit surprised when I added a bridge and it changed the curvature of a segment. I found the problem - when using the eraser tool to make bridges, you need to make sure "AutoReduce on Erase" is NOT selected. Otherwise Corel attempts to reduce the number of nodes at the expense of accuracy. I did not seen any glitches when that selection was turned off.

[paul j campbell]

Thank you all so much This is all very valuable information and i appreciate it greatly
i will try some of the methods described

[Rodne Gold]

By far the easiest way is to draw 2 parallel lines , the distance between em is the distance of your tab.
Copy/paste and drag em wherever you want your tabs to be and then use the virtual segment delete tool to delete the section between the lines and then delete the parallel lines

[Glen Monaghan]

To use the virtual segment delete tool, you first have to convert your text to curves or it won't do anything. But, you also have to break the curve apart or the tool will do really bizarre things to the former text. But even once that's done, it can still be a nuisance... For example, I placed two lines across the looped part of an "e" shape and then used VSDT to remove the two "virtual segments" between the lines. Not only did it remove the segments, it also broke apart one corner of the inner loop, making a visible discontinuity. You can reconnect those nodes with the VSDT by holding down shift and either clicking directly on them or dragging across them.

Seems much easier to just use the eraser tool... No extra lines to create, move, rotate, space properly, and/or erase afterwards, no extra prep to convert text to curves, etc. Just select your text, pick the eraser tool, click on the eraser thickness box, type in the size of gap you want and hit return, click once on one side of the "e" and again on the other side, and the straight line between those two points is erased from the "e", done!

[Richard Rumancik]

Glen, I'm a bit confused - is your procedure intended to make it so that the center of the "e" doesn't fall out? (as in making a "stencil" font?) The eraser tool would be great for that application, but the problem Paul has is not limited to that situation but applies to any shape - even a simple rectangle. He doesn't want the shape to fall out of the sheet.

Since you were discussing the loop of an "e" it made me think you were trying to make it so the center of the "e" doesn't fall out.

To be fair to Rodne my procedure also requires convert to curves and breaking at one node so it is not closed. But unless you are vector cutting letters, most shapes will be curves already. For making bridges, the eraser tool only works on an open shape.

Rodne I tried your procedure as I want to be open minded - I have not used the virtual delete tool. After much frustration I got it to work but only when I selected the segment to be deleted using a "window" i.e activate the tool, click and drag a window over part of the segment to be deleted. So it did work. But you would need two styles of "trimming tools" one for vertical and one for horizontal bridges. Plus it requires lots of zooming as tabs might be only .010" (.25 mm) or so, sometimes less. So I have to zoom in on each bridge location to delete the tiny segment. Am I doing it wrong?

[Rodne Gold]

Yeh , you would have to zoom in if the bridges are small. The VSD tool acts like an Autocad "trim" and it doesnt make the item you trimmed into 2 entities , it keeps it but just removes the trim parts. I don't think you * have* to use a window to select the items you want to trim.
Go to You tube and search for virtual segment delete tool some arent in english but show the useage
http://www.youtube.com/watch?v=S9jsYnXsBw4
http://www.youtube.com/watch?v=yHj3NTLCX0s
http://www.youtube.com/watch?v=V0sXv3ZYrbg
Etc etc
Very powerful tool , far better than welds etc

[Glen Monaghan]

Easy to see why you're confused, Richard, because apparently I was confused first! For some reason, I was thinking the OP was talking about making a stencil font, which must have been from another recent thread. Going back and actually reading what the OP wanted, just making gaps in outlines (such as a rectangle cutout) so the piece doesn't fall out, my suggestion isn't suitable. In that sort of case, the eraser tool will create two parallel lines across the shape, fine for capturing interior cutouts but not what is wanted for single closed curves like the rectangle.

If one node (existing or newly created, perhaps at the location where a tab is desired) of a single closed shape is opened, though, then the eraser tool will work as desired by the OP when used as I otherwise described. And that might still be quicker and easier than creating parallel lines, moving/rotating them into position, switching to VSDT and removing the unwanted segments, then back to picking/moving/deleting the lines. And, you wouldn't have to zoom in and out to use the eraser tool this way.

[Richard Rumancik]

Okay, Rodne, I tried it again and looked at the videos - some places they click on a segment and some places use a window. But I can't get a single "click" to work reliably. Sometimes it just snips out a .001" segment, sometimes .005", sometimes the whole thing, and I have no idea why. I'm using X4. The window always seems to work the same for me and deletes the segment. And I do agree it is a useful tool - will keep it in mind.

However, we will have to disagree with the use of this tool as a way for making bridges, because with all the clicking and zooming-in required I think it would be a bit too slow for my needs. With the eraser I can just select the shape, then the eraser tool, and sweep it over the boundary making multiple bridges in one command. Of course the bridges are all placed by eye, but I think that is not an issue for bridges. I just drew a star, broke it at one node, and added 10 bridges in a couple of seconds.