Vector Tabbing Problem

[chuck_p]

Here is a couple of posts regarding a problem I'm having with tabbing.....any comments?

**********my original post***********
Hello, I'm using the tabbing feature and having problems. Vector is generating wrong tool paths in the post. I'm using Vector 9.3c and Shopbot2g.cfg

Here are the steps I'm performing.....

draw ellipse in Turbocad, dxf out

open the file in Vector

shift select it, change/interpolate, draw/arc spline

use contour tooling to generate tool paths

change entities for tabs to TAB layer

insert nc, generate NC

After trying the first program and trashing a really nice red cedar panel, I looked at the Shopbot preview and seen the post had created extra tool paths where I had placed the tabs. I've tried several other variations but have had no luck in getting rid of them.

Any thoughts, Chuck

**********Fred's response***********
I have had a similar experience with tabs on the Shopbot. I found that if you Change-Break-Interpolate the arcs on the TAB layer, that they will cut correctly. If you try to leave any arcs within the tab, the Shopbot controller may lose track of it's position as it switches between absolute SA and incremental SR. Since you are cutting an ellipse, that would indicate that there were arcs when you started to add the tabs. You can use Pick and match to select the first entity and the all the rest by the TAB layer. Straight lines will cut with no problem. It seems to be limited to arcs contained within the SR commands.

For those not familiar with Shopbot Code, the G90 Absolute and G91 incremental commands in G-code are similar. The Tabbing function in the Vector 9.3 manual automatically lifts the tool a specified amount to leave small attachments between the part to be cut out and the surrounding material. This prevents spoiling the part or damaging the cutter or your self as your part nears completion and separation.

Best Regards,

Fred Smith IMService

[gerald_d]

See this post. (http://www.talkshopbot.com/forum/messages/312/588.html?1018529819#POST5832)

[chuck_p]

Thanks for the info. I want to use Vecotor to generate the tab so I can control the location. The Shopbot commands don't provide enough control. The tab really needs to be part of the program not a machine setting. I can make the tabs manually but that is awfully poor way of doing the job.


The problem appears to lie within the Shopbot software interpreting the .sbp Vector uses the SR command and makes shift in Z. As best as I can tell Vector generates the correct code but the Shopbot software doesn't interpret the SR and SA commands correctly.

Chuck

[Ted Hall, ShopBot Tools]

Hi Chuck,

Someone mentioned this to me a couple of days ago, but I was unclear on whether the problem was when ShopBot tabbing was on, or when trying to tab from within Vector. Could you send me a copy of the problem Part File (and maybe the vector version too) so I can have a look.

Also, have you played with the additional features of the tabbing command which allow selective activation of tabbing from within a file (look in the current Command Reference from the software with [HC])?

[srwtlc]

Hi Ted,

I thought I'd chime in here and say that if you recollect we e-mailed back and forth about this type of problem last fall. I was trying to turn the ShopBot tabbing command on and off in a file that had CG commands in it. Turning on, off, then on again works fine until it passes a CG move and from there on you can't turn it back on. I've since stopped using the VB command and tried using the tabbing layer in Vector which works fine until you again pass a CG command after which the machine gets totally lost. Apparently the switch from SA to SR, moving up and then the tab distance then down, then switching back to SA causes it to lose track or cut the CG at a different position or length. The two situations seem to be somewhat related since the problems begin with a CG command.

My remedy has been to use either Freds break/interpolate, or if I don't want to break a nice arc I divide to a segment that works for a tab and then raise that segment to the desired height (cut and paste) and draw line connect to complete the chain. I sometimes then reorganize the segments that were previously divided to get to my usable tab segment. It may take a little more time but not much, placement is where you want it, and you don't have to chase down an errant machine.

[gerald_d]

Hi Scott, your problematic experience is the same as ours. Your solution is what I have been calling "manual tabs" and we do it in AutoCad before going to Vector.

[Ted Hall, ShopBot Tools]

Ok Gang,

I've studied this one a bit ... First to Scott: Unfortunately, we don't have the inside file commands for turning tabbing on and off working yet for CG's ... it's a good project, and given the next part of the answer, probably time to deal with both.

On to Chuck: Ah gee ... well this one shows up a little flaw in our thinking. CG's were basically created by modifying the CC command. If you think about CC, it has no parameters that would be influenced by "Relative Mode" since this command always creates an arc from the point that it is at through some number of degrees. CG, on the other hand, has a destination with a location ... I believe that we basically never contemplated that a CG might be done with this location being a relative location (and thus needed to be a little different than CC). Thus in the Vector created tabbing which switches back and forth from Absolute to Relative, CG just doesn't work. Interpolating the file (which gets rid of the CG's) works fine. We'll get to work on this one.

[chuck_p]

Thanks for the info Ted. Sounds like its another one for the "to-do" list. Keep us posted!
thanks,
Chuck

[chuck_p]

Hi Ted,
I hadn't looked on the forum in awhile and thought I'd check on this. I noticed the latest SB software download sb233sx.exe 11/15/02 (which I have not installed yet) fixes something with the CG command. Does it fix this issue?
Chuck