Use of tabs

[Barry Anderson]

My problem with VCarve is simple. Every difficulty I have experienced traces directly back to operator error. So, with that admission, I am here to ask for help again. One of the projects I am using my cnc for is to cut letters contained in a circle. The font I am using is monogram kk in which the letters have curves as part of the font. As such, I have to watch closely while cutting since when cutting through on the final pass, the "curves" on the ends sometimes want to "chatter" which results in a poor cut or breakage. I want to try tabs to prevent this. I have used tabs on some other projects with good results. When adding tabs, I get a message stating that the text must be converted to curves, with a choice of yes or no. I choose yes. I place the tabs and they show on the 2-D view. I then create the toolpath, preview the toolpath, and the tabs are not there. I have attached one of my files. Help, suggestions, advice please. Thanks in advance.

Barry Anderson

[adze_cnc]

Your "A" not being curves and overlapping your ring is not helping your cause. Having said that, I still saw tabs (when I added them).

See attached file for my solution:

1. converted text to curves
2. removed overlaps between "A" and circle
3. recalculated toolpath with plenty of tabs

Steven

CircleA-cleaned.crv

(661 KiB) Downloaded 151 times

[Barry Anderson]

Thanks for the reply. I have not had any problems in the areas you put the tabs. My problems are in the areas of the "curly cues" on the letters.
Bary

[highpockets]

Reduce the length of your tabs. The tabs are too long for the "A". I reduced the length to .125 and was able to place tabs on parts of the "A"

[Barry Anderson]

Even when I did as you suggested, I still cannot get tabs on or near the end of the curly cues. I will try again tomorrow. I know I am doing something wrong.
Thanks for your help.
Barry

[highpockets]

I see your point. I can't get tabs added to the curly areas at any size.
May need to contact tech support on this one.

[Adrian]

Steven is right. There are lots of problems with the drawing, duplicated vectors, crossing vectors etc. Clean those up and you can place tabs on the curly bits and everywhere else no problem.

[martin54]

Would take a bit longer but the other thing you could do which might help is to run 2 toolpaths for the profile cut out, create your normal profile but don't cut quite all the way through, then create a second toolpath to cut the final little bit but run at a slower speed/feed rate so there is less chance of problems with the fragile parts

[tomgardiner]

Have you considered using double sided tape for this. I don't know what material you are using or the volume of the job but if everything was temporarily adhered to the spoilboard you would not need tabs and be able to achieve clean chatter free cuts. If not tape 3M makes aerosol adhesive in varying strength tack.

[Barry Anderson]

I have some time for a more detailed explanation

Would take a bit longer but the other thing you could do which might help is to run 2 toolpaths for the profile cut out, create your normal profile but don't cut quite all the way through, then create a second toolpath to cut the final little bit but run at a slower speed/feed rate so there is less chance of problems with the fragile parts

Your "A" not being curves and overlapping your ring is not helping your cause. Having said that, I still saw tabs (when I added them).

I did find the duplicated vectors and eliminated them. Oversight on my part I guess.

Steven is right. There are lots of problems with the drawing, duplicated vectors, crossing vectors etc. Clean those up and you can place tabs on the curly bits and everywhere else no problem.

Nothing I have tried has allowed me to place tabs on the curly parts. I have changed length and height as suggested to no avail.

tabs.jpg

See attached file for my solution:

1. converted text to curves
2. removed overlaps between "A" and circle
3. recalculated toolpath with plenty of tabs

Steven

CircleA-cleaned.crv

I did convert to curves. The overlaps was the only way when I started with CNC I knew to get the letter and circle to become one piece. I have since learned how to cut the overlaps out. I tried welding the vectors and have not been able to get it to work on these letters.

Have you considered using double sided tape for this. I don't know what material you are using or the volume of the job but if everything was temporarily adhered to the spoilboard you would not need tabs and be able to achieve clean chatter free cuts. If not tape 3M makes aerosol adhesive in varying strength tack.

I have thought about double sided tape. The problem is each letter has the curls in a different location and being able to place the tape in a beneficial location. I have the drawing and toolpath for each letter of the alphabet. I am just trying to improve my drawings and work flow. Some of the letters are able to be sanded to an acceptable finish after the chatter, but some break. Having the letter break takes all of the fun, and some of the profit out. As I stated in my original post, I have no doubt that the problem is not in the software but in the user(me). I am grateful to all for your advice and suggestions. Keep them coming. I hope you all have a good rest of the day.

[Adrian]

If you follow the steps outlined by Steven then you will be able to place the tabs wherever you want. Use the scissors tool if you can't get the weld to work. As the attached picture shows once you've cleaned the drawing up you can place the tabs wherever you want.

[Barry Anderson]

Adrian:

I have been working on this some with mixed success. I will continue and may send you a message. Thanks to all for your help.

Barry Anderson

[tomgardiner]

One other thing you might try is using a very thin onion skin. Depending upon your workpiece's tendency to stay flat you can cut an onion skin of .005" to .010" that is very effective at holding everything together. Clean up is a simple matter of swiping with 120x paper. When I work with melamine I remove it with a shank of a screwdriver.

[Barry Anderson]

Thanks Tom. If I can't get the tabs to work like Adrian and others have, I may have to try this.
Barry

[martin54]

Adrian:

I have been working on this some with mixed success. I will continue and may send you a message. Thanks to all for your help.

Barry Anderson

What do you mean by mixed success Barry ? Have you managed to join the letters & the circle using either welding or the scissors ?

The onion skin option or double sided tape might work better than tabs for something like this, you will probably need quite a few as those curly bits look a bit fragile. I understand what you are saying about the letter shapes all being different but you should have a fairly good idea where the tape would be needed just by looking at the preview & if you used a wide(ish) tape then it will probably cover enough to keep the bits in place. Worth experimenting with at least.

I was going to suggest making up a template you could use to place tape more accurately but that would really depend on how many of each letter you would be cutting
Having a vinyl plotter makes doing stuff like that pretty easy. Just throw a roll of paper on the plotter & use a pen to plot the template