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I wanted to make a simple sign for a neighbor. He is a young guy and is running a T-Shirt shop in his basement.
So I said I could make him a sign to hang on his garage door. I am using MDF. The outline cut is OK . The pocketing
is bad. I have some Pics and the Bob file . Any help please. I have been doing very well with engraving and Acrylic
but now I am trying something in wood. I need to start learning wood stuff.
Thank You
Don
You really only need one Feature for this. You're profiling the whole thing to 0.25", then coming back and pocketing to 0.12", which is a bit odd. It looks like there's some uncut stock in parts of it, but it's hard to tell from the pictures whether this is what's left from the profile Feature, which was then, "top cut" with the pocket. That's my best guess as to what I'm seeing, anyway. If you want it cut as a straight-walled pocket, then just select the whole piece of geometry and and do a pocket feature to whatever depth you choose. Make it multiple depths if you're going much deeper than the diameter of your endmill. You can allow a couple of hundredths for the rough pocket, then add a profile finish to the pocket if it doesn't give a clean edge with the straight pocket, but it may be unnecessary.
Personally, I'd Vcarve it. Vcarving looks really good on a sign. MDF is not a great choice for outdoor signs, but if you do a really good paint job, it should last a few years.
Luke
How deep wold you go on Vcarve. I have 1/2 V Bit.If I can do this in 1 cut then I would love it. If you could offer a little more I will try it.
Thank You
Don
How deep it goes just depends on the angle of the bit you have, and the width of the geometry's widest section. With a 90deg bit, I see a max depth of about 0.37", while with a 45deg bit, it maxes out at 0.88 or so. The depth you specify in the parameters of the Vcarve feature is basically a stepdown depth. It'll cut that deep, then step down where necessary to continue the v-shaped cut for wider sections. With a 1/2" bit, you'll definitely have some step-downs in this one, since it's wider than 1/2" in several areas. You want your max depth-of-cut to be equal to or less than the vertical flute depth of the bit, or you'll get weird cuts. Basically, you only want to cut as deep as the bit's angled flutes can go, in any given pass.
Just copy the geometry over into a new window in BobCAD, (select the geometry, then go to <Edit> [Copy], then <File> [New], then from the new tab, <Edit> [Paste].) and play around with it. You'll need to have your cutting tool defined, as to angle and diameter, but aside from that, just play with the settings, run Simulations, and see what happens with different settings. Vcarve is a very simple Feature. There aren't very many settings. You'll quickly figure out how it works by playing with it and Simulating.
Luke
I am trying to learn the engraving tool. I am having a very strange error. I am enclosing the Bobcad file. Each time I try to run the tool path I get a boh the wants me to stretch something.
I don't know why on executing the tool path its want to stretch. I have copied the vector file and started a new Bobcard session and keep getting the error. I even restarted
my computer.
Don
What's wrong is the geometry you're trying to Vcarve. Vcarve has its own specific needs with regard to geometry. It works on discrete enclosed areas only. By discrete, I mean having their own, non-shared boundaries. In that geometry, almost every single enclosed area shares borders with the neighboring areas. There are also some little orphan lines at the tips of the fingers and elsewhere that might not choke Vcarve, but aren't good practice, either. Also, the single lines that delineate the toes of the feet won't work.
Here's an example of what I mean. The shapes on the left won't Vcarve, but the shapes on the right will. The square is subdivided into discrete shapes, not sharing borders, and the circle is one area with complex borders. Hope that gets the ideas across.
Luke
For every pocket there has to be an "Island" or a non pocketed geometry next to it.
Ok in tomorrow I will check all of this.
Don
Trotline I d/l'ed your file. I cannot open it in my version of Bobcad as I have ver 25 and it looks like you used ver 26.
Don
Rats! Sorry about that. I can never remember what version everyone is using. Here's the same file in V25 format:
Luke
One thing I didn't mention is that the discrete areas can be nested. That is. One can be within another. This image is from the Simulation of the attached file:
Attachment 243840
It can get confusing until you grasp this. If you added another circle around that geometry, you'd get a negative image of the same thing, basically. It would alter the sequence of shapes. Try it and see. :)
Luke
I am following trotline and jrmach's advice and getting good results. I used a simpler vector to practice on. I did get it to work 2 ways using the vector. ! is an inverted cut of the other. No mod to the vector needed. Thank you all for the help in explaining this. I will have some questions about the parameters and what they control. I am getting some very nice results. Now I need to fix that vector and close it up and make islands' It looks like a long road ahead. I am getting a handle on how the tool matters.
Thank You
Don
Here is something fun,,,using the windows font "neurochrome"
Spelled your name wrong,sorry
I see that when I learn to use V-Carving it is going to be as much fun as the Acrylic lithos and things I have been making. I read on another forum about having to led lights go around the acrylic and have a back and frame. I cannot wait to try this. I need to think about the pocket and frame and how it will go together.
Don
Vcarving is a blast, once you get used to how it works. Here's a fun one that you might like, a celtic cross I messed around with. It's probably the most popular thing I've made. Hard to keep enough of them on hand. The file is set up to cut from 3/4" stock, with no tabs. Before you cut one, post a question about holding tabs, and I'll show you what Burrman showed me, about how to make them. The alternative is to leave a thin "onion skin" layer of stock to hold the part. Both methods work, but tabs seem like a neater solution, to me. :)
Luke