Start and Flat depth issues

[PawPrints]

The gcode generated is just a series of x y & z moves & has nothing whatsoever to do with those parameters so from a machining point of view it doesn't really matter[/quote]

Just thinking about that. Isn’t there some interaction between the tool database data, toolpath and the machine code? The x and y movements are different if you have selected a .25 dia bit or .50 in the database and if you edit or change the data, doesn’t that change the machining? Why is the tool side angle any different? Doesn’t the machine code change with the bit selected and the data stored or edited in the database? Why doesn’t the side angle effect the code any less than any other parameter and if not, what’s the point in having the ability to change or edit it? What am I missing in your explanation?

[adze_cnc]

Let's see if I can come up with a decent analogy. Imagine that you have the following three things in front of you:

• a tea cup
• a golf ball
• a gaming die (not dice as you only have one)

Also in front of you is one of those desktop sand-filled "Zen garden" things. At the left end is a green dot at the right a red dot.

Follow these directions in your mind:

1. pick up one of the three items listed above
2. place it on the green dot
3. move it through the sand to the red dot
4. notice the pattern that it makes
5. rake the sand smooth again
6. repeat for the remaining two objects

You'll end up with three patterns while following the same directions. The directions know nothing about the shape of the objects or the paths they leave behind in the sand. Just as g-code knows nothing about the routers bits or material. It just moves from a to b to c to d, etc.

Aspire on the other hand does know about angles of bits and diameters of bits. It makes sure that the g-code follows the correct paths and at the correct speeds. It also uses this information draw pretty pictures on the screen.

[PawPrints]

I understand, despite my age, what you are describing. I understand that all movements are described by gcode in their respective axis. What would help bridge, what I think is just a matter of terms, is to describe specifically how the gcode is created to move the correct amount when doing a step over if not for the diameter of the bit and the step over amount set in the tool database. If it uses that data to establish the gcode, then it is a matter of what data in the tool database it uses and what it doesn’t. I think the pass depth set in the database would establish the gcode for z movement in successive passes required for the desired depth set in the software. What I think is adding to the issue is that, to my understanding, tool database entries do effect gcode. What I think you are saying is not all data; in the case of step overs, it does. But are you saying that in the case of bit angle it does not use any bit angle data in the database to establish any gcode???

[PawPrints]

For clarification, I understand that the software uses the database to write the gcode.

[martin54]

I understand, despite my age, what you are describing. I understand that all movements are described by gcode in their respective axis. What would help bridge, what I think is just a matter of terms, is to describe specifically how the gcode is created to move the correct amount when doing a step over if not for the diameter of the bit and the step over amount set in the tool database. If it uses that data to establish the gcode, then it is a matter of what data in the tool database it uses and what it doesn’t. I think the pass depth set in the database would establish the gcode for z movement in successive passes required for the desired depth set in the software. What I think is adding to the issue is that, to my understanding, tool database entries do effect gcode. What I think you are saying is not all data; in the case of step overs, it does, but in the case of bit angles, it doesn’t. Thanks.

Haha, I can see where you are going with this stepover is based on a percentage of the tip diameter of the tool
For cutting something like small text which this post was all about then the stepover isn't going to come into play & I don't think it has been mentioned in the post anywhere although without reading it all again I can't say for sure

[PawPrints]

This was not about text or step over. It was about modifying bit angles in the database. I was NOT trying to turn this into a “got you”. The OP was just about start and flat depths in inlays. No mention that I recall about the specific project. So my questions were to challenge MY understanding not yours or Az’s.

The most significant and the only question that started this line of comments is does the bit angle in the tool database effect the gcode and the resulting carve? That was the whole point about TBN vs V-bit and the side angle descriptions that were a part of these questions and responses. I understand that the machine is just going to push a bit through the wood. But the gcode effecting that movement has to, in part, be determined by what is entered in the database. Az’s comment, which is what I quoted, suggested that the bit angle makes no difference. Does it? Your first comment was about “fooling” the machine which is what I thought changing the type of bit and bit angle in the database does. Az implied it makes zero difference”. So, does it or not? We are back to the beginning.

[PawPrints]

SOMEHOW I DUPLICATED THE REPLY WHEN TRYING TO EDIT IT.

was NOT trying to turn this into a “got you”. The OP was just about start and flat depths in inlays. No mention that I recall about the specific project. So my questions were to challenge MY understanding not yours or Martin’s.

The most significant and the only question that started this line of comments is does the bit angle in the tool database effect the gcode and the resulting carve? That was the whole point about TBN vs V-bit and the side angle descriptions that were a part of these questions and responses. I understand that the machine is just going to push a bit through the wood. But the gcode effecting that movement has to, in part, be determined by what is entered in the database. Az’s comment, which is what I quoted, suggested that the bit angle makes no difference. Does it? I know you can’t change the actual dimensions but does the entry in the database regarding bit angles change the code? Your first comment was about “fooling” the machine which is what I thought changing the type of bit and bit angle in the database does. Az implied it makes zero difference”. So, does it or not? We are back to the beginning. No trick was intended.

[PawPrints]

Martin, this was from your comment.,,,

“ The parameters such as tool diameter, side or included angle in the tool database are really so the software can generate the toolpath previews, The previews being a very accurate representation of what the machine will cut. The gcode generated is just a series of x y & z moves & has nothing whatsoever to do with those parameters.” Not that they would have limited impact if using a v-bit on small text.

So you shouldn’t wonder about “where I was going”.

Az’s comments were spot on with what the resulting carving would be with respect to changing those parameters. You said the gcode would have, “nothing whatsoever” to do with the parameters including bit diameter and was said after noting Az’s comments about the geometry.

I appreciate your desire to help but, my gosh man, the reply’s to my comments aught to include a review of them rather than the first OP’s question.

[martin54]

I got the small text from the original post

Having troubles with the start and flat depths in the V-Carve tool not working very well. We are using a 0.75 TBN bit rather than a real v-carve bit as the text is small and needs to run a bit deeper. Unfortunately, the fonts we need to use aren't compatible with single line, nor did it seem to work with the Quick Engrave.

For a job like this then the stepover wouldn't come into play HOWEVER I was wrong to say that the gcode generated does not use those parameters in the tool database because that was a general statement & I didn't think things through properly before I posted I did say that my Vectric standing was because I had been here a long time & it didn't mean I was any good

As far as I am aware for v bits & TBN's the software will use the diameter & the side or included angle to work out the cutting edge length, the diameter will be used to work out if in fact the machine needs to stepover at all to cut between the vectors to achieve the finished cut.
There are 2 stepover values for both, one is the clearance pass stepover which would generally be a larger value used for roughing & a final pass stepover which would be much smaller for the final pass to achieve a better finish at the bottom of the cut.
To be 100% honest I am not sure it is a yes or no answer, hopefully, someone with more experience or someone from Vectric will chime in & explain things far better than I ever could.
For a vcarve/engraving toolpath then the depth of cut is determined by the angle so from that point of view yes it will influence the gcode as using a side angle rather than an included angle will make the depth deeper if you have no depth of cut set. if the cut is very shallow then it may not be a factor & change the gcode at all.

[PawPrints]

Thanks. I hope you appreciate that my line of questioning was NOT to trap you. I understood what Az said and, by illustration showed, how the gcode WOULD be influenced by the changes in the type of bit and side angle entered into the database. None of my comments nor his responses had anything to do with the OP’s project, text or otherwise. The comments I made specifically to yours was based on your denial that ANY parameters in the database effected the gcode. That is why I pursued the questions about offset that I did. I knew your statement was wrong but I did it in order to get agreement that at least some changes have an impact and then move back to my original question about side angles effecting gcode.

A lot of time and texts wasted to get back to my original question about the tool geometry in the database and how changes effect outcomes. I agree with your conclusion that the angles would effect outcome and Az’s comment that changing the tool type would change the internal calculation concerning the expected length of a TBN vs V-bit. I think that at the end of the day, my knowledge base has grown.


PS. I think I made a couple of wrong references to AZ’s comments and yours early on. I’ve been making and reading these comments on my cell phone so it wasn’t always easy to check the author in my replies. My apologies to both of you where I made that error.

[martin54]

Yes I got completely hung up & blinkered by small text & that using a bit that was defined as something it wasn't would mean that the toolpath preview would be of no use even though the post had progressed beyond that which was wrong of me & all I can do is apologise.
I know I am often not very good at explaining things but I certainly wasn;t saying that none of the parameters in the tool database were used, the spindle speed, feed & plunge rates are obviously used.
My comment about knowing where you were going was because having just read the post which mentioned stepover it dawned on me that I hadn't even considered stepover, again another error on my part so yes you proved me to be wrong.
As I have already said all I can do is apologise, clearly I need to think a bit more before posting if I try to answer any questions in the future

[PawPrints]

No worries Martin. I’ve never made any errors. But I am unique.. You have always been available to me and others for help. This one just sent me into questioning what I thought I knew and with as little as I know, that’s not hard. In the back of my mind (that’s not far), I knew…you knew, and we were just on different paths. But I hoped once I determined why we weren’t on the same path, you would be able to answer the geometry question. Otherwise, I wouldn’t have tried so hard to get there. It really wasn’t a trap. I was just trying to close the divide which we ended up doing. I understood the step over part and used it to try and break the log jam. But I wasn’t certain about the tool geometry. I was scratching my head on that. I know so very little. I use to be pretty sharp on flying and aeronautical subjects but I am having a hard time with new things now. I do enjoy the hobby; blessed that I can afford it. You have helped me before and I hope you will again. Stay well, George