What on earth is going on? really stuck, need help!

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T4 Concepts
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Re: What on earth is going on? really stuck, need help!

Post by T4 Concepts »

Yeah, been watching those tutorials Adrian .................. also been following Mark Lindsay on YouTube, great Vectric CNC resource. I think what's been confusing me is the fact that my 'Profiling' isn't on a flat surface as in any cnc job I've seen, but mine is ontop of a 3 dimensional form. It's just the top part that I need to work on, but the material is 125 mm thick, I think that's where I get lost.

I'll be going through everything we've discussed here, hopefully things will make sense eventually :mrgreen:


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Re: What on earth is going on? really stuck, need help!

Post by Adrian »

As long as your jig holds the areas you're cutting flat then the fact that the rest of the shape is 3D at an angle doesn't matter. Same thing for the overall depth of the piece. You're only cutting a couple of mm into it so set the z-zero to the top of the material in VCarve and away you go. The toolpath would be the same for a 3mm piece you're cutting through as it would be for a 300mm you're cutting 3mm into.

You can map profile cuts onto 3D surfaces but from what I can see in your example there is no need to do that.

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Re: What on earth is going on? really stuck, need help!

Post by T4 Concepts »

gkas, you're an absolute genius! :mrgreen:

I just ran that code that you kindly supplied ................ and I managed to cut ( scratch pass ) my very first cut!
Chuffed to bits mate :mrgreen: :wink:
IMG_2664.jpg

In my mind this 'test' run is my way of determining if I setup and built my cnc machine correctly, if it doesn't cut perfectly round holes, it simply means that' something not quite right. In this case, it seems to have done quite well. When placing the headlight mounting bracket on the part I can see that the circle is just on the inside.
IMG_2665.jpg

Hard to tell at an angle, but if it's off, it's not by much ................ barely noticeable when viewed directly from above.
IMG_2666.jpg

I can't thank you guy's enough, now I'll go back and read and re-read everything mentioned, and I'll definitely pick apart gkas' code to see how he did it. My first impression would be that I selected the wrong 'Toolpath Operation' as a couple of you have already mentioned.


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Re: What on earth is going on? really stuck, need help!

Post by T4 Concepts »

Adrian wrote:
Mon Aug 02, 2021 11:48 am
As long as your jig holds the areas you're cutting flat then the fact that the rest of the shape is 3D at an angle doesn't matter.
That's what I had planned from the start Adrian, after all the reading and going through tutorials I considered that the height of my holding jig didn't matter. What threw me was that result I was getting when I chose a V-Carve bit for 'engraving' the circle. Why it was wanting to cut down to 174mm in depth I've yet to find out.

The jigs are millimeter precise, as are the holding jigs for the actual parts I'll be using. My cnc machine is built around them so to speak.



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Re: What on earth is going on? really stuck, need help!

Post by martin54 »

T4 Concepts wrote:
Mon Aug 02, 2021 12:27 pm
Adrian wrote:
Mon Aug 02, 2021 11:48 am
As long as your jig holds the areas you're cutting flat then the fact that the rest of the shape is 3D at an angle doesn't matter.
That's what I had planned from the start Adrian, after all the reading and going through tutorials I considered that the height of my holding jig didn't matter. What threw me was that result I was getting when I chose a V-Carve bit for 'engraving' the circle. Why it was wanting to cut down to 174mm in depth I've yet to find out.

The jigs are millimeter precise, as are the holding jigs for the actual parts I'll be using. My cnc machine is built around them so to speak.



TURK
Basically your problem was that you don't understand the various toolpath types & how they work, the tutorial Adrian has linked you to will help you understan them better, many come with files you can download & work alongside the video which may help you to understand them better, as Adrian has already said don't move on until you fully understand each one. Watching hours & hours of different tutorials may not be helping as it will be far to many different things to take in all at once

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Re: What on earth is going on? really stuck, need help!

Post by T4 Concepts »

Yeah, you're right, I didn't understand the differences between the types of 'Tool Path' types. I didn't even know there were different types! and according to what type of tool' you intend in using!

I have just been watching this tutorial > https://www.vectric.com/support/tutoria ... path-guide and the other one mentioned earlier.

As I'm new to this, not just V-Carve Desktop ( as I've just bought it ) but CNC'ing as well :wink:

It was something Adrian said that finally got me to realise what the error was I was getting. I just couldn't fathom out how the software thought that my Z axis travel was at 174mm .................. after I had set my cut depth to 0.2mm on a piece of material that was 3mm thick.

In order to 'use' a V-Carve bit correctly ( correct me if I'm wrong ), you need to have two vectors, one 'outer vector' and one 'inner vector', and once those two vectors are reached that determines the cut depth. As my circle only had one vector ( the outer circle ) the V-Carve bit will continue to cut until it reaches the bottom ( 174mm ). You'll have to excuse the way I explained that ( if it makes sense to anyone ), but that's the way I understand it.

So, as an example, if my circle had been smaller in diameter, say 50mm, the software would have generated the same error, only the cut depth would of been less, maybe 120mm in depth. It also explains the reason why the .CRV file was massive, 280MB! Basically thousands upon thousands of lines of code, spiralling until it reached the bottom!


You're also correct in saying that watching too many tutorials just causes confusion but in my case I had to, as I needed to know which tutorial ( or method ) best suited what I was trying to achieve. Also, I just couldn't download Vectrics 'test' files to use on my setup as my machine is modified ( Z axis much higher than standard ), and my 'part' or material if you prefer, sits further down inside the machine.

I'm pretty sure that I've got it now thanks to you guys .................. It's not just a case of cutting along the dotted line! :mrgreen:




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Re: What on earth is going on? really stuck, need help!

Post by T4 Concepts »

Oh, I forgot to mention ................... the job would of taken over 400 Hours to complete! :mrgreen:


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Re: What on earth is going on? really stuck, need help!

Post by dealguy11 »

One thing I see a lot of people struggle with at first is the idea of when/how to use a v-bit, especially given the name of the program is V-Carve. There's a difference between a V-carve toolpath and a v-bit. A v-bit is just a v-shaped bit and can be used in any of the main toolpath types, including profile, pocket, fluting, engraving, v-carving, and even 3d carving. The toolpath you are trying to make is a profile - just a line with slanted sides and with no variation in depth. Using a v-bit doesn't require a V-carve toolpath.

As you learned, a v-carve toolpath is a specific type of toolpath that just happens to use a v-bit. It does vary the final depth of the carve based on the distance between the inside and outside lines, as you discovered. You can limit the distance that it cuts into the model by setting a flat depth...so if you'd set a flat depth of 1/8" on your circle, then it would make a 1/8" deep circle with slanted sides - pretty much the same thing as a pocket.

Lots to learn.
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Re: What on earth is going on? really stuck, need help!

Post by martin54 »

Just to add to what dealguy11 has said.

There are lots of different types of tool bit
There are also lots of different types of toolpath that you can use.

Don't think that each type of toolpath can only be used with one type of tool :lol: :lol:

A vcarve/engraving toolpath will work with other bits beside a v bit although that is probably the most commonly used bit, you could also use an engraving bit, a ball nosed bit or a tapered ball nose bit :lol: :lol: :lol:

You will learn this as you move forward, learn to trust what you see in the toolpath preview & if your still not sure the forum is a great place to ask questions. The other thing worth mentioning is that for each type of toolpath the software will only let you select the type of bit that can be used for that toolpath. If you look at your vcarve/engraving toolpath as an example you will see that certain types of bit are either not visable or greyed out & you can't select them :lol: :lol:

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Re: What on earth is going on? really stuck, need help!

Post by T4 Concepts »

martin54 wrote:
Mon Aug 02, 2021 6:19 pm
If you look at your vcarve/engraving toolpath as an example you will see that certain types of bit are either not visable or greyed out & you can't select them :lol: :lol:
Yeah, I did notice that Martin and was wandering about that.
Capture3.PNG

After a much needed few hours sleep :wink: I'm back at it! :mrgreen:
I have to find out why the center of the circle isn't quite where I had intended it to be!? ( 2mm out ), and as you can imagine these headlight mounting positions need to be exactly right.

I also have to start from scratch, re-draw my vectors, use the correct toolpath and change from a V-Carve bit to a small end-mill. I've got a 3mm end-mill with an 8mm shank already, as I had intended in using that for the actual job.

What ultimately threw me was the 'scratch path' that I wanted to create, as an indication of where I wanted to cut. To me ( at the time ) all I wanted was to draw a small mark where the cut was going to be, and see if the circle was perfectly round. So the job in question did look as though all I needed was an 'engraving'. :roll:



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Re: What on earth is going on? really stuck, need help!

Post by martin54 »

If the circle isn't exactly where it is meant to be then there could be a couple of reasons for that, firstly check your drawing to see if the circle is correct within the software, if it is then the fault will be down to either how you set your x y zero in your material or the accuracy of your machine

The size of the bit you use isn't really a problem, you could use a bigger bit if you had one, you would just need to use a profile cut with it set to cut inside the line. you may want to add a couple of tabs to stop the centre of the circle moving as it is cut out :lol: :lol:

Now you have a much better idea how the different toolpaths work you won't make the same mistake again :lol: :lol:

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Re: What on earth is going on? really stuck, need help!

Post by T4 Concepts »

Thanks Martin, I appreciate all the tips you guys have for me they have been of immense help thus far :wink:

I think the original drawing may of been the culprit, as I may of moved it slightly.
I am getting a lot of issues with accuracy at the moment, precision is the key to getting these parts profiled correctly. I realise now that V-Carve is hardly an engineering package, to be precise to 0.5 of a millimeter when positioning your vectors is proving to be quite difficult.

The parts that I'll be machining will be firmly secured in a purposefully constructed jig, and know that I know how to cut a hole ( thanks to you guys ), I just need to workout how to put it in the right place.

This is basically what I'm working on >
IMG_1656.jpg


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Re: What on earth is going on? really stuck, need help!

Post by Charlie_l »

Once you find and understand the tools you will easily meet your accuracy requirements.
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Re: What on earth is going on? really stuck, need help!

Post by T4 Concepts »

I took a big gamble when I bought Vectric V-Carve Desktop, as I wasn't too sure that it would do what I needed it to do, particularly the design side of things, being able to draw out my design including all dimensions accurately was very important to me. Precision is the key in what I do, a full CAD package was out the question for me ................. being unemployed I have no money! :( So even V-Carve was a major expense.

I tried most of the OpenSource software, tried Blender 3D and SketchUp, but none of those come anywhere near to V-Carve .............. wish I'd bought it years ago. I've only been at this for a week or so ( very little sleep ) but I'm constantly amazed at just how good V-Carve is actually, well pleased with my purchase :mrgreen:

And I must'nt forget about the support, so far that has been fantastic as well !




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Re: What on earth is going on? really stuck, need help!

Post by adze_cnc »

T4 Concepts wrote:
Wed Aug 04, 2021 1:26 am
I realise now that V-Carve is hardly an engineering package, to be precise to 0.5 of a millimeter when positioning your vectors is proving to be quite difficult.
I'm really having a difficulty understanding the difficulties with the precision of VCarve mentioned above.

I drew a square with its lower left corner at the origin (0,0) and moved it 0.001mm in both the x and y directions. That is 4/10,000 of an inch or about one tenth the thickness of a sheet of regular printer paper.
Moved square's origin from 0,0 (mm) to 0.001,0.001 (mm) — VCarve v9.5
Moved square's origin from 0,0 (mm) to 0.001,0.001 (mm) — VCarve v9.5
Zooming in to see the results
Zooming in to see the results
Charlie_l wrote:
Wed Aug 04, 2021 4:40 am
Once you find and understand the tools you will easily meet your accuracy requirements.
This is so very true.


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