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Engraving question -- sections being left uncarved in letters

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  • Engraving question -- sections being left uncarved in letters

    I have noticed that when I set up text to be engraved, there are always areas within the letters that are only barely carved out. For instance, if the letter depth is 3/16", there will be sections left that are only carved out to about 1/16" depth. It's almost like the machine is leaving tabs, but in this case there is no need for tabs. Is anyone else experiencing this? And is there a fix that I simply don't know about or maybe something I'm doing wrong to cause this?

  • #2
    Does it look the same in the VCarve software or are you seeing it only when it is carved? It might help if you could post the file if it is the file.

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    • #3
      It shows up in both the wood and in VCarve. Here is a pic of the toolpath, zoomed in to make it easier to see the areas. I also attached a copy of the TAP file, if that helps. It's a simple toolpath, but I've had this same thing to occur in other experiments I've made. I've actually gone in and manually removed some of the material in one, but that was a real pain.
      Attached Files

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      • #4
        It looks like you are using a ball nose bit with a v-carve toolpath. If that is right then those areas are too narrow for the bit to get down to the full depth before hitting the side of the vectors, You can do an offset to the text to make the inside larger so that in those narrow areas in the letters are at least as wide as the bit you are using. This should work for you.

        The .tap file did not show up in your post

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        • #5
          Well, and I am, and today I wanted to change to end mills... but the problem is, suddenly today all my end mill cutters became grayed out. So, I can't select any of them, and I have some nice small ones that would work nicely. Don't know what happened to cause that.

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          • #6
            Name_eng.tap Here is my try to upload the TAP file again. Don't know why it didn't go through before.

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            • #7
              I suppose I am just an ignorant sod. I have done CNC before (milling machine and lathe), but in those cases, the machinery did not force me to use particular tools. If I wanted to use an end mill, a v-cutter, or whatever, I could do it. So, my guess is that the VCarve will not let me select any of my end mills when I am doing engraving. Annoying. If I adjust my parameters correctly, I should be able to use whatever cutter I wish.

              Another annoying thing: I can't get the text to stop ramping down into the letters. No matter what I do, there are little "ramps" at the corners of the letters, like serifs in a printed font. It's aggravating as heck.

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              • #8
                Here is a drawing to explain what is happening. You can not use end mills with a v-carve toolpath but you could use a pocketing toolpath. Like I said before you can offset the letters to make them bigger so your ball nose will reach full depth. If you want to send the .crv file I can do it for you and send it back, send me a PM and I'll give you my email.
                Attached Files

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                • #9
                  What you are describing as ramps in the letters is where the toolpath is trying to carve right into the corners of angles. If you were using a v-bit then you would get square corners where there are square corners and this is what the toolpath is trying to do with the ball nose bit. If you decide to use the pocketing toolpath you will have straight sides in the letters and round corners where there are square corners in the font.

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                  • #10
                    This is an example of what the corners look like when using the VCarve Toolpath and a 60 degree v-bit. It ramps down into the bottom from the pointed corner. This is what your ball nose is trying to do.
                    Attached Files

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                    • #11
                      I have to admit, I'm getting frustrated with it, and am beginning to regret purchasing the Piranha FX. The messing up of corners is annoying, but not fatal. But I'm also unhappy with the fact that the software chooses its own depth of cut, based upon what it feels is best for the cutter. I tried to do some work with a 1/16 ball mill to get finer details, so the machine insists upon setting the depth of cut to a mere scratch on the surface, almost invisible, no matter what I do. It could easily go 0.1 inches deep (using multiple passes) without causing issues with the sides, but it simply won't do it based on the machine's decision.

                      It looks like I'm going to need to modify the TAP files manually, to force the machine to do what I need it to do.

                      And the laser is not consistent in where it starts. I ran one pass with the laser last night, and it wasn't dark enough in a few places, so I modified the TAP file by increasing the intensity of the laser and slowing down the feed rate. Recreated the TAP in VCarve and brought it back to the pendant. I had not moved the workpiece, nor turned off the Piranha. Everything was the same, except for the intensity of the laser and the feed rate. My intent was to run it again, thereby darkening the lines.

                      Unfortunately, the new run started about 3/16" below where the old run had been, ruining the whole piece.

                      Lastly, Next Wave shows laser burning a picture of Elvis, a photograph, in their promo materials. That's great! But now I find that I need to get another piece of expensive software in order to process photos.

                      I'm not impressed.

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                      • #12
                        BTW, what is up with the forum site? Several times lately it seems to have been down. I try to get to it, and it says that the site is down or has been relocated. It's happened about four times in the last week, when I don't have trouble getting to other websites.

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                        • #13
                          Tony,

                          You have other toolpaths other than the v-carve toolpath that will do what you are trying to do but you have to set up your vectors correctly for the bit and toolpath you choose to use.

                          When you use a ball nose bit with the v-carve toolpath the depth is automatically calculated based on the radius of the bit and width of the vectors to keep it from cutting too deep if the vectors are wide enough that the bit will drop between the vectors. If you use a v-bit it will carve too deep if the vectors are wider than the diameter of the bit but the software will give you a warning that it will go through the board so you can add a flat depth.

                          Like I said last night you can use a pocketing toolpath but you do have to remember that if the bit is wider than the vectors nothing will be cut because the bit will not fit, the same thing you are experiencing with the v-carve toolpath in the narrow areas except the only thing cut will be where the bit will fit between the vectors. With the v-carve toolpath the round nose bit will cut to the depth it can reach until it gets to a depth of the radius of the bit.

                          If you re-size your text enough that the bit will fit between the vectors then you can use the pocketing toolpath and carve as deep as you want.

                          As far as having to buy expensive software to do raster images the software will be free for your use but they are still working on it so we will have to wait until it is released.
                          Remember this was a research and development project so I expected that it might take longer than the projected time frame they had anticipated.

                          That being said I do think they jumped the gun on the release of the CNC Piranha Fx if they were so far behind on software development. I do think that there should have been a lot more communication about where they were on the development of the hardware and software for this product because they are loosing credibility with people who have backed them in the past by buying their machines. Needless to say they are also loosing any credibility they did have from the backers of this project when they continue not meeting deadlines and not delivering the product in a timely manor and not honestly informing anyone when the software to fully use their machine will be released. Their lack of communication about issues with the project leaves you with an impression that their customer service is very very lacking and all they care about is the bottom line of they bank account, as if to say we have your money now so we don't need to get into any hurry to deliver what we promised. END OF RANT

                          I do respect your opinion of the way this release was handled.

                          Also you are right this forum is on a bad server and is down all the time even though it is seldom used.
                          Last edited by meb; 11-29-2015, 03:13 PM.

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                          • #14
                            Meb,
                            I did try using a pocketing toolpath, but it did not pick up on all the vectors. I also tried using a couple other toolpaths, with not very good results. I have not tried using a v-bit, though.

                            I did solve part of my problem by deciding to use the laser to make the graphic, instead of carving it. It looks nice enough, and there is the added factor that the name is engraved and the image is laser-burned. I think my granddaughters will like that, since they are very much into science. I really couldn't resize my text very much, because of the limitations of the size of the workpiece.

                            I agree wholeheartedly with your rant. My original anticipated shipping date was July... then it was moved up to August... then September... then October. Every time I called, I got a runaround. The person there would either tell me they didn't have any idea when they would be shipped, or tell me it would be shipped "next week." When I would call back, I couldn't get clarification. Even when it was actually shipped, my request for a tracking number was ignored. Communication is not the strong suit of these folks, but having worked in a technical environment before, I have seen the same thing other places. (Doesn't make it good, but it's common.) The people who develop things typically are lousy at communicating with others--either clearly about lead time and delivery dates, with technical documentation, or with training materials. I wrote documentation for a while, and developed training courses, and trying to get info from engineers and technicians was like pulling teeth from a dinosaur. (That said, I was also a technician and field engineer for a few years, so I've been on both sides of the fence.) Honestly, if they want to be respected as professionals at Next Wave, they need a dedicated communications person to handle things like press releases, documentation, etc. (And I don't mean somebody from Shipping who happens to have a couple of college courses in communication--I mean someone who is a professional.)

                            You are also right that they are losing credibility with both their backers, and those with whom the backers communicate. (Of course, the lack of clear and complete communication is a big part of that issue.)

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                            • #15
                              If the bit will not fit between the vector then it won't make much difference what toolpath you use. You said you have smaller diameter bits so I would use the pocket toolpath and a smaller bit, that should allow you to carve as deep as you want .

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