On Thu, 2009-04-16 at 19:19 +0100, alan battersby wrote: > Hello everyone, > I hope someone on this forum can offer some advice. I asked this > question on CNCZone Gcode programming but have not yet had a reply. > Perhaps I didnt word it clearly enough so can anyone on this forum help? > > I am in the process of building a cnc setup onto my wood lathe, to > hopefully cut patterns onto bowls see (http://imagebin.org/45774). I am using > emc > to control the steppers. At the same time as this I am developing > software to generate the gcode to cut the paths (see > http://imagebin.org/45775), there may be many paths > in a design. Paths probably will be wider than the milling tool used and > deeper than the maximum allowable cut per pass. Therefore I am placing > the code to cut a path inside a double loop. The outer loop will take > care of the width and the inner loop will take care of cutting to > depth. I suppose that I am cutting a long narrow pocket so cut full > width to common depth then deepen or the other way round? Is one way > better than the other so far as machining is concerned? > Expanding this question to many paths - Is it considered better practice > to cut all paths to the same common depth / width before looping to the > next depth / width value, or is it better to cut each path individually > to its finished width / depth before moving onto the next path. Or does > it not matter at all. > > You will gather from my questions that I have no experience in milling > (yet), this is a non-commercial retirement hobby project. I was an > engineering apprentice 40+ years ago and did some then, but have spent > the last 25+ years in computing. > > Hope that someone here will offer an opinion and I apologize in advance > if you think this post is off topic. > > Alan
If I were to do this, I would think about "What would I do if I were routing this out by hand?". I have had little wood routing experience, but it seems to me that there are issues with wood and shallow or slow cuts. Also when coming up to corners, wood can tend tend to split down the grain and you can knock the corners off. This can be avoided by knowing which way to approach the corner, with either a climb cut or standard(?) cut and looking for the run of the grain. I don't know the best procedure, so you may have to just try a test piece. I would tend to start by cutting all the path centers with as much depth as you can get without splitting corners too much, then cut the sides but leave enough depth and side so you can finish cut depth and sides with a final pass. For the final pass you need to leave enough material and cut with enough feed so that the cutter will actually cut and not ride over the wood. On the other hand I have seen plenty of router cuts that were cut in one pass. Hopefully the wood guru's here will chime in. You might want to do a search on "wood routing" on YouTube to see some examples. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA ------------------------------------------------------------------------------ Stay on top of everything new and different, both inside and around Java (TM) technology - register by April 22, and save $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco. 300 plus technical and hands-on sessions. Register today. Use priority code J9JMT32. http://p.sf.net/sfu/p _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
