Hello all! Let me just start out by saying that i am brand new to the world of CNC. I just finished assembling my Lead 1515 and just ran my Hello World and i am so excited with the possibilities. With that being said, i am also feeling very overwhelmed. I have a bunch of questions that are hopefully easy to answer and i am hoping for some help from you all. I would appreciate as detailed answers as you can and don't assume that i know anything because i likely don't know. I apologize in advance if i am asking questions that have already been asked on here before. I have never posted on forums before and have no clue how to effectively search for what i am looking for and honestly don't know how to ask some of the questions i need answered just yet. 1. I used the new xyz probe and it worked awesome to zero out the bit (i think, it looked awesome while it did it's thing). But i don't actually understand what i did during the process. Like, how is that actually working and what does it actually do? In the openbuilds video, he uses a piece of paper to zero out his bit and then hits the re-zero button before he runs the job. Is this something i have to do still even after the probe? 2. When i started the hello world, it looked like it started good and it made awesome precise cuts, but when it got to the WORLD section at the bottom, it cut the bottom edge profile off but the WORLD letters remained intact. How do i know where the position of the file will be and how to prevent what happened so i would still be able to see the border? ---Follow up question, if i wanted to re-cut the Hello World, is there a way that i can recreate it without moving the board? Like i want to move the program up ~1/2" and have it cut the same Hello World beside the first one but so it is correctly positioned. Do i have to re-zero? if so, how do i re-zero with the probe in the middle of a board when it has the 90 degree angle part for the edge of the board? I am very curious basically on how to correctly position my projects. Especially for ones that are going to be done on pieces of wood that are already at their final dimensions. 3. How can i easily resize the size of the print? I used a larger board because i had no clue how big the size of the actual cut area would be. 4. Where can i tell what bit i am supposed to be using? is there a location where you set this or modify what bit you are using / supposed to be using? 5. How can/do you decide what bit you should be using? 6. When running a program that requires different bits at different times, how do you know when to switch bits/set it to switch bits? 7. Where do you set feed rates and cutting depths? Thank you for helping me. I only have experience with some minimal 3D printing. So i do know how to draw in fusion 360 and i have access to adobe illustrator. I have a technical mindset and im looking forward to your answers. Reading this might give you the impression that i am way over my head but im just missing some simple things and once i get comfortable i will really get into making some cuts and getting more comfortable. i appreciate it!!
The procedure in the Hello World is without a probe. Purchasing a Probe makes setup faster and easier, replacing the process of finding zero manually Jog over, rezero X and Y (not z) Hello world demonstrates inside cut, outside cut and pocket. Depending what you are making, decides what toolpath to use. If you need to rezero Z in the middle of a piece of stock, flip the probe upside down so it lies flat, jog to above it. Run a ZZero operation Every cam has their own tools. In Openbuilds CAM that'll be the Transform tool on the toolbar on the left of the 3D viewer When you setup / edit the toolpaths Google - a whole field of its own to learn, keywords: upcut, downcut, o-flute, single flute, two flute, ballend, v bit, bottom clearing bit, endmill chip load, feeds and speeds and many more You don't. Grbl doesnt support toolchanges, so you export each tool, order of operation you need as seperate gcode files. When you edit or create Toolpaths.
I will add to this as someone that jumped into CNC without reading much about it and not having a complete understanding of Gcode. First and foremost, read the grbl Wiki it is a highly valuable resource that helps you understand what your machine is trying to od for you and how you can help your machine be successful in doing it. I have referred to it countless times in the past five years. It has even helped me save 3D printed parts that were 18 hours into a 30 hour print when something bad happened. I just edited the gcode to start at the layer height I left off. Read and re-read it: gnea/grbl Further points to which I can add experience to as someone that had no clue in the beginning: The probing is telling your machine where the top of your work piece is located. Therefore it knows how far down it needs to move to completely cut through (if that is the operation), or how deep to go to cut a pocket. A good rule of thumb for cutting wood or plastics that I live (mostly successfully) by is make each cutting pass 1/2 the diameter of your endmill at 2000-2500mm/min (80-100 inches/min). I use 2500mm/min, but you are using a larger machine that inherently may have more flex in the gantry beams. So, 1/8 inch deep/pass if using a 1/4 inch endmill. Further, every time you change a tool during a project, you need to re-zero (probe) the Z axis so your machine once again knows where the top of the workpiece is in relation to the new endmill. If you don't remember, you will find yourself panicking when you realize not only is your endmill cutting at full depth through your work piece, but an additional 3mm into your spoil board. Don't ask me how I know. Worse yet, it is a lesson I seem to repeat every few months as a "refresher." If you are going to cut on an object that is at or near its final dimensions, I would zero your X Y and Z in the middle and make sure your CAM knows this is the case. Then, measure and mark with a pencil the middle of your stock. Personally, I start by using a V bit to find the X and Y zero in the center then change the bit to the one that will be doing the cutting and then zero the Z on top the work piece. Here is how I do it, it is a little over 3 minutes. I use a paper template so I can use it repeatedly and maximize my use of the expensive stock material like the HDPE I cut in the video. You should learn to use a CAD software like Fusion 360. Then, you can create your own files, save them as a .dxf, and then generate the CAM your machine needs in OpenbuildsCAM, or you can use the one in Fusion 360 - which is far more complicated than I need. Fusion changed some of its rules for the free version lately, but I have done nothing different with my files, and have noticed no changes. But I do not use the CAM portion of that software. Fusion 360 for Personal Use | Fusion 360 | Autodesk You can open files in a CAD software and then take measurements to determine its size. Personally, I use Estlcam for CAM generation. It is similar to OpenBuilds CAM. I have never had it reject any file I have uploaded to it, and the tool path creation is super easy and works well with my thought process. I can generate all the tool paths I need in less time than it takes me to set up the stock piece in Fusion360, and I do not need to design in 3 dimensions for flat parts. As a bonus the creator has a bunch of videos detailing how to do things, and when generating the CAM, if you hover your mouse over anything, a text box pops up telling you what that "thing" does. I also prefer to use the Estlcam Controller because it allows for tool changes, but these are my personal preferences. First and foremost, you must choose a bit that will fit into the smallest hole/slot you want to cut. This is the same for inside diameters for pocketing. My personal choice when I am cutting something with - for example - 5mm holes is to use a 4mm diameter endmill and have a tool path for just the making of these holes while the work piece is clamped down. Then, I screw the piece down through these newly drilled holes to hold the part in place. Then I can remove all my clamps and I will not need holding tabs. Another way to avoid tabs is the painters tape method in the above video. After the drilling is done, I usually use a larger diameter endmill to cut the outside of the part. I can cut deeper per pass and a larger diameter endmill just cuts better and you get a cleaner finish. Cut with a 1/8" endmill and you can watch it flex. Especially while cutting hardwoods and aluminum.
