Hi, I was hoping someone might be able to tell me why this material is being left behind. Machine: LEAD1515 bundle with High Z, BlackBox controller, Touch Interface, Dewalt 611 Software is Vectric V-Carve Pro, with toolpaths saved to usb drive and loaded into the touch interface. Project: topographic 3D model of West Virginia On my first attempt, I used the Terrain2STL webpage to download the STL and modeled it with Vectric, creating 3 toolpaths. First was the roughing pass with a 1/4" endmill, next was a finishing pass with 1/8" ballnose, and finally a profile cut with the 1/4" endmill. I love the amount of detail and this would be perfect for what I'd like to accomplish, however, there are perfect squares of wood being left behind during the finishing pass. Here are a couple of pics of what I'm referring to: This happened on two attempts, so I decided to try downloading the topographic map STL from TouchTerrain to see if there was something wrong with the file. TouchTerrain offers three preset maps to download for CNC (small job, medium job, and large job), and I chose medium. This project fills out most of a 12"x12" plank. I just ran this job this morning. Vectric called for the 1/4" endmill for the roughing and a 1/16" ballnose for the finishing. I hoped the level of detail would be close to the first attempt but it is less. The perfect squares are gone, but now there are ridges along the finishing path's route during the pass. Hopefully these pics show what I'm referring to: None of these ridges or squares show up on the toolpath preview on Vectric, but it isn't very high-def to begin with. I'm brand new to CNC and to Vectric, so I really have no idea what I'm doing, but I read as much as I can, and refer to tutorial videos when I can find what I need help with. I've done some V-carving and some juice grooves on handmade cutting boards without a hitch, but obviously these topo projects are more intensive. I was hoping some of you more experienced folks might have seen this before and can offer some troubleshooting tips I can try to get this machine dialed in. I greatly appreciate any insight you can provide. Thanks for reading. -Josh
I have never seen anything like this before. How much stock are you leaving for the finishing pass? The bottom picture looks like the 1/4" roughing pass is cutting too deep. Are you re-zeroing in the same location after a tool change?
I have been zero-ing at the same place for everything so far. X and Y at the bottom left corner and Z on the material surface. I have the openbuilds probe and use the probe utility that is built into the "formatting USB wizard" in the openbuilds control software. I didn't even notice that piece leftover from the roughing pass in the pic until now, but I've only been doing passes at .100" for roughing because it sounded like it was stressing the bit. I need to do more research on feeds and speeds for sure, as I said, the machine and software are all brand new to me. Maybe the topo maps were a bit ambitious for my experience level.
Edit: this material is 21/32" thick or about .656". I was positioning the model with a .100" gap above the tallest elevations.
What @Giarc was suggesting was that you might not be leaving enough material after the roughing toolpath for the smaller bit to get all the fine detail, and he was asking about zeroing with regard to the bit for the finishing toolpath - are you resetting workplace zero (Z only, not X and Y) in the same place as you set it for the first toolpath? Alex.
I hope I'm understanding you correctly. I am using the touch probe at the same Z height when I change tools in the router. I can go into the job and recheck model height and base height sometime today to see if something stands out as incorrect. I would like to be able to make some of these topo maps without a lot of hand finishing. I appreciate your help Giarc and Alex!
I do a lot of topo maps. Here's my best practices 1 - Set your Z zero to the spoilboard. 2 - When you change bits, only probe Z zero. No need to re probe X and Y. You can use the OB probe, just turn it upside down. 3 - During roughing, if your cuts sounds "stressed" as you call it, then adjust speeds and feeds until it doesnt. On maps that have large difference in elevation, you should probably take multiple roughing passes. You can do this by clicking on edit for your tool and adjusting the Pass Depth. 4 - Make sure you are leaving enough stock for the finishing pass. This is what @Giarc mentioned. However, if you leave too much and you have a high stepover on your finishing pass, you wont be happy. You can adjust this in your roughing toolpath by changing the value in the Machining Allowance box. 5 - For a better finish: a - Make sure you are cutting in the same direction as the grain. It will make a world of difference. b - Change your stepover in Edit Tool There's obviously a trade off here. Smaller stepover = longer machining time but better results. But remember that you are taking light cuts so you can really max out the machine's feed rate. 6 - Buy yourself a sanding mop. Makes finishing the maps (and bowls) easy. A topo map as a first project isnt a bad idea. You'll learn a lot. However, its best to start out with just a section of it. No need to run a 3 hour job in order to figure out what settings work the best. Fail Fast!
Also, using Terrain2STL is an easy way to start with topos. However, as you see in your first pics, there are artifacts from the tile stitching process. If you really want detail, I suggest using The Earth Data website to get 1 arc data in hgt format. Then use QGIS to process it. Google it if you need more info.
@sharmstr , thank you very much for those tips, I will start googling. I have just done another file in vectric using the touchterrain map with a 1/2" vertical exaggeration and this gives me the look I am after. I'll attach the file if anyone would like to take a look and see if anything glaringly wrong stands out. Disregard the file name, haha, I've made several attempts on this one. In the meantime, I'll look into the Earth Data website. I can't thank you guys enough for the responses.
I don't know if this helps, but I have found that I can do roughing passes with a 1/4" endmill at 1/8" inch deep with a 40% stepover at 3000mm/min and about 16000-18000 rpms . For a finishing pass with a 1/8" ball nose and a 10% step over, I can run at those same speeds. My CNC gantry is only 850 mm wide though so the deflection may be a bit less.
Thanks guys for all the tips and help. I'm going to try this new file with Giarcs suggested feeds on the roughing pass and see what happens. I am using scraps so i'm only out some time on any experiments I do at this point. And I suppose I gain experience and knowledge along the way. Thanks guys,
