Right. I’m not talking the lead in. There is a setting for each bit in the tool menu for the plunge angle.
Fusion has a setting for that too… you want to have the cut ramp down at an angle instead of plunge… I think I usually do 2 degrees. You can cut way faster and it’s easier on the bits. If your bit is going straight down that might explain your picture.
Awesome… I was trying to figure out how to do that but assumed it was a tool path thing and not a tool thing.
I did some new calibration cuts and think I have it pretty well dialed in now. I used combinations of finishing passes (with and without tools) and ramps in my test cuts and the results are that +0.2 mm finishing pass with a tool gives me the most accuracy and that ramps really don’t help much. I think my plunge problem was solved by the set of rails I added so ramps just add time to the cut… no real benefit for cutting into the relatively soft plywood (all subject to change if I try to cut something harder).
With just a finishing pass, my 5-inch square came out 4.97V x 4.98H and my 0.25-inch hole came out 0.249V x 0.237H (good enough for the 1/4-inch bolt to be inserted). The 5.5 mm hole came out 5.3V x 5.6H and 4 mm hole came out 4.16V x 4.13H … I’m just amazed in all honesty… that’s really, really good for a CNC machine of this price range … that I assembled. I think the straight plunge with +0.2 mm finishing pass with tool is Good Enough™ for my needs.
For that material, keep notes.
In all honesty I get pretty stoked at some of the accuracy as well, even though I shouldn’t. I think those numbers will not scale either I bet if you make a 2X larger part it is still only that far off. I attribute that to run out that can not really be prevented and any initial loading conditions on the machine. So I think all cuts should actually be a tiny bit under and that says you have a very accurate build, any cuts that are a tiny bit over actually mean something is wrong (OD’s of course). Right? so if you think about it all spindles have some degree of not perfectness and that will always make them cut larger than they are. so. To a certain degree you could cheat a tiny bit on your bit size and might actually get stupid accurate cuts.
In the end. I’m with you, super cool, proud of the accurate build you have! Thanks for making me look good.
For certain…
That’s what I saw with previous cuts… really didn’t matter much, the amount of fudge I needed was always the same. I’ve already got my gcode ready for my next cut (a base for a robot I’m building with my twins) but I’ve got to find the time to do the actual cutting… Estlcam says 4 hours, but I’m not sure just how accurate it is.
I briefly thought about it, but quickly decided that the juice just isn’t worth the squeeze for what I’m doing.
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A real robot or a sci fi robot? Either way, I wanna see it!
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The hope is a real one. I’ve carried this book with me since 1981 to remind me of what I’ve yet to accomplish. I’m not building what’s in the book… it’s just my inspiration of completing something I’ve wanted to do since I was 12.
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Awesome! That book must be a fun read.
Because you asked…
The base plate, the top plate, and the wheels were made using the lowrider. Because the power distribution takes up so much space, I plan to create another level, maybe out of 1/4-inch or thinner stock, that sits between these two plates and move all the power parts to that. Less likely someone will touch something they shouldn’t.
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The pulley grab screws will slip more the closer you get the bit to the loose screw mind always do anyways
You can load estcam on multiple comps just 1 user though
That is awesome. Is it running ROS? I see a pi on there, but I am not sure you can run ROS on a pi. It would be fun to build up some SLAM using that connect. Does it have any localization sensors? Specifically, wheel encoders, gyro or accelerometer?
That looks like a bunch of fun.
I made a new thread for it…
Back on subject, I discovered my wooden blocks that the belt holders are attached to are just press-fit inside my unistrut rails. I forgot to insert screws in them to keep them from moving… which explains why my belts tend to loosen. I need to reset the blocks and all and secure them. I’m not sure if that explains the wandering or not though. When I cut the wheels for the robot above, I noticed issues with having a stepped cut again (I think it was the top right quadrant of the wheel).
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More ‘wandering’ issues AND some broken bits… Last night I cut new parts for V2 of the robot and broke three 1/8-inch bits. I had set my DOC to 5 mm and my feed rate was 480 mm/s (8 mm/min). I used 5-degree ramps for everything and all my ‘small’ holes came out fine. But when I went to cut out a large shape, a bit snapped. No problem, replaced the bit and modified the gcode to restart from the piece that was being cut.
Then I went on to another piece that was a couple of feet further down the x-axis. I broken two bits on that one. Both were on “large” pieces (10x2-inch hole and a 20-inch circle). Its VERY possible the bits broke because the board was slightly ‘bowed’ and I didn’t have it perfectly flat, and therefore it might have been cutting more than 5 mm on the first pass, but I hadn’t broken any bits before and this time I broke three. The last bit break was due to the wandering issue (below) where on the 20-inch circle, the bit wandered and definitely was trying to cut more than 5mm.
But, the real issue is that I experienced wandering again. Among having problems with the 20-inch circle, I noticed this with a 10x2-inch hole…
The top image is the dimensions of the hole and how the cut was performed on 1/2-inch plywood from HD. The bottom image shows the step that was formed as I can feel a little step on both sides of the cut… It’s not a precise depiction of the step, just made it based upon how it felt. The ends (where in the X-axis was steady) came out fine, but there the X-axis moved, there was a step. What I find odd is that both the top and bottom had steps. The question I have is why steps on both sides, and why at the bottom of the cut? Seems to point to Y-axis issue to me, but it just seems odd .
I don’t know that I have any answers for you, but I’m wondering what kind of bit? Or maybe something’s wrong with the collet or the router itself. I’ve only broken one bit. I didn’t get the collet tight enough, and the bit eventually slipped down. This wore down the collet as well. Even then the bit didn’t break right away. I tightened it back up and kept going, but eventually the bit broke and chewed up the collet further. I replaced the collet and have had no issues since.
I just finished a project cutting parts that are 24" square or so with an 1/8" 2 flute up-cut spiral bit from Ryan, with no issues. I had very similar cut settings (5.1mm DOC, 540mm/min).
I was probably using similar plywood too, ~3/4" BC HD plywood. This also had some significant warpage, that I could not pull out. I’m pretty sure I was cutting at least 9mm deep on the first pass in that area. My Lowrider just plowed right through.
They are cheap and I’m not so worried I broke them. My concern is mostly with the step and I had similar issues using nice quality 1/4-inch bits…
https://www.amazon.com/gp/product/B074R9VXKQ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
What I am thinking of doing is buying some 1/2-inch foam board and doing some cuts in it. If it comes out clean, then the problem is something ‘dynamic’ from the load of the cut. If it’s still stepping, then there’s some kind of alignment/structural issue causing it. At least that’s the theory.
Also, my Y-plate on the side with the controller ‘droops’ down some (think I mentioned this in another thread). When the z-axis is low, It’s really apparent that the wheels are tilted outward. I recalled this morning that when I was assembling the parts, the holes for the wheel bolts on the Y-plates were not perfect circles, but rather had some oval-ness to them. I didn’t get concerned at the time but I’m thinking maybe I should use my lowrider to cut some replacements… would allow me to make some tweaks to it to facilitate mounting the controller better.
You’re either going too deep or too fast.
Either reduce DOC or reduce feed.
The wandering bit could be due to the bit grabbing the wood and following the grain.
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So my test in foam should come out clean if it’s related to this, correct?
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correct.
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