okay hold tight for a video coming later today, im shooting it now.
sorry about the focus im not good with this camera yet its much different than my old one.
The pictures online for climb vs. conventional milling can be confusing (they were to me) since some show the direction based on the workpiece moving in the xy-direction instead of the spindle moving like it does on the XCarve. The carve youāre doing in the video is climb milling, so when the bit begins to cut into the aluminum the force from rotation is propelling it faster along itās path, which the XCarve isnāt really capable of doing properly. I have a lot of upgrades on my machine so I can mill metals and I wonāt go anywhere near climb milling because of the poor results I get. I use other software to mill aluminum, as do a number of other forum members. This makes it easier to control for things like climb milling (among other things). I think Fusion 360 is a free alternative you can look into to fix this issue compared with Easel.
At the end of the cut, where the machine stops moving, you can see your lower right eccentric nut come loose. The loose nut seems more like a symptom and less of a cause, since it happens after the machine is stopped, but itās something to look into.
I would also look at clamping the workpiece down more securely. I hear and seem some lifting and vibrations as it cuts. Also, check to see how level your wasteboard is by getting your bit very close in different positions in the xy direction and checking the z-position through Easel.
It looks like a combination of things going on. My best guess is that your workpiece isnāt held as securely as it needs to be, the surface of your workpiece isnāt level compared with the travel of the spindle (something called tramming), and possibly belt tensioning and v-wheel tightness (although youāve covered those areas well). Other than that, it could be that your spindle RPM is too high and is causing rubbing, or that your bit is dull from the attempts youāve done so farā¦ but I donāt think this is very likely, just something you may want to consider if nothing else works.
This picture shows climb vs conventional milling where the spindle moves and the workpiece is stationary, like on the XCarve. So for conventional milling, which is what you want to be doing, the circle would go CCW in your video instead of CW.
I will check those things in a bit but as far as climb milling goes I think I get what your saying but if I were to do the cut making the circle going the other way it still happens. As you know Iām using easel and for some reason it just seems to abatrarily decide which way it wants to cut and in this case I just had it make the smiley face that they have loaded in but my original piece I was cutting which is all those other circles was made in Google sketchup then converted to an svg and it made the circles going the other way producing the same result. But it is still helpful to know and in the case of the video may be part of the issue.is it possible that the table I have it on is moving and thats whats messing it up, because i havent gotten around to making a more permanent home for it yet.
good news i have managed to complete a full cut. there are still a few issues but compared to before its a massive improvement. It was a good catch seeing that loose v wheel because the reason it moved was that the nut wasnt tightened correctly. I am very close to being able to make nice clean cuts now however the first pass it makes still isnt great and the second pass is always a little off left to right but then it follows the same line with little deflection.
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Just a little observation from your video: you should not try to cut aluminum dry. Use some ethanol or WD-40 as a cutting fluid. Your bit seems to be completely clogged with aluminum. A few hours in a strong base like sodium hydroxide or potassium hydroxide will remove the aluminum from your bits.
Thanks for the tip about removing the aluminum from the bit. On the subject of milling dry I have read a lot of stuff on it as well as experimented a bit and the problem that comes with using a fluid is that the chips stick to it and donāt blow away so it remills the chips which isnt good. From what I have seen unless I have a bath there isnāt much point using fluid, my problems are being cause by something mechanical on the machine I just havenāt been able to pin point it yet.
Itās personal preference on whether to use fluid to cut aluminum. Other metals require it, but aluminum does well being dry machined so long as chip evacuation is being considered.
Thats pretty much what Iāve seen everyone else say too and since i have the 611 which exhausts down I havenāt had much issue evacuating the chips, its also good at making messes.That being said however recently I havent been making many chips at all. I fear a new x and z axis as well as a new 611 mount might be in my future.
FYI Brent - my initial experiments with aluminum were similar. I found 18k rpms at a MINIMUM of 35 inches per minute and dept of cut .005 works flawlessly. But my machine is very rigid. I also have a jet of air clearing chips. a THREE flute end mill in aluminum would require even more speed - probably 50 ipm. There should never be any aluminum stuck to your bit.
Thanks for the feed back, any tips on making my machine more ridged? Also I know my problem has more to do with the mechanics than my feeds speeds and endmill choice because I am having similar issues with much softer materials such as acrylic which is what I cut the most of. I have pretty much givven up on aluminum for the moment to maybe get it to work in something softer first. Id also like to say that all this started after a few months of having no issues cutting anything in both acrylic and aluminum.
Aside from the x-axis mods and y axis brackets just tighten everything down and make sure your belts are banjo string tight. You should be good. Grab your router and see if you can wiggle it. I bet you will find some loose v-wheels somewhere. Donāt forget about the backsides.
well I broke the mount for my 611 today trying to keep the v wheels from wiggling so now i have to wait for another one to come in. What happened was the holes for the Eccentric Nuts where wide enough and the aluminum soft enough for the nut to start pushing its way into the hole so when I would tighten it the wheels wouldnt move. Hoping this solves my issues.
The new mount and some new Eccentric Nuts did the trick. Managed to cut a whole circle two squares and a star in some aluminum without trouble. Now that I seem to have that under control I was wondering If a different endmill would give better results so any suggestions for one to try for milling 6061 aluminum. I dont mind spending a bit for it if its worth it. Perhaps a smaller one would mean there is less pressure on the spindle causing deflection?
I used Destiny Viper 2 flute end mills available from drillman on Ebay. I ordered four and after 24 brass key chains and a dozen or so projects in aluminum, some large, I am still using the first bit. But I do have a forced air chip clearning system.
Thanks for the input. A forced air setup is in the future for me, I just wanted to get this stuff figured out first. Now it seems the two biggest problems I have are the waste board isnāt level and I havent figured out a good clamping setup to ensure every bit of the material is held down because its ether the middle of my material is slightly higher or the left corner isnāt held down because of homing.
That will prove to be an endless struggle. I screw my materials down to a sacrificial wasteboard. And even after flattening the wasteboard by carving a pocket, I see those errors. When I mill aluminum and it has to be precise, like for engraving, I have taken to creating an aluminum jig. Carving a flat pocket in a piece of aluminum, and then fitting my work piece into that pocket. I keep hearing about software that will index your work piece and map its inaccuracies and automatically account for those differences, but I havenāt had time to explore.
Well I had an interestig idead to make some special clamps that have a spot for something spongy like two sided tape but then can be adjusted by applying different pressures to the material thus compressing the two sided tape slightly differently to account for the uneven surface. I saw a video of a guy engraving glass and he used springs where I would use the spongy material. I may loose some height on the z axis but not to much.
I had much the same issue with the nuts digging so I made some washers and cut the eccentric longer on the nuts. That kept them from digging in so much.
Those nuts are a good idea but they need a large flange with no sharp edges, this a would make much more stable and much easier to adjust.
I am going to suggest that, it will add a small cost to the nuts but a real savings in the end.
That helped a bunch. If you have a metal lathe this is possible, if not then it gets hard as the same problem will still be there with the new mount.
Might ask Inventebles to modify the nuts to fix this problem. It is an easy fix if done from the start, not so easy after.
The other big issue I have noticed is where the 611 is in relation to the X gantry, that allows way too much leverage thus causing large deflections.
I am working on fixing that but because of how the lead screw is mounted it requires a new design.
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Iāve been thinking about the way the router is mounted, havenāt said anything yet, but this seems a good place.
There are problems with this idea, but I think they are surmountableā¦
Iāve been thinking that if the two X slides were spread apart, and the router mounted in between them, the stability would be significantly enhanced. This would require a new X gantry, obviously, and some new end plates, or at least new holes in the existing plates.
This way any force on the router is exerted on both sides, avoiding canting.
Also, the v-wheels for the x-gantry (front versus back) would be further apart, helping in the overall stability.
Or, I could be completely wrongā¦ ;-}
-Kelly
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