My MPCNC made in China

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This topic contains 358 replies, has 43 voices, and was last updated by  Lionel 2 months, 1 week ago.

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  • #35438

    James Donnelly
    Participant

    I have just read this thread end to end and I am amazed at your productivity and ingenuity to put it mildly.

    So many of your ideas are excellent, and I will be using some of them for sure.

    I printed all my bits with the Volcano hotend at 1.0mm nozzle and 0.6mm layer height, and I can’t get enough of how fast to print and strong the parts are.

    While I am inspired by the water cooled head and the insane speeds you’re getting, I am curious, did it cross your mind to cut that enclosure door from a piece of wood and paint it red? 🙂

    Or just printing and plasma cutting for you?

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    #35460

    Dui, ni shuo de dui
    Participant

    While I am inspired by the water cooled head and the insane speeds you’re getting, I am curious, did it cross your mind to cut that enclosure door from a piece of wood and paint it red? ?

    Or just printing and plasma cutting for you?

    Hehe, yes, it just happened that I didn’t have any stock of wood at that time, otherwise I would have used it instead of printing the whole door. Plus it sounded like a good opportunity to test printing something big ^^

    Thanks for the kind words, I wish you the best with your machine. I think you made a good choice printing your parts with the 1mm nozzle, it is indeed way more solid. I wonder about the little details, could you post pictures of the parts whenever you’ll have time?

    #35484

    James Donnelly
    Participant

    I made some comments and pictures about the 1mm nozzle back when I was trying it out many months ago.

    After moving house and pulling my printer out of a box recently, I did a quick level of the bed by eye, and re-printed a roller I needed to get building in just over 1 hour. It stuck to the old blue tape on the bed and printed great first time – like you said in the thread, the big layer heights make printing more forgiving as well as faster.

    https://www.v1engineering.com/forum/topic/volcano-hot-end/#post-19160

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    #35489

    Philip
    Participant

    Sorry for the late reply, but thank you Dui for your descriptiveness and for answering all of my questions, also, how quiet is a water pump? Are you using the industrial ones or some other type, because if it’s quieter than a fan, I’d be willing to try to build it if you’d be kind enough to make an Instructable. Also, before buying a hot end, do you think that an EV3 Volcano clone would work fine, like this one?:

    https://www.amazon.com/gp/product/B01ESTJUL8/ref=ox_sc_act_title_1?smid=A1LT9LUD664XNE&psc=1

    Also, concerning bed leveling, (But I’m not sure it would work for your design due to the size of the feet on your MPCNC) I got a series of trigger clamps the other day and discovered if you reversed them to make spreaders and you marked on the clamp how high the legs should be, you can actually go around and level your machine by making sure all of the legs are exactly equal heights, I recommend doing this twice to get more accurate results, and then just tighten all of the screws. Picture of clamp with mark is attached below:

    Attachments:
    #35505

    buurin
    Participant

    Also, concerning bed leveling, (But I’m not sure it would work for your design due to the size of the feet on your MPCNC) I got a series of trigger clamps the other day and discovered if you reversed them to make spreaders and you marked on the clamp how high the legs should be, you can actually go around and level your machine by making sure all of the legs are exactly equal heights, I recommend doing this twice to get more accurate results, and then just tighten all of the screws. Picture of clamp with mark is attached below:

    Do you have a hard plastic cap on the clamp? I have a set of these reversible trigger clamps too but they have rubber pads that may throw off my mark ever so slightly. This trick may come in handy for my own build.

    #35506

    Philip
    Participant

    My clamps have rubber, but it is very tough and almost like plastic, but they are removable, so that could create more accuracy… might try without rubber next time

    #35544

    Dui, ni shuo de dui
    Participant

    Sorry for the late reply, but thank you Dui for your descriptiveness and for answering all of my questions, also, how quiet is a water pump?

    Extremely quiet, it’s almost impossible to hear… Sometimes I’m not even sure it is on!

    Are you using the industrial ones or some other type, because if it’s quieter than a fan, I’d be willing to try to build it if you’d be kind enough to make an Instructable.

    I’m using this one:
    https://world.taobao.com/item/525779359700.htm?fromSite=main&spm=a1z09.2.0.0.NRDLwW&_u=a23vfsu3395

    It is originally designed for computer watercooling. You don’t want a lot of pressure, something like that is perfect. The instructable is on its way, I just need to take some pictures. Probably won’t have time this weekend though.

    Also, before buying a hot end, do you think that an EV3 Volcano clone would work fine, like this one?:

    https://www.amazon.com/gp/product/B01ESTJUL8/ref=ox_sc_act_title_1?smid=A1LT9LUD664XNE&psc=1

    Yes, should be no problem. It’s basically the same one I’m using myself.

    Also, concerning bed leveling, (But I’m not sure it would work for your design due to the size of the feet on your MPCNC) I got a series of trigger clamps the other day and discovered if you reversed them to make spreaders and you marked on the clamp how high the legs should be, you can actually go around and level your machine by making sure all of the legs are exactly equal heights, I recommend doing this twice to get more accurate results, and then just tighten all of the screws. Picture of clamp with mark is attached below:

    I can adjust the bed leveling extremely precisely on my machine, because the table moves independantly from the legs, so I can basically set the table at any height or inclination I want for about 400-500mm. But the clamp trick is a nice one, I didn’t know you could do that and it’ll be definitely useful to me, so thanks!

    #36553

    James Donnelly
    Participant

    Hey Dui, I was surfing Youtube and found some stuff on 4-axis CNC.

    You can see it’s a lathe+cnc combo essentially. I saw it and thought of your lathe, which I assumed was going to be a standalone lathe when I saw it. Perhaps you thought of using it together with the MPCNC for 4-axix?

    It never occurred to me you could do this with a slow turn + CNC approach. The possibilities look awesome.

    Then of course I found some vids on 5-axis CNC – that looks like a level above.

    Edit: Why do I always think of Googling stuff after I post?

    #36566

    Dui, ni shuo de dui
    Participant

    Hey Dui, I was surfing Youtube and found some stuff on 4-axis CNC.

    You can see it’s a lathe+cnc combo essentially. I saw it and thought of your lathe, which I assumed was going to be a standalone lathe when I saw it. Perhaps you thought of using it together with the MPCNC for 4-axix?

    It never occurred to me you could do this with a slow turn + CNC approach. The possibilities look awesome.

    Then of course I found some vids on 5-axis CNC – that looks like a level above.

    Edit: Why do I always think of Googling stuff after I post?

    Actually, that was my intention when I built this lathe, that’s why I’ve got a spot to secure a stepper motor on it. But the problem is that I have no idea how to generate the gcode for it, so I couldn’t try it…
    If anyone has a clue on how to do this, I could try in a few days and that would be awesome

    #36658

    James Donnelly
    Participant

    Have you seen that leo69, an active member of these forums is the author of the second video?

    https://www.v1engineering.com/author/leo69/

    He seems to have adapted Scorchwork’s gcode ripper to use with his device:

    http://www.scorchworks.com/Gcoderipper/gcoderipper.html

    The file is in the thingiverse download

    https://www.thingiverse.com/thing:1877336.

    Maybe you’ve seen this already and it doesn’t do what you want, but I think I’ll be giving it a try. Impressive stuff!

    1 user thanked author for this post.
    #36875

    Dui, ni shuo de dui
    Participant

    Have you seen that leo69, an active member of these forums is the author of the second video?

    https://www.v1engineering.com/author/leo69/

    He seems to have adapted Scorchwork’s gcode ripper to use with his device:

    http://www.scorchworks.com/Gcoderipper/gcoderipper.html

    The file is in the thingiverse download

    https://www.thingiverse.com/thing:1877336.

    Maybe you’ve seen this already and it doesn’t do what you want, but I think I’ll be giving it a try. Impressive stuff!

    Hi James,

    Thanks a lot for your post and the information and links, it will greatly help me!
    I think I have now everything to try it, I hope I will have some time this weekend.

    For the rotary axis, I’ll use mine instead of the thingiverse one, since mine is made out of aluminum and steel it should be way better. But the gcode ripper seems to be exactly what I needed!

    Thanks again!

    #37879

    Dui, ni shuo de dui
    Participant

    Ok, well, I finally received my new 500W brushless DC motor and installed it on my MPCNC.
    The motor seems pretty nice, it is very quiet compared to my old brushed router, the difference is quite huge.

    I made a few attemps at milling 3mm thick aluminum plate. I’ve got somewhat successful results, but the quality is not great.

    I made several tests with different configurations:
    -4mm 2flutes bit, 0.5mm per pass @10mm/sec, 2mm/sec plunge
    -3mm 2 flutes bit, 0.2 per pass @10mm/sec, 1.3mm/sec plunge
    -3mm 2 flutes bit, 0.2 per pass @10mm/sec, 1.3mm/sec plunge with lubrication.

    For all these tests, I’ve used the CNC control knobs to try different feed speeds and different router speeds, but what worked “best” was full speed for the router and about 10mm/sec for the feed.

    It seems like the biggest problem I have is the accuracy of the first path. For some reasons, the CNC doesn’t bite properly into the matterials and chatters quite a lot. Is usually goes fine during the second pass.

    I believe this may be due to the structure of the CNC not being rigid enough, could be the belts or the gantry. For the belts, I plan to completely remove the zip ties and attach the belts directly to each corner, since I noticed that the zip ties stretch a tiny bit, no matter how short they are. But my zip ties are already as short as they could be so I guess that it won’t make a huge difference.
    Not really sure why this is happening.

    I’m not convinced that the MPCNC is very adapted to do aluminum milling. I know it can work, but it may take a lot of fine tuning and be unreliable. I just see too many things that can go wrong and at some point it will be expensive to ruin too many aluminum stock. so I’m considering purchasing a 3040 CNC metal frame, they are quite cheap, plus I have most of the electronics and motors to run it. I would use the MPCNC for giant 3D printing, big wood projects milling and plasma cutting (if I manage to make this work) and leave the aluminum job to the 3040. Apparently a 3040 frame with ball screws costs around 2600 RMB (350 USD), which is an acceptable cost for me.

    As usual, a few pictures:

    The 48V 12A PSU and the motor controller:

    IMG_4100

    The new brushless spindle at work:

    IMG_4104

    What the top side looked like right after milling: this is the side where the drill bit engaged into the aluminum. You can see that the first layers are pretty horrible. (made with the 3mm bit)

    IMG_4106

    The back side is almost perfect. It the top side looked like this it would be awesome.

    IMG_4105

    This was my first attempt with the 4mm bit, after a bit of sanding and bending.

    IMG_4103

    IMG_4102

    The finished parts. This is a little support for two 2.5′ Hard disk drives. Dimensions were accurate enough, the holes locations are good.

    IMG_4112

    In the end it worked ok, but the milling quality was quite poor. I used some brand new drill bits of pretty nice quality, so I’m pretty sure that the bits were not the cause of my troubles. I need to do some more tests.
    As usual, suggestions or remarks are warmly welcomed 🙂

    #37888

    Kevin Lopez
    Participant

    Yay finally someone gets my zip tie struggle. Just redid mine and I am still getting flex. I am actually surprised how significant it is. All of the flex is coming from the zip ties, and I even made both sides totally zipped down, extra thick zip tie. The deflection seen in our mpcncs is a combination of the linear flex of the zip ties, and the flex of our z axis. When milling with a short z axis, the belt’s ability to not move linearly becomes more relevant, at least for me.

    About the rough edges, that could be your bit. If you look at my first pic, mine were awful. I changed to a totally fresh bit (same exact one just new) and now my edges are really sharp. They are actually so sharp I usually file them down a little. Might want to switch to a single flute, just my opinion. Can you link me to the bits? Not tryin to start a flame war anywhere but most people avoid the cheaper “5 for $10″ packs, the grinds are just not up to par. I use Kyocera Tycom .125” bits, single and double flute. They work amazing for me and cost about $4 USD each. They are incredibly sharp, just holding them in your hand you can feel the bite.

    Are you conventional or climb milling? I always climb mill. I tried both and my dimensions were more accurate and my surface finish was better. My work piece stayed cool as well, with most of the heat coming from the dw660’s hot, gross dc motor air haha. You can just smell the brushes when you turn it on.

    I don’t know what CAM strategies you use, but highly consider trochoidal/adaptive toolpaths. They keep the load on the cutter more constant and allow you to do a higher DOC which results in better flute utilization and prettier/easier to clean chips.

    I wouldn’t be so soon to jump to a 3040, just my opinion. Then again I have only looked at them, but from what I see on youtube, they’re not that much more rigid than a SAME sized mpcnc. You already have the spindle though so that’s a bonus.

    I am having good success with .5mm DOC 10mm/s 2mm/s plunge. That is for full slots. On adaptive clearing such as a pocket, I run 2mm DOC 10mm/s. I messed up my 3 only bits due to me being dumb….more coming. I am about to experiment with 4mm DOC adaptive clear. I need more stock material, all I have left is computer cpu heatsinks lol

    What I find weird is that most CNC routers are best suited milling the material they’re made out of. Think about it. The routers you see made out of entirely plywood can usually only cut wood. The all aluminum 3040’s can usually only cut aluminum or very very slow mild steel. The mostly cast iron/steel heavy routers can mill steel but probably not titanium/inconel. The mpcnc is steel conduit w/ plastic parts….so aluminum? I don’t know what I am talking about anymore lol

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    #37890

    Dui, ni shuo de dui
    Participant

    Yay finally someone gets my zip tie struggle. Just redid mine and I am still getting flex. I am actually surprised how significant it is. All of the flex is coming from the zip ties, and I even made both sides totally zipped down, extra thick zip tie. The deflection seen in our mpcncs is a combination of the linear flex of the zip ties, and the flex of our z axis. When milling with a short z axis, the belt’s ability to not move linearly becomes more relevant, at least for me.
    […]
    What I find weird is that most CNC routers are best suited milling the material they’re made out of. Think about it. The routers you see made out of entirely plywood can usually only cut wood. The all aluminum 3040’s can usually only cut aluminum or very very slow mild steel. The mostly cast iron/steel heavy routers can mill steel but probably not titanium/inconel. The mpcnc is steel conduit w/ plastic parts….so aluminum? I don’t know what I am talking about anymore lol

    Hi Kevin,

    Thanks for the advices,

    I’m using this bit:
    https://detail.tmall.com/item.htm?id=543314049024&spm=a1z09.2.0.0.1f30a53fPhGPov&_u=a23vfsu0c1a

    Pretty sure it is not a crappy thing, it seems very sharp to me, but I’m a total noob about aluminum milling so it may very well be. I had quite a hard time finding something appropriate, I don’t really know what to purchase (and not everything is easy to find in China),

    About the CAM strategies, I’m only using conventional milling. Load limiting is great, but It seems only to work when milling pockets, while all my cuts are actually simple paths. If there is a way to do that I would be quite interested to know.

    About the 3040, they seems fairly rigid to me, I’m not really sure a MPCNC could compete, but I may be wrong. In my opinion, the main weak links of the MPCNC are the gantry being too soft and the belt system. Not sure they can easily be fixed.

    I will completely remove the belt zip ties, enlarge the holes in each corner and pass the belts through them, then loop them back and secure with zip ties. This should remove entirely the zip ties flexing. But I’m not sure it will be so much better.

    Another thing I did was to put a big spring along with the Z axis threaded rod, to push up the Z axis. The reason is that there is about .5mm of backlash there, and it caused issues whenever the spindle was pressing down on the material, it lifted it a tiny bit, then went down progressively while traveling around the path. That spring somehow limited this issue because now the router is always at it maximum Z position considering backlash. So when it hits the material, it cannot go up anymore, it is a solid hit now.

    #37891

    Kevin Lopez
    Participant

    Lot of words I can’t read on your link lol. My friend may be able to translate it for me. If you can try to find a cutter that only has 1 flute. A lot of people are having more success with a 1 flute but still, I don’t think that is the issue with your edges. Is your gantry perpendicular? Maybe try upping the feed a little. All I can tell you is that when I switched to a totally brand new bit, it did a lot of improvement for me. With these small endmills, or micro cutters, you have to be pretty careful. I dulled a few of mine just by having them scratch steel. Being the nature of endmills, the flutes are only designed for a certain chipload, quite sensitive.

    The 3040’s I see on youtube that cut aluminum tend to have upgrades done to them. The most notable upgrade is the spindle to a vfd system that have better torque across rpms and probably have less runout. With the MPCNC though…..you don’t need 1.5kw. I can barely bog down my dw660 which is not nearly as sophisticated. Your spindle is fine.

    Either way, I know that you can get more quality cuts it is just a matter of tuning.
    Things I would try first:
    Try climb milling instead of conventional
    Try to get a single flute endmill, preferable 3mm size
    Try trochoidal cutter paths(that’s not related to the crummy edges)
    Clear your chips. The issue with using coolant or whatever you’re spraying is that the chips gum up. When using a coolant/lubricant, you want it to be mixed into an air blast. Otherwise in my opinion it seems counterproductive because the chips clump up worse and block the cutter.

    #37892

    Dui, ni shuo de dui
    Participant

    Either way, I know that you can get more quality cuts it is just a matter of tuning.
    Things I would try first:
    Try climb milling instead of conventional
    Try to get a single flute endmill, preferable 3mm size
    Try trochoidal cutter paths(that’s not related to the crummy edges)
    Clear your chips. The issue with using coolant or whatever you’re spraying is that the chips gum up. When using a coolant/lubricant, you want it to be mixed into an air blast. Otherwise in my opinion it seems counterproductive because the chips clump up worse and block the cutter.

    About chip cleaning, I was blasting air from my compressor and using WD40 together, to avoid having too much chips. But most of the problems occured on the 1-2 first layers, when there were not much chips. It is really the first bite that is horrible, the other layers are OK.
    My bit may not be perfectly perpendicular, this is a possibility that I am thinking of since the beginning. But I’m not sure how could I correct it properly? I could use some crappy paper shims, but it would involve a lot of trial and error, plus the paper shims are likely to get thinner after being compressed for a while.

    I’ll look into the perpendicularity issue, but I think it will be hard to get 100% right.

    a solution that could satify me would be to add a finishing pass of X mm right after every path is done. It would remove all the imperfections and leave a perfect finish. But I’m not sure how I can do this in Estlcam, nor if this option is available no matter what type of milling operation I select.
    I’ll dig into that, but if anyone has the answer and could give me some basic instruction, it would be appreciated.

    #37893

    Dui, ni shuo de dui
    Participant

    The 3040’s I see on youtube that cut aluminum tend to have upgrades done to them. The most notable upgrade is the spindle to a vfd system that have better torque across rpms and probably have less runout. With the MPCNC though…..you don’t need 1.5kw. I can barely bog down my dw660 which is not nearly as sophisticated. Your spindle is fine.

    It’s not really that you don’t need one on the MPCNC, it is more that you can’t really install one, because it is a bit too heavy. If the MPCNC was rigid enough such a spindle would be an awesome addition, especially given the fact that the MPCNC can be really, really fast, thanks to the belt system.
    The people I see using the 3040 on youtube seem to me to be a bit too conservative on their milling settings, I saw a few ones milling at 2 or more mm per pass at very decent speeds (some even totally insane, like this one: https://www.youtube.com/watch?v=OSmoz00x5fA ), which I’m almost certain would be totally impossible to do with the MPCNC.
    I really wish someone can prove me wrong on this though.

    #37894

    Kevin Lopez
    Participant

    Oooh man..that video makes me cringe a little. Wayy to much chatter and vibration, he needed to fix his aluminum better. You can actually see the stock plate rising. The finish on those parts looks awful too 🙁 Honestly those settings looked too aggressive for sure.

    I have not yet maxed out my mpcncs cutting potential, I think I can push it faster than 10mm/s at .5mm DOC slotting. There was this one test I did…where I was going at 10mm/s single flute and accidently slotted a full diameter cut at 1.5mm DOC. Results were really scary, but strange. I had little chatter…what I actually got was this very fuzzy looking piece. I think it had to do with my stock being so thin (1.5mm). Plates of stock for routers are arguable harder to fix than small blocks w/ a vice. It looked as if the chips were cut but not totally cut, leaving this fuzz of chips on the outer walls. I will upload a pic later.

    I managed to get mine somewhat perpendicular by shimming the mount with tape. Get a coat hanger thats 3mm thick OD and fasten it to your collet. Bend it so the end is the lowest point. Then just spin it around and see where it touches first.

    If what you want is more MRR, then consider upping your feed and doing the trochoidal milling instead. With cnc routers in aluminum, the “proper” way is to feed fast, stepover/side load little, and use a high DOC.

    I will prove you wrong 😀 I am getting new endmills so I can finally start cutting again. Really though other than the burred edges, your cut turned out good

    You’re right the vfd systems are a little too heavy for the mpcnc, they’re also quite expensive. Not to mention I doub’t we are running into hp limits on our toolpaths. The limit for us is rigidity and nowhere near watts. HP comes more into play with expensive commercial cnc mills where they often run out of horsepower instead of rigidity.

    By no means am I saying I believe an mpcnc can dish out airplane parts, but I still believe it to be very capable especially considering its materials and price. Besides, most if not all the jobs I have done with it are much faster than 3d printing even with a 1mm nozzle. In my opinion it is worth dialing in settings that will achieve proper dimensions and surface finish even if it does take a little longer to make. If you think about it, MRR and just general speeds really matter when you are using the cnc for productivity in a job, such as manufacturing parts for customers.

    1 user thanked author for this post.
    #37898

    Dui, ni shuo de dui
    Participant

    Oooh man..that video makes me cringe a little. Wayy to much chatter and vibration, he needed to fix his aluminum better. You can actually see the stock plate rising. The finish on those parts looks awful too ? Honestly those settings looked too aggressive for sure.

    Haha, yeah, I think this guy just had a few bits to waste. My point here was that, if you do that with the MPCNC, you will lose steps and the cut will not work at all. At least here, if the drill bit doesn’t break, it has enough power to achieve the cut. During my first tests, it happened to me two times that the CNC missed steps, mostly because it was vibrating too much.
    But don’t worry, I do not plan to do anything like that ever!

    I managed to get mine somewhat perpendicular by shimming the mount with tape. Get a coat hanger thats 3mm thick OD and fasten it to your collet. Bend it so the end is the lowest point. Then just spin it around and see where it touches first.

    Very nice Idea, I’ll try the coat hanger thing, thanks a lot!

    If what you want is more MRR, then consider upping your feed and doing the trochoidal milling instead. With cnc routers in aluminum, the “proper” way is to feed fast, stepover/side load little, and use a high DOC.

    Yeah, but again, setting trochoid doesn’t seem to work when you do cut paths in Estlcam, seems only to work for pockets. Or maybe I just didn’t get it yet.

    You’re right the vfd systems are a little too heavy for the mpcnc, they’re also quite expensive. Not to mention I doub’t we are running into hp limits on our toolpaths. The limit for us is rigidity and nowhere near watts. HP comes more into play with expensive commercial cnc mills where they often run out of horsepower instead of rigidity.

    By no means am I saying I believe an mpcnc can dish out airplane parts, but I still believe it to be very capable especially considering its materials and price. Besides, most if not all the jobs I have done with it are much faster than 3d printing even with a 1mm nozzle. In my opinion it is worth dialing in settings that will achieve proper dimensions and surface finish even if it does take a little longer to make. If you think about it, MRR and just general speeds really matter when you are using the cnc for productivity in a job, such as manufacturing parts for customers.

    [/quote]

    My worry is not only speed here, it is more about reliability.
    I have two choices here: I can fine tune the machine to find the sweet spot where it performs as expected, or I can find a machine which has a larger sweet spot.
    I will continue to work on the MPCNC, but I think I’ve already made my mind about the 3040, I will probably give it a try.
    I will make my best to invest my time making the plasma cutter work with the MPCNC, I think it will be better.

    Of course, my point is absolutely not to say that the MPCNC is crappy at milling aluminum, there are plenty of videos who proved otherwise, just that I feel like it may not meet my criteria of reliability/speed/accuracy. I would like to have a more forgiving setting. Breaking a bit seems less a problem than ruining a job for me. You can always restart a job with a fresh bit, but once the job is ruined due to missed steps, it is definitely ruined

    #37900

    Barry
    Participant

    Use trochoidal paths, they will help. Peel for the pockets, don’t know if inside to outside our outside to inside are better with those.

    #37901

    Jeffeb3
    Participant

    Have you used this?
    https://www.thingiverse.com/thing:1525661

    Then, shim with tape.

    So you think the widening of the path is caused by the gantry moving around? The outside path looks pretty good (and I think the total part ended up looking nice, but I get that it should be better). Is it possible there’s some kind of coating on the material that is making the surface harder? Are you sure the spindle isn’t wobbling w.r.t. the gantry?

    What about making the first pass smaller, like 0.1mm? AFAIK, there isn’t a setting like that in estlcam, but you could add 0.4mm to the total depth, and just set your origin 0.4mm higher.

    #37928

    Ryan
    Keymaster

    Another thing I did was to put a big spring along with the Z axis threaded rod, to push up the Z axis. The reason is that there is about .5mm of backlash there, and it caused issues whenever the spindle was pressing down on the material, it lifted it a tiny bit, then went down progressively while traveling around the path. That spring somehow limited this issue because now the router is always at it maximum Z position considering backlash. So when it hits the material, it cannot go up anymore, it is a solid hit now.

    This is backwards, you are now fighting gravity and the direction of pull from the bit. The spring should add to this not subtract. I understand your thinking in this but I promise it should be pushing down. This could explain your first layer issues, you are preloading it and it can move that .5mm (which is pretty bad, you should replace your nut).

    Don’t forget guys, there is 18″ of z axis hanging out the top and a large vacuum system as well. Also this is on large linear bearings not the 608’s So I am not sure if there is any preload on them or if the initial material contact is the preload. Heavily modified, I want to help but there are tons of variables here.

    #37945

    Dui, ni shuo de dui
    Participant

    This is backwards, you are now fighting gravity and the direction of pull from the bit. The spring should add to this not subtract. I understand your thinking in this but I promise it should be pushing down. This could explain your first layer issues, you are preloading it and it can move that .5mm (which is pretty bad, you should replace your nut).

    Yeah, this was just a quick and easy thing I’ve tried, I will replace the nut system by using two nuts, as I did it before.

    Don’t forget guys, there is 18″ of z axis hanging out the top and a large vacuum system as well. Also this is on large linear bearings not the 608’s So I am not sure if there is any preload on them or if the initial material contact is the preload. Heavily modified, I want to help but there are tons of variables here.

    Nope, my Z axis is a short as technically possible, I only have something like 6 or 7 cm of travel, the router is as close and as centered as possible to the gantry and I removed the vacuum system for the aluminum milling tests. I’m pretty sure I followed the best practices here.

    IMG_4113

    But it is indeed possible that the linear bearings slide too well on the tubes, thus not dampering the vibrations, that’s a good point.

    Anyway, I tried again yesterday, using a different approach in Estlcam (rough pass and the a finish pass). It worked ok until it reached the very last path and cut through the aluminum. At this point the whole thing vibrated like crazy and I had to stop the machine. It is not the first time I notice that the path where the bit starts to go through the material causes problems. Does anyone knows why?

    Attachments:
    #37948

    Dui, ni shuo de dui
    Participant

    Have you used this?
    https://www.thingiverse.com/thing:1525661

    Then, shim with tape.

    Nope, it seems like it is for ER11 systems.
    But I could redesign it, no big deal, thanks.

    So you think the widening of the path is caused by the gantry moving around? The outside path looks pretty good (and I think the total part ended up looking nice, but I get that it should be better). Is it possible there’s some kind of coating on the material that is making the surface harder? Are you sure the spindle isn’t wobbling w.r.t. the gantry?

    Yeah, for some reason the outside path was a bit better. I don’t really know why.
    I don’t think there is any special coating, maybe just a natural oxydation.
    The spindle is wery tightly secured, when it moves the gantry moves too.

    What about making the first pass smaller, like 0.1mm? AFAIK, there isn’t a setting like that in estlcam, but you could add 0.4mm to the total depth, and just set your origin 0.4mm higher.

    Tried that yesterday. I was surprised to see that I ended up with similar results.

    #38539

    Dui, ni shuo de dui
    Participant

    Gentlemens, welcome back to the shop, today we have a threat especial: the chinesium 3040 milling machine!

    IMG_4122

    IMG_4124

    IMG_4133

    IMG_4134

    IMG_4135

    IMG_4136

    IMG_4138

    This one is entirely made of aluminum, with linear ball bearings and ball guided screws. Seems pretty rigid, not entirely perfect since the Z axis has a tiny little amount of play if you apply fairly good pressure on it, but it is far less than what I have on the MPCNC.
    As many people were wondering how the MPCNC actually competes with other CNC structures, I think it could be instructive to post my new build here, so I can try to make a somewhat objective comparison between both systems I own!

    So far, I’ve put all my energy this weekend to make it work, but I haven’t got time to actually try cutting something yet.

    I’ve only purchased the chassis. For the electronics, I’m using a similar setup as for the MPCNC: Arduino + ramps + MPCNC firmware. The difference is that I don’t use the tiny crappy drivers, I’m using some beefier TB6560 ones, capable of 3A per phase, in order to drive the bigger steppers. The only issue I see there is that those drivers are limited to 1/16 steps instead of 1/32. I’m wondering if this actually makes a visible difference in terms of cut quality. I hope not because 1/16 makes the machine pretty fast and torquey, it would likely be quite slow and weaker in 1/32. I’ll see if this proves to be a real issue, I always wondered about that. 640 steps per mm seems to be enough, at least in my noob opinion… Makes 0.0015 mm per step, I m’n not sure there should be any real difference going for 1/32 which would make 0.0007mm per step. In my opinion, backlash and other issues will happen far before we hit those numbers. But Maybe someone can correct me if my assumptions are moronic, I’m really no expert.

    I reused some steppers I had for other projects, X and Y are pretty normal ones except for the fact that they are rated at 84V, and the Z stepper is some pretty big ass stepper, it was actually the biggest and the most powerful one I could find at that time. Not necessary at all, but I had to use whatever materials I had. right now I supply them with 12V and it works fine, but I’ll try to find a 24-or 48V psu in a near future.

    I spent quite a bit of time doing the wiring, and I added limit switches for all axis in order to do homing. I’ll add a probe system later.

    It’s ready to work now, I’ve checked and adjusted the spindle squareness, set the proper step/mm values, jerk values, max speed and so on, and it seems to chooches fine.

    I’ll probably make the first milling tests this week, as usual I’ll post pictures. I’ll also try to make comparative cuts between both machines, to see which machines performs best at doing what.
    Of course, don’t take those as scientific experiences, and keep in myind that my MPCNC is probably a bit different than yours, for instance it is likely of different dimensions, different table structure, even different bearing systems. But anyway, it might be fun and interesting to see.

    Cheers!

    #38550

    Kevin Lopez
    Participant

    Looks kind of skookum to me…

    Very curious to see how far you can push it. If for some reason my future electric longboard business plan goes right…I may make something similar to a 3040. That or if Ryan comes up with a brilliant pro version for those seeking better rigidity and features at a price that reflects it 🙂

    Dui idk if you saw my youtube video but that can be a baseline of what the mpcnc can do if combined with correct cam and setup.

    Ordered a 7 dollar tiny vice for my build, I sort of want to try experimenting with a router/mill combo, where most of the build area is taken for a router space, then a small chunk reserved for a vice higher up for milling thick but short stock material.

    #38555

    Dui, ni shuo de dui
    Participant

    Dui idk if you saw my youtube video but that can be a baseline of what the mpcnc can do if combined with correct cam and setup.

    Just saw that on the other thread, it’s really great!
    (That’s right here, for those of you who may not know what we are talking about, you should really check this post: https://www.v1engineering.com/forum/topic/lionkevs-aluminum-attempts/page/2/#post-38463 )

    Now, let’s see if a 100% aluminum machine is able to beat a mostly printed one !

    I’ll need to buy a few good drill bits, any suggestion about diameter, number of flutes or whatever?
    I’ll buy at least 2 of each and test on both machines. I’ll also have to tweak my MPCNC to have similar results as yours otherwise any comparison will be pointless, so I’ll need you to share your settings, or even better, directly send me a gcode test file of your own (if you don’t mind of course).

    Again, great job!

    #38561

    Kevin Lopez
    Participant

    Test file for dui, and anyone else but I wouldn’t use this lol. Careful, this gcode is a bit unpolished. Included is me trying to be professional, a drawing of the “part” For the rectangle, the nominal is 26mmx21mm, but actual is 6mm less (20mmx15mm), as the gcode is a 3mm wide bit.

    1 user thanked author for this post.
    #38633

    Dui, ni shuo de dui
    Participant

    Ok, I just bought a set of aluminum bits of various sizes and types:
    -one flute
    -two flutes
    -three flutes
    -3 flutes slightly rounded
    -ball
    -rounded chamfer/fillet tool
    -V bit
    Almost all in 3mm, some in 4mm

    I should be able to make almost any kind of tests with that, just hope that they are good!

    #38651

    Ryan
    Keymaster

    I am starting to like the single flutes more and more they work great for everything and seem to have a larger sweet spot.

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