MPCNC Version 2 -opinions-

New Home Forum Updates MPCNC Version 2 -opinions-

This topic contains 441 replies, has 69 voices, and was last updated by  Ryan 10 months, 1 week ago.

Viewing 22 posts - 421 through 442 (of 442 total)
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  • #38217

    Jeffeb3
    Participant

    I think I like the fact that he’s just put it on the floor the best.

    I don’t really like the 2 motor Z thing for the low rider, but I really really like the 611 plate. I don’t know how you get something like the 611 plate without moving the pipes. I’ve never tried that machine, and it looks nice, but I am going to bet that the low rider will be way more popular and that there will be a lot more innovation around and support around it. Kudos to them for building their own machine though. But no remix credit?

    #38218

    Jakob A
    Participant

    “You will need to square any machine everytime” <– I don’t mean to be rude, but I don’t agree .. you square your MP3DP every time you print ? I think not 🙂
    If the design is rigid enough you shouldn’t be able to pull it out of square. Ex. if we had dual shaft steppers and linked the steppers with an 8mm rod or something (not suggesting this is a good idea, it probably isn’t)

    Its not that I have any problems getting my machine squared, its usually only off by 1mm or so, sometimes not at all. Its just annoying and you have to be very careful to get it exact.

    I’m quite happy with it as it is actually, this is really the only thing that bugs me a bit 🙂

    I have looked at the lowrider, it looks pretty cool. Only 2 measurements needed to square it 😉 Unfortunately it’s not easy to find 1″ stainless here. (well its easy enough, just really expensive)

    Btw. this is probably because I didn’t look carefully enough, but what keeps the wheels on the lowrider from sliding sideways ?

    #38219

    Ryan
    Keymaster

    “You will need to square any machine everytime” <– I don’t mean to be rude, but I don’t agree .. you square your MP3DP every time you print ? I think not ?

    If it’s travel was more than 8″ you would, if you make your MPCNC smaller you will not need to square it to get it within reasonable tolerances, putting a few feet of lever arm on any machine will make it not square. I understand what you are saying and am not offended by it at all, but without adding a ton of steel, it will need to be carefully squared, the only reason the lowrider does not need it is there are parking blocks at the end of the table. These can be very easily added to the MPCNC but most people do not start it in the same position. Just like the ones HFE linked, but they only work if that’s where you start every cut. That is not how I have ever used my machine so that is not how I am going to design or sell it. If you use it that way then no you do not have to square the machine but then you would have to very carefully square and secure your workpiece. It is a tradeoff. The squaring has to be done on something.

    If the design is rigid enough you shouldn’t be able to pull it out of square. Ex. if we had dual shaft steppers and linked the steppers with an 8mm rod or something (not suggesting this is a good idea, it probably isn’t)

    Yes, those machine are extremely expensive and have a tiny work envelope, made of cast iron and steel, weight hundreds if not thousands of pounds. Linking each side would depend on you have exact tension on both belts, not really feasible, and then you also get half power.

    #38220

    Jakob A
    Participant

    I have some similar spacers (I just cut 2 pieces of pvc in half), it does make it easier.

    I think its not a bad idea to basicly put the pipes on the table, should make it rigid and it also only has 2 sides to square :D.

    I didn’t notice it isn’t a remix, the parts look a lot like the lowrider and mpcnc.

    #38221

    Ryan
    Keymaster

    Well only two sides to square, if you build your table square. Typically building a table thats holds that kind of accuracy is more difficult that moving around some pipes. Summer heat and winter cold will move it as well. It all comes down to your definition of square, a lot of guys doing cnc work measure things off a granite surface, and would never consider a wood table as a suitable machining surface. I have to walk the line carefully on coast and accuracy, every decimal place of accuracy cost exponentially more than the previous one.

    The 1mm off or so you mentioned earlier is less than 0.1 degree off over a two foot axis. Pretty good for under $400 in my opinion. With that said My main focus on improvement is rigidity, not cost or time or ease of use. Rigidity would improve “squaring” and decrease cut times.

    #38222

    Jeffeb3
    Participant

    I think you should focus on “safety” not safety like things that make you safer, I mean “safety” like spinning lights, giant red buttons, and loud buzzers whenever the machine backs up. Users need to pass a quiz on the LCD before using the machine. Built in tests to determine when the machine isn’t properly lubricated, etc.

    #38223

    Ryan
    Keymaster

    Come on now my the more buttons the more dangerous it is, all my friends kids can not resist a button or some flashing lights. Even if you said something like don’t touch that is super hot, if you turn away for 2 seconds they will touch it every time.

    #38224

    Jakob A
    Participant

    if I where to build a prusa I3 design with a print area of say 100×80 cm .. using 25mm rods, would I need to square it every time ?.. and how would I even do it 😀

    Okay joking aside, I understand the lever issue, I was only trying to say that maybe this is something that I would like to see improved.

    #38225

    Ryan
    Keymaster

    I should really clarify these kind of posts. I know I seem kind of like a punk about it, or a know-it-all or something. I feel very strongly that I need to point out things like “less than 0.1 degree”, and honestly represent my design’s capabilities.

    I have defended the numbers of this machine a few times today in different posts and I do like feedback and suggestions, but I also need to defend every single number someone quotes because these posts are here forever, and one single post saying it is so hard to square, or bad tolerances, etc. will get read at some point and taken as fact. If I follow it up with less than a tenth of a degree or better than stand manufacturing tolerances I feel I am honestly representing my design and it’s capabilities.

    I hope you all understand and my smartypants replies are not taken the wrong way.

    #38226

    Ryan
    Keymaster

    Actually the new prusa i3 mk2 squares every axis every print, like bed leveling but on every axis. The only printer to do so, and it is there because all printers are pretty far out of whack.

    #38228

    Jakob A
    Participant

    The 1mm off or so you mentioned earlier is less than 0.1 degree off over a two foot axis. Pretty good for under $400 in my opinion. With that said My main focus on improvement is rigidity, not cost or time or ease of use. Rigidity would improve “squaring” and decrease cut times.

    Totally agree its good, its just that when you have tried to get it exact once .. you kinda want it every time 😀 (so greedy .. i know)
    and with stuff like my Ultimaker frame even 0.1 degree is really bad.

    #38229

    Ryan
    Keymaster

    The printer thing was pretty interesting at the beginning of this whole MPCNC thing, some printers were so bad the parts did not work or fit together. It didn’t take long to realize the printers were the issue so I had to redesign the parts to be more forgiving. Not very many people actually check for xy calibration, with the typical print a cube and measure it. Even fewer ever check the z axis, even less check the extrusion (100mm test, this axis is always the worst and the least to get calibrated). I have never seen anyone check for square. you just need to print a large cube and compare it to a square or measure the diagonals.

    We found this out from my first few parts people would show fit up gaps and tell me I designed them wrong, so I would just tell them to rotate the part on the bed 90 degrees and print it again.

    Most people just print trinkets and calibration does not matter, but as soon as a design firm tries to make engineering prototypes you quickly realize how far off it can be.

    #38231

    Jakob A
    Participant

    The prusa mk2 does it in software.. its only needed because of the threaded rod design (I really don’t understand why they still use those when the rest of it is completely custom stuff now anyway). And you don’t do it every print 🙂

    #38232

    Ryan
    Keymaster

    Okay

    #38233

    Jakob A
    Participant

    For sure there are a lot of “non-square” printers out there, thats one reason why i like the Ultimaker design. Basicly as long as the top is cut square the prints will be square. It’s really solid .. even when I throw it in the back of the car it will not even need a new bed calibration.
    Same thing with the itopie I cut.. as long as I make sure the cut is square, the printer will be too.

    #69080

    Bluff Chuffer
    Participant

    Hi,

    Where I live M3.5 fasteners are not available, but M4 ones are, readily so. I did look at Aliexpress but could not find anything, so wonder how difficult it would be to offer the International Versions as M4 sized bolt holes – saves drilling, and maybe the nut hexagons could be also made to fit  these M4 sizes. This would apply to all V1 Eng designs too.

    I have made two MPCNC’s and now almost completed two MP3DP’s, and appreciate the work that V1 does.

     

     

     

    1 user thanked author for this post.
    #69084

    SQLException
    Participant

    Where do you think you need m3.5 nuts or bolts?

    Speaking of MPCNC v2, I can’t recall a single situation where you couldn’t substitute with m4.

    #69087

    Bluff Chuffer
    Participant

    Hi,

    The M3.5 are used as a substitute for the #6 US sizes. I do use M4, but find 4BA series are OK, but would rather use those on my steam loco’s as they are very scarce, an import or make yourself. Much rather print to size than having to do the extra work.

    MPCNC uses them here,

    57 #6-32 X.75 ***M3.5 X 20  Amazon
    57 #6-32 Nylock nuts ***M3.5  Amazon

    and on MP3DP

     3  #6-32 x 1.5″  Hex heads. These are for the XYZ endstop adjustments.
     60  #6-32 x ??(1″)  Frame screw length depends on frame material thickness, round up in length. See Below.
     55  #6-32 Nylocs

    M3.5 is closest substitute to #6-32, but not available as a standard.

    Thanks.

     

    #69115

    Ryan
    Keymaster

    I have done my best to eliminate most of the embeded nuts and make all the holes larger. Other hardware sizes should fit, it might take a little extra effort but I think you will see as you build it it isn’t that bad, or at least not any worse than using the correct sized nuts. I built it to fit the largest (#6) but M4 nuts tend to be smaller. So worst case is you jam a little flat head screw driver in and wedge the nut while you tighten it (which I do anyway).

    At the same time you can’t find #6 hardware online at all? With all the online worldwide sources is seems a bag of nuts and screws wouldn’t be that bad to get a hold of.

    I am doing my best with each revision to make the parts more friendly for M4, promise.

    #69135

    Bluff Chuffer
    Participant

    I appreciate all that you have done for your MPCNC community, I really do.

    Is there some way I can alter an STL file to make the correct size. I accept that you need to reserve the 3D cad files, so am not asking for that.

    Importing is OK, I guess, but it seems to be un-necessary as M4’s are available in all forms. We have just had a postal strike here and I have 2-3 months to wait before the backlog for some of my imported items are cleared!

    I have all sorts of a spanners and sockets in many sizes and have resorted to the screwdriver wedge action for many a task!

    Cheers and thanks again.

    #69137

    mulze32
    Participant

    I appreciate all that you have done for your MPCNC community, I really do.

    Is there some way I can alter an STL file to make the correct size. I accept that you need to reserve the 3D cad files, so am not asking for that.

    Importing is OK, I guess, but it seems to be un-necessary as M4’s are available in all forms. We have just had a postal strike here and I have 2-3 months to wait before the backlog for some of my imported items are cleared!

    I have all sorts of a spanners and sockets in many sizes and have resorted to the screwdriver wedge action for many a task!

    Cheers and thanks again.

    I’d like to make a suggestion for getting the nuts into the slots. What I do is I take a long nosed pliers and a heat gun and heat up the nut until its decently hot. I then push the nut into the slot and it inserts like butter. This could help alleviate a lot of problems.

    #69140

    Ryan
    Keymaster

    Is there some way I can alter an STL file to make the correct size.

    It truly is just no where near that simple, I wish it was.

     

    Try a different hardware store. You have three sizes to look for, you have to be able to get one of them. M4’s will work so I am not sure why you want to alter the files beyond that.

    Poke around thingiverse. There are plenty of pre-altered files as well.

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