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  1. #41
    Member Tkamsker's Avatar
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    Default Re: VMC Mill Discussion

    Thank you m_c for thst Input that bring's me to my next thinking
    The Electronic box i think that the tormach Solution is sufficient
    My plan is to offer the box including Computer Turn Key if support is required
    The eu machine regulations would Force me to have it 100 % Turn Key or as Part of a machine
    Where the Customer would have to do all that (basically expensive paperwork ) testing to have emf TÜV and so on ,.. The Problem is thst i can find out what the Maximum is i can do because it is an bussiness Nobody can Tell me the Minimum
    Back to the Electronic Board i think of
    Emergency halt on off power on flood pc on etc. In the box so depending on your Need
    Of splasguard (i designed and Build a nice One but due to Electronics i do redesign )
    What options are needed for Electronics my Idea is to have a Kind of box where you have then Screen Keyboard mouse and some essential keys
    Any Must of no go ?



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  2. #42
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    Default Re: VMC Mill Discussion

    I believe to keep peoples interest in this tread, We need to start seeing some cool pics. I mean Defang peeked our interest with just some wooden molds!



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    Gold Member LeeWay's Avatar
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    Default Re: VMC Mill Discussion

    If you cannot market a machine unless it is a fully completed CNC, then market aftermarket replacement parts or assemblies for existing machines. That or put hand wheels on the ball screws.
    You could market it as a bare bones kit. I don't think all RC model plane kits over there include engines and electronics. There has to be a way if you do not intend to include motors and electronics with every machine base sold.

    I do agree. A few models of guys intentions or thoughts would help to carry the discussion. Lets see how many different welded tube designs we can come up with.

    Lee


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    Default Re: VMC Mill Discussion

    Leeway sorry i am not an native speaker (although i work in english on an daily base ,.. ) how do i translate tramming in your context did you build an manual gear ?
    About fotos no problem

    the design is based on an existing machine
    so here is an closeup of x and y VMC Mill Discussion-20131229_144245-jpg the manual wheels are still there but sling loaded so they don't turn when the cnc motor is in action.
    the other side of X axis is driven in my test setup by an well sized stepper (nanotec ) VMC Mill Discussion-img_20130928_173925-jpg for now i keep the setup because it works maybe in servo setup a direct drive is key,
    same for y axis this is well covered under the x and y table where it really make sense. The Z axis is covered by steel plates (like the bridgeport) the back side of y axis is covered by an industry rubber sheet (i have to see how this works by using it ) the front side of y axis only the spindle is covered i designed an sheet metal cover which works like the z axis cover.
    now the Motor the motor is an 2,3HP Toshiba VFD Driven one which has belt drive i did an setup to test the spindle orientation (for my Bridgeport 412 Retrofit )
    looks like VMC Mill Discussion-img_20131110_140118-jpg here you see the top side of the spindle (left side) the spindle is an ISO 30 M12 Manual one. (i tinker on an draw bar for that but not for now)
    the right side is the driving side of the motor. I think in that setup it makes sense to get an encoder on the spindle (AMT101 or similar ) which then helps at tapping and gear cutting if needed for orientation and speed only one is needed. (I have an mod bus board for the Toshiba where i can really direct control the motor but no time for exzessive testing) my idea is to make the spindle modular.
    That when you order an machine you say what flavor you like
    so i have a chance to keep the costs down i am awaiting the ATC Spindle which will then lead to test in an electronic wise setup like i did on the bridgeport means i can drive the machine till physical limits !!
    Now electronic setup i played around with an touchscreen box (an ugly fast hack but ok for testing ) VMC Mill Discussion-20131224_151527-jpg and the inside VMC Mill Discussion-img_20131207_181612-jpg here you see the
    din rail for the relays module (general mechatronics) and the benezahn bob board for VFD control on the left you see the backside of an 15" Touchscreen (i intend to use gmoccapy as on my lathe )
    bevor that i did experiment with an kind of external electronic box VMC Mill Discussion-img_20131110_140109-jpg here you see my test setup the box is also an proof of concept where
    the tripplebeast is inside all switches and on top there is an NCBOX (which runs linuxcnc and Mach3 if needed !) and beside that i tested an ITX board with linuxcnc because the servo require FPGA board and i use same setup in the bridgeport so the black box is an standard ITX pc with the Generalmechatronics FPGA board inside, with this setup i can drive servos and steppers only physical limitations ,..
    But the setup was mechanically not good it shaked and because of cooling i need an propper splashguard.
    so i did splashguard design i did the machine in scale on 3d printer then i started to tinker VMC Mill Discussion-20140413_154640-jpg in the right corner there is the electronics closet.
    other angle to get the picture ( i had 8 different iterations to find that solution ) VMC Mill Discussion-20140413_155558-jpg
    Good think is having the factory just 25km from home. I made an agreement with the owner that they can use my design for their customers and here pictures before
    painting where you see also the machine base. VMC Mill Discussion-20140711_073948-jpg and VMC Mill Discussion-20140711_074007-jpg and electronics closet VMC Mill Discussion-20140711_074021-jpg backside view.
    the design also has an steel holder where the front side (haas like ) is place for the 15" Touchscreen and the keyboard knobs mouse and so on to have it nice.
    so from the backside of that cover there is just an LPT Cable extension for the knobs , an VGA and usb extension and an extra line for special knobs like Emergency halt. cooling whatever
    i found an company here which would laser cut and bend the sheet metal so i will draw next weekend the LCD part and see when i get it.
    hope you like my findings so far



  5. #45
    Gold Member LeeWay's Avatar
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    Default Re: VMC Mill Discussion

    Tramming is tramming in German or English. I worked for a German company for a couple years. You English is at least as good as my German.
    It's aligning all three axes with the cutting tool. I haven't made anything special for it. I just think it should be designed into the machine from the start.

    Lee


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    Activation process G59's Avatar
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    Default Re: VMC Mill Discussion

    Nice! What I would suggest. Linear trucks should be mounted on the underside of the table. Less mass to move around and somewhat reduces contamination. Y axis motor should be mounted on the back side limiting exposure to coolant and chips and reducing overall length.
    Touch screen is OK for hobby, not so great when coolant, oil or dirt/chips get on it.(requires constant cleaning) . If you use resistive touchscreen, then it should be fine even with oil smudges on it.
    I love the modular spindle idea. That makes it special.



  7. #47
    Gold Member LeeWay's Avatar
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    Default Re: VMC Mill Discussion

    I do think the trucks should be mounted above the rails. That is to the saddle and to the table. This does help with contamination. I think the design needs some permanent type way covers to help prevent this.
    A lot of guys clear chips with compressed air. When you use it to help clean the machine, dust, dirt and chips get into spots where you do not want it. I did it like that somewhat on the Torus and most all the time on my 80/20 mill.
    I did have to replace 4 THK trucks on the Y axis due to wear and I think it was because of contamination. Lots of particles inside those trucks. Now I have replacements though after rehabbing the old trucks.

    The Pulsar I have now has a very nice coolant wash down system. After the day is done, grab the wash down hose and hit a switch. I am able to wash out all the chips into a screened collector tray that gets dupped every morning. It sits above the tank. The tank also has screens, so two filters. It uses it's own coolant pump for wash down.
    I can tell you that anytime you have to any sort of maint. on it, its nice having a clean machine and chip tray to work arouund. It helps keep chips from getting packed into the table slots as well.
    Just overall a very nice system.
    I would certainly implement the same on any future mills.

    Also, since we are talking the base and bones, the auto oiling system needs to be discussed at this point as well. To work effectively, it must be designed along with the way covers and rails as well as the screws.
    The location of the actual pump isn't important yet, but the location and type of oil lines and fitting styles are.

    Lee


  8. #48
    Member handlewanker's Avatar
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    Default Re: VMC Mill Discussion

    Hi all......I like to hear about the current machine builds and what they are capable of, but I'd prefer to stay with pure design for the ideal CNC mill.

    I would say that first we need to establish the machine build format for a universal acceptance, not different configurations for moving tables or jobs.

    For an opener, I would suggest that if steel tube is the preferred material for the main structure, it has to be pretty big in section and thick in the wall too.

    Personally, I would go to a 10mm steel plate construction....... that is, flat plates cut and welded together to give the shape you want........that's is so's you can give the column some strength as you go high, not like a narrow pencil like structure I've seen in a lot of builds where a straight piece of tubing is used.

    In Defeng's SVM-1 he has the base area bigger than the top section so giving the stability for a good foundation.

    I think the body, in the size of machine so far indicated, can not be less than 10mm wall thickness, and with that you would have no flexing in the structure or need to fill it with epoxy whatever......if the structure is still able to resonate or flex then go to 12mm thick etc, a casting will have at least theses dimensions for the machine we are contemplating.

    It does not automatically also mean that the head has to be a steel build also.......who wants to do peck drilling with a head weighing 50 Kilos or more......so I would suggest that a casting in aluminium for the head would be good.....inertia is a killer for steppers and ball screws.

    If there is a vacuum for the design, then it would be practical to look at the Defeng models and designs as they have been laid down, except using steel instead of castings.

    David D'Caussin of UMC-10 fame built his CNC mill with steel tubing and linear rails.

    BTW, putting the rails on the base and the bearing blocks under the table means you need twice the length of rail for the travel distance if you need to have constant support on the rails, and for a table travel of 450mm that means rails 900mm long......probably Hiwin 25mm minimum.

    What we are looking at there is more like a bed mill, the type of mill layout where the slide ways are sticking out on either side of the table.
    Ian.



  9. #49
    Member Tkamsker's Avatar
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    Default Re: VMC Mill Discussion

    Hi
    handlewanker
    funny i just checked my post now
    if you check the factory pictures you see 10mm welded base and i will stay with that design exactly of the reason you mentioned.
    Also the rails are set for now i think.

    for me also the debate about steppers or servos is set because depending of your requirements (and money) you should be able to choose but i have not figured out what is the best servo controller combo
    in reliability and price ,.. because the offers are a verry wide field.
    i am now at the head today i received the ISO 30 ATC Spindle for testing strange thing is that is milled of an alu block but perfect bearings and german accuracy
    so i now have to do the setup for test and then we see how this works in real

    i would expect that an alu block is not the best solution for atc milling head.

    thx for you input thomas



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    Member handlewanker's Avatar
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    Default Re: VMC Mill Discussion

    Hi, yes, just going to bed......its 4 AM......I'm heavily influenced by the SVM-0 mill design from Skyfire and that is the main reason I "invested" in it.

    I don't think it would be at all difficult to fabricate a mill body using steel plate and welding, as the final part is all ground over with an angle grinder etc and finally gets painted.

    What makes it work is the expensive peripherals that get bolted onto it, so provided you can align the various sections to be square to one another, same as you would for a casting, steel building is not a problem.

    It also makes adding and removing bits and pieces a simple process when you want to modify the structure as steel is easy to cut and weld.
    Ian.



  11. #51
    Gold Member LeeWay's Avatar
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    Default Re: VMC Mill Discussion

    My thinking is no casting at all. There are probably millions of welding shops around the World, but decidedly not nearly as many foundries.
    Say you want to make a run of 50 mills. That is a lot of output to the foundry. That design cannot easily be changed mid stream if needed. It can be easily changed with a welded frame. Not only that, but it's not as big of an investment upfront that way. You can have those built 10 at a time without any curing worries. Now don't get me wrong. I like me some cast iron.
    I just think it should be left for large companies making tried and true designed machine that do not change, even from one model to the next. In that case, they do become more affordable and less labor.
    Not the case that we are spit balling here.

    You can certainly buy over sized tube and cut it into thin slices that become the head frame. Add a web or two and then machine as normal. That will work in such a small sized machine without a doubt. The option to fill the machine cavities with epoxy granite is to alleviate resonance. Not to really add weight, though that is a side effect.

    I think I may be straying from the design somewhat to the machine Thomas is actually making.
    I though we were designing a machine from the ground up that could be welded. If that isn't the case here, maybe we should start a new thread to do just that. I know it has been done, but that was a while back.
    A modern machine requires a modern thread.

    Let me know if I am wrong about this thread. I have been wrong before.

    Lee


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    Default Re: VMC Mill Discussion

    Hi i think that the tread is about machine from Grund up in Terms of Head atc Stepper servo
    But i think we Agree That Base is welded so the tablet size gives the bed. size
    Dont get me wrong but wd. Are Talking of the Base and upright so i would then stay with existing Design as Long there is nothing wrong with it ,.
    But we can do an ground up thread and Keep this One and if then really 2 machines exist we compare result my Idea is also to compare real cuts and Speeds Foto of how does surfaces Look like i guess the mold People Need That
    Means the Mill will be an iterative approach so There will be Interaktion 1 use it learn Share integration 2 and do on and then Based on real Results we can Share opinions and See what worked or Not ,.. I Hope That People will like that approach ,..



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    Activation process G59's Avatar
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    Default Re: VMC Mill Discussion

    Leeway, can you elaborate on 'tubing' for the base. You mean like the base of a router only thicker?
    Is tubing also the material for the upright beam?

    BTW, putting the rails on the base and the bearing blocks under the table means you need twice the length of rail for the travel distance if you need to have constant support on the rails
    ???? Why am I thinking this is not true????? I need some enlightenment here. I would love to see the alternative. It would save us lots of money.
    From what I saw in defengs design, I did not like having the rails unsupported at the ends of the casting like he had. It was a poor design no matter how long he would argue his point for it. Defengs design in my opinion was just copy, carry over from other designs that are already out there.
    That being said, we can forget 'cast', unless the design has been proofed and you foresee high production. Cast is actually quite affordable, it's the investment in durable molds that is prohibitive. I have contacted a couple of foundries that are less than 50kms away from me, and they do custom castings for low production runs, and the prices beat welded steel plate design by an average of 33%. The problem where the price skyrockets, is in making the cope, coves and cores to their specs, as they can only "insert" your casting in their regular production runs and it must fit in their racks, conveyors, fillers and shakers etc.... .

    From what they told me, by the time you pay for shipping from China and pay the customs/import fees, it pays to have it cast at home even though their prices are twice as much as Chinese castings. 2 week lead time.
    I will look further into this.

    For now, I would like to see some drawing on this tube frame design. I'm not too familiar with the UMC 10 frame so can't really form an opinion on it. I have seen the videos however.

    Good day.



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    Default Re: VMC Mill Discussion

    Been following this with interest, and seeing as someone asked for a drawing of a tube frame design here you go.

    I'm (slowly) building a small vertical mill from 180x180x16mm RHS, roughly as per the below (although I've since made the stand from heavier 80x160x6 RHS as I found some cheap :-) :

    VMC Mill Discussion-bikepete-mill01-jpg

    It is designed to go into a floor space of approx 1100 x 850mm. That would be a convenient size for commercial purposes perhaps as it could ship on a Euro-2/3-pallet (1200x1000). Electronics box and computer all fit under the mill to keep everything compact, probably with some space to spare. Not sure where I'll put the screen yet. Enclosure to follow eventually too.

    I'm aiming for X: 400 Y: 200 Z: 250 and enough rigidity to get good accuracy on steel.

    Choice of 180x180x16mm RHS was mainly due to finding a length of it very cheap. Column pierces the two horizontal tubes so that it can get max support for the join at 90 degrees, and the twin horizontal tubes provide good support for widely spaced Y axis rails. The tubes are being joined with bolts, heavy angle iron pieces and epoxy rather than welding, and I intend to fill them with sand, both decisions for anti vibration purposes and to save any worries about stress relieving welds. End plates not shown - will close all tubes which will also add substantial rigidity. Sand because cheaper than epoxy and easily removed.

    The slab supporting the Y rails will sit on a bed of epoxy too. A separate slab is easier to machine and handle, and I didn't like the idea of rails on different bits of tube even if notionally securely joined together.

    The mounting surface for Z is also on a separate block rather than on the column itself, so that it can be trammed w.r.t. the X and Y axes before being epoxied into place - no need then for serious accuracy when assembling the main frame.

    Still working out details of Z (would like an AC servo but not come across a big one cheap enough yet) but am thinking it'll accommodate an 80mm or 90mm spindle cartridge so that bought options can go in.

    Currently still building the stand and main frame as per the picture above - slow work because I'm doing it on machines that are really too small for the task (and alongside a day job!). Will do more CAD work once the main structure is done, to bring in detail of the various axes. No point doing it sooner as I'm still acquiring the parts (rails, ballscrews etc.) as and when I see cheap enough bargains, and it'll have to be designed around what I end up with. But looking like 20/25/30mm profile rails, 25mm ground ballscrews with timing belt drive via steppers initially at least, although will design with a view to moving to AC servos when funds permit.

    Not sure the epoxy/bolts/angle iron construction is really relevant for possible commercial purposes - too fiddly and labour intensive. Probably better just weld it up and stress relieve if necessary...



  15. #55
    Member handlewanker's Avatar
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    Default Re: VMC Mill Discussion

    Hi, now we're talking turkey.....that design is pure steel tube orientated and a good example of a steel build versus a casting one.

    I don't subscribe to the epoxy adhesive for the frame fixing.....being an old school metal worker, but if you did stick two pieces of steel plate together face to face with a coating of just plain impact adhesive, it would be impossible to separate them without huge amounts of force, so epoxy being a million times stronger does have place in the engineers toolbox, but with huge reservations on that aspect.

    Personally I like breaking boundaries and looking over the edge of the pail etc, but at the same time I also adhere to the axiom of tried and true engineering methods....do it once the right way or don't do it at all if you are working with methods foreign to you with unknown outcomes.

    With a straight steel tube construction, there will not be many people who would place orders up front etc, not unless the final product has been road tested extensively, and has credentials acquired from satisfied users.

    I think with this thread the various methods for welded steel tube or plate construction can be broken down to a few parts, such as the base, column, and head.

    How they interface is going to take a few pages at least.

    I assume this thread is not slanted for production, where one off prototype design is a whole different path to tread.

    If it's intended to put a design together purely for eventual multi production then forget steel tube and stay with castings.....Defeng has already done it and there's no need to repeat the same exercise he so cleverly created.

    I would like to see a design that lays down the basics for a simple....relatively speaking......steel tube design, using applied mechanics for the strategic proportions for the components so that it will not end up a ton of door stopper potential or a flimsy cost cutting never will get made machine nobody will build.

    From the design Defeng created in iron to a steel tube or plate construction is just a small sideways step.....the dimensions for the base and column has to satisfy the need for 400mm X, 200mm Y and 200mm Z as indicated in post #1, I think, but would be a good starting point.

    I think the thinking has to steer strictly away from a "pretty" machine design and stay with the cold hard characteristics of functional welded steel construction with all it;s warts and bumps that are normal with fabrication........for those that like pretty machines to look at, no doubt there will be a dividing of the ways when the designs are on the table, and it's amazing what a bit of filler and a 2 pack paint job can achieve.

    I've slanted the direction as I see it to a one off design for that one off construction you want but no one else does, but no doubt there will be those that want to reproduce it for possible production.......best of luck as the one off prototype ones don't go down well when it comes to making more of the same.

    The UMC-10 design had a large thick wall steel tube for the base with bits welded on where needed, such as the feet, the linear rails mounts and column base.

    I have no doubt that with a design as simple and basic as that most of the construction could be achieved with your eyes closed, and without the need to lengthy CAD drawings.

    Most of the dimensions can be acquired by 2 D line sketches on a big board to get the tube sizes needed and/or a scale model to get the feel of it too.....that's how I'm currently making a 2530 moving table router design I've started to build.

    The base will be as long as the Y axis needs plus the depth of the column body that sits on it.

    I also think the starting point should be the column, as this dictates the ability to hold the head steady while the cutter does it's work.....any vibration here and the cutter is vibrating too.

    If we said a plain steel tube column 200mm wide and 300mm deep with a wall thickness of 10mm rising to 900mm high....what would that give you?

    BTW, I imagined that from an A4 sheet of paper I saw lying on my desk and thought that with that cross section it would make a very sturdy column in that size.

    That also means the base could be 200-250mm wide X 100mm high to mount the rails on, making a very stable base area etc etc.

    Without any internal bracing, just closing the ends with welded on plates would create a strong box like structure.
    Ian.



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    Default Re: VMC Mill Discussion

    I think we will See that but i cant See where defeng pictures are special ...
    If you Look at my pictures you See that Steel frame but today
    I received the atc spindle
    I love german Design and accuracy
    So on friday i will See How we get that on the Mill and How it Performs because i want to See real live Milling examples ..

    Attached Thumbnails Attached Thumbnails VMC Mill Discussion-uploadfromtaptalk1414612020973-jpg   VMC Mill Discussion-uploadfromtaptalk1414612138877-jpg  


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    Default Re: VMC Mill Discussion

    I'm so sick of hearing about how advanced and innovative Defeng's machine was. Is everyone awe struck by someone's ability to create molds for a simple design? What was so good about it? What innovative concept did he put out there that makes it the envy of all hobbyists? That's what I want to know.
    I have read the whole thread on his build, and nothing stuck out as extra ordinary except for the forecast ed price. As a matter of fact, nothing really came out of it except broken promises.
    Not one thing was new. The castings were old technology from the 20's. So give it a break already. No more Defeng BS. It was a failure period.
    Now back to the thread.

    This thread shouldn't be "just a one off". Make it a good design others can copy if they wish.

    I also think the starting point should be the column, as this dictates the ability to hold the head steady while the cutter does it's work.....any vibration here and the cutter is vibrating too.
    If we said a plain steel tube column 200mm wide and 300mm deep with a wall thickness of 10mm rising to 900mm high....what would that give you?
    No good. You are counting solely on the rigidity of the column to base via a steel profile. This is bound to cause problems.
    If I wasn't so tired I would draw you a model of what should be implemented into this build, but I really need to catch up on some sleep.
    I will draw something up by morning.

    Good night.



  18. #58
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    Default Re: VMC Mill Discussion

    Hi....being a Defeng fan probably puts me in a position to appreciate the end product that arrived from concept to finished article....it did get made, featured on UTUBE and actually cut metal and performed as predicted....where is there any other mill available in that class that comes anywhere near the end product.?

    BTW, we are talking about casting technology which goes back several thousand years and is state of the art in that format......you have to bear the cost whatever if you want to proceed down that road.....in other words the same old same old tried trusted and true.

    Anyway, back to the steel tube design per se.......the column I indicated from a straight piece of tube was a starter and I expected someone.....anyone?....to comment on it and show how it can be improved on.

    We are working with off the shelf straight sections that are continuous in their cross sectional areas, no matter how long you make them, so if you start off with a small base area you will get an aspect ratio for a column that is out of proportion to the height it needs to go......a toffee apple on a stick waving in the wind etc, but starting with 200mm X 300mm does give you a well spread foundation to build on if you want to go to 900mm high.

    For my personal preference I would rather make a column from plate material and use a slanting side and back format to make a broad base and small top section......just for starters.

    It would still have a hollow box format and if made from thick enough material be able to withstand any deflection loads that a cutter under CNC mode forces would exert against it..............we are talking about resisting cutter deflecting loads under CNC conditions when the design for the column is proposed not hogging off material as is common with manual mills many time bigger.

    Going to extraordinary lengths to resist forces that never occur or can be imagined is both counterproductive to getting any project off the drawing board and also make it expensive to produce.

    It places simple materials like off the shelf standard steel tubing stock sections in the too hard basket.

    So......a column 200mm X 300mm and 900mm high made from10mm thick steel plate welded on all corners and having a 20mm thick base plate........won't be able to survive an attack by a cutter going at high revs, small depth of cut and feed rate that suits the cutter and material????

    Off the top of my head, this would suit practically any design that needs to be made, but it's simplicity and low cost could be improved on.

    For the argument, in what aspect would a column using those dimensions and material fail to provide a stable basis for the cutter to work efficiently?
    Ian.



  19. #59
    Member Tkamsker's Avatar
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    Default Re: VMC Mill Discussion

    Hi i think we Agree on the Base now question i Tried days ago to Rough calculate estimate the forces a servo should have. I have the Stepper setup already so now with the atc i also want to See the servo do you Guys think in the range of 3nm max is sufficient or 3 nm Holding torque to be able to decellerate the tablet if it is on Speed ,.. If you have servos where you have good experience with i would like to know thx Thomas ,.


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    Default Re: VMC Mill Discussion

    Ok, quick design made of steel plate as it should be. This is rough but went with handles measurement. This is only the base, column and center section. It is not optimized yet, and is incomplete, but merely a representation of what can be done when you move away from the dreaded tubing. Very solid. If you say its too expensive to have it laser or plasma cut, then I think you are in the wrong hobby.
    Just my thoughts.

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