Close



Page 4 of 6 FirstFirst ... 23456 LastLast
Results 31 to 40 of 51
  1. #31
    Engineer
    Join Date
    Jul 2016
    Location
    South Florida, USA
    Posts
    542
    Add AutoWiz on Facebook
    Quote Originally Posted by Reefsider416 View Post
    Hi everyone, I have been given some aluminum extrusions and decided I would build a Delta printer with them. The extrusions are pieces of a sailboat mast that has been cut up. Each section is aproximately 1.5m tall but once they are cut square and all the same length i figure I'll probably have about 1.3M left. I have decided to cut the extrusions so the steppers and sliders will be mounted inside the extrusions. I found a 15" aluminum Mag rim from an old sports car that i plan to cut down and use as the center rim of the printer that the extrusions bolt to. The bolt holes will be used for lighting unless the face ends up being too heavy for the top of the printer. I will probably also use 20x40mm extrusions to link each upright around the outer part of the printer to form the triangle. I am hoping to be able to achieve a 500mm print bed/area. For electronics, I have an SKR 1.3 to use. I planned to use nema 23 motors for the sliders and I hope to use Hiwin rails and carriages if i can afford them. I am not sure what size is appropriate; I'm thinking 15mm but maybe someone can advise me on the right size? I will be liquid cooling the print head and maybe the steppers, the electronics will be underneath and cooled with fans. I would like to use the E3D Kraken 4 Head hot end with titan extruders but I may settle for the Chrimera or to start maybe even the NF W-01 with an e3d V6 block and heat break. I have the NF W-01 already. I don't really have much experience with delta printers but i have been working on cnc machines and printers for a number of years. I am going to start by designing the components on Fusion 360 and then creating an assembly and seeing what I can come up with. I know the minimum angle to the bed should be 15-20 Deg. besides that i don't know a lot about building this or rules of thumb for a delta.I will post pictures and 3D files as they are created. If anyone has an opinion or advice please feel free to share it. It should end up being a pretty cool looking and very sturdy printer... I hope anyways lol. Thanks for any input you guys have
    Back on the subject of this thread With the opening statements on materials used I honestly don't understand why you would use anything other than linear rails. I am going through this conversion with other things on one of my machines right now. You can look there at the last page or two and see what they look like going in if you'd like. They were also cheap. I have found great success with ebay rails so far. For some reason buying the sliding blocks by themselves seems to be a loosing proposition. But the rail with the block already on it has slid smooth every time. I got mine from here: https://www.ebay.com/itm/MGN12H-Line...53.m2749.l2649 You can get them in different lengths and you will also need to get sliding T-slot nuts for 3mm screws. I got those here: https://www.ebay.com/itm/50pcs-M3-Sl...53.m2749.l2649 And you will need to get m3x8mm allen head screws. I got these: https://www.ebay.com/itm/Stock-50pcs...53.m2749.l2649 And the holes to mount stuff to the sliding blocks are the same m3 threaded holes.

  2. #32
    Super Moderator curious aardvark's Avatar
    Join Date
    Jul 2014
    Posts
    7,016
    For the record the belt tensioners are a very good idea. They REMOVE elasticity from the belt, not add it. As cheap belts age, they might stretch or the reinforcing elements can snap. The belt tensioner simply takes up any slack.
    If you get a lot of stretch in a belt - particulatly on a delta where it's easy to see. A belt tensioner on one belt that is closed more than those on other belts, is a good indicator that the belt has stretched and might need changing.
    Mainly they simply ensure that all belts remain at the same tension at all times.
    Placed against manual tensioning systems - where people adjust based on the sound a belt makes when 'twanged' (honest, I did not make that up)- a spring loaded belt tensioner is like a digital thermometer versus someone sticking their finger in and saying: 'yeah that's warm enough.'

    ok the linear rails thing is unclear.
    I assumed they were used for the vertical movement of the carriages. With rods attached in the normal way to the effector and carriages. The idea was to take any movement out of the wheeled carriages.
    So, if not that - then what ?

  3. #33
    Engineer
    Join Date
    Jul 2016
    Location
    South Florida, USA
    Posts
    542
    Add AutoWiz on Facebook
    Quote Originally Posted by curious aardvark View Post
    ok the linear rails thing is unclear.
    I assumed they were used for the vertical movement of the carriages. With rods attached in the normal way to the effector and carriages. The idea was to take any movement out of the wheeled carriages.
    So, if not that - then what ?
    Ya exactly that. Instead of wheels rolling up and down the extrusion or making brackets to hold the rods the rails bolt right to the extrusion where the wheel would have been rolling at. There is just no plastic, rubber, or PC anywhere in the metal bearings of the linear rails.

  4. #34
    Engineer
    Join Date
    Jul 2016
    Location
    South Florida, USA
    Posts
    542
    Add AutoWiz on Facebook
    Quote Originally Posted by curious aardvark View Post
    For the record the belt tensioners are a very good idea. They REMOVE elasticity from the belt, not add it.
    TY CA. Wanna see the most expensive gt2 belt tensioner on the planet? lol. I am upgrading my bed to a 9mm gt2 belt and was only able to find this tensioner spring from the U.K. and it cost me $20 to get it with shipping. But that is the thing about building. If you make the theme of your build cheap then that is exactly what you will land with. If you make the theme of your build functionality it will hurt the entire length of the build and you will never reclaim the money you have into it. But it will function exactly as planned. No sacrifices made during the build really makes for a nice machine to play with in the end.

  5. #35
    Super Moderator curious aardvark's Avatar
    Join Date
    Jul 2014
    Posts
    7,016
    I get the rails slide up and down - but you still need rods to connect the rails to the effector.
    The sliding up and down is not a real issue with a delta (got 2). And good wheels tend to be smoother than rails.
    Don't really see what you gain and why you don't need to connect the effector to the sliding part with rods.
    The effector and print head still need to be able to move around, so you still need play in the rod ends.
    I like the magnetic ball and cup connectors.
    All I see - with deltas and rails, is a more complicated setup with a lot more places things might stick or lose glide.


    where's the tensioner in the picture - can see a small one - just - lol
    Reckon a clothes peg spring might have done the job, they're quite a bit larger than the 6mm belt springs.
    Last edited by curious aardvark; 09-30-2019 at 11:36 AM.

  6. #36
    Engineer
    Join Date
    Jul 2016
    Location
    South Florida, USA
    Posts
    542
    Add AutoWiz on Facebook
    I am going to post the response to this back in my thread out of respect to the OP. While we have got derailed here there is still good info on parts to and not to use. But any more is just talking about me and my stuff.

  7. #37
    Quote Originally Posted by curious aardvark View Post
    I get the rails slide up and down - but you still need rods to connect the rails to the effector.
    The sliding up and down is not a real issue with a delta (got 2). And good wheels tend to be smoother than rails.
    Don't really see what you gain and why you don't need to connect the effector to the sliding part with rods.
    The effector and print head still need to be able to move around, so you still need play in the rod ends.
    I like the magnetic ball and cup connectors.
    All I see - with deltas and rails, is a more complicated setup with a lot more places things might stick or lose glide.
    Thanks for the input, I don't really mind the side track on the thread it just helps me understand what other people use and have success with or not. I will take it all in and come up with what i think will work best for my needs.

    Linear rails are used on most industrial CNC machines, I know a printer isn't the same as far as forces etc. That being said, as long as they are properly maintained and of decent quality they are extremely smooth and have little slack/play in the mechanism. Less play is always better ;-)

    Also, because my printer will not be constructed with vertical extrusions, the expense of the rails is minimal as buying extrusions and pulleys and maybe carriages would probably not be that much cheaper than Hiwin rails.

    While ebay/Chinese rails may have a little grit and could have snagging issues, I seriously doubt Hiwin or Bosch or any other high quality rail would have these issues. I have personally worked on 15-20yr old wire EDM machines with linear rails and they were still incredibly smooth and had little play. Wire EDM creates a lot of fine carbon dust and metal dust, as long as the rails are properly maintained they have a very long life span with no drag, snags or slop. Especially on a printer where there is almost no processing contaminants.

    The only thing better is Linear motors. Basically a mag lev train sort of system but extremely accurate. I worked on a large CNC machine with those once and it was pretty amazing to see how smooth and friction free it was. Unfortunately they are insanely expensive. the mechanisms are minimum $1000 and then you need special drivers for the motors etc. A little overkill for our purposes as well lol.

    I like the idea of 2 smaller steppers Vs one larger one. I might do that but I will see what the difference is.

    I was thinking of trying to make a different belt system but I'm not sure its a good idea. I had a sea-flea once that had cable steering. the steering wheel (IE stepper) had a spool on it that allowed for a stainless steel braided cable to be wound around it about twice. on the motor side (IE carriage) there were hooks where the cable ended. at any corners the cable had to make there was a pulley on a spring. This automatically tensions the entire system and made for extremely smooth and accurate steering system. I know they use this same system on F1 Tunnel race boats because of the precise steering control. The "wings" off the back of the motor you see in pictures is where the cable is attached to the motor. This also allows the amount of mechanical advantage to be adjustable by changing the size and amount of pulleys in the system. You can also buy wire that is coated with plastic to stop any vibrations the braids may cause.

    What do you think?

  8. #38
    Engineer
    Join Date
    Jul 2016
    Location
    South Florida, USA
    Posts
    542
    Add AutoWiz on Facebook
    I think it would be hard to find a gt2 pulley that allows the toothed side of the belt to be wrapped around it twice. The cable steering is essentially a rope and it can be coiled and manipulated in many directions. But the 6mm or 9mm wide toothed gt2 belts might be more difficult to get to move sideways so as to wrap around a pulley like that. A good example of this is a serpentine belt in a car. Back in the days of v-belts we had pulleys that could be out of alignment with each other because we had multiple belts. But since the outbreak of serpentine belts which are wide and flat all pulleys are on plane with each other. Because the belt doesn't conform or deflect like that without taking major wear.

  9. #39
    I think you might be misunderstanding me. I mean to get rid of the GT2 stuff all together and use something like a large worm gear or acme gear and a small braided stainless steel wire with a pulley on a spring for tension.

  10. #40
    Engineer
    Join Date
    Jul 2016
    Location
    South Florida, USA
    Posts
    542
    Add AutoWiz on Facebook
    Yup I misunderstood. I am against gear drives for our printers because gear mesh generally requires a certain amount of backlash which is just bad for the definition or resolution of our printers. This is why so many people use 2 nuts and a spring on their leadscrews because they believe that soft spring counteracts the backlash even though at the first sign of any kind of load there is backlash but SSSHHHHH whatever you do, don't tell the masses that. Belt drive with a tensioner is the way to go. Tried and true. Wire with a pulley on a spring for tension is a bold idea for 3d printing. You must take into account that wire is going to be harder to make turns and so to use this means that the stepper motors and drivers might live at a higher load. But I would absolutely love to see an implementation of this. Do it! Your idea is solid. Make it happen.

Page 4 of 6 FirstFirst ... 23456 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •