5 Axis Router B/C Head Design

5axis_head_1Have been busy over the last few days working on a design for a B/C axis head for the 5 axis CNC machine that will produce all of the plugs for the bodywork and a few other parts. This design incorporates a belt driven dual axis run by Nema 34 motors with encoders.

5axis_head_04Also utilizing an air cooled 3kw 18,000rpm high speed spindle with an ER20 collet system will allow me to use various tools for machining MDF or different foams.
001_zpsdxbgqtsiThe Nema34 motors will use an HTD belt drive system with a 6:1 drive ratio. The 8.5nM stepper motors with the 6:1 ratio will produce 51nm of torque to maneuver the spindle and provide enough strength to hold position while machining some harder materials.

 

5axis_head_01Since the goal is to machine some MDF and different foams, I want to make sure I could keep the dust and swarf out of the drives and bearings so covers (likely made from fiberglass or carbon fiber) were designed that could easily keep all the crud out.

 

5axis_head_02Still in progress is the B rotational axis. Need to figure out an efficient way to design the bearings and mountings for the radial and thrust loads. You can also see the encoders on the stepper motors here. They will provide feedback to the control system so that the machine is always aware of how much each axis is currently rotated. This awareness is handy for the machine to not twist itself up as the wiring will have enough give to rotate 1 full rotation in each direction.

 

5axis_head_03Can see the 6 bolt mounting pattern here for the high speed spindle.

 

5axis_head_05The spindle mount itself is actually an aluminum extruded rectangular tube with one side cut off. This will reduce the amount of seperate parts and also how much machining is required.

 

5axis_head_06The axis of the spindle motor is perfectly lined up with the axis of the B rotation which will help create much more efficient toolpaths and result in quicker machining times.

 

5axis_head_07

 

s-l1600 (1) When setup properly, an HTD belt drive can provide a nearly backlash free power transmission. With belts and pulleys at nearly any size you can imagine, it’s easy enough to design around the parameters you need for your application.

 

MOT-184_1

The choice to go with stepper motors over servos was price and simplicity. The amount of accuracy needed didn’t require the use of a servo and the amount of power in the size of package was easily achieved with the Nema 34 motor size. Since my other CNC machines were built with stepper motors, I also felt more comfortable with the setup of these, plus the use of an encoder gives me everything I need.

Will be posting more on this machines build in the coming weeks and months as I juggle different projects. Stay tuned!

 

Join the discussion 28 Comments

  • Mauro says:

    hi,I am interested in this project.Could you share more details?
    Thanks
    Mauro

    • carljarrett says:

      Will be sharing more as I have time. Busy building a new space for all of the equipment! Thanks

  • pedro lopes says:

    Nice job. I´m a mould fabricator and i build my own cnc machines from portugal.
    I´m startind a new 5 axis cnc column machine with stepers. what you think about stepers with encoder?

    Regards pedro

    • carljarrett says:

      Hi Pedro. Thanks for taking a look. Since this machine will be used for making composite moulds, not necessarily injection moulds, the accuracy of the steppers with the encoders will work great for machining materials such as MDF (particle board/wood) and various foams.

      Would love to see some of your work, feel free to e-mail me at carl@ethos-tl1.com

      Thanks,

  • Michael Hart says:

    Thanks for posting this. I’m a student and was trying to get my head around the mechanics of how this could be accomplished without buying an industrial solution. I’m sure it’s tough in execution; however, it makes sense seeing like this. I was wondering, for your B-axis, is the belt drive on both sides or just one? I only ask because it appears to be on both sides in some of the renderings, and I am planning a custom small system that uses dual-shafted motors so I can attach encoders, and clean-dampers, to them simultaneously.
    It seems like this setup could work well just on one side, but seeing it like this, I was thinking if the motor had a dual- shaft it could actually be mounted in the middle and both sides could independently drive a belt reduction. You would have to be creative abut mounting an encoder this way, but my thinking is that having a dual-shaft motor and applying force from both ends could effectively achieve the same result as a damper (possibly even better than one) since equal force would applied simultaneously against both sides.
    I was wondering, what are your plans for electronics? Are you going with a pre-made product or something like using Mesa’s Anything I/O cards? Motors and drivers are easy to figure out, but there is always something popping up that makes my motion controller of choice not quick work out. Sorry for the long reply. This just fascinates me. Take care!

    • carljarrett says:

      One of the reasons I designed it like this, is using off the shelf components with easily manufactured metal components. The design could definitely be beefed up in some aspects, and improved in others to cut more aggressively. This one I believe will be more than suitable for hard foams and MDF patterns that I’ll need to make.

      I love the idea of having the dual shaft stepper running 2 belt drives for extra torque/rigidity, though I haven’t found NEMA 34 steppers with dual shafts long enough to be able to achieve this easily, especially ones with encoders built in. I’m sure I could have them custom made by the factory in China though. If I can find one with an encoder and some shaft still sticking out, I’ll put a secondary bearing to hold the the unsupported shaft which would help rigidity some and be pretty simple to implement.

      For electronics, I might go with the Gecko 214 drivers and then something like PMDX board, but I’m not 100% sure yet. I’ll likely run Mach 4 to run the machine as it’s what I use on my other machines.
      Thanks for getting in touch! Feel free to e-mail me as well.

  • Michael Hart says:

    Thanks for your reply, I appreciate it. I see what you mean about the reasons behind your design choices. For foam and MDF patterns, I believe you are on target. Actually this design is overkill, (which is always good) for soft materials. Lol, I am more interested in the automation tech than the machine’s function. I know that isn’t very practical, but I can’t help it. This stuff really is fascinating to me for some reason.

    Seeing your design, I am now really interested in seeing what can be accomplished with a dual shaft motor. I am making a mini machine that I think might get the 5-axis treatment, just to see what can be done. I have been collecting parts so and I am thinking about building a large machine as well.

    I was wondering what CAD software you are using. I no longer have a software package and I was hoping to avoid paying the Solidworks tax.
    It’s worth it if you need it in a production environment, but for an individual )especially a student) it is difficult to justify.

  • Michael Hart says:

    I’m sorry for all the messages, this will be my last one. I just wanted to share these links in case they are helpful to you. I’m sure you know about CNCZONE.com, but I just wanted to shares this guy’s link. I came across this post “http://www.cnczone.com/forums/diy-cnc-router-table-machines/264022-cnc.html” a couple of years ago. This guy did a great job and made an awesome machine from scratch. I’m sure it was pretty tough though. He has links to YouTube on there too. I think his design is top-notch, but I imagine the ballscrews make it a bit slow. I believe for a machine that size rack and pinion would be faster, cheaper, and last longer.

    I have one more link here. I found this guy on YouTube when I first became interested in automation. He is Polish but his responses are in English and seems to be a nice guy. In his comments, it appears he shares design information with folks who message him directly. I thought this might be helpful for you because he built his machine to do the same things you are looking to do. He does foams and different woods that he makes custom boat hulls from. I thought this design was particularly interesting because of how minimal it is. This seems to be very practical and probably costs much less than a lot of other design choices. “https://www.youtube.com/watch?v=nITLI_WcnuM”

    Thanks again, take care.

    • carljarrett says:

      That first link, looks fantastic. I have to read it more in depth but that design looks very solid and well done. Some similarities to how I wanted to do some things. I guess what I have in my head for the rest of the machine is somewhere between the 2 videos you sent. I’ve seen the 2nd one and it does nice work, though he seems to machine mostly lightweight foams with it.

      I am on CNCZone.com as well under Zer0fighter.

      In terms of CAD, I’ve been using Rhino3D for 20 years. I find it very fast, and it’s ability to do freeform modelling over something like Solidworks is what keeps me going on it. Also it’s relatively cheap. $995 on their website, less on eBay from a licensed reseller. It’s definitely not as complete for machinery/solid application like Solidworks is, but for me, since I’ve been using it for so long, I’m far faster with Rhino than any other toolset I’ve tried.

      Keep in touch, I hope to have a lot of updates to the site in September, currently sidetracked building a ballet studio/school for my wife’s business…

  • Gökhan says:

    Is this kit plans available. You can give me

  • Chris says:

    I like your design. I’m starting my 3rd, 3 axis machine build and am currently considering adding a 4th axis. I ran across your design and I just had to say its simple enough to actually be a possibility for the home hobbyist. Thanks for posting it online. Can you recommend a software package for a home hobbyist that can CAM for 5 axis machines?

  • Shaun Smith says:

    Hi I have also been looking at building a cnc with a 5th axis and have been pondering with the doughty drive, but at what will be approx £2000 pounds to purchase/ import. Seems a bit expensive. Have you got any further in building yours yet? And how have you fared? I would be willing to purchase a copy of the plans if all is well,

    Just a note with doughty drive the gear reduction is 33 to 1 giving a much higher resolution and higher torques with smaller motors any thoughts?

    • carljarrett says:

      Hi Shaun, great you are interested in the design. I do have plenty of things I need to update on it, and have also been debating selling a kit or plans. I’m leaning towards selling a kit which includes the bearings, pulleys, and the stepper motors, but not the spindle (possibly an option). Out of curiosity, what would your budget be? I designed this because it suits my needs better than the Doughty Drive, and the cost/capability would probably be better as well.

      So with this design, having the stepper integrated into the design, I can use a larger stepper with more torque, and with a 6:1 ratio, getting more torque where it matters. I have been looking at a multi-pulley setup that would allow me to go from a ratio like 6:1 to something more like 23:1, combined with the Nema 34 stepper would end up with a lot of torque!

      • Rod Harald says:

        Hi,
        I also like your design. I would be interested in purchasing a set of plans unless a kit of parts was cheaper than I could source locally.

        Cheers

        • carljarrett says:

          Thanks Rod. I will have a kit of parts available soon, with options for the spindle at a discounted price. It will be very competitively priced. Stay tuned.

  • Shaun Smith says:

    Thank thanks for your reply, I would definately be interested in buying a kit if you are to sell in that form. In terms of spindles I was looking at a slightly more powerful one than 3kw, would the kit have to be scaled up to fit? As for price the only one I have seen for comparison is the doughy drive, and obviously that come with import charges, VAT etc.

    Shaun

  • xufuqing says:

    I like it. l hope have more of sizes.

  • Daniel says:

    is not very strong, stepper dual shaft with dual belt. Rotation with large interior bearing and large surface belt and gear. I think.
    sory for linguage.

    • carljarrett says:

      For it’s intended application it will be very strong. I have been considering a dual shaft design as well, will come after I finish the first design.

  • Kamil says:

    Hello. What is the price of this plans ? How can i buy it ?

    • carljarrett says:

      Hi Kamil,
      Within the next 6 weeks or so, I will be able to offer a kit, including stepper motors that can be shipped anywhere. Will also have an option for spindle motor to be included as well. I won’t be selling plans for this, only kits or completed form. It will be very reasonably priced however. I have an update coming tomorrow for the website as well. Thanks for your interest!

  • krzysiek says:

    Hello,
    I’m writing from Poland. I am also interested in building a plotter 5 axis.

    It is is already known the date and manner of sale kit to build a head and its price?

    Sincerely
    Chris

  • krzysiek says:

    Hello,
    Can you buy a milling head?
    christoph

  • krzysiek says:

    Hello,
    Can I buy a milling head?
    chris

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