[benergy]

can you let me know what you got an how many /what condition. these kind of drives are new territory to me. just lots of experience with gears and belt builds.
regards
Benergy

[metalworkz]

Hello again,
It has been some time since my last post here and I did get a little bit more done with my 5th axis build, but I still have a long way to go. I have finally got my lower head assembly parts basically finished but don't yet have the motor to assemble the pinion wheel to it. I cut a rotation plate from some .375" 6061 T6 aluminum and the back plate and rotation plate are assembled to the front plate. I made a thin gauge aluminum cover to enclose the moving parts and it will be assembled with some sealant when I do the final assembly to keep dust and chips out. I did a quick mock-up with some misc. parts and a servo motor drive to get an idea if something like this might be workable with proper drive reduction. I am beginning to think I might have been better off with more offset on the rotation plate, but that will not be too hard to modify later if needed.

[zer0fighter]

How did your B/C drive end up working for you?

[Ultranoob]

Hey!!

Im looking for 5 axis low cost head too and i found this ZMorph 3d printers | 5-AXIS UNIVERSAL TOOLHEAD

I think is low cost to buy and low cost to clone solution
What do you think?

[metalworkz]

Hello Zer0fighter,
Sorry for the late response to your question about my B/C head, but I have not finished the head due to the work on the 48" x 60" CNC gantry router/mill that was in progress about the same time as the B/C head. I have the machine finished and tweaked finally so perhaps I can pick up on the 5th axis build since this machine was designed to accommodate the 5th axis. I designed the gantry so that the cross member can be rotated to a higher clearance for use with the 5th axis. There is still a considerable amount of work with the B/C head to get it to a testing point so even if I started now I don't imagine I would be done before summer 2015. I will update this thread as I get more done with it.

[metalworkz]

Ultranoob, that is an interesting option for the 5th axis but it does not look very heavy duty. I imagine for some things this would not be a problem, so let us know if you pursue it and how it works for you.

[zer0fighter]

Thanks for the update metalworkz

Sent from my SAMSUNG-SM-G900A using Tapatalk

[marbles]

I've just read lots of this thread as i'm interested in making a B/A head for a 5 axis wood and foam carving cnc.

I'm wondering why or why not use a Worm Reduction Drive or planetary gearbox and stepper, as in this or some variation off? I'd like to use Harmonic or hypocycloid but thy seem a little out of my price range and belt/chain may introduce too much backlash on wood.

NMRV030 Worm Gear 50:1 56C Speed Reducer | eBay

Any thoughts about Worm Reduction Drives would be most appreciated.

Thanks

[jsheerin]

Backlash. Standard gearboxes like that will have some. You want a minimal amount, as low as you can get. Think about having a long tool and long spindle on the end of your head. Any angular backlash will be magnified at the tip of the tool. You can do things to take the backlash out (preloading things in various ways), but those ways will typically cause wear and need to be adjusted.

[metalworkz]

Hello, so it is way past 2015 and I am just now trying to get back into this B-C head design and construction. I kind of lost my way and although I have the parts that were made and the drawings it will take a little time to pick up where I left off and get it moving again. I did some work with the drawings this past week and cut and assembled the parts to make the Z axis carriage for the head yesterday and today. I also took the head assembly apart to fit the motor and pinion wheel to it and had to modify the motor mounting hole pattern to fit the smaller motor to it. It looks like the mechanism will mesh and work but I have a bit more work to fit all the parts together before I can re-assemble it. I will try and attach updated drawings and some pics.Attachment 347074Attachment 347076Attachment 347078

[zer0fighter]

Awesome, keep up posted.

[metalworkz]

]I got more done with this build today and got the B-C head drive mechanism assembled and lined up inside the housing as well as to mount the motor to the rear side of the housing. I have been thinking today that a large through hole bearing would be great for passing the wiring through to the head and motor but will try and simply use the .5" diameter mounting hole that is on the top of the head as I originally planned so I can possibly finish the build and test the mechanism and I will try to use enough slack in the wiring harness and some kind of retainer to route the harness during use(with the idea that modifications can be implemented later if the head mechanism works well. I do not feel the time and extra effort to improve other areas of the design will be warranted if the mechanism fails to work well. I have a couple of pictures showing the motor attached to the head and the carriage positioned similar to the final mounting but they are no connected and those are some of the areas I will try to address in the next steps of the build. The motor and pinion wheel are mounted and meshing with the larger sprocket and I have spun the mechanism through more than 360 degrees rotation to verify smooth operation but the assembly has not been powered up yet and that will be some time before I get to that stage.
[ATTACH=CONFIG]347336[/ATTACH

Attachment 347338

[Master of nun]

Great to see you back at it Wes, keep it up.

Hard to find the time sometimes I know.


Liam

[metalworkz]

Thanks Liam, I am trying to keep motivated and it helps to see the encouragement! This is kind of a prototype build or maybe trial and error is a better title, so it could be kind of empty if the results do not prove to be useful but I was asked about it and decided to try and finish for better or worse.

Today i did some scrounging in my shop for materials to use for the next parts of the build and although I prefer aluminum for most parts I have some .375" thick dark grey plastic that I feel will work fine for the trim router mount base. The motor will be clamped to this with some .312" thick aluminum clamps and there are 3 of them spread across the plate so I feel they will support the router fine with the plastic base. I will make an aluminum boss to attach to the plastic base for mounting on the horizontal rotation shaft. The motor for the vertical rotation shaft will have an adapter I will fab to adapt the motor shaft to the rotation shaft and then the motor will be mounted with an aluminum bracket I need to fabricate from .063"-.125" aluminum (depending on what is available in my shop) that will mount it to the Z axis carriage. These parts all need to be fabricated so this is just an update with new drawings to show the planned parts.

[Master of nun]

A possible issue and a question to anyone reading this.....

do all 5 axis toolpathing softwares assume that the tool centerline is inline with the B axis?

Ive had a play with 5xMonkey | 5axismaker 5axismaker grasshopper script over the years while it is being developed but have had no practical experience on a working machine.

[jsheerin]

You mean the c axis (rotation about Z)? The machines on the website you reference don't have that alignment, so I'd assume their software would work with an offset there as well as others. When I was writing my own 5-axis code years ago I wrote it by controlling the tool tip. Then I worked backwards from there to figure out the machine movements necessary. An extra offset would just be incorporated into the math and you'd have to specify that parameter. Same as you though - no actual experience.

[metalworkz]

I had thought about the axis not being in alignment but to just test the mechanism I am trying to use, I assumed I would be able to include an offset as jsheerin mentioned. I do not have enough travel height on my current machine to accomplish the alignment you speak of so I did not have much choice but to try something else. That being said I have not worked with any 5th axis software either so no experience at that end here. Now if the head actually shows some merit as far as the mechanism goes, there is plenty of room for improvement and perhaps that would warrant a larger work envelope for the machine too. I do think I could use a smaller size motor on the back of the head as long as it had enough holding torque and then I may be able to get those two axis aligned. Back to work.

[metalworkz]

I got the trim router mount fabricated and together but it still needs the hole and boss for the axis shaft. Just have a couple of pics of the trim router mounted to the plate with the .375" aluminum clamps.
Attachment 347676
Attachment 347674

[metalworkz]

Hello,
I did some more work with this build today. I got the boss mounted to the router mounting base as well as to mount the router to the horizontal rotation shaft. It is not to a state where I can power it up yet but I am feeling good about the feel of the mechanism when I rotate the router by hand. Next I need to make a shaft adapter/coupler to go from the .25" stepper motor shaft to the .500" dia. vertical rotation shaft. Also I had drawn an aluminum bracket to mount the vertical stepper motor to the Z carriage base plate but I have since deemed that 4 standoffs would work just as well and that requires lest fabrication as well as may reduce the weight that goes onto the assembly. I am not sure I have a stepper the right size so I may need to buy one, but those are all needed steps to finish this stage of the work. I just have 3 pics of the assembly at different angles.
Attachment 349064

[metalworkz]

Hello, I did more work with this build in the past week but forgot to update here. I completely disassembled the head in order to remove the tall stepper and replace it with s shorter one. It was kind of a wasted effort because I was trying to reduce the needed offset for the vertical rotation shaft but I overlooked the fact that the router motor actually is offset further than the stepper on the rear side. So it amounted to a lot of work and I did reduce the weight of the B-C head although the offset for the vertical shaft was not affected. If I want to reduce some of the offset I will have to modify the base of the head to bring the shaft location closer to the middle of the total space, but the work to accomplish that does not change the offset enough to seem worth the effort right now. I have enough space on the Z carriage and have decided to just complete the build to fit the current shaft location. I drilled the needed hole for the shaft and pressed a bronze bushing into it but I need to make an arbor to use as the shaft for the vertical rotation axis and the mount for the stepper motor. So basically it will serve as the shaft and a coupler to mount the stepper shaft to the rotation axis. I had planned to make a bracket from aluminum for the motor mount to the carriage but have since decided to simply use some standoffs to mount it which will only amount to drilling and tapping some holes in the carriage as opposed to laying out the metal, cutting and forming to the required shape. I will wait until the arbor is turned and fitted and then get an accurate dimension for the length of the standoffs so the motor will be a good fit on them. I have a couple of pics of the stepper motor change and the revised drawing with the router motor flipped to the gantry side to view the clearance.
Attachment 350052
Attachment 350054
Attachment 350056