That's a nice machine. Is it your build?
Is that a single pinion system using servos and gear reduction?
I'd like to see the system from Damencnc using nema 34's do the 500 IPM 3D carving and 800 IPM rapids. That was my point, to validate the performance of that specific system. I believe comparable systems, for example, from CNCRP, are capable of that, but at the same time are certainly a step down from the all steel, servo driven machine that you have posted videos of.
Although, your post is definitely relevant for the OP who is thinking of using ballscrews for a huge router.
For a large wood working machine, I don't see a problem with a single pinion R&P system to give good performance. On a budget, perhaps he should spend his money on motor upgrades to servos and planetary gear reducers on a single pinion R&P system than to pursue a rotating nut design using stepper motors or even the expensive damencnc double pinion system? Tell us your thoughts.
NIC 77
Here is a photo of the Helical Pinion and lubricator, on that machine, this is what you need if you want / need accuracy and performance
Mactec54
That is quite the pinion! Obviously those are flange mount planetary reducers?
Is this system spring loaded or just carefully aligned?
I've never seen something like that before with the lubrication. Thanks for sharing.
I thought it would be interesting to show what a high quality pinion setup is like, No spring loading, you can not spring load a Helical Rack, It was all aligned with an indicator, the Racks where fitted on a machined surface, straight and parallel within .001 over 12' along with the Linear rails
Mactec54
Hi there
I am thankful of all you experts regarding your most helpful replies.
It took me a while to read them all,
I think I can conclude that the best system for over a meter long travel is the R&P systems.
But that backlash is the most challenging issue.
What do you think a bout Split Pinion design?
Double pinion, well I am not so sure since apparently it is not that common, and we just do not know much about them,
also NIC77 I agree with you on 1:5 ratio it is much better choice.
How about the Belt driven System? would you recommend it for my 2m*4m table?
Finally Mactec54 : Apparently your machine is single pinion with ac Servo Motor, Do you have a gear box of some sort with your servo?
Could you briefly explain it? and if you are not spring loading it, then how do you mounted on your Rack? have you just lay it on the rack?
Or do you some how tension mounting it on the rack?
Regards
johnansaro
This machine is not mine, I just helped with the build
Yes there are Gearboxes 10:1 on this machine, the AC Servo run up to 6,000 RPM
The Racks are Helical Heat treated and precision Ground, every part is precisely mounted on the machine so there is no problem with backlash
There is no spring loading, just precise alignment, you can not use any kind of spring loading device, when using a Helical Rack and Pinion
The Racks are mounted on a machined surface, Matching the Linear Rails, that has a machined Edge for the Rack to be clamped against to get precise alignment the full 12' , the alignment of the Racks were within .001" over the 12' length
No Belt Drive, would not be suitable for a machine this big
Most use straight cut Racks, these you can spring load the Pinion, or use more than one Pinion to help with the backlash
Rack and Pinion is the only worth while way at this time, even the Precision Helical Rack is cheaper than a BallScrew for this size machine, I'm working on a system for any type of router build, that will fill the void if it is successful, it is some time away before it will be for sale
Mactec54
Hi there
Mactec54 : many Thanks for your prompt reply.
But as you know machining such large or long Piece (about 4 meter Long) is not easy and cheap.
How about if my table is made of steel tubes, and then can I use aluminium profile in order to install the racks?
Basically this is the scenario, steel tube then aluminium profile and then rack and rail on them
Also you mentioned that "you can not use any kind of spring loading device, when using a Helical Rack and Pinion"
could you explain on it, Since the machine that I made, I am spring loading my system, and the rack and pinion is Helical.
I am attaching a picture, and video from it. (It seems that I can not upload the video since it is in my computer)
By the way what I am cutting is a musical instrument.
Finally sometimes when i am cutting, it smokes a lot and turns the piece to brownish or blackish color.
What could be the probable cause? My speed during cutting is 40 mm/sec, and spindle is 15000 rev/min.
regards
johnansaro
Mactec54
Hi there
many thanks for your reply.
But Mactec54 , could you also comment on me using aluminum profile rather than using a flat then precision machining it?
Is this a good idea or not?
Also lubricating the rack and pinion, is it a mandatory procedure or an optional one?
regards
johnansaro
Anything that has metal to metal contact, should have some form of lubrication, the wear rate would be high without any type of lubrication
Using aluminum profile that is not machined, would be no different than using steel that is not machined, short lengths of aluminum profile 1m in length for small machines, is about the limit without machining, you can buy aluminum profile with 2 sides machined from this company, I don't know what sizes they have that are machined
https://us.misumi-ec.com/vona2/mech/...num+Extrusions
Mactec54