New build: Optimum D280x700 with AcornSix ClosedLoop

[Spartan117]

Hey guys,

so here it is, my build-thread about my chinese-lathe cnc-upgrade Besides my Weiler Condor, i also own an older Optimum D280x700 lathe, a "better chinese 11x27,5" lathe". And because you don't need two conventional lathes, i decided to upgrade that to CNC.
First, i will let you have a loose look on the mechanical part that is almost done.

We need a new fixed-bearing-attachment for the X-axis. Most of my work here is done conventional, because somehow it's like meditating for me after a long day of work

Here on my Aciera F5 milling-machine (that i have resored completely and on my own). An absurdly precise piece of swiss art they built back in those days... This machine cost as much as a solid house at the time





Here the finished part, mounted with a cnc-ed motor-holder, some struts, fixed-bearing from SYK Taiwan, support-bearing for the shaft and TBI ball-screw 10x2mm:


This is the fixed-bearing-attachment for Z, also SYK Taiwan, really precise work and cheap! €44,-
Easily mounted, just needed a base-plate because of the bigger motor-flange:


Other side, loose bearing, also SYK Taiwan, absolutely perfect sliding-fit, €25,- ... I am really impressed:



Now for some turning. Made on my Weiler Condor VS2, that i bought from my technical-school, where i did some continuing education at the age of 35^^ I already had an older 16mm ballscrew, that i wanted to use for Z. It's from ABBA-Linear, around 15 years old, but never used before. I bought it to upgrade my first cnc-router, but i sold it before the cheap original old ballscrew was done
Hard-turning the fixed-bearing-side, i really like the finish of hardened-steel:


And thread turning:



Back to the mill, we need a mounting-block for the Z-ballscrew. I also like 3D-printing for prototyping complexer parts, safes that much effort and time...


But never as a substitute for solid-metal-work Still some work to do:


Again, everything conventional work:


And the threaded-nut needs a mounting-plate for fine adjustments:


Perfect fit:



So lets start up the cnc-router again, we still need a thread M17x1, all the way down to the ground of the hole, for the nut of the X axis:







Now the most of the mechanical part is done, so i also started with the control-cabinet:



More to come

Regards, Marc

[Aurelien]

Good job ! I have exactely the same machine in cnc.
But mine is optimum L28cnc. I have take off Siemens controller to put centroid acorn.
I have posted it here.

[richardb15]

Nice work so far

M17x1 thread, who's idea was that!

Good to hear you are a fan of Swiss machines, we have a Hauser jig borer from around 1960, with all the original tooling and optics, crazy accurate machine.

[Spartan117]

M17x1 seems to be pretty common in this regards, most other manufacturers also use this thread. The only problem was, the thread on the ballscrew has been eroded, via EDM. So the surface is really rough and i had to give the thread a helpful hand the first two times i screwed that in.

Not much going on here, just waiting for the shipment of some additional supplies i need (certain cables and stuff), so i only hooked up the VFD to the control (used separate shielded 2-wire-cable for 0-10V, spindle-benchtest went fine.



Oh, and in between i did another bench-test, just to ensure nothing weird happend until now, because i integrated an (shielded) ethernet-socket in the cabinets wall. Works like a charme

[suntravel]

You and your special cables and plugs

Cabinet is looking clean.

Uwe

[Spartan117]

While were are talking about cables and plugs...



These are the cables from AcornSix 5V Logic-Outputs to my TTL-Diff-converters, and to the drives.
The second cable is for some 24V-signals like Enable1, Enable2, Alarm, AlarmClear.

And i mounted an inductive reference-switch to the X-axis:



The secret to achieve precise and repeatable switching-points with inductive-sensors is a sharp and burr-free edge on a steel or iron-actuator, and, most important, an as small as possible air-gap between sensor and actuator.

[Spartan117]

This is why i don't like online photo-albums... The last two pics were here in my cache, but not really online (and, btw, no one seems to have registered and told me here... )
So here are the two pictures from above, first the cables:



And the reference-sensor:




Beyond that, not that much happened... at least not regarding CNC^^
I own that lathe for over 2007, and no one has ever greased that spindle-bearings (because there is no possibility to do without drawing the spindle from the housing...). Two tapered roller bearings, shouldn't be a problem at all.
And I always thought, it's the motor, that "brakes" the spindle that much when turning it by hand... Teaser: It's not the motor
As "the braking" did not change at all without the motor,i had a closer look on the spindle bearings.
First, the nut at the back of the spindle needed a VERY strong arm for loosenig it! A screw-clamped-nut, that should adjust the bearing-clearance...
Why the heck did they tighten that thing THAT STRONG?!
Well, have a look yourself (nut, pulley and gear are removed already):



Well, if you like it like that...:



Eat this^^
The fitting itself was not that bad, between 6 and 10µm interference over the whole length, but, like my chinese friends really often do, they cocked it up with bad deburring, and then drawing that tiny swarf all over the fitting surface with raw force... This is what they do so often...!
They have really good parts with good measurements, but they muck it up in detail when mounting that all together without even taking any care, why it doesn't fit like it should. They even used P5-bearings, but can't deburr a simple spacer or the spindle.



So i had to smooth the bearing surface, revise all the parts a little bit, regrease and reassemble and bam, there it goes! Smooth, silent, stiff.
Really can't understand that kind of chinese mystery sometimes...

So in only had time to print two fan-mounts for the cabinet, and that's it for now.

[Spartan117]

Today i built the encoder-assembly for the quilll-drive-encoder.
First the parts:



Then the assembly and a first try-on, looks good!

[richardb15]

Nice to see the encoder setup, are you planning to use that for rigid tapping? I haven't set my spindle encoder up on the mill yet, but because I have an air-hydraulic drawbar I cannot just put the encoder on the top of the spindle. It will have to mount beside and use a belt drive like your setup. I will be interested to see if rigid tapping is still okay with that slight decoupling from the spindle to encoder.

[Spartan117]

Yes, definitely no problem.
I used a play-free belt-type (HTD 5M 9mm), but I am sure it would work flawless with non-play-free belt types like T, AT etc., too.
The belts are under slight tension and there is not much force needed to spin the secondary pulley, I don't think there would be any slip, even if it wasn't a HTD.