Pete's Cincinatti Arrow 500 Retrofit...

Hey guys,
I am kinda new around here and some of you may know me from the CNCzone. I have built an RF45 retrofit machine awhile back and now I recently acquired a pretty sweet and clean Cincinatti Arrow 500 VMC. This machine has run with the original control but honestly I have spent my last nerve and dime trying to make the original control work as I bought it NON-working. I am now at the point that I need to make a serious decision about it. I either need to fix the original control regardless of cost or retrofit the machine to run via a PC like my RF45. For some time now I have felt that the original control setup was going to be better but someone recently posted their video of the exact same machine running under linuxCNC with Mesa components. After seeing that video and many other commercial machines running with LinuxCNC online I am starting to really lean towards performing a retrofit.

The machine that I saw in the video is running the mesa cards 5I20, 7I33, and 7I37TA boards and he has replaced the original motors in the machine with some newer chinese motor/driver combos. This setup seems to be quite nice and reasonable priced. I am seriously considering going in this same direction here. I am wondering what are your thoughts on the choice of boards and whatnot for the machine? The 5I20 as I understand it is the kinda brains of the operation and interfaces inside the computer via PCI slot. Then it is apparently ribbon cabled to the other two cards one of which is the servo motor control card and the other is for all the I/O stuff. Is this the best option for a simplest and most plug and play retrofit. I realize that this machine will not be simple to retrofit and it has the toolchanger and everything that needs to be configured somehow.

Here is what I am thinking and of course right now this is VERY tentative. I will gut the control back there removing all of the axis drives and everything except the busses for power and fuses and relays like that in case I need them later. Then I will remove all three axis motors and drives and install the newer more powerful china mfg drives and a new build computer that is optimized for this retrofit (looking for recommendations here). The GOAL will be to initally get the three axis motors and limits and homing switches configured allowing me to move the machine around under CNC contro. The next step will be to acquire a VFD to run in single phase to power the 10HP 6000RPM spindle in the machine and lose the very expensive to replace spindax drive. In essence the initial goal would be to just get the three axes and spindle working under LinuxCNC allowing me to run the machine without the toolchanger. I intend to install a simple manual pneumatic valve up front that will allow me to manually change the tools to run the machine.

I am interested in opinions on how difficult this first step will be and knowing that I am not having to make anything like mounts or machine ballscrews or whatnot is the basic electrical setup reasonably simple to accomplish? My hopes is that the basic three axis machine setup will be pretty straighforward and I can then use the machine to make parts. Then once it is up and running and I get familiarized with the control I can in my spare time work on getting the toolchanger logic and I/O /motor setup working as it comes. This seems to me to be the most complicated thing about it.

What are your thoughts about this? Am I crazy as a loon? Is LinuxCNC stable and powerful enough to run this commercial VMC? Is the setup going to last awhile? I am feeling like this would be a much more cost effective setup over time than trying to keep a near 20 year old control working especially when you consider just the repair of that spindax drive costs like $2500.00!! Nevermind the service guys want to charge a grand just to walk in the door..... I would really love to get this nice machine into a place where if something goes wrong I can fix it myself and I can source aftermarket motors and drives for reasonable prices if something does go poof..... I have a long sad thread about the adventure thus far over on the CNCzone in the Cincinatti section in case any of you are interested. The guy who did the Cincinatti arrow retrofit is named Lee and a fellow named Kudos also has been commenting about the LinuxCNC retrofits with a sweet leadwell VMC. How many other guys on here have what would be considered COmmercial machines and use them as such? Is this setup more for a hobbyist or will it stand up to some real use? I appreciate any and all feedback about this idea here. I would absolutely LOVE to be able to build this machine myself and get it working again, it is a sweet little mill that does not take up my whole damn shop. Peace

Pete

I'd back what Andy has just said .. keep the drives and just replace the controller , linuxcnc is more than capable , their are many commercial machines been retrofitted with Linuxcnc
using Mesa cards will make the conversion a relatively simple exercise to interface to your existing drives .

Dave

most of the 3 phase VFD's that i have ebayed can be used in single phase with a 30-50 % reduction is output power.
eg a 15 horse power VFD can be used reliable for 10 horse power motor.

some VDFs detect a missing input phase , usually you can disable this. connecting a jumper across two inputs may defeat this too.
I think some detect voltage ripple and you may not be able to defeat that.

I've done this with baldor servo drives that require three phase power.


But I don't see how this thread has anything to do with PNCconf?

Thanks for the ideas guys... Honestly while I would normally agree with you about the motors and drives one of the main reasons I am retrofitting this particular machine is because the drives are quite expensive to repair and the supply of spares is dwindling as well as the support from the original manufacturer. That and I have recently blown two Y axis servo drives and I am basically over the cost..... I intend to use some of the less expensive AC servo drives and motor combos online to replace the originals with that way if something bad does happen to the machine I am only gonna be out maybe a couple hundred bucks instead of a couple thousand. The only other avenue I would consider is keeping the axis motors and purchasing drives to power them online. However my motors are resolver based and the wiring is kinda old and crusty as well so my thinking here is to get new motors, new drives, and new harnesses in a package to make everything new.

As far as the VFD/spindle drive I have seen a couple 10HP single phase drives online for what I would call reasonable prices but I have to admit that I had never heard of using a three phase drive in single phase like that before. Had no idea that was even possible.

I posted here because it seemed from reading down thru the threads that there was a lot of mesa emc talk here so it seemed like the right place. If it is not I apologize and please move the thread for me.....

I started my new job today working for a largish CNC shop running their BRAND NEW Haas VF2's and 3's.... They are all equipped with renishaw tool probes and touch probe systems as well as programmable coolant and other sweet features. It sure is an eye opener what a nice machine runs and works like. The other main reason I wanted to retrofit this machine is because it is really the only way that I could afford to install a fourth axis and utilize a probing sequence without breaking the bank in a big way if it is even possible on my control I never checked because I know kinda what it costs. At least with the Linux CNC I have the option to try some of that stuff if I want...peace

Pete

Andy,
Not sure what drives and motors you are referring to but my motors are like 1k and they are quite large. The drives are AC servos with resolvers, brushless.... I will check with DMM and see what gives here when I get a chance...peace

Pete