Both Manual and CNC

[nsiters]

I need some help here please.... I have a grizzly G0463 (X3) and I want to make it both manual and CNC. I keep hearing not to do it. my original post is at http://cnczone.com/forums/showthread.php?t=54261 I was just hoping that I might get some more hits if i was more specific. there has go to be a way to do this. This is my first conversion so I am pretty clueless. I know that it can be done because i run a bridgeport at work that is both manual and CNC, but I don't know how to do it with my Grizzly. is there anyone out there that can help? I need a lot of specifics since I am new to the conversions. Any help would be greatly appreciated. Thanks a lot
Nate

[Bubba]

My question would be "Why?". I find that using the MDI and Jogging controls are more than adequate for simple jobs. No, I don't have an MPG, but that might be another option.
It also sounds like you don't have ballscrews on the the unit at work because they can be easily "back driven" and this could be a real pain if you were trying to do a manual job with them.

Just my .02 worth.

[nsiters]

I get the why a lot..... I just love manual machining. I know that I will get some gasps from this but i prefer manual. I just want to have the ability to run some programs in CNC when manual would be too hard to make it. I don't need to have ballscrews if I can't have them. I would just like to be able to do both CNC and manual and I don't know how.

[Bubba]

Depending on the machine you cnc, this may or may not be possible. When I first did my mill/drill, I used the original lead screws. Well to make a long story short, that lasted just a few weeks until I just plain wore the brass nuts out! Then I went to ball screws and haven't looked back. Like I said earlier, if you want "manual" operation, plan on an MPG to do it. I don't have any handles on my axis and don't miss them. For that quick job, I just use either the jogging functions or MDI. Works for me and sure beats counting turns:})

Think of it as power feeds!

[nsiters]

That's true and it all makes sense, but for the sake of sounding stubborn, I would still like to see if it is possible. the mill that I have is http://grizzlyindustrial.com/products/Mill-Drill/G0463 is there anyone that knows if this will work? Thanks a lot,

[Stepper Monkey]

You aren't the only one to want to do this, and there are a couple of strategies I've seen people use. I do not know if any would work well for your particular type of machine though, you'll have to decide that for yourself.
One nice strategy I've seen is to mount the motors at one end of the screw, leaving manual crank handles at the other. Obviously, this only works if you are messing with the screws and bearing blocks, or getting new ones entirely.
Second is to make it convertible with removable indexed mounts that essentially interchange with the handles.
Third is to have double-shaft steppers and mount the handles on the back where the encoders would normally go.
The first may or may not be possible, and the second two have some potential disadvantages. In any case the motors will need to be unplugged from the drives during manual operation to prevent damaging them with voltage generated by spinning the motors by hand.

Don't know of any of these that might work for you, just different ways I've seen it done successfully in the past on various machines.

[nsiters]

StepperMonkey,
thanks, those are all good ideas. I had even considered the double shaft motors, but someone warned me of generating electricity by cranking the steppers, but of course i missed the obvious and never thought of unplugging them from the controller. 2 questions with that if you don't mind. Will cranking the stepper motors give me enough "drag" to make manual feasible? And will i damage the stepper motors at all? Thanks a lot

[Seb]

I'm planning to convert an X2, and I also want both manual and CNC available after the conversion. My plan is to use servo motors, driving the leadscrews via timing belts, and leaving the original handles basically where they are. The servo encoders will provide DRO in manual mode.

This is how the dual mode bridgeports I've seen have been set up.

[nsiters]

I thought about this as well..... but like i said i am pretty clueless..... what kind of pulley ratio would i need? Where can i buy them? thanks

[Al_The_Man]

My plan is to use servo motors, driving the leadscrews via timing belts, and leaving the original handles basically where they are. The servo encoders will provide DRO in manual mode.
.

Where are you going to feedback the encoders to, to get DRO?
Al.

[nsiters]

Ok i think that I am developing a plan, but since I have absolutely no idea what i am doing i thought I would run it by you all and ask some questions.

On roton.com i found some 5/8-10 acme lead screws that are .100 per rev and i think that I want to switch out my stock leads for these since I am used to the .100 per rev. Now a lot of people recommend anti back lash nuts.... i don't know what these are. (i know what they are meant to do) if i change the lead screws do the anti backlash nuts take place of the regular nuts? also where can i buy them? Does MSC or McMaster Carr offer them?

Now if i did a pulley system I am thinking that I would make a bracket off to the side and mount the stepper on it and leave the handle on the lead screw in front of the pulley. what kind of ratio is needed and where can I get these?

I have also head from Hoss that if I buy the Keling dual shaft steppers and put a handle on the second shaft as long as the steppers aren't connected to the driver board I can use it manually this way.......

I am not worried about positioning because I have a DRO kit that I can put on or I have 2 new Trav a Dials that if no one buys them on here I can use. So what do you think?

I know that these are probably questions that are simple to you or that you have heard before, but I know how knowledgable everyone is on here and I really don't want to screw this up.

Thanks for all the help.

[The Blight]

You can make your own anti-backlash nut. One way is to take a nut, and split it partly in half (hard to explain, but if you cut all the way through, you would end up with 2 nuts). Then put a screw through one part so that its pushing against the other. The harder you tighten the screw, the less backlash you will have.. Be aware that there will be a lot more friction. You might also make your own nut out of delrin or something similar. Less friction, but it won't last as long as a brass nut.

Ratio? Depends on several things. What motors are you going to use? What power supply, and how tight are the gibs on your machine? With steppers, most people tend to go with a 1:1 ratio.

You can use a handle on a steping motor as long as it's not connected. The motor wont take damage.

Once you have learned how to machine works in CNC, my bet will be that you will hardly use the manual side. But it won't really hurt to implement the manual system as it probably won't cost a lot more.