Messages

931

General Mach Discussion / Re: Source for servo motors

« on: November 19, 2009, 02:24:33 PM »

You don't need to worry a lot about matching the voltages and amps precisely.

i.e. you can run a 90V motor on 80V and vice verse. The drive limits the current, so you can use a motor that is rated higher than your drive.

For servo motors, you can pretty much ignore the 'continuous' rating unless you are running a conveyor or some similar truly continuous duty mechanism. For a typical CNC machine tool, I suggest using only the peak numbers for your calculations.

Note this applies to servo motors only. Steppers are altogether different animals.

I am using both Keling and HomeshopCNC servo motors. The NEMA23 motors peak at 20 and are a good match for the Gecko. The Homeshop versions seem to be better quality, but that's based only on a single motor from them, so take with a grain.

932

General Mach Discussion / Re: Problem with XBOX 360 Pendant...?

« on: November 19, 2009, 02:10:56 PM »

Just a caution for you to be aware of.

I tried the wireless Xbox controller and it disturbed the CNC setup. The setup was also compromised if I used a wireless network adapter, so it was obviously very sensitive to the RF noise.

Others have used the wireless stuff and had no problems. I have an entirely differtent setup now, but I already have the wired Xbox controller and have become accustomed to moving programming with a thumb drive, so I am not inclined to try the wireless again.

Just a heads up  . . something to be aware of. If you get 'spooky' problems  . . . disconnecting wireless devices should be high on the diagnostics list, IMHO.

933

General Mach Discussion / Re: M3 / M4 Problem (yes, I'm a noob)

« on: November 19, 2009, 01:57:09 PM »

When I call for spindle reverse, M4, output #6 comes on just like it should.
When I call for spindle forward, M3, output #1 AND output #6 both come on.

Anyhow, any help or suggestions would be greatly appreciated.

Considering the behavior you observe, it seems to me you could simply use output#6 for on/off and output#1 for direction . . . . maybe I'm missing something.

Anyway, what I want to contribute is that I played with this issue a bit and could never get Mach to switch the direction prior to turning the spindle on. This causes the spindle to reverse at speed . . not good. Recently, I gave up on that and simply rewrote the M3, M4 and M5 using separate outputs for on/off and directions and organizing the proper sequence. Very easy and it works beautifully.

Many thanks to Ray and the fellow who indexed the new programmer's guide. This is my first use of it and time saving was enormous.  

934

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: November 17, 2009, 12:13:47 PM »

I would assume that heat treating is the easiest step in making a spindle.
What PCB are you talking about and who is CNCdrives and what's their story?

Heat treating is easy enough if you know what your doing AND have the equipment. I sold the whole shop many years ago and the furnace went with.

Here on the Mach forum a search should turn up a thread where I did a review of several available servo drives. In that review I refer to a weakness in the error line of the DNCdrive products which prevented them from driving my optoisolated BOB reliably. I am not an electronics guy, but I came up with a sort of Rube Goldberg contraption that did fix the problem. CNCdrives showed me the better way to do it and provided the information I needed to design the physical PCB that would not only boost the error signal for an optoisolated BOB, but would also drive a remote LED indicator light that I insisted on having. Credit goes to them for the circuit, I just made the physical parts . . . which was actually big fun for me.

The circuit was born of those necessities, but it has many applicatons since it can take in a pretty wide vaiety of voltages and signal strengths and convert them all to a clean 5V signal, as well as split out a second identical clean 5V to power a remote LED from the same input.  For example I had a lot od problems with false e-stops from the limit switches. One solution is to run the switches at 12V, but you then must convert that back to 5V for the BOB or you burn things up, so this little board is a perfect solution to that.

My BOB is a CNC4PC brand and has lots of LEDs on it. I love that whole concept of montoring what's going on, and in it's present iteration, Mach is pretty vaugue as to why it e-stopped and an indicator is not much good under the counter in a closed steel box. This little cicuit board can tap into literally any signal in your boix and drive a remote LED. I think it is a very important solution. 

935

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: November 17, 2009, 10:08:22 AM »

:DYou got to leave something from the X2, otherwise we won't believe you it was an X2
Daniel

I found a heat treating place about a hundred miles away here in Texas, so I *might* be making my own spindles after all. We shall see

Here is the latest video showing the final iteration of the PCB routing and drilling operations. http://www.youtube.com/watch?v=r9Zf_5yHB1I

Based on some feedback I got, I kicked up the feedrate and am using my mister to provide a constant air stream. I'll mount a vacuum nozzle on the fixture, but not make a new video just for that, so this will be it until I finish or make significant progress on the new frame including the all new Z axis.

After much whining on my part, I have convinced CNCdrives to provide these little circuits free to US customers of their drives until the function is built into the drives (planned for future version apparently) I even offered to make the parts (just for fun really, cause I think it's very cool that I can actually make an electronic anything that actually works . .LOL!!) Well, they said OK, but it would need a cap across the power pins and also a top quality IC socket. The one I used initially was apparently an embarrassingly cheapo version that they object to. So I made the changes and the part will be available to anyone who wants it . . free to US buyers of any CNCdrive Whale or Dugong servo drive.

936

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: November 11, 2009, 04:16:44 AM »

Well, with all those modifications it can't be an X series any more... should move on to Z1 ("Y1" doesn't sound well)

Daniel

When I was a teenager, someone remarked that my car could be very easily fixed up nice. All I needed to do was jack up the gas cap, roll a new car underneath and then let the gas cap down. 

If I use only the spindle from an X2 . . . . would that be considered 'contamination' of the 'Z1'?

937

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: November 11, 2009, 03:54:59 AM »

Simpson,

Can't see how the aluminum parts are heavier than cast iron Are they that much bigger in size (almost 3 times) or what?

Yes, bigger. Bigger and also thicker walls. The table for example is much bigger. Aluminum is light, but not THAT light. You would not want to carry a 1" x 6" x 48" piece of it very far. The X2 is very light, very thin wall castings. There really isn't a lot of material there.  I'm old enough to remember when cast iron was dirt cheap and aluminum was stupid expensive . . . and the very idea of an aluminum soft drink can was pretty outrageous . . . . . well, obviously . . . . things have changed.  In designing with aluminum, it is cheaper to go heavy with a less expensive alloy than to get the same strength from smaller parts made from the more expensive high strength alloys. If you are designing aircraft parts, weight and strength are primary, so you usually stick to the 7000 series, but for a machine tool, you have room for 'fat' parts and the weight is an advantage, so it plays well. I am making the head heavier intentionally to absorb as much vibration as possible on the tool side of the slide bearings. That mass has to be moved around by motors and leadscrews, so you can't just go crazy with it. I'll be putting cooling fins on the spindle for sustained high RPM running.

I will be building an entire new machine frame also from aluminum and making a complete new head from aluminum.

Got to find a new name for your machine... you can't call it X2 any more I guess

Daniel

Suggestions?

938

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: November 11, 2009, 03:39:50 AM »

I watched your video of the grinding on the leadscrew. Impressive adaptation as always. Is there any reason why you grind rather than turn? Is the screw hardened so much regular cutters dont work well? Also I see you using rotary tables and indexers, do you control the table with a distance on the DROS referring to inches traveled or degrees? Seems like inches traveled would be different depending on how far away from the center of the rotary table as the work is spinning. Does any of that make sense?

Good questions. The shaft is very hard. In general: you can turn hardened shafts with ceramic or boron or diamond, but it takes an extremely rigid and powerful machine and the tools are very expensive. In the case of a leadscrew, you are facing an interrupted cut as well so to have success, you would probably need one of the reinforced versions of the inserts  . . now you are talking 30 times the cost of carbide. 

I'm not using a rotary table. I had a big one many years ago and recently I bought a small 6 inch rotary table  (PhaseII brand, pretty nice actually). But I only used it once before I sold it after converting to CNC.

I have only turned small 3/4" and down alum and steel parts, so for turning, the 4th axis is always running flat out at approx. 1,200 to 1,400 RPM. Other than that I use it for indexing and position it via azimuth (degrees). I have not messed with trying to set a surface speed via Mach using the part diameter. 

939

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: November 10, 2009, 04:33:52 PM »

Nice job Simpson!

Looks like you lost a fair amount of travel on your Z with these slides

Are the mounting plates and the bearing plate made of aluminum??? Or is just the photo?

Daniel

Well, lets find out. It is 4.4" from the dovetail flat (on the X2 base) to the top of the table. I sold the original table and saddle, so if someone with an X2 can measure, we'll have the answer. I had over 12" of Z travel, so I wasn't particularly concerned about it. The new base plate is 3/4" and doesn't need to be for an X2 (the table is designed for an X3), so an other .25" could be eeked out of there on an X2.

Everything is aluminum ground jig plate. The solid aluminum table weights only 0.4lbs less then the original cast iron table.

I will be building an entire new machine frame also from aluminum and making a complete new head from aluminum. The total weight of both head castings on the X2 is 16lbs. The new aluminum head will weight 24.6lbs  . . both figures do not include the spindle, bearings, motor, drive parts, etc.

The stock X2 column weights 17.5lbs. The new column will be 20lbs. X2 base casting weighs 17.25lbs. New base will weigh 19.5lbs

940

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: November 09, 2009, 11:58:15 AM »

Those hose fittings are being used as stand offs?

YEP!!   Waste not want not . . LOL!  Those are test pieces from my 4th axis project . . .  I have <ahem> quite a few   

Speaking of recycling, I just listed these Thompson ball screws in the 'Bargain Basment'. Somebody may as well get use out of them. They are brand new and I have no further need for them.