CNC Control Panel And Pendant Functions

[HimyKabibble]

I've just bought myself a lovely new Birmingham knee mill, which I will be immediately doing a 3-axis CNC conversion on. As part of the conversion, I want to build a nice control panel, which will house the computer display (LCD panel), keyboard, and a nice assortment of controls for common operations, and simple manual operations. If it makes sense, I'll also make a pendant, wireless if that has benefit. I'll be using Mach3 for the controller.

So, the question is: What functions does it make sense to put on the control panel and/or pendant. Some are, I think, obvious:

E-stop
Spindle speed/direction controls
Jog controls for all axes (joystick?)
Coolant on/off control?

What else should I include? Being an electrical engineer and a software guy, I have no problem with putting some "intelligence" in the control panel, if it's used to include some useful functionality.

I've never used a "real" CNC machine, just my self-converted X2 mini-mill, so I'd be interested in learning what kind of front panel functionality real CNC machines have as well.

Let's have some ideas!

Regards,
Ray L.

[colin1544]

Hello there for guidance log onto AJAX CNC site and look at there accessories they do a Hand held control panel and an MPG unit, this plus the keyboard should be all that you need. Cheers Colin

[rppman]

I am looking into buying a birmingham knee mill. Could you take a second and list some inforation about the mill. Quality? Thanks

[rppman]

I ment to say that when I get my mill I was looking into the control system from machmotion for $3500. You get the pc. Mach3 sortware.nice enclosure. And this comes with 3 stepper motor drive and control board all in the encloser. Then I was looking into the nema34 stepper motors. Their is also a deal on ebay right now that has everything you need to get going. Motors.control.pendent. for like $2300

[Al_The_Man]

Originally Posted by HimyKabibble So, the question is: What functions does it make sense to put on the control panel and/or pendant. Some are, I think, obvious: E-stop Spindle speed/direction controls Jog controls for all axes (joystick?) Coolant on/off control? I've never used a "real" CNC machine, just my self-converted X2 mini-mill, so I'd be interested in learning what kind of front panel functionality real CNC machines have as well. Let's have some ideas! Regards, Ray L.

Because software based systems that use the parallel port are often I/O restricted compared to "real" CNC controllers, many functions are done on screen by touch or keyboard etc.
Controls that are not I/O starved have assets such as manual over ride switches for Feedrate, spindle speed over ride, feed hold etc.
Controlling many of these features by actual switch/push buttons tend to have a more positive real time feel to them.
For example, when rapiding or feeding into a part, it is nice to take the feedrate or rapid down to 0 and few % over ride, while monitoring distance-to-go to avoid a crash etc.
This is difficult with a screen slider O/R or similar.
This has always been my personal preference anyway.
Al.

[HimyKabibble]

Originally Posted by rppman I am looking into buying a birmingham knee mill. Could you take a second and list some inforation about the mill. Quality? Thanks

I am completely satisfied with the quality. For the price, I think it is remarkable. If there is any benefit to a "real" Bridgeport, I don't know what it would be. This machine is very nicely made, powerful, smooth, quiet. I've had absolutely no problems with it. A friend of mine bought an identical machine a few months after I did, and he's had the same experience. I've CNC'd mine, and push it very hard, and it just keeps on tickin'....

Regards,
Ray L.

[rppman]

i am planning on doing the same to mine. was wandering, did you have to replace the ball screws for less backlash or are they pretty tight stock? also, do you use steppers or servo's? do you use pullies or direct drive mounts? i dont see too many companies offering mounting brackets. seems like everyone just makes their own.

[HimyKabibble]

Originally Posted by rppman i am planning on doing the same to mine. was wandering, did you have to replace the ball screws for less backlash or are they pretty tight stock? also, do you use steppers or servo's? do you use pullies or direct drive mounts? i dont see too many companies offering mounting brackets. seems like everyone just makes their own.

It comes with leadscrews, not ballscrews. They're pretty good, but I don't think they'd last long in CNC duty. I replaced them with ballscrews and double nuts. I used servos from homeshopcnc.com, with home-made 2.5:1 belt reducers (there are pictures on CNCZone, somewhere....), though I will be increasing that to probably about 4:1, just to bring the top speed down to something safer. Right now, it'll do about 400 IPM wide-open, which is downright scary. I normally run 200 IPM rapids. I"m running the servos on Gecko G320s on a 70V/24A power supply.

Regards,
Ray L.

[rppman]

Thanks for the info. I am quite new to all of this. When or if you get time could you list where I should get the ball screws and nuts. I am planning on using 1200oz stepper motors. I have noticed from pictures on the web that when using servo's people use reduced gearing like you mentioned above about slowing them down. But most of the pics I have seen with steppers were set up with a 1:1 ratio or close to it. Is this just a personal preference or is the steppers just slower? Thank again

[HimyKabibble]

Originally Posted by rppman Thanks for the info. I am quite new to all of this. When or if you get time could you list where I should get the ball screws and nuts. I am planning on using 1200oz stepper motors. I have noticed from pictures on the web that when using servo's people use reduced gearing like you mentioned above about slowing them down. But most of the pics I have seen with steppers were set up with a 1:1 ratio or close to it. Is this just a personal preference or is the steppers just slower? Thank again

Servos run much higher RPM than steppers, and are basically constant torque, where steppers have high torque at low RPM, but torque falls off quickly with speed. So the reduction is a tradeoff between machining force, rapid speed, and resolution.

I got my screws and nuts from Nook - 1" XPR screws. Just go through their website, and you'll find them very helpful. You might also check with seller "linearbearings" on E-Bay. He has very nice screws, nuts, and bearing blocks at excellent prices. He'll also do custom end-machining on the screws (don't even think about doing this yourself on good screws like the XPRs....).

Regards
Ray L.

[rppman]

I was wandering if the birmingham you bought had the china base or the tiwian base? I am looking at the china base but I am scared that it mike be junk. They said they are iso9002 certified.

[HimyKabibble]

Originally Posted by rppman I was wandering if the birmingham you bought had the china base or the tiwian base? I am looking at the china base but I am scared that it mike be junk. They said they are iso9002 certified.

Mine is the 1649C, which is a Taiwanese head, Chinese base. I have no complaints whatsoever with any part of this machine. I think it is first-rate top to bottom. The only (minor) issue I have is a slightly loose fit between the spindle spline and the dog clutch, which causes a bit of rattle at times. But my impression is this is not unusual on BPs either.

Regards,
Ray L.