Topics

51

General Mach Discussion / Basic questions about dual lathe toolholders

« on: August 09, 2012, 02:56:50 PM »

I’m getting closer & closer to actually cutting metal with my Denford ORAC lathe retrofit project and am seeking some basic tooling knowledge from ye grizzled CNC lathe vets.

The ORAC is pretty small (8” swing) and has a small t-slot table on the carriage.  It didn’t come with the turret option unfortunately.  My plan is to bolt on an extension plate (5/8” x 4” x 10” ish steel) via the slots, install 1 AXA100 wedge QCTP in the normal location and either a 2nd identical QCTP on t’other end of the plate or make a parting blade holder to go on the end of the plate.

1)  Do dual QCTP’s make sense in the real world or is that a waste of money on such a small lathe?  I have one for the lathe now and would have to purchase a 2nd one if I go that route.

2)  Do the tool table & offset features in Mach work pretty well in preventing crashes with dual tool holders?  I can’t afford “real” lathe CAM at this time so I’ll be using the Wizards and doing some hand coding.  I’m still reading and trying to get my head around tool tables, tip radius and the like.

3)  Do any basic dual tool holder tips or hard earned lessons come to mind?  I have a lot to learn and any thoughts on the matter would be greatly appreciated.

Thanks!

52

General Mach Discussion / Has anyone actually got a C11 to control a KB speed control via Mach?

« on: July 01, 2012, 08:45:34 AM »

I must be a complete idiot because I can't.  I have Mach neatly switching the KB power on & off via M3 commands or clicking the onscreen "spindle" button.  If I leave the manual pot connected, the KB varies the speed of the Baldor 3/4 hp motor beautifully (yay KB!)  If I take off the pot & connect the C11 to the KB, the motor instantly spins up to a much higher top speed with no control via "S" commands.  No Mach config changes make any difference.

The C11 manual (to me) is vague but the C6/KB hookup section has more verbage on hooking up to a KB and I assume the 0-10V analog circuits are the same in the 2 boards.  My interpretation of the C11 instructions is that the pot is to be removed and the C11 0-10V analog outputs connect to the P1 & P2 terminals on the KB which leaves the P3 terminal open.  The C6 instructions (pasted below) to me imply that the outputs are connected to the pot terminals.  Can that be true???

"These are the steps for replacing a potentiometer:
1. Measure the voltage difference between P1 and P3. Make sure it measures
under +12vdc.
2. Fine tune the analog output to the output voltage you got from step 1.
3. Connect the ground from the analog output to the ground of the
potentiometer (P1).
4. Connect the analog output to the wiper connection of the potentiometer
(P2).
If the reference voltage from pot is between +10 and 12vdc, you can use it to
power the analog circuit (not for the C6, because the relays might draw too much
power). In this case, connect P1 to the ground of the power terminal, and P3 to the
+12vdc power connector."

I checked the voltage across the KB P1/P2 terminals with the pot attached & turned up to max, motor running at full chat and get 3.5VDC.  I checked the voltage at the gnd/0-10V outputs on the C11 (with nothing attached) and it varies up & down in concert with varying S commands from Mach.  I set it to 3.5V max with the onboard trim pot.  I know, not what the inst says but I had to try something to slow things down!

When the pot is removed from the KB and the 2 leads are connected from the C11, the voltage across P1 & P2 is locked on approx 6.5 volts, no matter what is commanded by Mach.

Somebody please smack me up side d'head and clear up my stoopidness!!

53

General Mach Discussion / CNC4PC C11 question

« on: June 15, 2012, 12:18:24 PM »

Hi there, esteemed CNC gurus.

I am retrofitting a Denford ORAC lathe and have a couple of CNC4PC C11 B.O.B. questions.  I emailed Arturo who is usually extremely quick but I guess he’s on vacation and I haven’t heard back yet.  I’m hoping to get the spindle on/off via Mach going and then proceed on to speed control.  The ol’ eat the elephant one bite at a time applies here.

I have it installed and working as far as the stepper motors go.  I have the control PC’s USB connected to the C11’s supplied USB 5V power cord and am using a converted PC power supply for the other 5V and 12V connections.

Does the C11 require that one of its onboard ground connections be connected to the machine's central ground point?
 
I want to use one of the C11 onboard relays to switch power on & off to the 24VDC coil in a separate larger relay that switches the 110VAC power to my DC motor speed control.  I must admit I'm confused by the manual and various wiring docs on the website.  It’s probably just a lack of electronics terminology knowledge on my part.

If I have +24VDC going "in" to my large relay's coil, do I just connect the other side of the coil to the "NO" connection on the C11 and the V_IN1 to the -24VDC wire on my 24VDC power supply?  I know I’ll have to configure Mach to supply a pulse to the C11 via pin 1 or 16.

54

General Mach Discussion / Toolpath display question in Turn

« on: January 14, 2012, 10:04:55 AM »

Hi all, new user/purchaser...trying to muddle my way forward.  Great program & forum!;D

So far all of my CNC'ing has been in Turn and has been modification/repair work on existing parts with the code being handwritten from CAD drawing coordinates until I get better at the wizards and/or LazyTurn.

I have had to touch off & zero on an external feature of the parts with the x-axis zero point nowhere near the spindle centerline.  The toolpath display screens on most are rather bizarre and I have trouble determining if the path "looks right" before hitting cycle start.  Is there any way to offset the display screen's zero point?

55

General Mach Discussion / Neophyte question about Video Window Plugin

« on: October 20, 2011, 09:40:58 AM »

Hi all; new member, 1st post.

I've been cramming as much info as possible from this great forum for the past few weeks.  What a fantastic group!  I'm positive you guys could solve any problem.  Matter of fact, could ya'll take a few weeks and fix our economy?  Should be a piece o' cake for you fellers!

Anyhoo, I installed a webcam on my little CNC lathe to use for a very fiddly, precise setup procedure.  It installed fine, Mach 3 (Demo version) recognized it and opened up a video screen perfectly.  Awesome!  By the way, the job I'm trying to do will pay for a license when it's finished...yay!

Only problem is that I thought I would be able to watch the video image and jog the tool into position at the same time.  Unfortunately, as soon as I switch to the video screen, the jog keys stop working.  I close the screen and the keys work again.  Is that normal or is there a way to get them both to work together.

Thanks!