Messages

131

General Mach Discussion / Re: Perfect Lathe threading

« on: April 11, 2015, 12:47:49 PM »

WOW! (Dope slaps head)

1/4" Pressboard ways & a masking tape toolholder...the secret to perfect threading!  How come nobody thought of that before.

132

General Mach Discussion / Re: Hood's Birthday tomorrow: Happy birthday Hood

« on: April 10, 2015, 08:33:53 PM »

Happy Birthday Hood....and many more, PLEASE!

If I was smart enough, I'd send you quick bit of G-code that would play the Happy Birthday song on the Chyron and the toolchanger clapping it's little toolholders at the end but alas, I'm not.

It's the thought that counts, right?

133

General Mach Discussion / Re: Added Second Parallel Port - Now spindle is no longer smooth

« on: March 31, 2015, 03:56:26 PM »

Never mind, I'm slow today.  Took me a 2nd look to click on your link.

134

General Mach Discussion / Re: Added Second Parallel Port - Now spindle is no longer smooth

« on: March 31, 2015, 03:54:48 PM »

What was the fix?

135

General Mach Discussion / Re: feed rate changing during machining

« on: March 29, 2015, 01:11:14 PM »

I'm not code savvy enough to follow what you've posted but I had similar issues using G95.  They were caused by (I think) Mach "sampling" the spindle speed while it was still on the way up from stop, ie: not yet up to full speed and the feed rate would be wierdly random.  Putting a 2 second pause in my spindle setup options fixed it for me.  Dunno if that's the problem or the correct way to fix it but it worked.  This stuff is still black magic to me!

136

General Mach Discussion / Re: constant velocity same as css??

« on: March 29, 2015, 01:00:49 PM »

I use "CSS" all the time & it works fine for what it does: spindle speed increase/decrease proportional to the work diameter & chosen SFM using a constant feed rate of the tool.  G95 Feed per rev does not work though which means it's not true CSS.  For my piddlin' projects, it doesn't really matter that much.  You do have Mach3 v.062/piddlin right?

137

General Mach Discussion / Re: Analog servo spindle drive questions.

« on: March 22, 2015, 07:36:49 AM »

Great, thanks!  Funny,  I read that part but totally missed that sentence.  Since I don't have a Halls device on the motor, I must have mentally skipped over that part.

138

General Mach Discussion / Re: Analog servo spindle drive questions.

« on: March 21, 2015, 08:51:59 PM »

Oops, missed your post.  SWMBO went on an errand & I laid down for quick nap...4 hours ago.

Here's the manual.  It covers a range of drives, mine is the brushless type with a built-in power supply.
http://www.a-m-c.com/download/manual/AMC_AnalogDrives_InstallManual.pdf

139

General Mach Discussion / Analog servo spindle drive questions.

« on: March 21, 2015, 10:49:50 AM »

I have purchased an AMC BE25A20AC Analog Servo Drive to replace the KB SCR speed control on my lathe.  Got decent deal on it and want to install it place of the KB to stabilize the spindle speed.  I have a week before it arrives to bone-up on the installation.

I plan to leave the existing Baldor ¾ hp PM DC motor & its belt drive system in place.  I had previously installed a Servo-Tek 7v per1000 rpm tach generator on the Baldor and plan to use it for the velocity input to the drive.  I have no plans for spindle positioning with the drive at this time, just accurate speed control.

Baldor says my motor’s armature inductance is 7.098 mH at 90V/.75HP and the AMC manual says “Minimum Load Inductance, Line to Line” is 250µH. 7.098 mH is way more than 250µH so I should be OK with that motor yes? Or do I have it backward?  I have very little understanding of inductance figures.

The drive’s speed & direction is controlled by a +/- 10V input which my CNC4PC C11 happily provides the positive direction for, but not the negative. I’ll need to reverse the C11’s 0-10V output polarity via DPDT relay for reverse spindle direction commands, yes? I already have a reverse-polarity relay wired up to reverse the tach/gen input signal to the existing KBMM drive so it should be easy to rewire it if that’s what I need to do with the servo drive.

Even though the drive is described as being brushless type, the manual says it can be used with single phase brushed motors by switching the commutation DIP switch to 60-degree phasing.  It’s unclear though, which of the 3 (A, B & C) motor output terminals to use.  Hopefully it either doesn’t matter or I’ve missed it in the manual & can find it later.

I was able to attach the drive basic manual but the one with more detail is too big?

140

G-Code, CAD, and CAM discussions / Re: tool library Mach3 vs CAM

« on: March 20, 2015, 08:47:50 AM »

I suffered from the same confusion but it's pretty simple.  You define the tools in CAM: (Dolphin in my case) with the same numbers you have them set as in Mach.  In CAM set up each tool by number (Type of tool: Turn, Bore, Groove, Drill, Ream) - set the tip radius, direction of cut, ft/rear turret etc. & don't worry about the offsets.  Do all of your offsets in Mach.  When Mach runs the code with the tool changes you set in CAM, all is peachy.