Messages

71

Show"N"Tell ( Your Machines) / Re: Seeking guidance on router-lathe automation project

« on: March 25, 2016, 03:40:22 PM »

....a word of advice: Start NOW writing your "Owner's Manual", and begin recording ALL information in the book. Design drawings, actual dimensions, parts, materials, component specifications, where they were obtained. Also any alternate suppliers. (There will come a day, when these parts wear out, and are in need of replacement- it is good information to include in the Owner's Manual for your own easy reference). Also include Part numbers for things like bearings and belts. Thread sizes, and such for every nut and bolt used to construct the machine. All materials used.
 Screen captures of configuration screens for all software used (especially Mach 3). A well organized, and written Owner's Manual can be almost as much work as actually building a machine. But it is time well spent for your own reference.

Wow, I just stumbled onto this comment.  I wish someone would have slapped me & made sure I did that while retro-fitting my lathe!  I can't tell you how valuable the recording of that info is; especially when you're old & forgetful as me.  Every time something breaks or I want to upgrade it's like starting all over again.  Especially any circuits & wiring I did.

72

General Mach Discussion / Re: M3 M4 switching

« on: March 13, 2016, 08:30:53 PM »

Okay, back to the original subject 

Sorry RT, you're absolutely right!  When you get your relay setup working, please post up a diagram.  I'd like to have it around for possible future use.

73

General Mach Discussion / Re: M3 M4 switching

« on: March 13, 2016, 08:57:52 AM »

Those relays are only rated for 28 vdc.  I read a thread on another forum (HSM) that warned about the difference in arcing of the contacts between switching DC vs. AC and the consequent shorter lifespan when using under-rated switches & relays.  I think it may be wise to chose relays that are rated correctly for the job?  I'm sure those will work fine now but if they see heavy usage, may cause a problem down the road & the contacts stick closed at the worst possible time.  Just a thought.

You guys with more electrical smarts & experience can tell me to shut up & go back to my hole if need be.

74

General Mach Discussion / Re: M3 M4 switching

« on: March 11, 2016, 10:32:31 AM »

Could you somehow just add mass to the spindle drive? That can be really effective.

You would think so but it didn't.  It exhibits the same symptom with the same work held in a light ER32 chuck & in a heavy 4 jaw as well.

Besides, I just wanna play with a servo drive when I get time.  I had already mounted a Servo-Tek 7V/1000 rpm tach generator on the motor & wired it into the feedback circuit of the KB.  The variation problem got better but was still there.  That's when I hunted down the AMC servo drive.  The existing tach/gen will be wired into the new drive & it will be configured in the velocity mode.  An encoder might be better but since the tach is already there I'll try it 1st.

(Sorry for the hijack RT, we're just keeping your thread warm 'til you get back. )

75

General Mach Discussion / Re: Lazyturn Problems

« on: March 10, 2016, 08:46:07 AM »

Ahhhh, free, simple lathe cam that works; the holy grail.  I couldn't find one either.

If it's a simple taper, will the wizard that comes with Mach3 Turn work?  I've used it and it works well.

76

General Mach Discussion / Re: M3 M4 switching

« on: March 10, 2016, 06:55:34 AM »

Thanks Roger, as usual all that linear/non-linear stuff zings right over my noggin.

Fortunately I chose commercial equipment & got real lucky on the price.  The KBSI 240D has adjustment pots, the KBCC-125R has adjustment pots and the CNC4PC C-11 has an adjustment pot.  When I finished twiddling them, I have solid Mach spindle speed control in both directions within a couple 10's of rpm from 50 to 1700 rpm.  Way better than I need for 99% of my lathe work.

It does have a teeny cyclic variation that affects threading at times.  With that in mind I picked up an AMC BE25A20AC analog servo drive a while back but haven't  yet taken the time to install it.  Too busy making parts to undo all that hard-earned success and start over!

77

Show"N"Tell ( Your Machines) / Re: got the bug to start my lathe project NEED ADVICE/OPINIONS, Microstar N1

« on: March 09, 2016, 10:51:47 AM »

Hi Arnie, sadly I don't have any info for you other than to say I envy your nice MicroStar.  Main reason for the post is to knock that friggin' perpetual motion drivel off the top of the list.

This is one of my favorite parts of the forum & every day when I check I have to see that thing at the top!

78

General Mach Discussion / Re: M3 M4 switching

« on: March 09, 2016, 10:38:15 AM »

Both designs seem to have somewhat arcane interfaces, which may be fine for manual controls but are a pain for CNC interfacing. The KBWT unit analog input controls are at -100 VDC!

Hi Roger, I was going to defer to your superior electronics training & keep my mouth (keyboard) shut but I have to voice my opinion.  I know my electronics knowledge is sadly lacking but I do read about this stuff & have been able to make my hacked-together stuff work pretty well.  I just don’t want someone down the road to stumble onto this thread searching for spindle drive info, take your statement as gospel & go away misinformed.

I have never owned or used a KBWT-26 but just couldn’t believe that KB would make a drive has a “somewhat arcane interface” that is “a pain for CNC interfacing.”  I took the trouble of Googling the drive’s manual & found the following:

“Signal Input: The drive can be operated with a 5 kΩ Main Speed Potentiometer (supplied), an isolated 0 – 5 Volt DC analog signal, or an isolated Pulse Width Modulated (PWM) signal from a microprocessor.”  To me that doesn’t sound like a pain.  Granted, one does have to observe the “isolated” instruction without fail.  Don’t ask me how I know!  “Note: If an isolated signal is not available, an optional signal isolator must be installed (KBSI-240D or equivalent).”  I picked up 1 of these on ebay for $30 and solved my isolation problem. 

As to the old school KB SCR drive’s propensity to “make the motor hot if the motor is not designed for them” both the minilathe’s drive & the treadmill motor’s MC-68 drive are both SCR types so the motors will be fine as far as heating is concerned.

I hope I don’t come across as argumentative; just trying to be factual.   I was wrestling with the exact issues as the OP with my ORAC conversion a few years ago & the KBCC-125R was suggested to me and was an immediate revelation.  When necessary, the lathe can be spinning a 6” 4-jaw at full chat in one direction, receive an M5 command & the KB quickly & smoothly brakes the motor to a stop, receives M4 command, relay clicks, motor reverses & smoothly accelerates to the set speed, all in a couple seconds.  I had asked around and was struggling with relays & a big resistor trying to do it myself.  When I stumbled onto the KB, the problem was solved & I was able to get onto the next thing on the list.

Granted, you fellows with solid electronics knowledge can design the circuitry needed to do the same thing using the OP’s MC-68 but I was just trying to provide an easier alternative.

79

General Mach Discussion / Re: M3 M4 switching

« on: March 08, 2016, 02:00:56 PM »

A nice solution to this issue is to look around on ebay & find a deal on a KBCC-125R drive.  They're old school (compared to servo drives, vfd's, brushless, yada-yada) and are very reliable, being a industrial product.  They come with built-in circuitry & relay to allow instant reversing & dynamic braking plus easily configurable for different HP motors, PM magnet or wound field types.  I have one on my lathe & really like it.  I didn't have the patience or knowledge to do a bullet-proof relays circuit like shown above & kept looking 'til I found one for $65 NIB!

The on-board reversing function is also available in other later KB drives (PWM & others) but I like the older SCR types 'cuz they're usually cheap but good.

Here's the manual: http://www.kbelectronics.com/manuals/kbcc_manual.pdf

80

General Mach Discussion / Re: Mach3 and rigid tapping and Encoder threading (;-)

« on: March 03, 2016, 12:52:32 PM »

Is this something that will show up "down the road" on its own or is it something that TP alone has in his pocket?