Messages

3551

General Mach Discussion / Re: axis calibration problem

« on: June 01, 2011, 10:48:11 PM »

May I suggest you use Mach's calibration feature which is available via F6 or the Settings Tab in ach Mill.
RICH

3552

General Mach Discussion / Re: Using a Stepper motor as a spindle motor

« on: June 01, 2011, 10:45:45 PM »

The true rpm is read and if necessary the feedrate is varied accordingly on the next cycle to adjust the threading.
You set the rpm manualy, so on the Sherline, you turn the rpm adjusting pot to get a desired rpm.
The wizard will generate the required gcode and also check that your velocity and acceleration is adequate for the chosen rpm.

RICH

3553

General Mach Discussion / Re: Using a Stepper motor as a spindle motor

« on: June 01, 2011, 07:29:01 PM »

Have a Sherline here and have cut threads on it using Sherline's spindle motor, threading accuracy was not good enough for myself ( backlash even with the anti backlash nuts installed), good to about 1/4-20.
You will get spindle slow down but the thread cycle reasonably adjusts for it.

I would not recomend a stepper for the motor as it has no torque at higher rpm's and is rpm limited.
Servo should be fine if adequate.

Threading is built into Mach3 Turn, but, the thread cycle will not work if it is unlicensed / trial version.

RICH

3554

General Mach Discussion / Re: axis calibration problem

« on: June 01, 2011, 07:19:12 PM »

Even a plain threaded rod with nuts won't have 1/2" backlash.................something is loose.
RICH

3555

General Mach Discussion / Re: axis calibration problem

« on: May 31, 2011, 08:27:50 PM »

Suggest you check that all the mechanical stuff is right, ie; that a pulley is not slipping or something is loose.
RICH

3556

Show"N"Tell ( Your Machines) / Re: RICH'S ATLAS CNC CONVERSION

« on: May 29, 2011, 07:28:44 PM »

The one pictured is 18000 rpm / 1/4 hp.  The Dumore  is 12000 rpm under load and also 1/4 hp. Have others that are air driven that go to 60,000 rpm.
The spindle holder gets up to around 105 F so maybe the spindle is around 110 to 115F after an hour of use.
May need to make a water cooling jacket or add air blowing on it since it will get somewhat warmer when cutting SS.

RICH

3557

Show"N"Tell ( What you have made with your CNC machine.) / Re: MODEL 629 S&W MAGNUM

« on: May 29, 2011, 12:14:16 PM »

Back at it when time is available. I modified / improved the Atlas mill so it could reliably do 3D machining.
The engraving machine I used is limited in feedrate and 4-5 hour test runs is just not something that could be tolerated.
So attached are pics of a test done at 45 IPM. Took just 35 minutes to do, thus big decrease in milling time and quality is
good. An end mill was used  but a  ball mill will be used latter on for a better suface finish. Since there are places on the
barrel ie; top ramp and sides of the ramp that require a mattered or lined finish i wanted to see what the sharp end mill would
do.

Attached a few pic's of half the barrel showing machining steps and magnified view of both contoured and smooth
machining.
RICH

3558

Show"N"Tell ( Your Machines) / Re: RICH'S ATLAS CNC CONVERSION

« on: May 29, 2011, 11:23:11 AM »

The mill served me well until I got into 3D miling and it just would not do the job.
So improvements to the mill were required.
I reworked the  the X and Y bearing holders and installed new and better bearings, upgraded the stepper motors,  and per
the last reply modified the head to use a ball screw to drive the Z axis.

What a difference to have no backlash and all the axis can  now can do 80 ipm reliably.

I attached the old adapter plate for the high speed spindle  and tested her out....machine worked  like a charm.

RICH

3559

General Mach Discussion / Re: Blue smoke

« on: May 28, 2011, 06:29:55 AM »

Echo what Hood said.
I understand that cost is a consideration, but, I never regretted doing the following:
- Power supply - 30 amp  ( can handle running 4 steppers at 7 amps each, ie; X,Y,Z,A axis)
- ( 4) drives  ( and i would recommend Gecko's also )
- dedicated computer for CNC
- controller / computer on portable stand which can be used at any machine

Then you need to consider software, Controller / CAD / CAM and that is as much or more than the above.

No need to rebuy and satisfies all I need now and possible future,

Look at it this way....sort of like the machine and then you add tooling and fixtures to the picture.
The mistake is that some folks spend a fortune for the machine  / tooling / fixtures and chintzy on the other stuff that's makes the CNC
part of it actualy work well.

FWIW,
RICH

3560

Tangent Corner / Re: Ooops !

« on: May 26, 2011, 06:07:02 PM »

"NICE RIP TWEAKIE"  
           or
Like the saying goes "HOLE IN THE HEAD" 

RICH