Topics

41

General Mach Discussion / This cut is as bad as it gets

« on: May 19, 2015, 03:45:03 PM »

I could use some help sorting this out. Please don't ridicule me at the poor state of this test cut, I really want to get this right.

Details as follows.
6mm 3 flute cutter running at 2100rpm
Feed rate is 250mm per minute
Pass depth of cut 1/2mm
Coolant used is 'Parafin' misting.

So why all the burring

I ran a file across the top of the job for the second picture.

Any helpers

George

42

General Mach Discussion / Cutting Aluminium

« on: May 05, 2015, 08:03:52 AM »

I bet it has been asked a thousand times but here goes.

I'm attempting to cut some Aluminum sheet 12.5" thick,
Some pockets will go right through up to 2" diameter. A profile around the plate will be approx 9" x 4"
There will be a few 6mm slots.

My bench mills fastest speed is 2100rpm
If I use a 10mm 3 flute slot drill and cut at 0.5mm per pass , what speed should my table be running at in inches per minute to get best results.
I'll mist with white milky stuff from a spray bottle.
Is .25mm per pass too little ? What is the easiest grade of aluminum to cut?

George

43

General Mach Discussion / Test Cuts

« on: April 27, 2015, 04:00:33 PM »

I recently converted my Bench milling machine for all 3 axis.

I was checking accuracy on some cuts and came up with the following numbers.

Desired Circular Pocket drawn at 50mm Diameter and cut using a 10mm end mill. Result was a nice pocket but came out at 46.98mm :-(

Desired  75mm square profile using 10mm end mill. Result was 77.91 x 77.91 :-(

Motor tuning is set to 800 steps per for both x & Y

Looks like the error is constant and is same for both axis.

How do I correct for this error ?

44

SmoothStepper USB / Slotted Opto Schematic

« on: April 10, 2015, 04:41:23 AM »

I need a schematic of how to wire in an Slotted Opto to read the pulses from my Spindle encoder disc.
I will use Smooth Stepper with Motion Control Break out board.

Can someone help please ?

George

45

General Mach Discussion / PWM or step and Direcrtion to control inverter drive ?

« on: March 31, 2015, 04:16:13 AM »

Which is best ?

My Break out board supplies PWM output 0-5v

If I use this to control my Inverter drive hence my spindle speed I will need to put the PWM through a PWM to 0-10v circuit to the input of my Inverter drive.

Alternatively, I could use one of my axis drives via an off the shelf Step/Dir to 0-10v to the input of my inverter.

Any advice on which is the better method?

Additionally, my BOB has two outputs for Fwd and Rev. I'm assuming if I use the second method I would not need these ?

George

46

General Mach Discussion / Hall Effect or Slotted Opto?

« on: March 29, 2015, 08:45:04 AM »

My break out board calls for a Hall Effect sensor to get the spindle pulses into Mach3, however my old TCL160 under conversion already has a nice big encoder disc mounted directly on to the end of the spindle shaft.
It has 100 holes on the inner and 1 slot on the outer ring and uses two slotted opto switches.

I really don't want to use magnets mounted onto my encoder ring for fear of introducing a balance issue.
Can I use the slotted opto switches with my break out board. And if so can you suggest a hook up method.
I have attached some pictures which may help.

I understand I can then calibrate the spindle speed by running the spindle and comparing the speed from Mach3 with the actual speed recorded by an electronic speed gauge and then applying a difference offset into Mach 3. Is that correct?

Many thanks

George

47

Mach4 General Discussion / Power supply for steppers

« on: October 07, 2014, 05:38:21 AM »

I'm in a bit of a quandary when it comes to the Current capability of the power supply to run my 3 steppers on my converted bench mill
X and Y axis use 1605 Ballscrews with a 2:1 pulley drive and Y axis uses a 2.4:1 pulley drive (no ballscrew)
Maybe someone can help.

I have two power packs available.

24Vdc 10Amps
48Vdc 5 Amps

Given that I'm about to run a bench mill with 3 of the steppers of the specification below. Which power supply would be better suited ?

Model                   Voltage(V)    Current /phase(A)    Holding Torque(Nm)    Inductance /phase(mH)
M60STH100-4004S    2.8             4.0                             4                             3

George

48

General Mach Discussion / Bench Mill Conversion

« on: September 21, 2014, 02:46:17 PM »

At last! I have now got my bench mill converted to Ballscrews 1605 on bath X & Y axis.

I need a little help so here are just a few questions.
I have retained the glass scales as you can see in the picture.
On the Y axis the Main readout shows -42.690 and on Mach3 DRO it shows +42.9837, a difference of 0.29
I have my 'Steps per' set to 800

Question Glass Scale shows a positive readout whilst the other shows a negative readout. I would like them both the same. How do I do this ?
I have two separate micro switches for each of the X & Y axis. For the Y Axis, Switch 1 serves Y++ whilst the other Switch Shares Y-- and Home, Is this the correct setup ?
If I jog to either end of the Y axis, the switches are trigged but I cant Jog back away from them. How do I do this.?

Here's a good one, Under normal milling operations:-
If the table is moving away from me is this a positive or a negative movement ?
If the table is moving from right to left, is this a positive or a negative movement ?

Lots of questions, I hope you may be able to help.

Thanks

George

49

SmoothStepper USB / EasyPC New smooth stepper

« on: September 18, 2014, 03:47:40 AM »

Been Running Mach 3 on my router table for 5 years or so with no issues.
I have now converted my benchtop mill to 3 axis ballscrew and have purchased a ' Revolutionary 3 Axis Mach3 CNC USB Smooth Stepper Motion Controller Card 200KHz' which is USB to run from my Laptop. Ebay £106.00
No docs but did come with drivers so plugging it into the laptop was fine as the board was recognised and the wee red light comes on.
However this seems to be different from the Smooth Stepper discussed here.

Is there a special Plugin for this board

How do I tell Mach 3 to talk to the USB port rather than the Parallel port ?

Any help will be very much appreciated.

I have attached a PDF of the board ,

50

Mach3 and G-Rex / Cant jog of the limit switch

« on: April 18, 2013, 03:51:45 PM »

Finally!
I got my inductive proximity switches working correctly.
X Y & Z all go to the home position when the Home Key is pressed. Hooray!

Now the problem,

If I set the x--- to be the same as my X home. Now when triggered I cant Jog away from it to a safe position. ??
Message is correct saying 'Xlimit switch triggered' but pressing 'Reset' has no effect

Have I still got it wrong ?

Thanks

George