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Author Topic: Bridgeport Knee Mill Conversion?  (Read 159133 times)

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Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #600 on: December 18, 2016, 05:50:47 AM »
Seems some people get that problem and others, like me, never do but now I have said that ::)

Anyway maybe adding this to your macropump would help, it should stop the machine if the spindle is 10% out from commanded speed.
http://www.machsupport.com/forum/index.php/topic,16290.msg110182.html#msg110182

Hood

Finally got round to adding this code in but then realised the high-speed spindle has no encoder so no feedback of real speed or lack of. :(

Maybe i need to look at a simpler fix like spindle power DRO = 0 after maybe 1s delay therefore spindle can't be running??

Not sure how to code a short delay, I guess i need to add some logic like "If M3/spindle is ON and PowerDRO=0 then fault" but needs a delay maybe to allow spindle to ramp up?

Would this be better added to the M3/M4 macros so "spindle start" -> "check spindle running" -> "ok or fail"

I will have a play when i summon the whatnots to go out in a cold shop and stand at a keyboard ;)
« Last Edit: December 18, 2016, 05:56:47 AM by Davek0974 »
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #601 on: December 18, 2016, 07:07:50 AM »
Maybe as simple as this?

m3.m1s

DoSpinCW()

If GetDRO(1010) = 0 then ‘DRO1010 is spindle power meter
  msgbox “Spindle Failed To Start”
  Call DoOEMButton(1021) ’no spindle so go into reset
End if

Is it ok to add code to the m3/m4 macros?
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Bridgeport Knee Mill Conversion?
« Reply #602 on: December 18, 2016, 02:45:09 PM »
Not sure if that idea would work, ie putting it in the M3. Might be better having it in a custom macro and having your PP put it after the M3 in your code.
My reasoning is that if Mach decides the M3 macro has a compiler error then skips it it will likely do the same whether you have additional code in it or not.
If it is in a separate macro after the M3 then it should pick up when there is an issue.

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #603 on: December 18, 2016, 04:15:28 PM »
Hi Hood, good point.

Looking at it from the compiler fault view, maybe better in the macro pump after all, as a self contained monitor but if we suspect the m3 will not be called so no led's to monitor, what would it look at?

Just trying to find a way to avoid editing the PP if there is one. I have several code sources - sheet cam, fusion, vectric etc.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #604 on: December 19, 2016, 06:17:50 AM »
When the cycle start button is pressed (2010 screen set) it turns green, is that a detectable change like an OEMLED etc?

Trying to find a way of knowing if code is supposed to be running or not without looking at spindle led's etc.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Bridgeport Knee Mill Conversion?
« Reply #605 on: December 20, 2016, 03:20:41 AM »
I am not sure if the macropump is the best place for this , I would be much happier personally with a custom macro.
Cycle Start LED does have an OEM, it is 804 if I recall.

Hood

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #606 on: December 20, 2016, 03:26:33 AM »
Hmm, but if the compiler is kaput as it won't run the m3.m1s will it run the custom macro?

Would it even run the macro pump?

Maybe this is why nobody has trapped this intermittent bug??
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #607 on: February 02, 2017, 02:30:07 PM »
Hi all,

been a while since this thread ;)

For those who don't know, my Bridgeport was rebuilt with servos and larger motor, plus i added an auxiliary high speed spindle for aluminium work. The job in hand is shown in the pictures below, 5mm Aluminium, lots of holes and intricate features. I use 2mm single-flute and 5mm single-flute carbide tools for these.

Also, I already had built a custom mini-mill to make these (and learn CNC) and still have this, its currently up for sale but no takers yet. My reason for adding the aux spindle to the Bridgeport was two-fold - one to save space and two to make more use of the very expensive Bridgeport conversion.

Now, when doing the on the Bridgeport, I am seeing bad vibration or chatter on the tool, it appears to be vertical oscillation but tonight also suffered bad enough radial oscillation to break a 5mm tool ! When it goes into oscillation it makes you jump as its very noisy and you instantly know it will end badly either in poor finish or broken tooling.

So, something is not happy - my reservation is the spindle mount (shown below) - its canted out over to one side and although its clamped to the quill and into an R8 collet in the main spindle, it must be allowing deflection from the cutting forces.

Ok, so I have a bad situation, is there a way forward here?

Obviously I can take the dust-sheets off the mini-mill and carry on but I just don't have the space long-term and wanted to make more use of the Bridgeport as mentioned. I really want a one-size fits all solution here.

If I run the small tooling on the BP at 3000rpm (top whack) the run time per part-set will go from about 30minutes to several hours probably - feed rates go from 900mm/min to 25mm/min so i don't think thats an option - it needs more RPM's.

What can be done here guys???

One idea I quite like is to spin the ram on the BP around and build a custom Z-axis completely and mount where the BP slotting head normally sits. This could be built as heavily as desired with linear guides and a servo or stepper etc.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline RICH

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Re: Bridgeport Knee Mill Conversion?
« Reply #608 on: February 03, 2017, 07:57:05 AM »
Quote
What can be done here guys???
Just some thoughts..........


The holder for the high speed spindle looks to be rigid enough.
I would leave it alone for now.

Check the Holder:
Put an indicator on holder plate to measure the force of pushing with your finger on the holder out at the high speed spindle and see any rotation of holder about the Z and do the same for the pushing upwards. It should take a fair amount of force to see a measurable deflection. Fix the deflection problem if it exists.   

Check the spindle:
Check for any side and vertical play in the spindle. Should be no sideways
but you will probably have some vertical. I modified the hand / cable drive spindles I use. Needed to be carefull since there is expansion of the spindle as it warms at high speed. Some high end high speed spindles require that the spindle bearings be replaced after so much run time.
You may not be able to do any improvements and have what you have,but, t least you know that runout can accur if feeds, chip loads, loading, etc. can cause problems and need to adjust machining parameters.

Feed rate - Chip load etc:
First you may want to consider using a two flute high helix end mill rather than single flute as that can help with the chatter. STep over and cut depth will vary depending on material, feedrate etc. There are some guidelines to start but some experimenting is worth doing to find what works.
For quick range of machining paramters  there is an end mill chart in Members Doc's or use some of the manufacturers on site calaculators for quidence.

Good flooding of the end mill to assist in chip removal is required.

Oscillation / resonance can be discussed ( it can get complex quickly)
,BUT, it the above is looked at you may find you don't that type of problem to begin with.

Finaly........
Yeah, you want to get things done efficiently / quickly as possible but if the basics are out of whack to begin with you will have problems.Everthing is just a trade off.

RICH

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #609 on: February 03, 2017, 08:08:35 AM »
Thanks Rich, I'll do some test/measurements this weekend.

The tool that broke was a 2-flute HH type, it was sent out by my supplier as a better option but didn't last long, about 10" of cut :) I was running at just below book specs which were 10,000rpm and 1000mm/min feed and 2.5mm DOC IIRC, I was running at 850mm/min, 2.5mm DOC.

Maybe I'm being too overzealous bye running hard? Maybe back off DOC some?? I just copied the settings i had on the mini-mill, but did not take into account the wobbly Z mount on the BP ?
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives