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Author Topic: Bridgeport Knee Mill Conversion?  (Read 158954 times)

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Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #100 on: May 18, 2016, 07:39:30 AM »
Ok, its done now so 400w it will be, if it stalls then I can always fix it later, lesson learnt. I have a feeling it will be ok though, still a 2:1 reduction going in.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Bridgeport Knee Mill Conversion?
« Reply #101 on: May 18, 2016, 07:40:43 AM »
Not really sure what you are meaning with GT5 is that the Gates belts? If so then BSL or  Brammer  as they are now called should have them.
I just use HTD now and notice no difference at all except cost.
On the lathes spindle I went for a Gates GT3 just because of the power, it is just a 20mm wide belt with 8mm pitch but can handle the 12KW servo no problem at all. No problems in the time I have used it, probably 6 years more.

Hood

Offline Hood

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Re: Bridgeport Knee Mill Conversion?
« Reply #102 on: May 18, 2016, 07:43:37 AM »
see you already mentioned the motor whilst I was typing my one before last :D 400w should be fine although 750w struggled on the Beaver NC5, think the ballscrew pitch and gearing wasnt helping though and also it is a much heavier quill than a BP one.

Hood

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #103 on: May 18, 2016, 07:53:58 AM »
Im only looking for GT profile as it is supposed to have much less backlash than HTD and be higher power size for size.

I could probably change the motor to 750w still, won't be dispatched for a few days yet??

Yes, just found Brammer and they do them.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #104 on: May 18, 2016, 08:32:11 AM »
Ok, I'm sticking with the 400/750w combo on the motors, my reasoning is that the table is a considerable weight with a lot of bearing surface i.e.friction the quill is relatively light in comparison, even with large tooling installed, drilling will present the largest load on it in use, the table does most of the work on a mill, the quill is mainly for tool positioning and plunging. Will see how it plays out.

Drive belts, just had a chat with a very knowledgeable guy and it seems HTD is the best option here, GT is better but more expensive all round. The backlash concern is valid but equates to approx 0.25mm linear which if i have my sums right on 5mm pitch screws and a 75mm pulley will give me an error of 0.0053mm - I think thats acceptable on a 30+ year old machine ;)

He did however strongly recommend going for 8mm pitch and 20-30mm wide belts.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #105 on: May 18, 2016, 02:01:09 PM »
Panel controls...Looking for ideas...

As well as the complicated dual spindle system I have to get going mentioned a few posts back, what about things like manual spindle on/off buttons - would they control Mach3 or would they control the vfd directly as well as Mach3?

Also, with the Bridgeport back-gear system, you have run the spindle in reverse when in low range, would there be a smart way to control this from Mach or is it still a manual fwd/rev choice and selector switch on the panel?

Axis ref - hows about a single "Ref" button and a multi-positing knob to select "All - X - Y - Z - Z2"

VFD for main spindle, with the var-speed system I'm not sure if i should try using the vfd as variable or leave it fixed, the top speed is fixed at 3500rpm absolute max as it tends to wreck the spindle bearings above that and low down it probably would not have the torque needed.

So many ideas but not sure of what will work in reality here...
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Bridgeport Knee Mill Conversion?
« Reply #106 on: May 18, 2016, 04:53:35 PM »
Gates do a nice wee sizing calulator/programme, helps getting suitable belts/pulleys etc if you know a few dimensions of the machine, it is called Design Flex, you will find it here
http://www.gates.com/catalogs-and-resources/resources/repository/engineering-business-applications/design-flex

Regarding buttons,
Spindle should go via Mach if Mach is controlling the spindle on/off. You can do it a few ways with the IP-A, you can use a Brain to look at the switches input and then have it do the spindle toggle, you can use the macropump to do the same or you can set up an OEM trigger to the port and pin number of the switch and under system Hotkeys enter the OEM code for spindle toggle. Personally I use the macropump but the other ways will work fine, just don't use  the inbuilt modbus via brains or macropump and at the same time use Port and Pin via Machs Inputs page as you may get a conflict.

Back gear can be handled under spindle pulleys from  Config menu, just have to choose reversed option for the back gear and set the ratio. Should work fine although I have never used it with the CSMIO.

You could do that for the ref button, you would have to do it either via the macropump or a brain, when it sees the button press it will look at the inputs from the rotary and do whichever option the rotary is set to. I wouldnt bother myself as if I ever wanted to just home one axis I would just use the screen  but everyone is different.

When I had a VFD on the CNC BP I used it to vary the speed and just found a happy medium on the vari pulley and left it there, it was good enough for most things and if doing heavier stuff I would be in back gear anyway.

Hood

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #107 on: May 19, 2016, 02:20:16 AM »
Thanks Hood,

On the BP CNC, when you had the VFD variable, did you have a fixed point that you left the vari-speed wheel set at - I'm just trying to get a handle on Mach calling S2000 but your spindle is only giving 1000 or 3000 because of the setting on the actual pulleys? Wrong speed would make a mess of feed-rates and chip-loads etc.

So maybe set mid-point on the mechanical, mark it on the dial and the calibrate Mach to that point?

I see with OEM triggers we are limited to 15 I think, so maybe Macro-pump is the best way if more is needed, the CSMIO book goes with OEM triggers.

I'm a bit quirky with Ref's, probably just lack of experience and this one will likely be different than the mini-mill, I am making notes of each use on the mini-mill to see just what buttons I do actually use, that should narrow it down. I want just enough buttons on the panel to do some work without having to think about which button to press - panels should be clear and easy to figure in a hurry if needed.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Bridgeport Knee Mill Conversion?
« Reply #108 on: May 19, 2016, 04:58:05 AM »
I just had manual control of the spindle via a pot but I just found a sweet spot in the pulleys that seemed to be fine for all different speeds (within reason) and left it set there.

So if controlling spindle speed from Mach then you would just decide on a spot for the pulleys and then set Max and Min in Spindle pulleys for that and it should work fine, same for backgear.

CSMIO shows all different ways you can do it, think the extra I/O manual has more explanation that the IP-A manual butthere is also this page whic gives good info for all the controllers and modules..
http://www.cs-lab.eu/en/artykul-128-Digital_and_analog_IOs__configuration__its_easy.html
Hood

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #109 on: May 19, 2016, 05:25:11 AM »
Thanks Hood,

It might even work out that the speed knob can be left unnamed position and VFD control range would work ok in normal or back-gear setting.

When using pulleys in Mach is there a control setting for this - I can see a "Pulley" DRO on hidden away on the settings page but in the 2010 screen-set it's missing completely.

I guess the "pulley" DRO can be controlled externally via macros or OEM trigger? Will have to get the manual out....
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives