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LandyManLuke

Bridgeport Milling Machine

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Normally you have a separate VFD for the spindle. You get 3 Ph to 3Ph VFD's for this.

Also, the axis drives are usually DC and have their own speed control. If they were fixed speed, they would be pretty worthless. Old machines sometimes had a gearbox to set a number of fixed speeds for the Axes - but I've never seen this! Thus, in all probability the Axis drives wont care. The coolant pump will change speed - but you almost never use the max coolant flow - and it increasing when the spindle is running faster is exactly what you want!

Try it with a 1 Ph to 3Ph VFD. If you have problems add a second one or the spindle.

Si

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Yes, indeed the table has its own variable speed control. I had never considered that this would be anything other than 3ph AC.

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In my case, I will be using seperate appropriately sized VSDs for spindle and coolant pump control.

I don't have powered feed motors, so no issue there. If I add them, they will probably be geared-down stepper motors.

I am planning to re-wire the Bridgeport switch box to use it to switch the low voltage control signals to the inverters.

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In my case, I will be using seperate appropriately sized VSDs for spindle and coolant pump control.

You might be able to just add a capacitor to the coolant pump to get it runing on single phase. I added a cap, from

an old fluorescent light fitting, to the motor for the oil pump on my mill, it works fine.

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That sounds like a great plan Luke.

Perhaps you wouldn't mind sharing a wiring diagram once you've changed the wiring.

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Will do.

To be honest, I don't like how the Bridgeport switches are 'down for on', I much prefer 'up for on', so I will try to change them around, either electrically or physically.

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If I remember rightly from the last time we had the Lillian apart, the switches are just in a round hole.

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Whats wrong with the tap on the suds pipe?

I'm sure the big cinncinati at work uses more suds than the bridgeports on the odd occassion it has the 14 inch face cutter on.

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Just installed a Starrag VT-800 at work, it has a 2000litre coolant tank and filtration system, and pumps rated at 500lpm, there's coolant everywhere!!! in 3 minutes you could empty 1500l of coolant over the shop floor before the machine sensed 'low coolant' in the tank and goes into e-stop....

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Wow, the dates on this thread make me feel bad...

Having run the milling machine on the VFD (sat on a bench) for a couple of years, I've decided I really should do something about it.

So, it's out with the old control gear. I'm pretty glad I've never used it, actually.

post-84-0-93673600-1422314899_thumb.jpg

And a mock-up on a fresh new (ish) backplate.

post-84-0-22674300-1422314901_thumb.jpg

Followed by some marking out, ready for drilling and tapping.

post-84-0-28093200-1422314898_thumb.jpg

Meanwhile, one of these,

post-84-0-94812500-1422315075_thumb.jpg

Along with some of this,

post-84-0-61383000-1422315074_thumb.jpg

Means I've actually got a way to control the VFD, once it's tucked up inside its new panel, away from swarf and oil, etc.

Luke

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Here's the test rig

post-84-0-37075100-1422813105_thumb.jpg

And here's the display showing the material type, tool diameter, setpoint spindle speed, actual spindle speed, inverter output frequency and motor current draw.

post-84-0-56277400-1422813116_thumb.jpg

Here's a video to show it in action.

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If you're controlling it from Mach3, you could re-write the T - Toolchange macro to select the cutter size on your controller!

I like it a lot - ticks all my boxes (Arduino, Blue LCD & Machining)!

Si

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Mach3 one day! That sounds cool. Does Mach3 already have the ability to vary spindle speed?

Now, I need to test this, and get the right gear ratio factor between the inverter setpoint and the spindle. It's not far from 1:1 but it definitely isn't. I have a feeling the reference speeds for each material might need playing with a bit.

This is my first foray into Arduino, (as opposed to Microchip, raw Atmel AVR, basic stamp) and I have to say I'm impressed. Certainly takes the faff out of building a board and at less than 20 quid for the Leonardo it's a quick and easy way to get up and running.

Blue LCD is worth the extra few quid, it's certainly bright.

Luke

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Mach3 one day! That sounds cool. Does Mach3 already have the ability to vary spindle speed?

Now, I need to test this, and get the right gear ratio factor between the inverter setpoint and the spindle. It's not far from 1:1 but it definitely isn't. I have a feeling the reference speeds for each material might need playing with a bit.

This is my first foray into Arduino, (as opposed to Microchip, raw Atmel AVR, basic stamp) and I have to say I'm impressed. Certainly takes the faff out of building a board and at less than 20 quid for the Leonardo it's a quick and easy way to get up and running.

Blue LCD is worth the extra few quid, it's certainly bright.

Luke

Its a cnc control, why wouldnt it?

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Mach, through a breakout board will produce a 0 to 10v signal to control the speed. It will also take an index pulse from the spindle (only one pulse per rev) and can control via a PID.

Si

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