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Author Topic: 1987 Bridgeport Production Center Interact 412 to Mach3 Conversion  (Read 160153 times)

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Offline cnc-it

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Re: 1987 Bridgeport Production Center Interact 412 to Mach3 Conversion
« Reply #30 on: December 23, 2009, 03:11:36 PM »
Not sure about 400 pulses per rev as my old Fanuc DC motors on my Bridgeport BPC320 have 2500 ppr...and the machine is rated at 0.001 mm accuracy but in real terms will manage around 0.005 mm accuracy due to temp change etc.

John
Positioning Accuracy
« Reply #31 on: December 23, 2009, 04:08:41 PM »
Hey John,

The CPR/PPR does not correlate 1:1 to machine Accuracy or Repeatability.  Yes, if the CPR/PPR is low you will decrease machine Accuracy but the Repeatability would remain the same. 

I have not checked the specs in a while on the BP412, but I think the stock Accuracy was rated 0.0003in (0.008mm), with the 100CPR/400PPR we should get 0.00025in (0.006mm), just a little better than stock and very close to your 0.005mm.   I do not think the Accuracy can be increased much more than stock, due to the belt drive, thrust bearing and ball screw Accuracy stack-ups.

After a quick check on new Harding/Bridgeport XR760, I found it’s rated at 0.00024in Positioning Accuracy.  I think we are on track with this, please correct me if we are off.

Link to XR760 Specs
http://www.hardingeus.com/productView.asp?prodID=50

Thanks,
JH

Offline cnc-it

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Re: 1987 Bridgeport Production Center Interact 412 to Mach3 Conversion
« Reply #32 on: December 24, 2009, 03:01:19 AM »
Hi JH,

Yes I agree unless you put the encoders directly onto the ball screws with couplings it would be hard to improve over the original machine accuracy spec.
I think your calculations are correct just be a case of testing and seeing how well the figures actually come out under machining conditions!

 My Bridgeport is a horizontal and was actually built for Bridgeport by Yasda in Japan under licence so it was built with high accuracy and thermal stability in mind hence the good results I seem to get...but I still think the machine manual is a tad over optimistic!

Great to see a full size machine getting the Mach 3 treatment..looking forward to more updates!

John
Re: 1987 Bridgeport Production Center Interact 412 to Mach3 Conversion
« Reply #33 on: January 17, 2010, 12:09:46 AM »
How are you controlling the spindle orientation with your VFD, so that the tool change can take place?
Re: 1987 Bridgeport Production Center Interact 412 to Mach3 Conversion
« Reply #34 on: January 17, 2010, 09:09:44 PM »
How are you controlling the spindle orientation with your VFD, so that the tool change can take place?


The plan is to us the stock spindle orientation sensors with Mach3 to signal the VFD when to stop. 

During a tool change the spindle speed will be set to a slow speed ( maybe 50 RPMS), then Mach3 will monitor the Spindle Home Sensor and count n number of pulses from the orientation encoder before signaling the Spindle to Stop.  While the Spindle is stopping and slowing, Mach3 will continue to count to verify the Spindle is in the correct position.  If its not in the correct position, these steps will be repeated until its correct, up to 3 times or so before generating an error and stopping.

I might even add some code to automatically adjust the triggering point to teach Mach3 with to signal the Spindle to stop during each tool change.

However, this is only the plan....  I have not tried it yet.

Ideas are welcome :)

Thanks,
JH

Offline Monty

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Re: 1987 Bridgeport Production Center Interact 412 to Mach3 Conversion
« Reply #35 on: January 29, 2010, 05:29:55 PM »
JH,

Nice looking project. What are you going to use for break out and machine/computer interface?

Monty
Re: 1987 Bridgeport Production Center Interact 412 to Mach3 Conversion
« Reply #36 on: January 29, 2010, 06:34:45 PM »
Thanks Monty,

So far, for the core machine I/O, I am using 2 CNC4PC C10 breakout boards with a C4 Charge Pump on 2 Parallel Ports.  This covers the 3 Axis and Home Sensors, Tool Changer Motor, Pneumatic I/O, and Various Sensor Inputs and Coolant Control. 

The Spindle ON, OFF, REV, FWD, SPEED, RPM Monitor and Current Monitoring is all done via Modbus using a simple USB to RS484  converter.

This is working well so far, still playing with the servo encoders, acceleration profiles and tuning the 3 Axes.  I hope to have this finalized soon and start integrating the tool changer to the Spindle. (Need Spinlde orientation for tool changes and taping)

For the User Interface, I am looking at PoKeys or NC Pod, something like that to handle all the inputs.   No sure yet.

Thanks,
JH
Encoders, Servos, Drivers and Power Supplies
« Reply #37 on: March 04, 2010, 06:24:41 PM »
I spent the last couple of weeks evaluating drivers and encoders.  Evaluated Viper200, CNCdrive Whale3, CNCdrive Dugong and the old stand by Gecko 320….  Ended up using Gecko 320s, 100CPR/400PPR HEDS Encoders with an 80Volt DC PS.  (86VDC no load)

The Viper200 was hard to tune, several times it had a runaway condition without generating an error and slamming the table into the mechanical stops.

CNCdrive Whale3 was very promising for the first 3 hours until the driver failed.  Customer support was great and they sent me a new CNCdrive Dugong upgrade for FREE for to test.  

CNCdrive Dugong also was very promising with 35 Amps of drive. I am saving this one for the Mori Seiki CNC Lathe Project….

Gecko 320s were easy to tune, and I also had 3 of these left over from older project, the performance was fine for the X and Y (250IPM with 0.00025/step)  I didn’t prototype the Z axis yet, but the servo motor is the same so my guess is it will work fine.  It looks Gecko has a new driver too, one that you can change the servo error limit.  Bottom line is, I am happy with this configuration as is for now, if I need performance I can swap it out later.

Below is a picture of the Power Supplies with Gecko 320 Drivers being assembled:

I should have the XYZ running soon under this configuration.  I’ll post a movie when its up and running.

JH
« Last Edit: March 04, 2010, 06:27:46 PM by JHChoppers »
Re: 1987 Bridgeport Production Center Interact 412 to Mach3 Conversion
« Reply #38 on: March 05, 2010, 11:19:09 AM »
Small update of the Gecko 320 Drivers and Power Supplies...

JH

Offline Sam

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Re: 1987 Bridgeport Production Center Interact 412 to Mach3 Conversion
« Reply #39 on: March 05, 2010, 03:50:06 PM »
I see a major problem. The Captain Morgan cup is EMPTY! You'll be making chips before ya know it. Is there going to be a transformer for each axis?
"CONFIDENCE: it's the feeling you experience before you fully understand the situation."