Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: mikekuru on September 03, 2015, 05:55:01 PM
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Hi, i am using a bridgeport cnc series 1 and mach3 pro..
im having to run my machine to cut at finishing depths or mach3 jumps to reset....it will cut at 0.5mm and it usually takes all day for the smallest jobs...
even cutting aluminium...ive been running it like this since Jan this year.......soon as i try cutting at proper depths......reset kicks in and i lose a couple of steps...and results in cocking the job up.
i am stumped...i have been searching the net for months looking for answers to this....i see videos on youtube of the same type of machines cutting at proper depths without a hitch...and still no answeres
thanks for listening
Mike
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Mike,
You may want to post some info on the drives, type motors ( steppers ) and size, Mach version used.
Also post your xml file that your using.
RICH
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check your z upper switch they are bad about tripping due to vibration i have a series1 cnc as well. i ended up replacing the z switches in the quill housing to stop it.
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thanks for the replies
i contacted Hood here on the forum he has informed me about the noise filtering,
i tried his method today and for the first time cut alu at 3mm per pass.
out of interest where did you buy the switches from?
thanks
mike
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Oh well that must of been a lucky cut...tried the mill today and it stalled again in mid path.....cutting at a light rough pass with 0.5 depth sooo
i detroyed more stock and time and money.
im about to give it all up after 8 months of loss after loss after time consuming headaches....i wish i never bought this thing....its a bridgeport that wont cut aluminium....
thanks
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Stalled? Are you meaning stalled or are you meaning it going into E-Stop?
If the latter then as a test disable your limit switches in Ports and pins and see if it helps. Remember you wont have limits so caution is needed.
Hood
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Going into Estop,
ok Hood, i will disable the limit switches in ports and pins........i guess this will disable the bed and z axis limit switches then?
thanks
Mike
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cant seem to find an option to....theres a pop up with ticks and crosses refering to x y and z........homing limits?
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Config menu, Ports and Pins, Inputs.
Click the green tick for the X Y and Z + and - limits so that they turn to a red cross and your limits will now be disabled.
Hood
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disabled them......seem to work ok....it just kept rattling the tool holder out of the chuck....and was super noisy...it didnt stop though....im cutting 7075 t6
at 3000 rpm 1272 feed at 0.5 per pass.....using 20mm 3flt hss long flute......60 stickout. with white water coolant (flood)
thanks
Mike
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I take it that you have a QC30 spindle ? If so then yo may need to adjust the QC nut so that it is engaging the lockdown tab more. IF it just barely engages teh vibration will make it slip back and drop out the tool holder.
IF you are cutting at 50IPM(1272MMPM) that is way to fast for that rpm and size of tool on a low powered BP. Lower the feedrate and increase the DOC . For normal cutting you will be MUCH better off if you limit your endmill sizes to .500"(12mm) then plan your feeds/speeds to that size cutter based on available HP.
The settings and tool Diam/#flutes you are using now will make the BP chatter badly and damage the Quill/spindle over time.
(;-) TP
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Bit more than I would push a BP but everyone to their own ;)
Hood
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Thanks for replies
il drop tool diam..to 14mm and run at 3500.....460 feed 0.5 pass
Mike
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Why only going 0.5mm DOC?
I would tend to have a lower RPM and lower feed and go deeper.
Hood
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at 3000 rpm 1272 feed at 0.5 per pass.....using 20mm 3flt hss long flute
Yikes!
3000 RPM with a 20 mm cutter? Moon, here comes something orbital.
Wrong direction. Much smaller cutter or much lower RPM.
My 2c.
Cheers
Roger
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Top spindle bearing goosed........just ordered one (7209)....bottom 2 seem fine.......im using g_wizard for the speed and feeds... i know the mills only 2hp...didnt think 20mm was that bad to be honest....im still learning though.
Thanks
Mike
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You have to remember that a Bridgeport is a knee mill and it is not very rigid when comparing to a VMC, add to that the Z axis being a quill and you have even less rigidity. You need to take things much easier on such a machine.
I use HSM Advisor a lot and it usually gives me good feeds and speeds for the type of operations I do, it is also configurable for slotting or high speed machining etc.
For slotting with a 20mm 3 fl HSS in 7075 it is telling me 1553 rpm, 639 feed. On a Bridgeport I would reduce the rpm and feed a bit due to the lack of rigidity, HSM Advisor allows you to do that and it gives you info on tool life, deflection, HP required etc.
See screenshot for using a generic VMC, you can set the specs of your machine up in a profile so that it is taken into account.
Hood
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Thanks Hood i owe you a drink!
replaced the top bearing today and its running noticably quieter.......i wont be taking it past 2500rpm in future, i adjusted the QC nut too, it tightens right up now when before it came to a stop and didnt feel that tight.....i had to make some screws to fit it, and the longer one to stop the nut totally unscrewing, its got 6 screws instead of the 3,
ran it tonight using some 20mm mild steel.......faced it, shaped it, put a couple of 12mm pockets in it then chamfered the whole edge all using the midi function, everything went really well, then i turned the mill off and it tripped the lecky, everything went black and i banged my head trying to get out, then the misses gave me a wollop for bringing chippings in the house,
so im sitting here with 2 lumps on my head...... progress
Mike
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HSM advisor looks similar to what i been using, only on g-wizard it only gives 2 options for alu, cast or wrought.
(http://i169.photobucket.com/albums/u217/abalmoe/g-wizard.jpg)
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then i turned the mill off and it tripped the lecky,
Yeah, happens. Many CNC controls mix up the neutral and earth, so that the leakage breakers trip.
I had to remove all of them from my CNC circuit to get reliability.
Cheers
Roger
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Been quite regular here too Roger,
the strange thing is if i run it from an extension cable to the house into a Kitchen (http://en.wikipedia.org/wiki/Vance_Miller) wall socket it never trips, now i had an electrician install my garage with full power and fuse box with an extra earth strap just for the BP.....it trips....not always though ...some days i would be running the BP for a few hours and no trip....other days 10 minutes and a trip, had a sparky down with his boss on the phone ...they were still baffled......the garage is on its own breaker on the house consumer....makes sense what you said though....its a common thing now.
Mike
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I think this could be solvable, but with some effort.
Go through ALL your electronics and make sure everything has a common 0 V reference point. That includes the FRAME of the machine. Hard-wire all that to the Neutral ONLY.
Then connect the Neutral to the Earth via a 10 ohm power resistor. That should stop the leakage going to Earth, and send it all to neutral.
The problem is that this may, or may not, violate the machine grounding rules where you live.
Underlying all this is the real problem, that the electrical grounding rules and the design of the earth leakage breakers, were all designed before the advent of switch-mode power supplies and power electronics on machinery. They are, to a significant degree, simply incompatible.
An alternative is that you comply with the grounding rules as far as the frame goes, but you float your entire electronics system, using a Neutral bolt as the 'safety ground'. Got a large heat sink panel? Float it. Got screening on your power cables? Float all screening. Got an earth wire going to a large motor? Make sure the windings are floating wrt the motor frame. Then, finally, you rely on the Neutral/Earth linkage back at your main switchboard.
But the simplest solution is to remove ALL earth leakage breakers from your CNC machinery. A bit of a scary thought in some ways at first - but remember that the machines will still be fully earthed, per regs.
My 2c
Cheers
Roger