The Craftmans Shop > New from Old
The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
WeldingRod:
When I'm designing hydraulic machines, I specify Turck polyurethane cables with moulded on DIN 43650 ends. I spec both a light and an MOV. The whole thing is much cheaper than good cable plus labor for field installed connectors and is actually watertight. AND field installed 43650's totally suck!
They also make ones with two lights for switches.
Sent from my SAMSUNG-SM-G891A using Tapatalk
awemawson:
The Field Coil Driver PCB turned up curtsy of the UPS man Mac - motor specifies a maximum voltage for the field coils of 170, I really wanted to set the system by current but the motor plate carries only the max voltage - OK they are related, but the actual current is pulsed DC so not exactly by Ohms Law.
During testing I've set the maximum field voltage to a conservative 100 as the spindle will see no machining load until everything else is sorted. Field current is proportional to torque as I understand it.
:ddb: :ddb: Anyway - we now have a spinning spindle :ddb: :ddb:
awemawson:
So now I am able to actually do things with the machine it's time to get to grips with the programming. The Sinumerik input method at the console is not exactly intuitive. For example this morning I spent two hours finding out how to delete or edit previously input code. I suppose really it's intended that code is generated off the machine and uploaded, but the controller does have quite a comprehensive graphical set of guides for the various G & M codes
Nothing so simple as a 'destructive backspace' key to delete characters - there is a complicated sequence you have to go through, which is now printed out and magnetically attached to the cabinet until I've learnt it :bang:
It also seems that programs that are deleted still take up memory, and you have to run some sort of sorting routine on what's stored to release the unused bytes - but that's for later - got to go to a BBQ now - it's hard life. :clap:
This morning I was experimenting with 'feed per rev' - G96 on this machine - whereby the machine alters the spindle RPM to keep the surface cutting speed constant. It was doing this when the need for 'backspace delete' became apparent :palm:
awemawson:
I've had an intermittent fault on the Tool Turret for a while - it seems to come and go but I convinced myself that it was heat related. Manifests itself as the SMCC card and or the 820T controller reporting it is at a wrong tool location when a tool change is commanded. Leave it alone for half an hour and the fault clears only to come back later.
So today I've been having fans pointing at things and trying in vain to locate the issue, until . . .
. . . the fault came on, and I happened to read the data word on the controller that indicates tool position, and blow me the least significant bit was missing! Now there is a four way proximity switch in the turret that I'd looked at before and all seemed well, but while the fault was on I was able to chase the wiring and the issue was definitely the proximity sensor - so pull it out. Shame really as having been in here before I'd already sealed the chamber with Blue Hy-Lo-Mar sealant.
Out it came and certainly bit zero is different from the others. Unloaded it's giving about 7 volts not detecting, but goes correctly to about 24 volts when detecting, whereas a good channel sits at about 2 volts and also goes to 24 in the presence of a spanner.
Loaded with 4K7 ohm to ground, so about 5 mA load, both good and bad go close to zero undetecting, but the bad channel stays at about zero in the spanner test.
So the hunt is on for a replacement. I could if necessary make up a bank of four individual proximity sensors but I'd rather avoid that if possible
Incidentally in previous posts I've referred to this sensor as made by Euchner - it's not it's a Balluff BES 516 B4 T0B-08-650 in case you have one in the odds box :lol:
awemawson:
Not surprisingly it turns out that these proximity sensors are modular. After much unscrewing the defective module came out revealing another part number. I've traced one to eBay in Germany and am waiting confirmation of postage charges, but it does mean that if the module isn't available, I can get a two or three way version and rob it for spares
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