1200mmX900mmX170mm 4axis cnc

[Nr1madman]

I have no ideas for you.. I went with the 5$ bob.
Beginning to question if that was a good plan !

All the expensive ones seem good... But expensive ;)

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[Nickhofen]

There must be a solution somewhere in the middle out there..lol

[JAZZCNC]

I have no ideas for you.. I went with the 5$ bob.
Beginning to question if that was a good plan !

All the expensive ones seem good... But expensive ;)

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Cheap Bob's are like playing Russian roulette with a nearly full magazine.!! . . . . Long term they are not worth the hassle because at some point they will fail or cause issues along the way which will appear like coming from other areas of the machine. Before I started with CNC I had full head of hair and now I Dazzle planes on sunny day and I blame all on of cheap BOB's.!!!

[Nickhofen]

Cheap Bob's are like playing Russian roulette with a nearly full magazine.!! . . . . Long term they are not worth the hassle because at some point they will fail or cause issues along the way which will appear like coming from other areas of the machine. Before I started with CNC I had full head of hair and now I Dazzle planes on sunny day and I blame all on of cheap BOB's.!!!

I work at Air Force so I have enough help from my job to grow a bald! Lol!!!
Any suggestions about a proper bob that I can make it work like a Swiss clock with the uc300 and all that at an affordable price...ops!

[Nickhofen]

Finish the power supply, thanks everyone for the help.

[Clive S]

Brill

It is good practise to not to daisy chain the 70V across each drive ie. use separate power leads from each drive to a common block and then connect the PS to the block. This ensures you are not getting a volt drop to each drive from the first one.

[Nickhofen]

Thanks Clive, I will keep this in mind!!!

[m_c]

Brill

It is good practise to not to daisy chain the 70V across each drive ie. use separate power leads from each drive to a common block and then connect the PS to the block. This ensures you are not getting a volt drop to each drive from the first one.

I'm going to engage pedant mode for a moment.
It's not to do with volt drop, it's mostly to do with the risk of harmonics.
Stepper drivers are essentially a complex switched mode power supply, which means they don't draw a constant current, they're constantly switching at high speed. If you place multiple of these on the same wire, then you risk harmonics, which is where multiple spikes at the same time lead to high voltage spikes, which can destroy electronics very quickly, and in extreme cases will burn out the wiring, even though the total current may be well within the current limit of the wiring.

Off course the latest drivers are far more likely to contain some internal filtering to help avoid noise being propagated into the supply, as part of them meeting various approvals, which should avoid any harmonic problems.

Avoiding daisy chaining also helps minimise any potential damage from a failed connection, as a connection failure during deceleration is very likely to result in an overvoltage failure, with resultant smoke release from drives. By having them wired direct, the worst case is one drive fails, but if daisy chained, you risk every drive after the bad connection failing.


Personally, I always wire drives directly to the main smoothing capacitor, as it avoids having any more connections in the wiring than needed.

[Desertboy]

That's super tidy, I see you went DC in the end. What voltage output transformer is it? 50v?

I wired the transformer to a 13 amp light style switch and then my VFD and water pump to another switch and both of them are wired from the emergency stop.

This way I can easily turn the transformer on/off and if the vfd is powered the water pump is on. I have both switches and the emergency stop at the front of the machine for easy access in a row.

If I hit the emergency stop it kills power to both the steppers and the vfd, I still have to work out how to get it to trigger an estop on the pc but it's good enough for me at the moment.

[cropwell]

I still have to work out how to get it to trigger an estop on the pc but it's good enough for me at the moment.

Just use a relay with a 230VAC coil.