MK1 Steel router build log 1500x800x200

[Doddy]

I connect the steppers direct to the drives. Some use connectors at the input panel to the box but for me this is just another source of potential noise.

Noise?, okay, with an unshielded connector and a (very) poor connection. More likely, you'll be introducing resistance , and that will have a detrimental effect on the machine (whether measurable, is something else - if the PSU is spec'd correctly and the drivers are in constant-current then it should will have a limited effect).

It is a balance between cost and convenience first and foremost. If I had a cabinet with the holes for the steppers pre-drilled (as appears to be the case in that impeccable cabinet) then I'd go connector. If you never disconnect them, then the convenience never comes into play and you've lost the cost of 6-12 connectors over the life of the machine. If you have to disconnect them then, without the connectors, you're suffering inconvenience each time. It also helps to be able to isolate cables from cabinets during construction, installation, maintenance, etc.

Call me lazy - I prefer to make life as easy as possible for myself.

How often do you need to move the machine? Unscrewing a few terminal blocks on the drive takes just minutes.

Sods law : if you provide connectors - you will never move it. If you don't - you will :)

Remaking screw terminals is not a great use of time - you shouldn't re-use the existing wire/crimp without remaking (I would re-use, in the knowledge I'm doing wrong, again out of laziness - it'd bite me in the end).

Up to you

Absolutely.

My only caveat on my view above - I'd make sure to use a vaguely appropriate connector.

[driftspin]

Oh connectors. No i was thinking using the bottom row of terminal blocks or not.

So lost time while moving is not in the equasion then. it is both screw terminals.

I agree with you on the resistance issue, it is to be avoided. also connectors if not done right are an other source of errors.

So straight to the drives it is.

Thanks guys

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[routercnc]

I think Doddys first paragraph sums it up better than my quick description
I’ve had good experiences with connectors- My first CNC machine used aviation connectors and I had no issues with them at all so it can work fine.
I’ve also had bad ones where the connector to the spindle flashed over and blew the expensive VFD. Totally my fault as I didn’t provide much strain relief and the spindle moves around.
So I just have an aversion to them which is probably not very scientifically based when you do it right.
In terms of time spent disconnecting the steppers the drives usually have a green terminal plug which you just pull out and feed out of the cabinet so it comes down to how easy it is to feed the cable out.

[driftspin]

Hi guys,


I was finally able to make some progress again today.

Now a new question ...

Does UCNC work with soft limit end switches?

For the y & z i am able to do home end switches both ends..


In my design it is al lot harder to do x1 home and end, and x2 home and end.


So just home switches on x1 and x2 ... is that enough?



Grtz Bert.

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[driftspin]

Hi guys finally,


Things are moving

https://youtu.be/DGThYTQ_QdE




Scary stuff, this thing is powerful.


Homing.

So now i am trying to get the combined home / limit switch working.

I played with the softlimit and offset settings.

After homing , this works everytime, the UCCNC software goes to reset because it is at the limit position.
I cant reset until i move all 3 axis out of home position.

Is there a way to automatically backoff from home, to home +5 or so, to not directly trigger limit/reset after homing?


Reading the manual did not point me to a solution yet.


Grtz Bert.











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[Clive S]

Things are moving

https://youtu.be/DGThYTQ_QdE

Its alive at last:

[driftspin]

In honesty, I'm doing this for me, as much as anything - I will need to start thinking of wiring pretty soon, and you're bringing up the questions that I need to answer for myself.

I think the NPN sensors the black wire is actually the collector, not emitter (I guess the emitter is connected to blue/0v)

Re your proposal. Think carefully of what you're trying to achieve. With the NPN providing a switch to ground (current sink), by placing a resistor from the output to ground will give you a low(ish) resistance to ground even when the NPN transistor is OFF - the LED will still illuminate (you'll get around 1.5mA through it - enough to illuminate it, probably enough for the current through the opto's transistor to actuate the input to the UCx00 - the input impedance of that is something like 50k to ground (and 4k7 to +5).

Try it, by all means, but don't be surprised if the input is permanently on.

The easiest solution is to simply tack a small signal diode (1n4148 is probably the most common) across the pin 1/2 of each opto - in the opposite sense to the opto's LED (i.e. cathode to pin 1, anode to pin 2). That way you cannot reverse bias either diode beyond the forward conduction voltage of the opposing diode - max of 0.6V by the 1n4148 across the opto's LED, or around 1.5V by the opto's LED across the 1n4148. Essentially, this will limit the voltage at the input to the BoB to the V-Ref provided by the BoB's onboard regulator (~10V) plus 0.6V.

Of course, this (and the idea that you proposed) both serve to reduce the switching voltage to something around 10V, which is why I still think that just using a 12V supply to the BoB and to the sensor is an easy alternative.

Hi doddy,



All in all i had to add 500 ohm to 4.7k to have the inputs switch reliably. I ended up at 8.65 volt. after switching the inputs would not drop..

Adding 500 raised it to 9.15 ish. which is ok
So you where right it needed to go near 9 and or slightly over.

0.5volts still illuminated the input opto's just enough to screw up somtimes

I still have a glitch in 1 of the inputs though..

Need to find out why.
maybe wiring issue or a slightly off 4.7k resistor.

ill try 1k instead off 500 first... maybe there is a switching effect or so.


Grtz Brt




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[AndyGuid]

It looks good from down here Bert

[Nickhofen]

Nifty Job!

[driftspin]

Ok more good stuff today.

I got myself started on cad with fusion360.
I will run into walls later i am sure.

But for now i managed to produce Gcode with it and made my first air cut.

So i am really in good spirits now :-)

I do realize now i need a probe sooner or later. For finding the workpiece position without to many f ups.
So i need to wire in my 2nd 5 axis bob.

I used up all inputs. e-stop home switches on x y z and a axis

I do have the B and C axis step en dir output spare on the 1st bob.
Can one use them for any misc purpose?

Maybe i need to get me some 5v coil relais boards soon


Also i need to start work on the bed surface.
Mounting points for a vice and clamps.

And maybe start with pouring epoxy for some basic cuttable surface to level the surface on the crossmebers.


Question.

Did you guys put your cutters all in the F360 library?

And does F360 do a good job on estimating feed speed doc and step over?

Somehow i feel a cutter library and a standard probe surface, is pointing in the direction of workpiece holding at known stationairy coordinates...

Can anyone please point me in the direction of best practice?

Probe the actual workpiece everytime or make solid default coordinate workpiece holding pins and vices relative to a stationairy bed probing surface.

Because i have no experience, education or well founded opinions on these things yet, i might just as well ask you all right :-) ?


Grtz Bert.

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