air compressor to control UCcnc

[Robertspark]

That is why I suggested using an optoisolated input and a relay.

It is highly unlikely that there would be an insulation failure between the contacts and the coil

If you are really worried then use a coil in conjunction with a reed switch as the magnetic flux will break and make the reed switch.

[Robertspark]

Note.... Rest of the world runs on 220v..... Only America and Japan (I think) run on 110v

If you buy a quality relay omron?? Then you should never ever have a problem. But I've never seen a relay failure between coil and contacts yet (except maybe lightening...)

[Koen Vissers]

Hi All,


Resuming on the above question, I want something simular. but slide different

Problem:

My shop is in the back of the garden, the distance from main fusebox to the shed is 70m. I have a 4mm² cable from front to the shed and 25 amps fuse.

But the compressor is a big one with 4hp motor on. When the cnc is running with a 2.2 hp spindle and the compressor starts it dont get enough power(electricity) the go tru the start run. I already put an extra valve to start pressure free but not enough.

My thought for solution:

I use some kind of macro( but I cant write) that checks the pressure of the compressor. If the compressor is running out of pressure it pause and STOP the spindle( maybe raise the z a little). The compressor can start, build up again and when complete send back a signal and the spindle can start up (raise down) and resume the cut.

I have a festo pressure sensor PEN M5 https://www.festo.com/net/en-us_us/SupportPortal/default.aspx?cat=1952&tab=3&s=t the can measure max and min pressure.
I can put this into the pressure line.

I need constant pressure because Im running a columbo ATC spindle that uses pressed air for cooling.

I hope someone understand my problem and can help with writing a macro.

Thx and Happy holidays for you and Family

Koen

[Robertspark]

..... that checks the pressure of the compressor. If the compressor is running out of pressure it pause and STOP the spindle( maybe raise the z a little). The compressor can start, build up again and when complete send back a signal and the spindle can start up (raise down) and resume the cut.

What you have listed is a pressure SWITCH..... ON/OFF are the output options....

How do you see that SWITCH being able to "checks the pressure of the compressor".

That pressure switch is a differential pressure switch with what appears to be a hysteresis (i.e. a window of control)

really your solution is to determine how much air you require or how much air you use in so much time passing and then programme in a pause in your motion to allow for the receiver to be fully recharged.

I'd suggest installing a bigger receiver and also consider charging it to a higher pressure.

[Koen Vissers]

Hi Rob


Thx for the qiuck response, appreciated

What do you suggest? The same switch as mentioned above , but how to connect to the main board (in/outs)

Could you plse suggest me something.


Thx again.

Koen

[Robertspark]

Suggestion:
Fill your receiver up until the compressor switches off / unloads.
Question 1: What is its pressure (Bar / kPA / PSI) ?
Question 2: What is your receiver (air tank) size (LITER / UK GALLON / US GALLON)?
Question 3: What is the minimum air pressure requirement of your ATC / tool cooling (Bar / kPA / PSI)?
Question 4: Are you using a regulated air supply to your ATC? {you should be, what is its setting (Bar / kPA / PSI)?}
Question 5: Are you using a regulated air supply to your tool cooling? {you should be, what is its setting (Bar / kPA / PSI)?}

Question 6: Ok, now get a stopwatch, and run a couple of minutes of Gcode (either time the pressure drop or check the differential pressure after a set period). What did your get?
Pressure drop of ??? (kPA / Bar / PSI) ....... what was your time limit (seconds / minutes)?

This is not a very accurate way to measure the air demand...... because its just one piece of g-code..... and I'm not sure if your ATC just requires an occasional pulse of air or a constant air flow..... (you mentioned "...Im running a columbo ATC spindle that uses pressed air for cooling." (unfortunately it means little to nothing to me....)

So you may require a little further explanation of what exactly you require the airflow for and what is constant and what is periodic demand????

Question 7: (HAVE THAT STOPWATCH HANDY) run off the air (slowly) opening a bypass / drain tap..... at what pressure does the compressor trip in at (kPA / BAR / PSI)?

Question 8: time how long it takes to fill the receiver from the compressor cut-in to the compressor cut-out (unload valve open) (seconds / minutes)

Question 9: running your machine normally how long does it take for your compressor to cut back in from the time the machine starts and the receiver air pressure drops (this one is relates to question 6).

Do you know what the rating of your air compressor is? 4HP normally implies 3-phase as they are normally 3HP (which is ~2.2kW and therefore ~10A at 220V), 4hp is ~2.9kW ~ bit over 13A..... which is normally the rating of a std plugtop (I know that in south africa they do a standard round pin plugtop which is unfused and rated at 16A)

Ive done a fair bit with compressors and testing home / hobby compressors..... {I have a few :/ } ..... basically I got a few small brass plugs and drilled different size holes in the end of them using carburetor drills (as they have fine increments.....) and then charged the receivers up opened up the air valves and ran the tanks down until when the compressors kicked in and checked what the pressure would stabilize at (air out = air in)...... given I knew the orifice size I was able to approximate the actual air compressor volume delivered at a known air pressure and could then approximate that to other air pressures

https://www.tlv.com/global/UK/calculato ... ifice.html

[Koen Vissers]

WOW

Robert

Give me some time(few days ) to check these all.
I ll anwers the Q I know now already.

But first some extra info.
It is a proffesional compressor belgian made by DUBA in Gent Belgium
Its a 450 liter airtank (vertical)
Its a two stage pomp 350l/min max pressure 16 bar
Original it was a 3 fase motor 4hp, but I don't have here 3 fase at fuse box. So I ordered a new motor 4hp with double capacitor (start and run) normal 2 fase 220v 4hp
It runs on 220 v 16.3A (read on indification plate)

This the manual of the spindle, here you can read about the cooling. i also never had seen this before but I m not a proff cnc user


Quest 1 now fixed at 8 bar
quest 2 450l (vertical)
Quest 3 2 air inlet 1st 4 bar 2st 2.5bar
quest 4 tool change 6bar
quest 5 2 regulators 4/2.5 bar


Robert this is what I can teel you for now. Give me some days to come back on this.

You help is very appreciated


Happy holidays

Koen

[Koen Vissers]

Hi Rob,


You asked me some questions, but I made it more complicated then needed.
When I was taking the time for anwser yoyur questions my neighbor came to take a look. (he also interested in all the big boys toys.
Told him about my problem, then he told me that the start relaese valve was regulated.

i opend it a bit more en the pump could run a few seconds more pressure less and problem was gone.

I tested a few times with different gcode and all ok

Thank you very much for your time and expertise for help with this issue.

From zero pressure to 8bar airtank filled takes 6.30 min. Pushed further to 11bar takes almost +-9min and regulator complete open it pushed up to 14.5 bar. Did't took that time.

Thx again

Problem solved

Koen