Water Protect & Air Assist Switches

[Knight]

Hi All,
After completely ruining a perfectly good 100W tube when a water flow switch failed to operate, I am about to fit a new one to my AWC708 based system. At the same time, I will be fitting an air flow switch to (hopefully) shut off the air assist when the Laser head travels from one cut to the next. I will explain why later in this post.

First, the water flow switch. I have read in this forum that the water flow switch can be fitted to the LPSU or to the Controller. I have a solenoid based Water flow switch, so only 2 wires. My question is, which method will give the best protection. I understand how to connect to the LPSU, but I am not so sure about the Controller. Is it simply a matter of 1 wire to one of the IN1 to IN 6 and the other to ground (and the software part as well)? Do the inputs work differently? Why would I use the Controller over the LPSU or vice versa?

Now the Air assist switch. Again it is a solenoid based switch.
A lot of my cutting will be small pieces and I have the knife type of cutting table. It is not possible to easily replace the knives with a honeycomb bed or I would go that way. with the small amount of cutting I was able to do before blowing my tube, I found that the air assist tended to tilt a number of the smaller pieces after cutting, so that, when the cutting head moved around, it would sometimes catch on one of the tilted pieces and drag the whole work piece with it.

I should add here that my cutter allows only a very small gap between the tip of the cutting head and the work piece when properly focused. Perhaps 4-5mm.

What I want to be able to do, if possible, is to shut off the air assist when a cut is finished and leave it of while the head travels to the next cutting point, then turn the air back on. Sometime this will be a very short amount of time.

Is it even possible to accomplish this? I use a compressor, so I am expecting that the air shut off should be as fast as the electronics will allow. Will that be fast enough to achieve my goal?

If anyone has experience in this area, I would very much appreciate your input.

While I wait for my new tube to arrive, I am fitting a sheet of aluminium (yes, I am in Australia) fly mesh across the knife table. The main problem with this seems to be that fly mesh comes in rolls and is very hard to flatten again, so it tends to want to lift the cutting sheet to some extent. I have yet to come up with a successful method of holding the mesh down. I could use weights on the work piece, but without a Red Dot Pointer, it is hard to be sure of keeping the weights away from the Cutting head.

Thank you all for taking the time to read this post. Hopefully one of you will be able to offer some answers.

The 100W tube that broke was made in 2001. Yes, 2001 and was still cutting beautifully (after I worked out how to focus it properly). I have added a photo of the label to verify this. Unfortunately I can only afford to replace it with a RECI tube, so it won't be 14 years before I need to replace the RECI.

Regards,
Albert

[Techgraphix]

Hi Albert,
What kind of cooler do you have? in case of something like a CW5000 or similar: these have a flowsensor onboard... A connector on the back can connect this flowswitch/sensor to your controller or LPSU.
Your Flowsensor is probably just a switch operated by a kind of valve that opens when there is a flow.. This is a mechanical thing that can cause trouble more than once.
I prefer to connect the flowsensor to the controller and set the software accordingly: When you connect it to the LPSU your laser won't fire but the controller doesn't notice anything and your job will continue without result.. Even when you forget to start the waterpump/cooler you can start the job..
When you connect it with the controller, you will be noticed with beeps and a message in the display.

The tilting of cut-out parts will also be effected by gravity and some vibrations of the machine. You can use a honeycomb or the cheaper square profile light-armature (grid).. To prevent reflection-marks on the back of your object you can make little acryl T's that can be placed in the grid to lift the object about 3mm.
Personally I doubt that airassist will blow the pieces away. Unless you have 6Bar... Just enough to keep the debris away from the lens is enough..
And if it does, it will probably tilt the parts when it just finished cutting the part..
Ergo: I would skip the idea of placing a valve in the airsupply..

Kees

[Knight]

Hello Kees,
Thanks for your reply.

My chiller is a proper refrigerated unit, but quite old. The Alarm on it covers many functions of the operation of the Chiller, but does not allow for any connection to the Laser Cutter.

Because I want the cutting as well as the Laser to stop in the event of a water flow failure, I will take your advice and fit the Water Protect to the Controller, but on which Input? I have the AWC708c Plus, with 6 Inputs. Does it matter which one. I have found where to change the software part of it in the Controller and I am assuming that I would need to change it from Close to Open. Is that correct?

I ran water through the Flow Switch yesterday, connected as a closed loop, Chiller back to Chiller, with no power connected to the switch.

Water was able to flow. I will try it again with power connected and see what happens.

I have added a photo of the Alarm capabilities.

Again, thanks for your reply.

Regards,
Albert

[turkletom]

Hey Albert,

You have to connect the flow protection switch to the "WP" and "GND" terminal on "LASER1". WP should go LOW when there's flow. (Hey, that rhymed! )
And yes, you have to set the "water protect" parameter to OPEN (which is supposed to mean ENABLED and has nothing to do with the state of the switch).

To prolong the life of your compressor, you can hook up a small solid state relay to OUT2 and 24V. OUT2 is in a HIGH state when the machine is idle and drops to GND when the laser fires.
(Don't try to hook up the solenoid directly to the DSP because it probably draws more current then the DSP can handle.)

[Techgraphix]

That part is answered..
Concerning your cooler.. Maybe there is a connector on the back.. many coolers have it. You can check the manual if there is any unknown connector. it can be handy in your case.
I would connect the cooler-SSR to OUT1.. This is on during the whole job. OUT2 can switch on and off more than your cooler can handle..
Kees

[Knight]

Hi All,
Thanks for the replies.

I connected the water switch to the WP & Gnd of Laser1. No LPSU connected because I am still waiting for my new tube. Water was running on a loop back, solenoid switch in the middle of the loop.

Did an air cut with the water running. Switched the chiller off and nothing happened. Should the Controller have shut down?

Not sure if I can actually measure the High & Low that Turkletom spoke about, but putting a meter across WP & GND on Laser1 shows .249V whether the water is running or not. I also noticed that the solenoid switch I fitted says 24V, so perhaps it is not going to work anyway because it requires 24V to activate.

Update: Doing an aircut, no LPSU, Water running and not running, disconnect 1 wire from the solenoid switch and Water Protect activates and stops the work and shows the Water Protect message. This is what I need to have happen, so it seems that I do not have a suitable switch.

Any suggestions as to which switch I should be using?

Thanks again,

Regards,
Albert

[Techgraphix]

Yes, you have to notice the controller that you use its WP circuit:
For the X7 there are two ways to do that:
1) In LaserCad > Options > System Options > Manufacturer Parameters > IO > Water Protect.
First Read info from your controller, then alter the info you like and then save this to the controller with password.
2) in the controller itself: press STOP-SHIFT to enter the Manufacturers Parameter Settings. Select the Laser Parameters (2) and on that page toggle Water Protect Laser 1 from close to open..
With my X7 I couldn't change the WP-value in LaserCad,, When I send it to the controller and read it back again, the value, I entered was gone, so I had to use method 2..

Kees

[Knight]

Hi Kees,
Thanks for that info.

I now know that I can set the water protect in the Controller.

However, I still need to find which is the correct Water Protect switch to you. Can you nominate one? The one I purchased operates on 24V so it is never going to be successful.

Which one do you use?

Regards,
Albert

[Techgraphix]

Which one do you use?

I can't find it on internet anymore but it looks very similar to this one:
http://www.ebay.com/itm/120W-1PT-Female ... SwyvBV-GIn

But nou i have it connected to my CW5000 error-output (this cooler has a flowswitch in it)

Kees

[Tech_Marco]

Or try ours:
http://www.lightobject.com/Water-flow-p ... -P815.aspx

http://www.lightobject.com/Water-flow-O ... -P680.aspx


Marco

[Knight]

Hi All,
I have a water Flow switch which was originally fitted to my Laser Cutter. There never was a decent Circuit diagram for the original electronics, so I can't refer to that. I have attached a photo of it.

The data sheet can be found here: http://www.dginstruments.com.au/wp-cont ... r-2013.pdf.
The Manual is here: http://www.dginstruments.com.au/wp-cont ... iom-09.pdf.

There is so much information in these 2 documents that I find it very hard to understand. I do know that the original fitting used only 2 wires (there are 3 pins on the switch) and the wiring, as seen in the picture was very very thin. Both are white, one has red marks and the other has black marks, so I would assume Active & Ground.

Would it be possible( read sensible) to run 5V from the Laser1 connector to this switch, not sure which pin), then from ground back to ground on Laser1, then use the 3rd pin on the switch back to IN1 on Laser1? Would that setup just send 5V back to IN1 rather than just a High or Low signal? As you can see, I have about enough knowledge in this area to be dangerous.

The switch should need a power source in order to operate correctly and Laser1 has a 5V connection, which should be enough to run the switch.

Can anyone see a way to connect this unit to my AWC708C Plus Controller?

My preference would be to use this unit if possible because fitting it is easy. It just goes back where it came from.

Thanks,

Regards,Albert

[Techgraphix]

As it has only two wires, I suspect there is only a switch in it, or a reedcontact.. These don't have a polarity thus: you can connect one wire to WP and the other to GND..
I guess that will work fine..
Kees

[Knight]

Hi Kees,
Well, I tried connecting my Flow switch into the chiller water flow and connected 2 wires to In1 & Gnd. The Water Protect alarm came on as soon as I tried to Air cut. Reversed the connections and again nothing. Perhaps the switch is faulty.

I also re-read the manual for my Chiller. There is a water flow alarm fitted to it, so I am trying to figure out a way to connect that to the Controller.

I have attached a photo of the information it provides. It shows that when checking the functioning of the flow switch, there should be no resistance when the main power is on. I am guessing that it means the chiller is running and water is flowing.

How does that relate to putting a jumper across IN1 and GND on the Controller. Is it the same thing? Is the jumper providing no resistance?

Perhaps this means that if I connect a wire from each of the 2 pins on the Chiller water flow switch (19 & 20) to IN1 & GND on the Controller, I would then have a method of providing my cutter with water protection.

Does that sound correct or do I have it backwards. Of course, I have to find the Chiller water flow switch first, then the connections mentioned, 19 & 20. Finding them should not be that hard, even for me.

What do you think?

Regards,
Albert

[Techgraphix]

Why IN1 ??? the two wires from the flowswitch should be connected to WP and GND of Laser1 This is mentioned a few times before..

Kees

[Knight]

Hi Kees,
Finally, I have found the problem with my original water flow switch.

My machine is almost 15 years old. It was in use for the first 10 of those years and then left sitting unused until I bought it. The insides of the flow switch has apparently 'seized' due to a reaction to the water being left in the cooling system.

The 'trigger point' can be set by moving the sensor section of the switch. It can be set to between 1 and 5 LPM. When I set it above a setting of 1, the switch is constantly on and when set below below 1, it is constantly off. So it seems to be frozen. Water pressure should move an internal magnet past the set trigger point to tell the Controller that water is flowing.

I am going to try cleaning it before I replace it, but an original replacement will cost me Aud $290.00. A massive price considering what it is.

At this point, I will try to clean it internally. I will also try to replace the magnet and spring, which is all that is in the water path. I think that the magnet may break if I put pressure on it to get it to move.

I could have it serviced at Aud $70.00 per hour, but they would only replace the spring and magnet anyway. Electrically, I know it will work.

I will let you know how it goes. I still have about 2 weeks of waiting for my new tube to arrive.

Thanks for all your help.

Regards,
Albert