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Topics - wild.bill

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Engraving / White tile painted with flat white primer
« on: January 01, 2020, 06:17:17 PM »
Not sure I understand fully how it works but I painted some white tiles with flat white primer and then etched images. The places where the laser burns makes the tile dark.
So here are a few I made this week using my ACRO system with an old 2 Watt laser.

Trouble Shooting / Cohesion/GRBL-LPC - not etching image
« on: February 02, 2018, 09:39:10 AM »
To start I am doing this on a K40 with the Cohesion controller loaded with GRBL-LPC.
Postprocessor chose Cohesion & GRBL, & max/min are set to 1000/0. This requires S values from S1000 to S0.

Problem 1:
Trying to etch any grayscale image at 400 -> 40% of power.
On the control page I can manually turn the laser on and off, and I can outline the frame with the laser on. When I run the image the head moves but the laser never turns on.
I have been able to make grayscale images on this hardware setup using other software
and have done grayscale with T2 on the hardware using Smoothie firmware in the controller.

Problem 2:
I tried to save the machine G-Code but I can't see if/where it is being saved. I was going to try to debug the problem but without the G-Code I can't see what is being sent to the controller.

T2 Engraving / Difference between Smoothie and Cohesion3D postprocessor
« on: January 25, 2018, 03:43:38 PM »
I was wondering what the difference was between the post processors for Smoothie vs Cohesion3D?

I am in the processes of putting a Cohesion3D board running Smoothie on my ACRO machine and want to make sure that I am using the correct one.  When I have it all working I will do a write up on the wiring and configuration file. I am working toward running the machine without a computer connected all the time using the SD card and LCD display.

General Discussion / Grayscale with K40
« on: January 23, 2018, 12:47:19 PM »
It's been way to quiet so I figured I would show this grayscale image I just etched on Birch using the K40. I did photoshop - curves to get a more linear result.

General Discussion / Technique for Creamic tiles with diode laser
« on: January 05, 2018, 08:58:22 PM »
I found a new technique for Ceramic tiles and really like the results so I figured I would share it so other can give it a try. I have been doing a lot of work with the tiles on the CO2 laser and kept thinking there must be something I could do with the diode laser even if it won't cut the surface.

So what I am doing is taking white tiles and spray painting the surface with black paint, and after the paint dries I can burn some of the paint off. This is giving me a black tile with a white image. There is not gray scale since its a white tile with black paint so I can do black and white or dithered images. I have found that you need to make two passes to make it come out correctly. My first try was at 1500mm/min and found that I needed a second pass so the next tile I tried 750mm/min and it still needed a second pass - so I am sticking with the 1500 and making two passes. The first pass seems to always leave some of the paint on the surface and the second pass always cleans it up great.

Attached is a dithered image that I did tonight. Someone on this forum posted the picture quite a while back and I have kept a copy because its a great gray scale test.

have fun with it.

General Discussion / Made for my wife today
« on: December 10, 2017, 12:15:03 PM »
I built a little something for my wife that goes into the shower today.

K40 Safety Modifications / Water cooling system modifications
« on: November 10, 2017, 02:25:38 PM »
Having a good cooling system is very important for this laser. It's ideal operating temp is between 60 - 70 degree F. Any higher the laser starts to loose some power and will not cut as well.

These laser's come with a pump for the water but no instructions on how to use it or how much water you need. On mine I use about 2 gallons because I didn't have room for anything much larger. What I found was that with this amount of water it would heat up about 15deg in an hour of laser usage so it was getting a little warm - so pause the cutting to let things  cool down. The problem now is you are just pumping water through the laser with nothing to cool it down so 1 hour of running took about 5 hours to cool down. This didn't work because I have been etching a lot of ceramic tiles and it takes about 1 1/2 hours for each.

So what have I done:

1) put a temperature gauge on top of my water bucket.

2) added radiator and fan's so I can actively cool the water to air temp (no cooling elements)
         I did get carried away and put in fancy fan's with LED's - I just liked the look.

You should use distilled water so you don't get minerals building up in the laser and also add something to prevent algae from growing in the lines and laser. At this point I have added a little bleach to my water. May not be the best solution but it works for now.

K40 Safety Modifications / Air assist
« on: November 10, 2017, 02:25:03 PM »
Place holder for now.

K40 Safety Modifications / Getting rid of fumes
« on: November 10, 2017, 02:20:33 PM »
With a CO2 laser you can create a lot of smoke and fumes that are not good to keep around. After I set the smoke detectors off a second time it was time to make some changes. The fan that comes with the K40 is junk and was not effective so I went and found some new parts. I found a 4" horn that fit the back of the K40 almost well enough to meet my needs Link here
The only problem is that it was a little loose on the back of the unit but I found an easy solution - a close pin - I took the spring out and put one on each side to hold it tight. You can see one side in the attached picture.

I than got a 90 degree elbow at ACE hardware and attached that onto the horn and them put an inline fan on to of the elbow -- LINK I installed a dryer vent where one of my windows was to vent outside connecting them with 4" dryer hose from ACE. Having a good fan and solid connection to the K40 back works much better.

K40 Safety Modifications / Adding an meter to a digital K40
« on: November 10, 2017, 02:08:13 PM »
While the idea of having a digital control panes sounds nice there are some serious issues with them. They are not calibrated and there is no way for you to do it your self. They are all different. When I installed the meter I found that my machine was running at full power when the display said 40%. A real good way to shorten the life of a laser is to over drive it.

Here is a link to the meter I got

I am providing a link that I used to install my meter.

K40 Safety Modifications / Adding a water flow switch to a K40
« on: November 10, 2017, 01:59:34 PM »
My K40 came with a flow switch that worked some times and not others so I decided to replace is with a better quality switch. In the attached picture you can see that the water line going from the pump to the laser has been cut and the switch is inserted inline with the hoses. Again it is connected to the "P G" pins and connected in series with the other safety switches.

Here is a link to the switch that I used.

K40 Safety Modifications / hooking up an emergency laser shutoff switch.
« on: November 10, 2017, 01:50:40 PM »
I wanted to add a switch that I could easily hit to disable the laser. And I will say that I have used it a number of time to stop it like the one time I didn't have the flow switch connected because it had been having some issues and wanting for a new one to be delivered. While it was running it blew all the water out of its container. I stopped the laser before it could destroy itself and I was lucky and will not run the laser again without it.

The only hard part of installing the switch was drilling a hole for it to go through. I just happened to have a hole saw the needed size. I don't have a link to the switch but I got it off of amazon (actually I got a couple) for my CNC machine.

K40 Safety Modifications / Putting a safety switch on the laser cover.
« on: November 10, 2017, 01:42:22 PM »
For safety reason you want to make sure that the laser is never enabled when the door over the laser head is open. Reflections from the CO2 laser can cause serious damage to your eyes and its actually a very easy update.

You can see the micro switch in the attached picture. I used the normally open connections so they are closed when the cover is pressing down on the switch.

I took the switch and found a spot that the switch is pressed when the cover is closed. I marked where one of the screws would go and drilled a hole there. The I fastened the switch with the first screw moved it into position and marked the second drill spot. I swing the switch out of the way and drilled the second hole, moved the switch back and added the second screw. Oh I should say I soldered some wires to the switch before fitting it. After the switch was installed I ran the wires through a hole into the power supply compartment. I hooked the switch up in series with the other safety switches I installed.

K40 Safety Modifications / Getting started with the K40
« on: November 10, 2017, 01:29:46 PM »
I am going to make a series of small posts each covering one item rather than one large one with everything so we can talk about each item separately. The very first thing in looking at the wiring.

Before using a new K40 you should do a full review of the wiring. Make sure that all of the connection are made well. Some machines when delivered some of the wires are ready to fall off. I had a power connector between the power supply and the controller that was not well crimped and a small pull and the wire came out. Make sure the machine is well grounded. Fix or replace any connections that are questionable.

You should do this before you ever plug the machine in because the power to the laser can be as much as 20,000 volts. After the power has been turned on the capacitors can stay at these high voltages for a long while.  So when looking at the wiring keep in mind that you life could depend on having good solid and insulated connections on all the wires.


What I am going to show here is how to disable the laser from firing. This does not stop the head from moving around because we are going to make the connection on the laser power supply - not the controller.

The picture below show's a picture of my power supply. Notice the connector that is marked "P G". These two pins need to be connected together to enable the laser. On some power supplies they are marked P+ and P-. So how I have used it is to hook up a micro switch on the cover, and emergency stop button, and the water flow switch. I have all the switches wired is series so if any on of them opens the laser will no longer fire. I will show each component in separate posts but the important part here is they are all in series.

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