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M-140 diode death?

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Take it easy. We are all glad that you are
okay. Working with lasers has almost given
me a heart attack many times.
 

rusirius

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For $11, could we use something like this?
USB 5 Axis CNC Breakout Board FOR Stepper Driver Controller MACH3 | eBay

It looks like it has X and Y, and then I'm assuming one of those other pins could be mapped to the laser.
The thing is, that's nothing but a breakout board. Basically it just takes the parallel output from a PC (running Mach3 or you could use LinuxCNC if you mapped the pins to be the same) that gives you convenient terminals to then wire to stepper motor drivers.

I haven't had time to update my other thread, but I promise I will soon. In my opinion the easiest way to do this is to use grbl on an ATMega. This way the entire unit is self contained and with the addition of a wireless card you can make your control to it completely wireless.

Even though I have all the programmers and knowledge to load an Atmel up myself, I've actually decided to use a pre-made board. It was an open source build by Spark Concepts and was only $120. It runs an ATMega with grbl already installed. It has X,Y and Z axis outputs (stepper drivers are built into the card) and an additional axis that can be independant or a clone of an existing axis. This works great for me since my z-axis will utilize dual motors. You CAN run two steppers off the same driver, but it's really putting too much on the driver and not a good idea in my opinion, so this is a perfect way to set things up and it's nice and compact (using SMD components) whereas anything I built myself would be considerably larger. Further, if you load grbl 9g on it, it'll then support a PWM output for spindle speed. This is what I'm going to use to generate an analog voltage (originally I was going to drive it like a stepper using a digital pot, but I've decided to use PWM through a low-pass filter with fast response time as I think it'll ultimately prove to be quicker in adjusting the output level. Even has headers in place to pop in a wireless interface card (I'll likely use bluetooth). Last but not least, it's completely hackable. It's the CNC xPro by Spark Concepts.

I don't like Mach3 simply because it's a commercial program and not open source. LinuxCNC could certainly fit the bill, but I just like the idea of having a "self-contained" unit. Especially one that can be controlled wirelessly which means I can use my laptop and not have to leave a dedicated PC sitting in the garage.

The only thing you need to add to the xPro is the laser driver, which in my case will have an analog modulation input. Again the PWM output for spindle speed will just feed an RC filter and the resulting analog voltage will feed the modulation.
 

Joelaw

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Okay, I am mostly here again. It took 14 days of hell to get out of the hospital but now that I am home getting better every day. Compliations with a-fib, and blood pressure. Still cannot stand up very long but have to get things moving again. I DO NOT recommend trying this at home!!!!!

rhd, I am ordering the changes you recommended to lower the noise on the output. I am a tech and can do about anything except calculate values for a design. Thank you for doing that for me. When I get the parts I can compare noise values before and after.

Did you get your bangood unit yet? If so inital thoughts.

Rusirus, It looks like you have started a design of your own. Looks good. I have a design floating around in my head for a router and laser cnc to allow carving and burning on wood bowls. I dont have easy access to my design computer so formulating in my head what I need. It will have to accommodate bowls of different depth so my design has to be open instead of a table inside. Many ideas to consider.

Again thanks for all the help from all of you.

Joe L.
 

Joelaw

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Guys,

I finally ventured into the 58 degree basement to make the suggested mods to my Maxium controller. The difference was dramatic in the noise level on the signal. Still don't know if this is the right approch. The control by rusirius using the counter and opamp probably is the best answer since I believe that this still allows 256 steps between the low bias and high bias. My method does not. maybe it doesn't matter anyways.

RUsirius, can you post a schematic of your design? Hopefully you are using a single supply opamp without all of the external power supplies and controllers that were posted a while back.

I have pictures of scope wave forms before and after the rdh mods but could not find out how to post. All of the forums that I use just drag and drop but when I tried that here I got a new screen and lost my complete post that I had typed.

I am going to try to burn something today to try out the controller again but am scared of blowing another laser. Gun shy now.

Joe L.
 
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rhd

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Guys,

I finally ventured into the 58 degree basement to make the suggested mods to my Maxium controller. The difference was dramatic in the noise level on the signal. Still don't know if this is the right approch. The control by rusirius using the counter and opamp probably is the best answer since I believe that this still allows 256 steps between the low bias and high bias. My method does not. maybe it doesn't matter anyways.

RUsirius, can you post a schematic of your design? Hopefully you are using a single supply opamp without all of the external power supplies and controllers that were posted a while back.

I have pictures of scope wave forms before and after the rdh mods but could not find out how to post. All of the forums that I use just drag and drop but when I tried that here I got a new screen and lost my complete post that I had typed.

I am going to try to burn something today to try out the controller again but am scared of blowing another laser. Gun shy now.

Joe L.
Glad to hear that my suggested mods to your driver worked. Would love to see the scope waves! When posting, or editing a post, as long as you're in Advanced editing view, there's a "Manage Attachments" mode that lets you upload photos. You may need to resize them down a bit depending on their existing resolution. LPF is stuck in the VGA monitor days and limits upload size to tiny pics.
 

rusirius

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Guys,

I finally ventured into the 58 degree basement to make the suggested mods to my Maxium controller. The difference was dramatic in the noise level on the signal. Still don't know if this is the right approch. The control by rusirius using the counter and opamp probably is the best answer since I believe that this still allows 256 steps between the low bias and high bias. My method does not. maybe it doesn't matter anyways.

RUsirius, can you post a schematic of your design? Hopefully you are using a single supply opamp without all of the external power supplies and controllers that were posted a while back.

I have pictures of scope wave forms before and after the rdh mods but could not find out how to post. All of the forums that I use just drag and drop but when I tried that here I got a new screen and lost my complete post that I had typed.

I am going to try to burn something today to try out the controller again but am scared of blowing another laser. Gun shy now.

Joe L.
Joe,
If you take a look at my other thread there is a rough schematic there. I went through several variations of designs to try to figure out what to do but in the end the most simple design I had seems to work flawlessly. And that was to simply use an analog modulated driver but drive it with the PWM output from grbl. I didn't even bother to RC low-pass it first.. Just feed it direct in. The driver output definitely has a sawtooth pattern to the wave, but again we're talking such high frequency that it doesn't affect the final product. There aren't any nasty spikes or transients or anything else that make me the least bit concerned about the health of the diode. It was simple and it worked so I just rolled with it. I like keeping things as simple as possible when I can.

Currently my road block is one of speed. My table is capable of an excess of 12,000mm/minute on the x/y axes. However the use of the "S" command in grbl causes a dwell state that locks me down to a max of 425mm/minute. I tried another branch of code that supposedly fixed this but while an improvement it didn't fix it. I'm currently preparing for a deep dive into the code to see if I can patch it up. It's not a problem really, I just have to cut the power on the laser back and run at a slower speed. It's just that I want to take full advantage of the power I have available and speed things up at the same time.
 

Joelaw

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rhd,

I have tried to burn something this morning without much luck. I then removed the mods to find the same thing. Then I got a little smarter and looked at the laser I was using and found that I was using a laser with a driver. NOT GOOD.

I will have to start over with a new laser. Forgot that I blew the last one and replaced it with one with driver so lost all morning. I got the wood stove going with the help of my great wife and now it is 68 degrees in basement.

It has only been 3-1/2 weeks since surgery so I get tired quick, maybe this afternoon I will start over.

Did you get your banggood going? Wondering how it is working.

I will try again to post the pics.

Joe L.
 

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rhd

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rhd,

I have tried to burn something this morning without much luck. I then removed the mods to find the same thing. Then I got a little smarter and looked at the laser I was using and found that I was using a laser with a driver. NOT GOOD.

I will have to start over with a new laser. Forgot that I blew the last one and replaced it with one with driver so lost all morning. I got the wood stove going with the help of my great wife and now it is 68 degrees in basement.

It has only been 3-1/2 weeks since surgery so I get tired quick, maybe this afternoon I will start over.

Did you get your banggood going? Wondering how it is working.

I will try again to post the pics.

Joe L.
Oh wow, that's a really dramatic clean up of the output. Cool! Glad it worked.

I've got the banggood going, but I already want a larger engraving surface ;)
 

Joelaw

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rhd,

I was a little too hasty. Now the Max is pulsing the laser all of the time. I removed the mods and re-installed the changed components and it is still pulsing. ????? Something probably wrong in the Max board again.

I ordered an analog laser driver from Russia (the same as rusirius) but out of stock until February, so I might have to put the laser project off for a while. I will have to find out what happened later.

I just got a load of PCB's to stick smt IC's on and will not have much time for the laser. Probably take me a week in my (not up to par) state. Some ic's don't have leads and have to be soldered in the oven and some cannot be put into an oven. Have to work out some sort of order of installation.

The banggood is probably too small for much more than a couple inch parts. Welcome to the so called DIY cnc world. Everybody feels that their machine is too small and they convince themselves they need a newer, BIGGER machine.

I was interested in the software/hardware controller and if it works at all. My grbl/arduino setup was just too slow. I use MACH 3 for everything. The best $150 I have spent. I have purchased many CAD/CAM programs for a lot of money and have not been satisfied with any of them. I draw in Turbocad or BobCad and then use CamBam to generate the g-codes. I have used FeatureCam ($10k package) and it doesn't do much better for the simple drawings I need.

Let us know what you find good and bad about the 'Banggood' machine.

Joe L.
 

Joelaw

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rhd,

I got some time to look at the problems with my laser driver and found that the 12v supply was bad. Under load it was producing about 4.5v causing the on period to reduce the voltage and cause the laser to pulse.

I ordered a 12v 10a power supply that should arrive on Monday. Will try to scope it out before and after your mods again and let you know.

I finished the PCB's early since those super small chips are not really that hard to install using an oven and solder paste. Cannot wait until they are tested and see what happens.

Joe L.
 
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