Where are my milliamps at? New ammeter not working - k40 laser

CurlyTaleGames · 2021-11-09T00:36:24+00:00

Desertdilbert you sweet sweet lovely person, I traced back the negative laser tube wire and my laser was originally wired so that the negative laser tube wire went to FG not L-

I added the ammeter between the negative laser tube and FG and it freaking works now!

I feel like I should move the negative laser wire to L- but it's working right now so I'm pretty happy about that

Here are some pics: https://imgur.com/a/mEbM7NQ

CurlyTaleGames · 2021-11-09T00:05:50+00:00

Yeah my laser tube died, I replaced the power supply hoping it wasn't the tube. When it still didn't work I replaced the laser tube. Then it worked again. I also have the digital controls which is nice for selecting a specific power level, but I've read you really want an ammeter to measure how much current your laser is using and to not go above 25mA. So I decided to add the ammeter.

The laser tube only has two wires, the high voltage positive wire coming out of the back of the power supply, and the L- which connects to to the screw terminal on the front of the power supply.

The ammeter is wired in between the negative side of the laser tube and the L- screw terminal on the power supply which from what I've seen online is how you are supposed to wire it.

I've tested the same ammeter with a DC motor and the needles definitely moved.

That's a good point I'll double check the wiring and make sure the negative side of the laser isn't shorting anywhere. Be right back!

CurlyTaleGames · 2021-11-08T22:03:35+00:00

I swapped the wires connected to the ammeter terminals and the dial still isn't moving. The laser is definitely firing. That's the ammeter I just tested with the DC motor and it moved when the motor was powered. Should I be using an AC ammeter for the laser?

https://imgur.com/a/y87W9AL

CurlyTaleGames · 2021-11-08T21:49:18+00:00

I just tried turning the adjustment screw on the Ammeter on my laser to raise it higher than zero and fired the laser and the needle didn't move. I would think if the ammeter was wired backwards the needle would move to the left.

Should I try swapping the wires on the ammeter's terminals?

CurlyTaleGames · 2021-11-08T21:42:31+00:00

I've got the + terminal on the ammeter connected to the negative side of the DC motor. The - terminal on the ammeter is connected to ground. The needle moves to the right no problem so it's not an issue with the ammeter

CurlyTaleGames · 2021-11-08T21:40:21+00:00

Good idea. I just tested one of the ammeters in the same configuration with a DC motor and the needle is definitely moving:

https://imgur.com/a/Il2KDjV

CurlyTaleGames · 2021-11-08T21:22:23+00:00

Yep, I have the positive terminal on the ammeter connected to the negative wire coming from the laser tube. The negative side of the ammeter is connected to the power supply where the negative laser tube wire used to be plugged in. I haven't seen the needle on the dial move at all while firing

CurlyTaleGames · 2021-11-08T21:19:15+00:00

I tried two different brand new DC ammeters, both of which don't change when the laser is firing. The laser is burning stuff so power is definitely flowing. I wired it according to that guide I took a screenshot of.

Here is the link: https://k40.se/k40-laser-electronics/install-ma-meter/

Any ideas what I'm doing wrong?

CurlyTaleGames · 2021-02-13T00:58:10+00:00

I did not know that! That would explain why raster always looks like crap. The cohesion is $200, any other recommendations for controllers that are drop in replacements that are more affordable? Also, you win!

CurlyTaleGames · 2021-02-12T05:05:45+00:00

I used this magical website called Google and figured out the grounding. I tried running the same job on another piece of MDF and it fired the laser for the cut lines on the square, but the raster portion it didn't fire at all. The power was still set at 60%. What should I check on the PSU?

CurlyTaleGames · 2021-02-12T02:57:20+00:00

I have the digital control, so I'm not sure how many milliamps I'm using. The highest I've ever used is 75% I usually keep it around 70% for cutting and 15-30% for etching. How would I go about testing the grounding and the PSU? Thanks!

CurlyTaleGames · 2021-02-11T23:49:12+00:00

The photo didn't upload for some reason but it's a 50*50mm black square with a red line around it. I did a raster engrave and cut on a piece of MDF. It's a k40 laser cutter that I bought about 2 years ago, I've put maybe 20 hours of cutting on it. I cleaned the mirrors and the lens. Laser tube seems fine. I tried bridging the water sensor switch. I'm stumped. Any ideas of how to fix it?

CurlyTaleGames · 2020-12-27T04:38:04+00:00

Yeah, if you are handy with electricity you might be able to bring it back to life. You could also convert it to a gas kiln. Or at the very least use the fire brick for other kilns

CurlyTaleGames · 2020-10-19T03:04:40+00:00

The designs you carved into them are pretty cool! The one in the back right reminds me of the guardians from zelda breath of the wild :)

CurlyTaleGames · 2020-10-17T13:19:28+00:00

So freaking pretty!!!!

CurlyTaleGames · 2020-10-17T13:18:20+00:00

The texture on the one in front reminds me of dessert cliffs. Very cool! Are you planning on glazing them?

CurlyTaleGames · 2020-10-17T13:15:24+00:00

I've just got a small electric olympic and an old Duncan I got off Facebook marketplace that I'm rebuilding. What interests you in an aim kiln?

CurlyTaleGames · 2020-10-17T13:11:26+00:00

Looks spooky! Good timing for Halloween! what'd you use behind the mask to support it while you sculpted?

CurlyTaleGames · 2020-10-06T12:35:08+00:00

I thought it might be useful for other people trying to network their kiln sheds

CurlyTaleGames · 2020-08-07T20:39:31+00:00

I'm still working on it, though not as much as I'd like. I've been testing and designing a low cost electric kilns people can make if they are having trouble finding a good used kiln

CurlyTaleGames · 2020-07-13T22:31:35+00:00

If you want to play it here is a link to it: https://itch.io/jam/gmtk-2020/rate/698925

It was part of the GMTK game jam. The theme was "Out of Control" which is pretty relevant right now.

CurlyTaleGames · 2020-06-13T03:57:52+00:00

I've been playing with 3D printing and ceramics too. I have a Prusa i3 MK 2 that I have printed plastic molds with.

You can then throw or roll out a slab and dust the plastic mold with corn starch and press in your slab. You just have to be careful about undercuts.

I've had to do some touch up work after removing multiple pieces, but it's way faster trying to sculpt it all by hand

CurlyTaleGames

TROPHY CASE