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Replacing the driver board?

Posted by kd6hq 
Replacing the driver board?
January 22, 2018 01:54PM
I'm trying to work with a laser that I purchased off of e-bay.
The laser only has a voltage input, none for TTL or PWM.
When the laser is on it is at full power all the time.
I am considering taking the laser apart, remove what ever driver board it has and replacing it with one that has both voltage and TTL/PWM inputs.

Are there any reasons why this would not work?

Current laser type:
[www.banggood.com]
Re: Replacing the driver board?
January 23, 2018 03:14AM
No that should work. Just make sure you connect ( shortcut ) both legs of the LED while soldering. The LEDs are usually sensitive to static charge.
Don't forget to remove the shortcut before testing, either winking smiley
Re: Replacing the driver board?
January 23, 2018 02:55PM
Thanks O.lampe, I would think that might be a good idea for de-soldering also.
Re: Replacing the driver board?
January 23, 2018 03:11PM
Quote
kd6hq
I'm trying to work with a laser that I purchased off of e-bay.
The laser only has a voltage input, none for TTL or PWM.
When the laser is on it is at full power all the time.
I am considering taking the laser apart, remove what ever driver board it has and replacing it with one that has both voltage and TTL/PWM inputs.

Are there any reasons why this would not work?

Current laser type:
[www.banggood.com]
.

Do you have another driver board already picked out or were you going to make one?
Re: Replacing the driver board?
January 23, 2018 05:42PM
Not really. I have been looking at the driver module from J Tech.
[jtechphotonics.com]

I have not confirmed that this unit will work yet but I believe it will.

In addition to the driver board, it provides emergency shut off, reset switch and power connection in one package. However it also cost quite a bit more than just a driver board.

Are you thinking of doing the same?
Re: Replacing the driver board?
January 23, 2018 06:33PM
If it increases the life span or makes the laser more efficient I would buy it. Can lasers be more efficient? I do like the extra safeguards like the key switch and estop they offer in the package. I've been using a RAMPs PWM terminal and it seems to be working okay but I've never had a laser before so I don't have anything to compare it too. I'll have to read up on the driver boards some more. It might more economical to make one
Re: Replacing the driver board?
January 30, 2018 02:24PM
Well that did not work out very well. Once I got the fan off and removed the connector
board the container was filled with a white substance about 1/2 way up the driver board.
So I closed the unit back up and restored it to the previous condition.

So I decided to look into building my own laser module. It appears like this is the route
I will follow. My only requirements are : I will be using a RAMPS 1.4 / mega 2560 board
setup and using PWM signal to drive the diode. My main interest is engraving with
the possibility of cutting thin materials and possibly soft wood up to 1/8" thick.

I have been looking at DTR's web page for parts. At this time I am trying to keep the
power level in the 2 - 3 watt range. So far I have been looking at the M140 diode.
It has a suggest current rating of 1.8A. The test results show that at 1.8A the power
output is approximately 2.34W. and at 1.5A the output is 2.073W.

To go along with this diode I have been looking at the BlackBuck 8 laser driver.
This driver is capable of 8A which is way over kill but it has separate inputs for power
and A 5V TTL/PWM signal. The most appropriate driver I see is the X-Drive V7 with a
current rating of 1.8A or the Super X-Drive (SXD-V3) at 4A. With this driver I would have
to remove a resistor to be able use it for PWM/TTL modulation. Not a big deal but the
information states the modulation frequency "Up to 1kHz. Modulation Voltage 0-5V Full range: 1.6V ON "Max 12V" & 0.6V - 0V OFF".

Ok, so to me that last statement sounds like I could use Pin D9 (PWM Fan control) on the
RAMPS board for modulation. It also says that 12V is the max that this pin can take.
So I'm guessing that if for some reason D9 were to go over 12V it would blow the driver board?

Would it be better to move the PWM signal to a 5V pin? In this case would the 5V pin give the full range of PWM values (0-255)?

Is their a better driver for what I'm trying to do?
Re: Replacing the driver board?
February 01, 2018 02:34AM
Everything above 1.6V triggers the TTL input, so 5V is plenty.
DTRs page is a pretty good source for information, but he is focussed on torch-light lasers. IDK if his drivers are meant for hours of engraving or even cutting?
1kHz is really slow.
VDX
Re: Replacing the driver board?
February 01, 2018 02:53AM
... when using PWM for laser-engraving, then you can't accelerate while engraving, or the (accelerated) starts/ends of lines will burn more.

Better use the STEP pulses of the extruder pin for the pulsing.

I'm building my own drivers with powers of up to some ten Amperes (for high power IR-laserdiodes) and frequenzies of up to 100kHz with this powers or with up to 1MHz with lower currents ...


Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org]
Call for the project "garbage-free seas" - [reprap.org]
Re: Replacing the driver board?
February 01, 2018 04:28PM
o lampe on the TTL trigger - that's what I thought, thank you for the conformation.
I had not thought about there being different types of laser diodes (torch-light), but then why shouldn't there be.
I have the feeling if the driver pcb's have proper heat dissipation they should work as long as they are not pushed past their limits.

VDX using the step pulses sounds like a interesting idea. I'm not a programmer though and to me that means that
I don't have any idea of what part(s) of the firmware code I would need to change to do that. So yes PWM may not be
the best way to operate the laser but it dose work.

o lampe & VDX, thank you both for the input.

I will still be building a laser but it's been put on hold for a couple of weeks. It occured to me that when I build the new
laser the one I have will be put in the parts box. So I decided to take it apart any way. The white substance I was talking
turned out to be sort of a rubber texture. I' guessing it was mainly just to hold the driver board in place. I thought the
driver board might be hard wired to the diode but it was not. It was attached by wires. In doing all of this of course
I ended up destroying the driver board, no worries. For now I have a jumper on the diode while it waits. So last night
I ordered the driver module from J Tech. It should be here the first of next week. As long as I did not destroy the diode
along with the driver board I should have a proper working laser next week. I'm hoping I will be able to get 2 - 2.5W out
of this diode. I wanted a smaller (power) laser for engraving because of the smaller focal point. Once this is all working I
will continue to build the "other" laser. However I will most likely jump the power up to 4-5 watts. I was able to cut 1/8" plywood
in 3 passes with this one I just took apart, so 4-5W should make it interesting.
Re: Replacing the driver board?
February 02, 2018 03:02AM
Quote

I have the feeling if the driver pcb's have proper heat dissipation they should work as long as they are not pushed past their limits.

That's right, but there are more things, like ramp-up time. In a laser cutter/engraver situation you want fast on/off reaction, but for a torch ligth this isn't important, so they might have added some capacitors to stabilize the voltage. Hence the slow switching rate of 1kHz?
Re: Replacing the driver board?
February 02, 2018 06:28PM
I went back and re-read what I said above and realized that I forgot one step when modifying
the X-Drive module. As stated the 10k resistor is removed, a wire is added to allow for TTL/PWM
input and then capacitor C4 is removed. C4 is labeled as a ramp up capacitor. I suspect that is
done to make the switching better.
Re: Replacing the driver board?
February 03, 2018 10:33PM
For anyone who is interested. I received my driver module from J Tech today. [jtechphotonics.com]
This driver has several features to it along with being able to supply current up to 2.5A.
There are 5 jumper setting which allows for the setting of current in 0.5A increments. In addition there is a trim pot to fine tune the current
level. So you can adjust the current for 1.3A instead of just 1.0 or 1.5A. The adjustment of the diode current is done without the laser
connected. I think that this is a nice safety feature. The unit came with a power supply with an extra long connector cord.
The cord allows you to mount the control unit just about anyplace you want. So now everything is working as it should have,
if I had only purchased the proper laser to begin with. smileys with beer
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