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Two drivers on one Diode?

StridAst

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So I have been wondering if this will work. Could a laser diode have two drivers on it? Wanting to set up a laser torch for melting wax for sculpting with it. What I need is a low power beam to see clearly when the laser focus is exactly where you want it, then a foot pedal to step on to kick it up in power quite a bit , for a short period of time, until the foot pedal is released. I know little yet about what kind of abrupt changes LDs can handle, so I am hoping someone can enlighten me as to if this would work. (so far everything seems to point to them being *very* allergic to abrupt changes)

My first idea was a laser diode being connected to two drivers. driver A would be set to 40mA, Driving a PHR (found that this is near the threshold as posts seem to indicate a varied threshold of 30-40 being average with some down in the 20s and some in the 50s) Connected as well would be driver B. which is set to 80mA. with driver B operated by the footpedal, and driver A being connected to a main power switch. Result therefore would be a jump from 40mA to 120mA when stepping on the footpedal. Would this blow the diode?

My second idea was to combine two beams. I have a PS3 sled now, so I could easily use the cubes from the sled to combine the two beams. but this would be much trickier to properly align the optics in, However if I can align the beams well enough then this method should work for me as well. with a diode just for spotting the focus point of the lens, and a diode for quickly heating the wax to the melting point. however everything I have found on using the PS3 sled optics for combining beams referred to using different wavelengths not a single wavelength which I would prefer for ease of eye protection reasons. I am assuming one of the cubes is a polarized beamsplitter/combiner but that is an assumption, I haven't checked up on it yet.

Any feedback anyone can provide would be greatly appreciated and thank you for your time :yh:

StridAst
 

StridAst

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While I DO use plenty of "carving knifes" and needles, sometimes you need to fuse things together.

Melting two pieces of wax together is something I frequently do, and doing it as carefully as possible is a must. I am a jeweler, and the primary method of manufacturing jewelry is lost wax casting, where you essentially make a plaster mold of a wax, then melt the wax out, then centrifuge the metal into the now empty mold. It's a little more complicated then that, but you get the general idea. Precision is a good thing. I currently use an electricly heated wax pen. Similar to these Jeweler's Electronic Waxers
The problems with electric heated wax pens is the wax sticks the the pen. also if the pen is hot enough, and you have enough wax surface area on the sprue tree, the liquid wax will static jump and stick to the surface. Other problems are adding molten wax to an existing ring, to build up prongs to hold the stone, or add texture, is less precise when small changes in the heat of the wax pen, will result in significant changes in how much wax wants to stick to the wax pen, and how much sticks to the wax you are trying to get it to stick to. Also the pen often heats up more wax then you want it to, which can result in a puddle rather then a carefully extended prong. I could go on for a long time about the downsides of the existing techniques, however I suspect you are already bored by now reading this. So to sum it up: a wax melting tool with no physical part touching the wax, and a very precise melting zone would eliminate a LOT of the usual problems that slow you down in making new designs and modifying existing designs. It wouldn't replace an electric wax pen, but would come close to it.

What actually gave me the idea for using a laser to do this is the use in the jewelry industry of laser welders. These are expensive gadgets. YAG Jewellery Laser Welder machine red Manufacturer exporting direct from Guangdong, China

At any rate. the concept is the same. you have a visible focal point, and when you choose to weld, the laser turns on and you can quickly and precisely fuse together two things without applying too much heat and melting anything you don't want melted. or damaging vulnerable stones. (i.e. opal, emerald, amber, pearl, turquoise, etc) My idea is to essentially construct a laser capable of melting the wax I wish to melt. without melting anything I don't want melted, or providing a medium for the liquid wax to accumulate on. The catch is how to build. and to decide which laser works best for this, how much power is enough to melt the wax, and how much is too much. And of course, most importantly, how to build it. I am of course going to enclose this device in a box to limit stray reflections, Haven't yet searched to see if there is anything available to protect against laser light that I can install on the top of the box as a viewing plate, or if I simply need to use goggles and some sort of shroud to protect other people.

Sorry for the long winded responses, I tend to ramble quite a bit.

StridAst
 

drlava

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This is a good application for the FlexMod N2 driver. It has an adjustable bias (standby) current setting as well as a full-on current setting. It's actually easier on a diode to go from a low state to a full on state instead of straight to a full on state.
 

StridAst

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I see. So it IS possible :thanks: I haven't looked much at the flexmod drivers. I seem to recall the name lava being used in conjunction with flexdrives. so I assume you are connected to them. I will have to be looking some info up on them. It sounds ideal.

StridAst
 

drlava

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yep I'm connected with them, I made them. :) Let me know if you have any questions. Also, your original question about using two drivers would work also, but you would have to put a regular diode in series with the driver that is turned off so the first driver doesn't interact with it while it's off.
 

maxh

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I imagine you could take any of the adjustable drivers and add a simple circuit consisting of a resistor and a switch in parallel with the adjusting potentiometer to achieve your desired operation. No need for multiple drivers or diodes.
 

zxn474l

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You could always have two lasers setup in a PBS cube in a closed small box container made out of plexi glass or what ever and get the weaker laser set on target and then use a momenaty switch to activate the higher power laser you desire already focused on the spot of interest to you. This kind of set up would allow any kind od nm laser for the heat and nm qaulities you might want to use not just one because different nm have different absorbtion abilities on different materials. I would use a 405nm or a 808nm for the heat part and a 650nm for the spot focusing.
 

FireMyLaser

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It would be very easy just having one ddl driver set to 40mA with a fixed resistor and then with a switch connect another resistor in parallel with the 40mA resistor set to 120ma total.
 




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