Ever want to know if the buyer is abusing the laser?

After reading scumbag's bad experience I was thinking how can you know if the buyer runs the laser too long and that is what caused the damage and how do you know that they didn't try to take the laser apart.....

To tell if the had taken it apart this can be something really simple that is used in the aviation industry. With the strict quality that i demanded on aircrafts every detail must be documented and checked. With hydraulic plumbing lines they require a certain torque and it has to be checked by quality the it is correctly torqued. Then to ensure that it is not tightened or loosened we use something called Tamper Proof Torque Mark. You would make a line going from the nut to the threads of the bolt. If the nut is turned it creates a broken line and a misalignment.



There are places you can possibly use this to indicate if the laser has been taken apart




Ok so now how do you know if they are listening to your recommended duty cycle. If the buyer contacts you saying the diode has died all of a sudden the first thing that comes to mind for me is how long they were running it. As far as I know there is no way to tell what kind of duty cycle they were actually using. If the buyer is a trustworthy person they will tell you their actual runtime but you still don't know for sure. Then I was thinking about our cellphones and the water detector stickers on the inside..... well what if they had stickers that would irreversibly indicate if a certain temperature is reached or exceeded.

Well they do have these!



Telatemp Irreversible Temperature Labels

What is an average temperature that is considered unsafe and i likely to cause damage to the diode? We figure out the max safe temp for each type of diode and then you use that sticker on the heatsink. If they run it too long you will know!!!


What do you guys think

I think you really did your homework, well done and good idea.

Sounds like a plan. Solid ideas, just make sure the complainer doesn't know your tricks... if they are aware of your temperature sticker they could replace it with a new sticker...

That orange crap is all over my plane! Now I know what it is haha. I like the stickers. Can the easiky be removed and replaced by the individual though?

+1
I'll be using this

Well thats why each person should have their own little secret about sticker placement, type, markings, etc. And you just keep a log of your sales with pictures of it before you send it out I don't want to give to many ideas away but I think each person can easily make their own little secrets with it. Also the might have the feature like the void warranty stickers that when pealed of it leaves void like this



The next thing would be to determine what temperatures are dangerous. or you can do this method....


I am about to post a C3 build I just made. It has a m140 diode at 1.8a so you know run time wont be anything real long I am going to recommend 60 seconds. Well I just bought a digital thermocouple and I tape it to the head of the laser and I record the temperature every 15 seconds while doing the LPM. Well it is around 90 degrees at 60 seconds so If I had a sticker that identified temperatures above 105 i know they went too long.

subbing so i dont loose this page

The effectiveness of the stickers would be affected by how well the diode is transferring heat to the part that you have the sticker adhered to

Most of the places to which we could place the colored "lines" would have to be disassembled by the builder to look for tampering anyway

I don't think that most buyers are going to be accepting of a colored line on the outside of their laser

Usually, we can tell by how the laser is damaged.
It is easy to see if a laser has been disassembled incorrectly

Also, a builder can use other ways to limit un-discoverable tampering

However, NONE of these things have any value if the buyer is unwilling to send the laser back to the seller for examination, as in this case

Peace,
dave

if the buyer is unwilling to send the laser back then by default they accept all responsibility for the broken laser. this will be part of my sellers contract since this what i think is fair. if a buyer doesnt give me the chance to inspect the said broken laser then for all i know it works perfect and they are just using trickery to try and get a refund and free laser. slight of hand is very easy on camera with editing

just my 2 cents

Something is better then nothing. I forgot I actually had some of the stuff

Also dave that is the one thing i was thinking because it will vary depending on it placement from the diode both in distance and the differences in thermal conductivity of the metals being used. you are 100% right in what you are saying.

Now here is my what if scenario.... It appears the small center of the stickers are the thermally reactive areas. What if you could manage to place a small piece either on the backside of the copper module or inside the bottom of the threaded part of the module? I know there are still variables but i feel if you are recommending 60sec run times then a warning sticker for 120 (guestimation) would be reasonable if it is directly attached to the copper module.

mhemling33 said:

Now here is my what if scenario.... It appears the small center of the stickers are the thermally reactive areas. What if you could manage to place a small piece either on the backside of the copper module or inside the bottom of the threaded part of the module? I know there are still variables but i feel if you are recommending 60sec run times then a warning sticker for 120 (guestimation) would be reasonable if it is directly attached to the copper module.

Click to expand...

There are quite a few variables for this to work effectively and even then it still wont be 100 % conclusive... Thermal transfer of the materials shouldn't be an issue, if they have been made with the same specifications, materials and tolerances.

Some variables include:

Amount and placement of heat sink grease / compound (reproducibility here)
Placement of hand holding laser wrt sticker placement. (small factor and dependent on heat sinking and how well the host can thermally equilibrate)
Time laser on
Outside/indoor temp (with a bigger T differential ie at -5 the host would cool more effectively, increasing run time , but remember the opposite is also true!)
Diode efficiency (Some are less efficient and therefore run hotter - big margin of error here)
Driver placement and heatsinking wrt sticker.

Ultimately you should work out the temperature at a certain place in the host at a specified run time for each individual laser, which would require testing and measuring each time. Basically run your completed laser with the sticker to the specified run time (+ maybe 5 -10 secs to account for user error). Then carefully remove the heat sink without disturbing the grease too much and take the reading. Don't add any more heat sink compound and put it all back together exactly as it was. If the value has changed when you receive the laser back you know the laser has over heated, which is probably due to excessive run time.

I say probably because in your graph if you exceed 60 secs it looks like the laser only hits 92-93 F as a max temp and then the temp actually begins to fall. Not actually sure why it does this, as it should have a close to exponential increase until thermal equilibrium is reached? Maybe there are some power input issues ie power dropping from the driver/ batteries or maybe expansion of the metals allows better thermal contact or maybe the diode is becoming more efficient (J/K) Anyway, if you are specifying 105 F as the max to determine excessive run time, according to your graph, you will never hit that even at double your run time...:beer:

@grainde i that's what I was thinking about measuring the temp at the point you pick then run the last for the duty cycle you recommend and see what the temperature reaches

And add for the magic cooling diode I have lol it drips because I turn it off at 60 seconds I should of included the lpms to. I went a minute past the cycle to see how quickly it appears too cool down.

These are some very interesting ideas!

This is an very interesting idea, how to implement it is the question.

mhemling33 said:

And add for the magic cooling diode I have lol it drips because I turn it off at 60 seconds

Click to expand...

Ah got it, I was wondering why it should start to cool!:crackup: :beer:

Edit:

Mattronium said:

This is an very interesting idea, how to implement it is the question.

Click to expand...

Read the posts above, they should give you some ideas...

Yes, I did read the thread , Well, I was trying to say that these are great ideas, but actually using them might be different, I don't know.
Sorry I wasn't clear, I haven't got this internet communication thing perfect yet.