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screen printing => Equipment => DIY - From master engineered marvels to cobbled together jury-rigged or Jerry-built junk! => Topic started by: Prōdigium on July 21, 2016, 09:54:42 AM
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As many may know I posted (a lot) about how it should really not cost so much for a decent UV LED exposure unit. The prior conversation was informative, lively even though it struggled to stay on topic. Either way I have spent the past several months since doing my homework, testing theories and simply reading about the good traits and bad problems that all brands have now.
So I am now in the process of producing the first 2 test rigs. One will be shipped back to a friends shop in the US for "real world" testing and the other kept here to run scenarios on. It will employ some very unique technology than ones from either M&R or Anatol. I do not have any pictures to post yet, were still producing the components and the LED company will not have our custom made LED's done for another couple weeks. The design will only employ 850 LED's so as to make it a little more affordable, but with design improvements I am of the mind that performance should not be much less as for exposure times but I do believe that my design will produce a significantly better image with less undercutting.
For starters I will NOT be using those crappy flex strips. My testing revealed so many problems with them I am actually shocked to see them in those high priced models. Point blank flex strips are junk, cannot be repaired by the customer and they warp & buckle like crazy from heat. My system will use custom made aluminum backed PCB's. NO flex, no heat problems and ensures perfect LED alignment.
Secondly my testing revealed that the layout for the LED's is wrong...unless very special lenses are used to correct it, which is doubtful. But to be fair, here in China I do not have access to any of these LED exposure units, so my testing is based on what I can see and read online and running tests at my friends LED factory. He does not make UV LED's but has all the fun tools to help me with my project. Here is a composite image of square block LED layout..from this image its really easy to see the problem.
(http://i6.photobucket.com/albums/y218/calibratedsps/mr_light_plane.jpg)
The design is meant to keep it simple. A power switch and a digital timer. No stupid apps for your phone, no easy to crack LCD touch screen panels, it will include only what you need. Just turn it on, set your time and close the lid..everything else is automatic. There will only be one base model which can burn up to a 23x31 screen.
There will be a very sweet feature in the future that I wish I could talk about, but I am currently doing the patent paperwork (pain in the rump) and I cannot give it away yet...but lets just say that it will easily double/triple production of the unit. To be honest I hope to sell the patent, as I could use the money but if there are no takers it will be offered as an upgrade option.
Lastly, and I know what everyone wants to know is pricing...well, that's still up in the air but the target price is between $1500~$1800 a unit. It will include the unit with legs, a 5 year standard warranty with a LIFETIME LED warranty. It will even ship with an extra LED strip in the off chance you need it, and it has been designed so you can replace it in mere minutes.
Once I have more details I will post some updates and pics. I would like to hear what features are missing or complaints about the ones offered on the market now as I have time to address them with my offering....in fact I may have already? But what I will offer by the end of the year is a professional performance UV LED exposure unit at entry level pricing. Like I said before, there is no reason why these things should run $5000 and I will prove that you can have a quality product without breaking the bank.
I will be looking for distributors for this unit, so if there are any distributors who are looking for a unit in that price range drop me a private message and I will keep you up to date when I get close to production. There will be generous tier based margins offered. A new website is being developed that will feature it when its ready for the market....stay tuned.
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Sounds like the next time we see a post on this, it may be in the Industry News and Product Promotion section as it will have progressed past the user DIY stage.
I do find it interesting however that you can't get your hands on an M&R or other commercially available unit for comparisons. It does sound like their stuff sets the benchmark. Hopefully, your friend in the US has access to one.
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Sounds like the next time we see a post on this, it may be in the Industry News and Product Promotion section as it will have progressed past the user DIY stage.
I do find it interesting however that you can't get your hands on an M&R or other commercially available unit for comparisons. It does sound like their stuff sets the benchmark. Hopefully, your friend in the US has access to one.
Well, I am sure somewhere in China M&R has sold one....but its very unlikely I can just stroll in and take a look at it. I have friends that have provided detailed up close pictures, some basic information like the vacuum pump size and the like...but nothing that could even be close to "specs" on the LED's. Which is really not the problem anyway as I have access to two R&D labs for the LED companies here in China.
My design might actually suck? Who knows until the boards are done and I have mounted all the LED's. However I have built a couple scale models for making screens about the size of a piece of paper and the results are more than satisfactory. That said, access to a lot of emulsion brands here is not very good and my testing has been mostly with Autotype & Murakami brands.
My technique and research has mostly focused on the actual LED design and is why it has taken so long. There are only 3 companies that I could find to make the chip I want to use and only a handful of companies that I can find place the LED's on the chip. Even still the vacuum pump costs more than the LED's do per unit. But yes, it would be nice to see the soon to be competition units before I get into manufacturing my unit.
All that said, really its not rocket science and the hardest part was just deciding to do it or not. Finding all the stuff other than the LED's took less than a week. Having my friends R&D and access to his staff to do the tests was also huge...its saved me a huge chunk of change.
Now all I need to do is come up with a catchy name.. :D
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Actually, I thought that buying one for comparison tests could be considered part of the cost of research and development to aid you in your quest to build the better mousetrap.
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Call it "PrōLightium" :)
With that price, they would disappear from the shelves pretty quick.
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Have you considered putting the lights 60 degrees apart instead of 90 degrees? This might reduce the cold spots.
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Have you considered putting the lights 60 degrees apart instead of 90 degrees? This might reduce the cold spots.
this is the trick!
Bulbs need to be set up in an equilateral triangle rather than a square pattern. The problem is that with the distance between corners of the square, it is different than the sides thus creating the areas with less light. . .
pierre
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Have you considered putting the lights 60 degrees apart instead of 90 degrees? This might reduce the cold spots.
this is the trick!
Bulbs need to be set up in an equilateral triangle rather than a square pattern. The problem is that with the distance between corners of the square, it is different than the sides thus creating the areas with less light. . .
pierre
You are correct on the lighting, but there is no problem with shape....LED's are square but the part that emits the light is round. Since I am not using crappy flex strips I have full control over placement and spacing. Having a lab to do the "mathematics" has been very useful. Less lights, but vastly superior distribution of light.
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it is going to bu crucial to have the distance to the emulsion calculated correctly. The cones of light have to overlap just right to create a uniform field distribution at the middle of the emulsion layer. You'll have to add the glass and the thickness of the average coated screen into account.
other decision will be the time it takes to expose. Some frequencies will expose faster, but not as completely. Do you go for faster exposure or better stencil?
pierre
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Call it "PrōLightium" :)
With that price, they would disappear from the shelves pretty quick.
Thats actually one I had not considered, its catchy though....However my Prodigium company is not actually the one that will sell the unit, in fact my Prodigium company is a "digital logistics" business, not a printing supplier. The units will sell under the Calibrated S.P.S. (http://calibratedsps.net) company name.
I hope they can move well in that price range, which I consider to be reasonable. To keep the price lower I just had to keep the design basic, but in reality who really needs half those "features"? Job recall, presets...its called an exposure chart next to your unit. From what I watch in the promo videos it takes longer to get to the job recall screen than it would to simply turn the timer to where you need it.
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Actually, I thought that buying one for comparison tests could be considered part of the cost of research and development to aid you in your quest to build the better mousetrap.
For the cost of one M&R unit, I can build about 10 of my units. My total "investment" to date has not even been $2500. Filing a patent for an idea I ahve will end up costing me the most.
Like I said, these are not rocket science...and the last thing I wanted to do was just make a COPY. I wanted to make it better and less expensive. It may not have the same total wattage, but from what I have learned it does not need it too. Even if its 15-30 seconds slower...for the price, I do not think I will get any complaints.
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it is going to bu crucial to have the distance to the emulsion calculated correctly. The cones of light have to overlap just right to create a uniform field distribution at the middle of the emulsion layer. You'll have to add the glass and the thickness of the average coated screen into account.
other decision will be the time it takes to expose. Some frequencies will expose faster, but not as completely. Do you go for faster exposure or better stencil?
pierre
The same as Rich Hoffman says, I will not go into much detail about the actual LED design, but to suffice it to say that wavelength(s) have been worked out. I am not going after superman speeds, and a lot of thought has been placed on quality. My tests as show in my first post showed huge gaps in light and resulted in not only undercutting but bad moire patterns with halftones. Distance to the glass is actually a factor based on the LED lens angles, which are NOT 120 degrees.
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I am just wondering. Why not do something like Saati? Wouldnt that be cheaper and easier?
Sent from my SM-G930F using Tapatalk
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I am just wondering. Why not do something like Saati? Wouldnt that be cheaper and easier?
The Saati unit uses the same idea as a single point light source. The bulbs in the same wattage are actually pretty expensive. 1-3 watt bulbs are fairly cheap, get over 7 watts and the price jumps quickly and they get hot! Furthermore there is added cost to build (and crate) a unit that has the light at the base versus a compact box with screw on legs. My other reason for not going that rout is that the Saati unit does not have a wide spectrum of UV light, at least according to their own specs. As mentioned, I was trying to improve not just copy.
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Steve,
Thank you for the post edit, one good turn deserves another....so my post has been edited to reflect that courtesy.
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Hey,
Out of respect I will remove the post and apologize for the inconvenience.
I will leave the below as a follow up (less shameless)
In the thread many questions were asked on why a machine wasn't built a certain way or why current manufacturers don't make things science based. A light analysis was done and posted about current machines in form that doesn't shed a good light on current manufactures. You mentioned not wanting to build a "copy" of something that exists @ price point that was more economical. The details and the light analysis I laid out was something that already exists within the industry. A science based benchmark, take it a challenge to see if you can make it better. Good luck on you endeavor I will be excited to see how far you can push limitations of LED exposure units.
Thanks!
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FWIW, I saw it as helpful usefull information that now is edited and gone for eternity.... Guess your on your own now Pro.
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Yeah I didn't take it that way, Steve. I saw it as an industry professional HELPING out the small time guy with information he may not already have on-hand. Especially taking in to consideration that Pro hasn't seen ANY of the industry's production LED units in person. Best of luck and I will be following this as far as it goes!
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I also didn't see it as a hijack especially since it was in a discussion thread in the DIY section, rather than in a particular manufacturer's promotional thread.
You may remember a recent similar occurrence with a squeegee handle post that due to forum "newbieness", actually was a hijack, and was split to it's own thread.
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FWIW, I saw it as helpful usefull information that now is edited and gone for eternity.... Guess your on your own now Pro.
I'll summarize:
405nm (which is the accepted light range for most thorough penetration of the emulsion, frying vs. baking).
LED's are 4" from the screen. (not sure this matters as much) -- however it does play into more consistent light, and speed. -- Inverse Square rule applies here as the the light strength is inversely proportional to the square of the distance from the source.
I like a slower exposure as it makes for more latitude. Our starlight was literally exposing some emulsions at 3 seconds!... 2 was undercured, 4 was over...
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Hey,
Out of respect I will remove the post and apologize for the inconvenience.
I will leave the below as a follow up (less shameless)
In the thread many questions were asked on why a machine wasn't built a certain way or why current manufacturers don't make things science based. A light analysis was done and posted about current machines in form that doesn't shed a good light on current manufactures. You mentioned not wanting to build a "copy" of something that exists @ price point that was more economical. The details and the light analysis I laid out was something that already exists within the industry. A science based benchmark, take it a challenge to see if you can make it better. Good luck on you endeavor I will be excited to see how far you can push limitations of LED exposure units.
Thanks!
Steve, as a person who long ago built a business using forums to promote my business (sometimes a bit shamelessly as well), there is a way that you could of discussed the topics without turning it into a shameless plug for your product. Your post was only missing some fancy graphics and PDF brochure to qualify as a full on advertisement. You spent all of 2-3 sentences talking about the topic, then the advert...surely you can understand why I replied to it the way I have.
The details I laid out certainly make a case for what I will offer, and a about why I think its better than some current designs..but lets please note that this is the proper forum for me to do it. I am not a mfg company (yet) and even though I have been granted access to resources that are typically reserved for big companies that does not make it any less of a DIY project.
The questions asked to me, were not why "a" machine was not built to copy others, it was asked why "I" chose a certain design path. The light analysis you provided was merely part of your sales pitch, complete with a pat on the back for your design staff. It was not my intentions to come across so harshly, and really I am not trying to make an enemy here, but your post was a shameless advert and I called you out on it.
I hope as well that my research and design has pushed the technology (at least a little bit further) but in reality it was not my intention to build the "best" mouse trap or even push the limitations as you stated... I just want to offer professional performance on an affordable level and prove that a decent exposure unit does not need to cost so much. from which the initial idea came from a prior thread on the same matter that you may or may not have read about?
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Hey Pro,
I am excited to see research in action and believe that there is a place in the market for everyone. I read this forum and as many others as I can daily to keep pulse on the industry as well as watch for ideas, or reoccuring themes. I will rarely chime in as this website is a community that is moderated well and provides great discussion amongst printers. I only jump in when manufactures are being put out there in a negative light (For unfair/unlikely reasons) While you were promoting your concept and your way of thinking, you routinely mentioned manufacturers by name and pointed out what they were all doing wrong. Including posting a model of light analysis done without and actual exposure unit just an assumption made for reading their literature. The light analysis i provided is an actual analysis of a current unit in the field. (Side note: I ran Pierre's idea through light simulation software in Atlantic City roughly 2 years ago, it has promise but as all ideas it would need to be perfected)
I play on a team, the patting on the back is for my team members as i expect them to follow the forums as well. I also believe when they have created something that is truly exceptional they deserve to publicly congratulated (I enjoy reading stories on here about a employee(s) who have done something that makes a difference in shop whether a print shop, a manufacturing facility or a supplier.)
Current units in the field range from:
$2,500 - $15,000+
If you call out a company that is retailing @ $5,000 and than remove all the features (important to some or not) and and build it for less you are no longer building the same unit and discrediting there efforts (Phone Apps, Light Integrator chips, lensing research.....)
If you are building a basic exposure unit @ a more economical price than your goal is to compare to those that are already at economical price. The unit and features are on a unit that retails @ $2,795. I believe there is another commercial unit @ $2,500 as well.
If you simply promote your ideas and plans, I will stay silent and wish the best of luck and continue to push my team to make the best available unit in each price category. If you call in question to efforts of other manufactures and downplay there inventions than I will chime in by posting the science behind some of the efforts and inventions.
As always best of luck, i am firm believer that competition brings out the best in all people. It can get a little chippy at times but that simply drives people to try harder!
thanks
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Your patents, analysis reports, and sequential manufacturing capabilities, have more than likely pushed your project beyond the scope of the typical DIY (*IMHO).... A build to me is born of love and merely a creative outlet utilizing multiple designs, all done late in the night as the world sleeps . Its not to save money, be cheap or competitive, but as a marriage of ideas and concepts. Buying materials and equipment is quite expensive, fabricating and welding high carbon steel / aluminum is a daunting task that few have the patience or skill for, not to mention the safety aspect in terms of engineering and electrical.... One should almost ask themselves, why bother?, I could just go buy one. ;)
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Steve,
Its all good and this is more along the lines of a beneficial discussion. To be fair I was merely noting that my approach to design was meant to resolve some inherent design flaws that in a $5000+ exposure unit should NOT exist, such as warped or distorted UV strips. It would be like having a Mercedes's C class with faux leather seats. Its just something that should not be done in that price class....at least from my perspective.
To be fair, I did state clearly that my tests were done on the layout design, NOT on the actual units. Fully admitting that either mfg could of corrected this flaw with special lenses, but that I doubted that this was the case based on evidence provided to me. If I am incorrect, than either mfg named is more than welcome to step up to the plate and set me straight. I will edit or correct my post with an apology as well. I recreated in a testing environment the layout and was provided the image by the lab who performed the tests. I did not mention your product at all, so it was never meant as a comparison. But of course you can easily create a uniform light coverage by simply lowering the lights until you get even distribution, as you have done but that can have an impact on performance. What is an average exposure time on your unit with a dual cure?
However now that current LED designs are in the near flash of any eye, some screens burning in 5 seconds (or less) the performance measurement really comes down to measuring screen quality. Again, I stated that I am merely at the stage where I am beginning to validate my design and that until its tested in the real world.."it might suck" Also like you, I do not think its so great to have near instant exposure as your latitude is so small that 1.5 seconds may be the difference in proper exposure....that would be for most, an annoyance to say the least.
As for removing features, that is not exactly the case. In some models for example, having the lights turn on when the vacuum blanket has drawn is called a "feature"..in what I am building its just how it works and its not an option, so its a fair comparison to make and I did. Its a $2.00 sensor switch, so there really is no valid reason why it should not be standard on any unit over $2500. AN LCD screen to some may be called a feature, I call it an accident waiting to happen. Anyone who has cracked a cell phone can attest to just how easy it is to break and when your handling a roller frame its bound to get broken sooner or later and I am positive that the cost for replacement will not seem like a feature when you cant burn a screen. Sometimes a good feature is just plain simplicity, and reliability. Like being able to replace the LED without a service tech or the bill that comes with it, again its a fair comparison to make.
I cannot compare some of the other base units to what I am building as they lack the performance (I hope to achieve in my initial design) and in most cases ANY features so it would be foolish to compare my design to say a Lumitron unit, which even falsely claims as a feature that the "light never degrades" This is factually incorrect as told to me by the UV LED mfg directly as we discussed the life span and luminous output. UV LED's do degrade over time, especially in the ranges below 390nm which degrade at nearly double the rate of 400nm wavelengths, with 365nm typically being rated for a mere 8000 hours due to the ingredients used to make them, regardless of the company that makes them.
My talking points were not to compare what I am trying to accomplish simply based on price, but on performance and serviceability as well. Its like comparing the performance of an American muscle car such as a Mustang Shelby GT350 to say a Ferrari. They can be compared in terms of performance, but they are in wildly different price ranges. In many circumstances the Mustang will trash the Ferrari and where the Mustang really wins is being able to afford to still buy your groceries and drive them home in it as well. I am just making the same type of arguments.
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Your patents, analysis reports, and sequential manufacturing capabilities, have more than likely pushed your project beyond the scope of the typical DIY (*IMHO).... A build to me is born of love and merely a creative outlet utilizing multiple design concepts, all done late in the night as the world sleeps . Its not to save money, be cheap or competitive, but as a marriage of ideas and concepts. Buying materials and equipment is quite expensive, fabricating and welding high carbon steel / aluminum is a daunting task that few have the patience or skill for, not to mention the safety aspect in terms of engineering and electrical.... One should almost ask themselves, why bother?, I could just go buy one. ;)
Agreed on so many levels. I have built many projects not because it would save anything, I just like to tinker with stuff and sometimes a better product is the result even if its not the intended goal. After the thread about me complaining of the costs, I just purchased a bunch of stuff and started to play with it not serious about building a unit to sell. But I was astonished at how easy it was to achieve fairly decent results for pocket change, so I decided to see what I could do with the plan to keep the costs inside a specified range. The end result is such that I would be foolish NOT to build it, even if I can only sell 10 units a year.
Although the patent I seek actually has nothing to do with the LED exposure system itself. There may be something in my design approach that is "patent-able" but its not something I will spend any efforts to protect. In fact I am of the Open Source type, but the reality is that sometimes you stumble as I did across a really good idea when trying to resolve a problem. So that is why I am getting a patent on the idea...but I will gladly sell the idea or license it to anyone once its protected, well all need to make a living.
Also to be clear, I do not think I have anything that could be called "sequential manufacturing capabilities" The parts will be made by various small companies here, many by people I know from my pizzeria here and I will hand build each one myself in my little 150 square meter space until such time as it becomes impractical. Help with board design is by a friend here whose company builds radiant gas heaters. The LED companies are of course wanting the business and its normal to provide testing, especially when developing custom made LED's. After all they need to do in house tests to ensure they are designed to specs as well so many of the tests were ones they would of done anyway.
My initial developments were in fact all DIY...but when you plan to mfg something you bring in professionals to make sure your not overlooking something and ensuring that its done in a cost savings manner. So as Frog mentioned in the beginning, it may not qualify as a true DIY project..but until they are being sold as a viable product its just me, my ideas and my one off test product at this stage...and its certainly a labor of love working late at night on ideas. When I go into production, then I will post it under a more correct section.
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6 months ago:
Diazo exposure time 30-40 seconds
Now:
Diazo exposure time 20-30 seconds
In order to expose photo polymers use a variable power supply to run the LED's 50% power (Increase life for all those using Photo Polymers as well as control exposure times)
Photo Polymer Time without variable power supply: 1 - 5 second
With Variable power supply: 15-30 seconds (Depending on power supply out put)
Degradation of LED's are exponentially increased by excessive heat, which is why you keep them as far away for the glass as possible. The heat has somewhere to go and glass does not act as a insulator increasing the life of the LED's. LED's also degrade faster if ran @ 100% capacity.
Optimal: size the LED's 25% greater than what is necessary. Use a light integration chip to drive them harder as they degrade.
Like posted in the Vega video we have unlensed LED chips that produce up 8w/cm^2. (Two expensive for this industry and complete overkill, but will give you and idea of how it is possible to use 28 LED's and achieve the above stats)
Cool LED things to look @ With lensing/dibonding a few companies have reached heights of 24w/cm^2 (Different industry but cool to watch)
As far as the Ferrari Vs The Shelby, it is something we fight in every industry sometimes perception is better than performance.
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Steve,
All good information...thanks.
I tested higher power LED's, a couple were actually rated at over 100 watts as one idea was to develop a single point style, the problems were that UV LED's in that range are stupid expensive and degrade too quickly not to mention heat issues. Ironically with my current design, heat is NOT even a factor to trouble with. The bulbs so far have never got hot enough that its even hot to the touch. This is most likely due to my LED board which is in fact a copper clad aluminum heat sink. Maybe we have a different idea about "affordable" LED's, but even the more powerful ones 10-Watt Cree units I purchased were under $2 each in bulk. I just found that its too much power, and heat. More LED's of lower power resolved all such problems.
There are no current plans to use a "dimmer" for different emulsions, at least not in the typical analog sense. As stated I have found that more power is not always better. In testing my ideas, uniformity of light won out over sheer power, unless maybe you need to burn a 400 micron Film, but still that should not be a big problem? Of course testing will tell. That said my power supply is rather unique for my unit (I think) in that it will not provide constant line current, and that will help keep temps low. However my plan is to operate at 100% of the rated LED power.
I am not troubled at all by LED lifespans. Even at 10,000 hours your talking about decades of life @ 30-60 seconds per screen, so to spend much time worrying about it is nonsense. The company that is mfg my LED's states that the spectrum does not alter very much with age, but wattage does drop over time. So if your using an integrator I hope it measures wattage and spectrum.
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The above I posted about the 8w/cm^2 example is a poor example as it does not apply to this industry or exposure units. Just a cool way to see how far LED's have come.
The example you posted of a 100 watts or 10 cree units (roughly 70 watts) is missing a area to compare to the latest technology.
Assume the following 100 watt led chip, that is going to illuminate an image area of 16" x 16". 256 in^2 or roughly 1,651 cm^2.
100 watts/1,651 cm^2 = .06 watt/cm^2 delivered to the area.
You can a buy a grow light off the shelf that is 300 watts over the same image area 16x16 for $375, nearly 3 times the output. Ironically the grow lights are in the 410-420nm, which does work on many emulsions.
The 8w/cm^2 I was referring to is
.06w/8w = 133 times the amount power the 100 watt chip would deliver over the same 16x16 area.
Edit: There is a distance not being accounted for in the above formulas, when I get second I will go back and recalculate. (Since I didn't include a distance in either one the comparison is accurate but the concept impossible without an array)
Edit (2): traveling again had time to fix the equation:
Power is reduced by a square of the distance
Above example of you had a single chip that was 100 watts at the chip like he above example the further away the chip got from the source the less power it would deliver by a square of the distance:
Ie. Let say I took a chip that was 100 watts and put it 16" away to achieve uniform light, the chip would have to be 4 times as powerful as the chip that was pressed against the glass to deliver the same amount of watts/cm^2.
What is cool about this:
We are looking for the same thing how many watts/cm^2 does it take to expose a screen @ 405 NM wave length. It is irrelevant how you deliver those watts (852 chips or 1 chip the science equation remains the same) now the questions is which one delivers longevity, ease of use and a unified light pattern. Let the best design win!!!
Side note: the answer to above is very different when considering both photo polymer vs. Diazo's.
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6 months ago:
Diazo exposure time 30-40 seconds
Now:
Diazo exposure time 20-30 seconds
In order to expose photo polymers use a variable power supply to run the LED's 50% power (Increase life for all those using Photo Polymers as well as control exposure times)
Degradation of LED's are exponentially increased by excessive heat, which is why you keep them as far away for the glass as possible. The heat has somewhere to go and glass does not act as a insulator increasing the life of the LED's. LED's also degrade faster if ran @ 100% capacity.
Optimal: size the LED's 25% greater than what is necessary. Use a light integration chip to drive them harder as they degrade.
Smart. 0.5s exposure times are not beneficial in any way.
I'm also impressed that you are addressing the very real fact the LEDs will degrade over time. I didn't know about the heat expediting the degradation. We have been running our unit with glass and film and it's over 100˚F on the blanket during production. One has to wonder what that's doing to the array. I'm pretty sure ours has become dished/warped from the heat, the glass certainly has warped significantly from the heat forcing us to reset our "flat" on our roller table, screens and presses. I'll be confirming if the array mount is flat this weekend as we're removing the glass in prep for a cts install. I think an LED expo with variable power and integrator is brilliant if you'll excuse the pun.
Love threads like this and interested to see what you come up with on your project Prodigium. Good luck.
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Hey Zoo,
We have a couple units in the field with temperature sensors on the boards to measure the max operating temp. It is unknown what temperature will ultimately cause the boards to fail and what the life span is @ different temperature values. Currently we have the machines set to alarm around 40 c or 104 F. The best formula we can put together is that 50 c or 122 f will not harm the boards or shorten the life span, but in complete honesty I can only stand behind 2 years of data. It is a pretty safe assumption that these numbers are congruent across all LED exposure unit lines.
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Love threads like this and interested to see what you come up with on your project Prodigium. Good luck.
I as well, and I am very excited about my project obviously. Screen printing has traditionally been an affordable business opportunity to get into and over my prior 20+ years experience I have seen lots of entry level products that sadly not only fail to produce a quality product but are so poorly made they actually make the process harder for a newbie. My product is meant to alter reality in that it will by design simplify the process while at the same time producing a quality screen no matter your needs. Because the actual costs for LED units are so low, in reality there is no reason for some of the prices out there.
I don't begrudge anyone making a buck, heck its my intentions as well..that's why we all are in business but its like being charges $50 for a grilled cheese sandwich. However I will fully acknowledge that when buying a "name" product your also buying support and service and that is a very valid consideration for anyone and that is part of the purchase price. But that is also why I am designing my unit to be 100% user serviceable...so long as you know which end of a screwdriver to use.
Steve, to clarify. The Cree unit I spoke of was a single UV LED with a rated output of 10 watts. Not 10 Cree units. On my mini test rig they were intense, very hot even without the matter of being enclosed in a box or even having glass over them. This was the same for many units I tested. Ultimately I opted the path as M&R, which I will give credit too....More bulbs, lower wattage = less heat & more uniform light distribution. I just do not agree on how the lights are spaced, or mounted. Its layout is counter-intuitive, strips are cheap and require some sort of methodology to resolve. The effects from heat will have more of an effect on the bonding agents used to glue it down and keep it level which will adversely effect exposure quality. However I will concede that its very possible that in the real world its simply not that big an issue for the vast majority of customers. Sometimes lab tests lead you to resolve problems that really never really existed to begin with. But keeping the LED's on a flat plain is a real problem.
If there is any heat issues to my design it will not be caused by the LED's themselves, but will be the result of its working environment. Obviously if you in a shop where temps are high that will have some effects, even with fan cooling drawing hot ambient air over the LED's will accomplish little to nothing. However I will concede that heat can significantly shorten the useful life of the LED. Higher operating temperatures lead to higher junction temperatures, increasing the degradation rate of the LED element, causing lower wattage output of the LED and decreased life over the long term....as explained to me by my LED mfg.
I left the technical details of this to my mfg as they fully understand how to compensate for heat since they are the mfg. I merely provided the working environmental details and design parameters and they stated to me what I had to do to best counter these effects. This is why I opted for a copper backed aluminum heat sink mounting board in fact.
But as Steve stated, and as my mfg told me that 50c is not really an issue. And once again lets be realistic here...even if you half the life of a standard LED rated at a conservative 30,000 hours your still in the DECADES time span. A replacement LED strip in my unit will be lifetime warrantied for the original purchaser, so even IF you had to replace all the strips it would be FREE...sans shipping, and it would at most require 20 minutes to swap out. This talk about LED degradation really is much ado about nothing.
Should you find yourself in such a hot ambient shop, your bigger fears should be on the effects to your coated screens. Most emulsions will start to harden or even expose at such temps. So talk about heat may be a problem for some designs but its not one that has troubled me.
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In building these LED units, I believe the most important thing in preventing under cut is the beam angle. No matter how accurate we place the LEDs, it will never be in the perfect spot. So to reduce the errors, we need steeper beam angle.
(https://whichledlight-cdn.azureedge.net/static/education/LED-light-bulb-beam-angle-diagram.jpg)
The draw back of steep angle is:
1. Increase the number of LED.
or
2. Increase the distance of the glass from the glass.
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In building these LED units, I believe the most important thing in preventing under cut is the beam angle. No matter how accurate we place the LEDs, it will never be in the perfect spot. So to reduce the errors, we need steeper beam angle.
(https://whichledlight-cdn.azureedge.net/static/education/LED-light-bulb-beam-angle-diagram.jpg)
The draw back of steep angle is:
1. Increase the number of LED.
or
2. Increase the distance of the glass from the glass.
Your on the right path, but your diagram is only representative of a light that has a single angle of exposure. There are very inexpensive ways to fix that problem...all you need to do is buy a Maglight and you'll figure it out. Optics much like wearing glasses solve such problems when used properly. Its called collimation.
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I just do not agree on how the lights are spaced, or mounted. Its layout is counter-intuitive, strips are cheap and require some sort of methodology to resolve. The effects from heat will have more of an effect on the bonding agents used to glue it down and keep it level which will adversely effect exposure quality. However I will concede that its very possible that in the real world its simply not that big an issue for the vast majority of customers. Sometimes lab tests lead you to resolve problems that really never really existed to begin with. But keeping the LED's on a flat plain is a real problem.
our Starlight is 2-1/2 years old now and the LED strips are still perfectly flat to the pcb. I'm not sure what they did to mount them, or how they got them flat to begin with as usually they come on a roll, but they certainly haven't moved, bubbled or changed.
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our Starlight is 2-1/2 years old now and the LED strips are still perfectly flat to the pcb. I'm not sure what they did to mount them, or how they got them flat to begin with as usually they come on a roll, but they certainly haven't moved, bubbled or changed.
Good to know, and to be truthful I have not heard of this matter with M$R's product. It may also just be the volume of screens your producing? If you only making 15-20 screen a day, you will most likely NEVER have a problem with the LED's.
But if you do, it would be interesting to know how difficult it would be to repair/replace them. Has anyone had to have one repaired, how long were you down and how difficult was it?
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After having some companies talk to me about possible distribution and listening to what they think, I have decided that the product dimensions will be altered somewhat from my original plans. Originally the plan was to max it at 1 - 23" x 31" but several people wanted to have it handle 2 - 20"x24" screens so were going to listen to what people want.
The unit will now be sized slightly larger to accommodate either 2 - 20"x24" / 1 - 23"x31" / 1 - 25"x36"
UPDATE: Actually I have decided to make 2 sizes, one for only 20x24 screens and the full size one above. I wanted to be sure that we can be the most competitive on pricing and for many dealers I spoke too they want them for new startup shops where 20x24 screens is the norm.
Just got in one of our testing sample boards....nice, clean and should prevent ANY issues with heat, that I have had any with my tiny test rigs, but 16 LED's is not the same as 750 or more. Now I get to practice doing some manual reflow soldering in my oven. When we get into production I am thinking that they will not be white, but when you get samples they do not offer many options.
(http://i6.photobucket.com/albums/y218/calibratedsps/triple_row_pcb.jpg)
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Just to follow up we do indeed have a warped array panel. (being replaced)
I can't attest to whether this was truly heat related or not but it's wise to plan to keep the array both cool and perfectly stable. Even a small amount of warp or distortion to the mounting is going to mess with the collimation. Your heat sink mounting looks solid, maybe mount it on honeycomb al?
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Our frames are larger than 23x31. :(
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Just to follow up we do indeed have a warped array panel. (being replaced)
I can't attest to whether this was truly heat related or not but it's wise to plan to keep the array both cool and perfectly stable. Even a small amount of warp or distortion to the mounting is going to mess with the collimation. Your heat sink mounting looks solid, maybe mount it on honeycomb al?
Because I am well aware of problems related to collimation it was one of the major reasons for NOT using those cheap strips. My boards are exceptionally rigid, and while there is no need to mount them to anything else for strength, they will be mounted to a rack that allows the whole LED panel to slide out like a desk drawer for easy service or cleaning. Because of careful design considerations heat as I have said is not a problem that I expect to deal with.
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Our frames are larger than 23x31. :(
Sorry for the unclear update. Larger screens will not be a problem. Originally my plan was to make one size that could handle up to a 23x31 screen. Then after some feedback from possible dealers it was decided that it should handle up to a 25x36. However after some extra thought on the matter and trying to keep the base model in a price range I have opted now to produce 2 models.
1) Base unit will handle 1-20x24 screen & will come in at an even lower price than originally stated.
2) Large unit will handle 2-20x24 / 1-23x31 / 1-25x36 will be priced at the higher side of my original price. (still under $2000 with crate)
3) (Still Undecided) but a model for graphics printers that will accommodate up to a 31x41 screen.
I do not want to get carried away with multiple models and building the 3rd option for graphics screens will greatly depend of my success with the first 2 models. One thing that I will add is that the case is being redesigned to accommodate a pre-press registration system which more or less involves making the top a little bigger. It will be a very affordable upgrade option.
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I would aim to be able to fit 2 23x31 or 23x33 in the largest size, with the added benefit that it will hold single larger poster/sign screens as well.
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Our frames are larger than 23x31. :(
Sorry for the unclear update. Larger screens will not be a problem. Originally my plan was to make one size that could handle up to a 23x31 screen. Then after some feedback from possible dealers it was decided that it should handle up to a 25x36. However after some extra thought on the matter and trying to keep the base model in a price range I have opted now to produce 2 models.
1) Base unit will handle 1-20x24 screen & will come in at an even lower price than originally stated.
2) Large unit will handle 2-20x24 / 1-23x31 / 1-25x36 will be priced at the higher side of my original price. (still under $2000 with crate)
3) (Still Undecided) but a model for graphics printers that will accommodate up to a 31x41 screen.
I do not want to get carried away with multiple models and building the 3rd option for graphics screens will greatly depend of my success with the first 2 models. One thing that I will add is that the case is being redesigned to accommodate a pre-press registration system which more or less involves making the top a little bigger. It will be a very affordable upgrade option.
AWESOME!
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I would aim to be able to fit 2 23x31 or 23x33 in the largest size, with the added benefit that it will hold single larger poster/sign screens as well.
Like I said, I am not going to get carried away with multiple models. The plan was, and still is to make a powerful unit that is affordable. Most people will never need to burn 2-23x31 screens at the same time, especially with exposure times sub 2-minutes. A model to fit 31x41 would be for graphics users but as mentioned its merely an idea at this time, no commitments.
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I think a large sized unit would be worth making. 31x41 or thereabouts would be ideal for us, it matches our max frame size for cts and dovetails well with max frame on presses like the S.roque XL machines and you could shoot 23x31 2up.
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I know its an old thread now, and I wish that I could report back with some pictures...but the reality of manufacturing in China is one of where if you want to make something, there is everything you can imagine. However like most things its about numbers, 1 of something = forget it, 100 = maybe and 10,000 is a "base" but still a price that makes it hard. Well that is kind of where I am at, debating on how much I want to invest in order to get the price point I want.
My LED mfg wants a (min) order of 50,000 in order to make my custom design and there is a 90 day lead time due to special tooling and fitting my "small" run into their production schedule. Whats nuts is that they can make them in just one day....its the scale of capacity here, its insane. Under 50,000 unit order and they are made in the prototype lab and the prices triple!! The budget for this is already tight and I am weighing my desire to make a professional unit right off the bat, or as I am considering making an "entry level" unit with off the shelf LED's and testing the waters.
However I am intrigued to see that Anatol has obviously been reading this thread and has even implemented my design into their own equipment. LED's surface mounted on metal boards and in a staggered position for even light distribution. Not really very surprising though, but I guess that in a way it does validate my own design concept so maybe I should be flattered?
Either way a sneak peek at Anatol's new design that completely implements what I have clearly stated here as my own design.
(http://i6.photobucket.com/albums/y218/calibratedsps/anatol-board_sm.jpg)
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I would aim to be able to fit 2 23x31 or 23x33 in the largest size, with the added benefit that it will hold single larger poster/sign screens as well.
Like I said, I am not going to get carried away with multiple models. The plan was, and still is to make a powerful unit that is affordable. Most people will never need to burn 2-23x31 screens at the same time, especially with exposure times sub 2-minutes. A model to fit 31x41 would be for graphics users but as mentioned its merely an idea at this time, no commitments.
We have a pretty large vacuum frame and burn 2 - 23 x 3`1's routinely, with a 5K Metal Halide lamp, but the difference in the exposure times would probably render that moot. The question would be perhaps whether you are getting 2 screens at a much faster time than currently burning 2 up...
Steve
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I know its an old thread now, and I wish that I could report back with some pictures...but the reality of manufacturing in China is one of where if you want to make something, there is everything you can imagine. However like most things its about numbers, 1 of something = forget it, 100 = maybe and 10,000 is a "base" but still a price that makes it hard. Well that is kind of where I am at, debating on how much I want to invest in order to get the price point I want.
My LED mfg wants a (min) order of 50,000 in order to make my custom design and there is a 90 day lead time due to special tooling and fitting my "small" run into their production schedule. Whats nuts is that they can make them in just one day....its the scale of capacity here, its insane. Under 50,000 unit order and they are made in the prototype lab and the prices triple!! The budget for this is already tight and I am weighing my desire to make a professional unit right off the bat, or as I am considering making an "entry level" unit with off the shelf LED's and testing the waters.
However I am intrigued to see that Anatol has obviously been reading this thread and has even implemented my design into their own equipment. LED's surface mounted on metal boards and in a staggered position for even light distribution. Not really very surprising though, but I guess that in a way it does validate my own design concept so maybe I should be flattered?
Either way a sneak peek at Anatol's new design that completely implements what I have clearly stated here as my own design.
([url]http://i6.photobucket.com/albums/y218/calibratedsps/anatol-board_sm.jpg[/url])
Will send you a PM in a minute regarding your LED unit.
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We have a pretty large vacuum frame and burn 2 - 23 x 3`1's routinely, with a 5K Metal Halide lamp, but the difference in the exposure times would probably render that moot. The question would be perhaps whether you are getting 2 screens at a much faster time than currently burning 2 up...
Actually the speed of LED would be vastly quicker than Metal Halide, so in my mind is whether the extra COST of a larger exposure unit is worth it? If you can use a smaller unit, burning screens as fast, or faster than a big unit....why pay the added price and waste the shop space? When you in the 10 second exposure ranges or less than the bottle neck becomes simply rinsing the image out, not burning the screen. Having a larger unit would be for shops that physically have bigger frames...in my opinion at least.
My current situation is one of merely negotiating with vendors to get the things I need, at a reasonable price without having to buy them by the million as is often the case here in China. The custom LED's I had made for me have far exceeded my expectations, but 50,000 of them is a chunk of change. I am in talks with a few vendors in an effort to find a partner/investor willing to fund the manufacturing startup phase. As noted the problem is bulk purchasing, its simply beyond my financial means at this time to get the ball rolling on building the professional unit I have designed. However its likely that will change soon. I will keep everyone updated when I have more news.
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Well, progress has not gone as quickly as I had anticipated on the PRO-unit, however I am currently testing 2 demos of my "economy" LED unit that uses high quality parts based off my testing rig. The units will be available soon, not sure of the venue yet as I am trying to negotiate a deal with a large supplier that would become my exclusive distributor. If I cannot close a deal by Christmas, the unit will be sold on my website and Ebay.
The unit will be a very sleek, compact unit that uses 120 multi-spectrum UV LED's, which work good but are not the same as the ones that will be on my Pro-Unit. The intended target audience is newbies, home based and start-ups looking for a high quality unit that gets the job done. Its a no frills unit, simple on/off button without a timer....at least yet, because the case is tight and so far I have not been able to locate a timer that fits except one and its a little hard to use. It will use a compression top, vacuum top may be offered in the future, I am working on it now and I am hopeful that it will be something that can be upgraded later.
Here are some shots of the model, it will be for 20x24 screens. Its 100% plug and play from the box - completely assembled. It uses my own custom designed LED boards and each LED is multi-spectrum. The glass is real PPG Starphire non-lead 6mm and is locked inside the channel to fully protect it from breakage. All electrical components are enclosed inside the extruded aluminum dual channel frame. At this time I am not disclosing a price until I complete negotiations with a US dealer, who will hopefully pickup the product.
The pictures are from its development stages, not very pretty but it shows the design....very compact, and all parts are plug in so you can replace anything simply by unplugging it and removing at most a couple screws. If I end up selling direct then it will also come with a full 5 year warranty on all parts, except the glass. Hope to have more word on this in the coming weeks. More or less I am hoping to sell enough of these to fund the next phase professional unit which is in testing, but I need to raise funds to get it into production as buying all the components in bulk is a hefty price tag. A 23x31 size might become available? I am a little concerned that the glass may get broken in shipping.
(http://i6.photobucket.com/albums/y218/calibratedsps/promo1-sm.jpg)
(http://i6.photobucket.com/albums/y218/calibratedsps/promo3-sm.jpg)
(http://i6.photobucket.com/albums/y218/calibratedsps/promo2-sm.jpg)
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I like the low profile and the overall build, but I'm a little curious about the distance between the LED's vs the proximity to the glass. I'm not seeing how the current geometry wouldn't lead to hot and cold spots based on the distances between the led's on the strips vs the distance between strips especially.
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Great looking starter model. Heat will be a concern with your design unless you are selling it for fast shooting pp emulsion only. Your LED boards will resist warping much better than the "top of the line" led unit out there but you can still warp that nice glass with the heat generated.
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WARNING: THREAD HIJACK ALERT!!!!
I have been buying T-8 LED Fluorescent tubes in 4 foot lengths. They have come down in price, and I just got a case of 50 for $8.00 each, which included shipping and sales tax. They are 5000 Kelvin temperature range but they also sell 4000, and 6500 at least, if not more color ranges.
I wonder if a guy could use those? I have no way to measure or evaluate for correct UV energy, but it just hit me, that it might be a possible light source.
Each tube includes its own driver, so they run on a 120 volts, as supplied. Each fixture requires rewiring so that both pins (of the Bi-Pin tubes) are "hot" on one end and Neutral on the other.
These lamps would not technically be optimized for UV emissions, but I wonder. They are STUPID bright! The die spacing in each tube is very close. From tube to tube would be a minimum of 1".
:o :o :o :o
I'll shut up now.
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Stan, you can get a 19.5' reel of the 400nm UV output LEDs for a couple hundred bucks online. A starlight is basically a bunch of these stuck on a board with a simple driver. You could go a lot further for not much more expense and put a dimming driver on there for shooting different emulsions, etc. Would be a way better investment/project than trying to make some lighting product work.
Prodigium's concept here is superior to the strips which will likely never be 100% accurate in mounting but for a diy project check out those reels.
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Thanks Chris.
LED's are definitely making inroads into the world of lighting.
I use mostly Diazo (WR 25) and from what I've read, LED isn't the best light source anyhow. The thought just passed through my mind. I enjoy building projects so I won't rule it out for some point in the future.
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Thanks Chris.
LED's are definitely making inroads into the world of lighting.
I use mostly Diazo (WR 25) and from what I've read, LED isn't the best light source anyhow. The thought just passed through my mind. I enjoy building projects so I won't rule it out for some point in the future.
The histogram for most of the UV LEDs aren't optimal for diazo added but they do work, I can attest to that, albeit slowly.
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The unit will be a very sleek, compact unit that uses 120 multi-spectrum UV LED's,
I'm no lawyer, well at least until I can find a $19.95 online degree. But I'm pretty sure the multi spectrum led unit approach for a exposure unit is already patented in the states.
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To address some of the concerns raised.
For starters, its a "Starter" unit and of course will not be as capable as say a $4500 LED unit, that said its performance will give more bang for the buck than any fluorescent-tube unit. The LED's are not high power, in fact they are only 1 watt each, Anatol's are 5 watts and I can assume that M$R is roughly the same. So they must be raised a bit closer to the glass for better performance. As for dispersion of light, the LED's have a wide 120 degree angle lens so the light is no as directly focused as it looks, the layout is staggered to lower the chances of hot/cold spots. Given its not a perfect layout, but it will more than meet the needs of any startup shop by comparison to anything that will be in its price range, and many that are much more expensive. But lets be real, its audience is home startups, hobbyist and maybe even for PCB plates, not for shops running 3 autos doing 85lpi sim process.
Heat is NOT a factor, at only a watt each and exposures taking roughly 15~30 seconds with the emulsions I have tested heat has simply not a problem. Like most startup shops I do not think there will be continuous screen burning, as in making 30+ screens a day, so really again its not a factor. The glass is 6mm (1/4") thick and as such can take a lot of heat if need be. If I find with testing that heat becomes a factor, than a simple solution will be to use a 3cm fan in the back of the frame to draw heat out...easy enough and its already been considered, but as yet not required. Lastly, there is no way in the world 120 watts of LED's will "warp" 6mm glass, no-how no-way. The glass is sealed in the frame, like a window pane its not going anywhere.
Patent...well possibly? I have read thoroughly the patent given to one company about this and my take on it is that it pertains specifically to the design of the multi-spectrum "bulb" which is in fact multiple LED's, each with its own wavelength built into a large screw in bulb, which ironically is commonly available already in China. While my PCB boards are custom made to fit the case, the LED's are in fact off the shelf units, not custom made. This design is not even close to the same, the LED's I am using are just a broad spectrum UV LED commonly used in wide format digital printers that use UV inks. So I guess that I should state that they are not true "multi-spectrum" but rather "wide spectrum."
One idea that I have considered is also to sell the strips and matched drivers as replacements for anyone who uses fluorescent tubes, or for those wanting to make their own home built DIY's. With the metal LED boards it would be a snap to retrofit a case and the drivers are also very small, but requires 1 driver for every 2 boards. This may be something I will offer if I see there is a demand, I can also produce longer boards with up to 36 LED's on each strip. Dramatically more power than any "rope style" LED light.
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Just an update on this old thread.
As those that have read, I was trying to build an affordable LED unit for the masses of small and startup shops that could deliver performance for a price that would make it pretty much in a class of its own. After a lot of work, multiple design changes and some plain old luck it now looks like this will finally come to fruition. At this time I cannot say when, but I can say it has passed a number of basic performance tests and will soon be evaluated by an industry leading emulsion company for further performance testing.
Unlike my my original plan to build them here in China, they will instead be built in the USA using my LED strips and a few select parts. It will be sold through distributors and of course on my new website when it re-launches. It has taken 3 times longer than I anticipated and it may still be awhile before its out there, but its coming soon and it will be the first of many other products to come.
More news when its ready.