Lexan Polycarbonate and CO2 laser wavelength
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Odd Holstensson
Oct 17, 2014, 4:53:10 AM10/17/14
to lase...@googlegroups.com
Hello.
I have got an offer for clear Lexan Polycarbonate sheets and aluminium composite sheets needed from a local company.
I have done some research and found out that the CO2-lasera emits light at 10000nm+/-600nm. What I can understand the infrared spectrum starts at about 700nm and above. Is this correct?
I have got an offer for clear Lexan Polycarbonate sheets and aluminium composite sheets needed from a local company.
The datablade for Lexan 9030 states that transmittance above 2200nm os near zero. What I understand, the color of the polycarbonate sheet does not affect the ir blocking at CO2 laser frequecies?
https://sfs.sabic.eu/wp-content/uploads/resource_pdf/1345453948-48623687-Technical-Manual-Coated-Uncoated-Sheet.pdf
https://sfs.sabic.eu/wp-content/uploads/resource_pdf/1345453948-48623687-Technical-Manual-Coated-Uncoated-Sheet.pdf
I would appreciate feedback on my thoughts.
The phase in my build is still collecting parts and knowledge.
Best regards
Odd Holstensson
Wolfgang Kraft
Oct 17, 2014, 5:29:02 AM10/17/14
to Odd Holstensson
Hello,
you need to take into account, that the cutting process generates as well light in different wave-length from near IR down to UV.
Especially, when you try to engrave or etch metall surfaces.
Regards
Wolfgang
------
In Antwort auf die folgende Mail
From: Odd Holstensson <o...@digitum.se>
To: lase...@googlegroups.com
you need to take into account, that the cutting process generates as well light in different wave-length from near IR down to UV.
Especially, when you try to engrave or etch metall surfaces.
Regards
Wolfgang
------
In Antwort auf die folgende Mail
From: Odd Holstensson <o...@digitum.se>
To: lase...@googlegroups.com
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Odd Holstensson
Oct 17, 2014, 5:39:40 AM10/17/14
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The supplier only have clear sheets and I intend to use regular sunfilm to make those sheets darker, alternativly replace some of the sheets with the composite sheets and make a smaller window instead. The cost cut is more than 700 USD, or over 5000 SEK incl vat, in comparement to misumi. Of course, I can select critical sheets of darker material. Total price inkl VAT is about 1500 SEK for all the sheets, including cuts with better than 0.5 mm tolerance.
To view this discussion on the web visit https://groups.google.com/d/msgid/lasersaur/395126305.20141017112854%40WKraft.org.
Derek Seabury
Oct 17, 2014, 10:26:42 AM10/17/14
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Hi -
For the same reason we used clear polycarbonate and a bit thicker than the mitsumi. I have some welding goggles for people that want to stare at the bright light of organics burning but the clear makes it easier to see what is going on with materials like acrylic that emit very little light while cutting.
One note, the door is big! Changing the material can change the weight a lot and effect how well the gas struts work. We have had them slide when not tightened a LOT. :)
/Derek
For the same reason we used clear polycarbonate and a bit thicker than the mitsumi. I have some welding goggles for people that want to stare at the bright light of organics burning but the clear makes it easier to see what is going on with materials like acrylic that emit very little light while cutting.
One note, the door is big! Changing the material can change the weight a lot and effect how well the gas struts work. We have had them slide when not tightened a LOT. :)
/Derek
To view this discussion on the web visit https://groups.google.com/d/msgid/lasersaur/CAPRS2zm9i%2B5ZM6cg6wtQ%2Bb9%2BPm4OC7N7%2BH38muJncXoDZ%2BTA5Q%40mail.gmail.com.
namit
Oct 17, 2014, 11:35:20 AM10/17/14
to lase...@googlegroups.com
We boght 0.5 mm Polycarbonate however we did find when aligning the laser we have a small divit in the front peace already from the laser of which is slightly worrying. I need to look into this more myself.
Also if you go with slgithly larger Polycarbonate you will find the gascit is much harder to get in we had to cut center peace with a dremal to make it fit.
Steve Baker
Oct 17, 2014, 11:37:38 AM10/17/14
to lase...@googlegroups.com
I get really nervous about cost-cutting in areas where safety matters -
and we know that the base frequency of the IR laser isn't the whole issue
here. After all, we don't point the laser directly upwards at the lid.
The concern is that when the laser hits something - either the material
being cut - or the grid beneath - you get intense light all over the
spectrum from UV all the way down to IR.
This stuff is dangerous because intense light from outside the visible
range doesn't trigger the iris to shrink down.
When a bright light hits your eye, the pupil constricts in about 100 to
200 milliseconds to shut out more light and protect your retina. But it
only does that based on the light detected in the eye - so it doesn't work
to shut out IR and UV.
Another problem is that our laser cutters flash the light on and off as we
cut/skip/cut/skip - and that fools the pupil into not responding fast
enough. The pupil muscles get tired very quickly, and then your response
rate to bright flashes is too slow.
So our natural protection against bright light is totally ineffective with
laser-cutter light and we're completely dependent on the plastic in the
lid. Intense light anywhere in the spectrum is capable of damaging your
eyes - and often without you even realizing it's happening until it's too
late.
Since the amount of light bouncing up from the bed depends critically on
what the laser is hitting, we can't know with any degree of accuracy what
the spectrum of the light coming back through the lid is likely to be.
Specifically, we fondly imagine that we won't be cutting metal -
completely forgetting that the grid beneath the material is metal. Then
we claim that "well, the grid is edge-on to the laser, so it doesn't
reflect much"...forgetting that the grid gets beat up a lot and inevitably
has bent flanges all over the place that will perfectly reflect the entire
energy of the laser back up to the lid - spread all over the spectrum by
the interaction with the metal. (As you cut, you can see those bright
flashes at regular intervals lighting up the entire interior of the
machine beneath the bed.)
So getting clever and picking a plastic that blocks the precise frequency
of the laser itself and is nice and clear so you can see what's going on
is a great way to blind yourself!
This is really no different than with welding goggles.
Hence, I really wouldn't mess around with this. My eyes are worth a
great deal more than $700.
If you really need to save money, buy a couple of cheap web-cams to mount
inside the machine and use solid metal for the lid!
-- Steve
Derek Seabury wrote:
> Hi -
> For the same reason we used clear polycarbonate and a bit thicker
> than the mitsumi. I have some welding goggles for people that want to
> stare at the bright light of organics burning but the clear makes it
> easier to see what is going on with materials like acrylic that emit
> very little light while cutting.
> One note, the door is big! Changing the material can change the
> weight a lot and effect how well the gas struts work. We have had them
> slide when not tightened a LOT. :)
>
> /Derek
>
> On 10/17/2014 5:39 AM, Odd Holstensson wrote:
>> The supplier only have clear sheets and I intend to use regular
>> sunfilm to make those sheets darker, alternativly replace some of the
>> sheets with the composite sheets and make a smaller window instead.
>> The cost cut is more than 700 USD, or over 5000 SEK incl vat, in
>> comparement to misumi. Of course, I can select critical sheets of
>> darker material. Total price inkl VAT is about 1500 SEK for all the
>> sheets, including cuts with better than 0.5 mm tolerance.
>>
>>
>>
>>
>> 2014-10-17 11:28 GMT+02:00 Wolfgang Kraft <Lase...@wkraft.org
>> <mailto:Lase...@wkraft.org>>:
>> <mailto:lasersaur+...@googlegroups.com>/.
>> To post to this group, send email to /lase...@googlegroups.com
>> <mailto:lase...@googlegroups.com>/.
>> Visit this group at /http://groups.google.com/group/lasersaur/.
>> For more options, visit /https://groups.google.com/d/optout/./
>> <https://groups.google.com/d/msgid/lasersaur/395126305.20141017112854%40WKraft.org?utm_medium=email&utm_source=footer>.
>> <https://groups.google.com/d/msgid/lasersaur/CAPRS2zm9i%2B5ZM6cg6wtQ%2Bb9%2BPm4OC7N7%2BH38muJncXoDZ%2BTA5Q%40mail.gmail.com?utm_medium=email&utm_source=footer>.
-- Steve
and we know that the base frequency of the IR laser isn't the whole issue
here. After all, we don't point the laser directly upwards at the lid.
The concern is that when the laser hits something - either the material
being cut - or the grid beneath - you get intense light all over the
spectrum from UV all the way down to IR.
This stuff is dangerous because intense light from outside the visible
range doesn't trigger the iris to shrink down.
When a bright light hits your eye, the pupil constricts in about 100 to
200 milliseconds to shut out more light and protect your retina. But it
only does that based on the light detected in the eye - so it doesn't work
to shut out IR and UV.
Another problem is that our laser cutters flash the light on and off as we
cut/skip/cut/skip - and that fools the pupil into not responding fast
enough. The pupil muscles get tired very quickly, and then your response
rate to bright flashes is too slow.
So our natural protection against bright light is totally ineffective with
laser-cutter light and we're completely dependent on the plastic in the
lid. Intense light anywhere in the spectrum is capable of damaging your
eyes - and often without you even realizing it's happening until it's too
late.
Since the amount of light bouncing up from the bed depends critically on
what the laser is hitting, we can't know with any degree of accuracy what
the spectrum of the light coming back through the lid is likely to be.
Specifically, we fondly imagine that we won't be cutting metal -
completely forgetting that the grid beneath the material is metal. Then
we claim that "well, the grid is edge-on to the laser, so it doesn't
reflect much"...forgetting that the grid gets beat up a lot and inevitably
has bent flanges all over the place that will perfectly reflect the entire
energy of the laser back up to the lid - spread all over the spectrum by
the interaction with the metal. (As you cut, you can see those bright
flashes at regular intervals lighting up the entire interior of the
machine beneath the bed.)
So getting clever and picking a plastic that blocks the precise frequency
of the laser itself and is nice and clear so you can see what's going on
is a great way to blind yourself!
This is really no different than with welding goggles.
Hence, I really wouldn't mess around with this. My eyes are worth a
great deal more than $700.
If you really need to save money, buy a couple of cheap web-cams to mount
inside the machine and use solid metal for the lid!
-- Steve
Derek Seabury wrote:
> Hi -
> For the same reason we used clear polycarbonate and a bit thicker
> than the mitsumi. I have some welding goggles for people that want to
> stare at the bright light of organics burning but the clear makes it
> easier to see what is going on with materials like acrylic that emit
> very little light while cutting.
> One note, the door is big! Changing the material can change the
> weight a lot and effect how well the gas struts work. We have had them
> slide when not tightened a LOT. :)
>
> /Derek
>
> On 10/17/2014 5:39 AM, Odd Holstensson wrote:
>> The supplier only have clear sheets and I intend to use regular
>> sunfilm to make those sheets darker, alternativly replace some of the
>> sheets with the composite sheets and make a smaller window instead.
>> The cost cut is more than 700 USD, or over 5000 SEK incl vat, in
>> comparement to misumi. Of course, I can select critical sheets of
>> darker material. Total price inkl VAT is about 1500 SEK for all the
>> sheets, including cuts with better than 0.5 mm tolerance.
>>
>>
>>
>>
>> 2014-10-17 11:28 GMT+02:00 Wolfgang Kraft <Lase...@wkraft.org
>>
>> Hello,
>>
>> you need to take into account, that the cutting process generates
>> as well light in different wave-length from near IR down to UV.
>> Especially, when you try to engrave or etch metall surfaces.
>>
>> Regards
>>
>> Wolfgang
>>
>> ------
>> In Antwort auf die folgende Mail
>>
>> Hello,
>>
>> you need to take into account, that the cutting process generates
>> as well light in different wave-length from near IR down to UV.
>> Especially, when you try to engrave or etch metall surfaces.
>>
>> Regards
>>
>> Wolfgang
>>
>> ------
>> In Antwort auf die folgende Mail
>>
>> From: Odd Holstensson <o...@digitum.se <mailto:o...@digitum.se>>
>> To: lase...@googlegroups.com <mailto:lase...@googlegroups.com>
>> Cc:
>> Subject: [lasersaur] Lexan Polycarbonate and CO2 laser wavelength
>> Date: Fri, 17 Oct 2014 01:53:10 -0700 (PDT)
>>
>>
>> Hello.
>>
>> I have done some research and found out that the CO2-lasera emits
>> light at
>> 10000nm+/-600nm. What I can understand the infrared spectrum
>> starts at
>> about 700nm and above. Is this correct?
>>
>> I have got an offer for clear Lexan Polycarbonate sheets and
>> aluminium
>> composite sheets needed from a local company.
>>
>> The datablade for Lexan 9030 states that transmittance above
>> 2200nm os near
>> zero. What I understand, the color of the polycarbonate sheet does
>> not
>> affect the ir blocking at CO2 laser frequecies?
>> https://sfs.sabic.eu/wp-content/uploads/resource_pdf/1345453948-48623687-Technical-Manual-Coated-Uncoated-Sheet.pdf
>>
>> I would appreciate feedback on my thoughts.
>>
>> The phase in my build is still collecting parts and knowledge.
>>
>> Best regards
>> Odd Holstensson
>>
>> /--
>> To: lase...@googlegroups.com <mailto:lase...@googlegroups.com>
>> Cc:
>> Subject: [lasersaur] Lexan Polycarbonate and CO2 laser wavelength
>> Date: Fri, 17 Oct 2014 01:53:10 -0700 (PDT)
>>
>>
>> Hello.
>>
>> I have done some research and found out that the CO2-lasera emits
>> light at
>> 10000nm+/-600nm. What I can understand the infrared spectrum
>> starts at
>> about 700nm and above. Is this correct?
>>
>> I have got an offer for clear Lexan Polycarbonate sheets and
>> aluminium
>> composite sheets needed from a local company.
>>
>> The datablade for Lexan 9030 states that transmittance above
>> 2200nm os near
>> zero. What I understand, the color of the polycarbonate sheet does
>> not
>> affect the ir blocking at CO2 laser frequecies?
>> https://sfs.sabic.eu/wp-content/uploads/resource_pdf/1345453948-48623687-Technical-Manual-Coated-Uncoated-Sheet.pdf
>>
>> I would appreciate feedback on my thoughts.
>>
>> The phase in my build is still collecting parts and knowledge.
>>
>> Best regards
>> Odd Holstensson
>>
>> You received this message because you are subscribed to the Google
>> Groups "lasersaur" group.
>> To unsubscribe from this group and stop receiving emails from it,
>> send an email to /lasersaur+...@googlegroups.com
>> Groups "lasersaur" group.
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>> <mailto:lasersaur+...@googlegroups.com>/.
>> To post to this group, send email to /lase...@googlegroups.com
>> <mailto:lase...@googlegroups.com>/.
>> Visit this group at /http://groups.google.com/group/lasersaur/.
>> To view this discussion on the web visit
>> /https://groups.google.com/d/msgid/lasersaur/c3fe3be5-b9c4-4b06-9ef0-e4001ef519a7%40googlegroups.com/.
>> For more options, visit /https://groups.google.com/d/optout/./
>> --
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>> To view this discussion on the web visit
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>> To view this discussion on the web visit
>> <https://groups.google.com/d/msgid/lasersaur/395126305.20141017112854%40WKraft.org?utm_medium=email&utm_source=footer>.
>> For more options, visit https://groups.google.com/d/optout.
>>
>>
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>
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-- Steve
namit
Oct 17, 2014, 1:23:14 PM10/17/14
to lase...@googlegroups.com, st...@sjbaker.org
Just a note we went with the opac (brown) plastic and find it to be fine. Its 2mm thicker than standard and cost 190 euro
Odd Holstensson
Oct 17, 2014, 5:05:03 PM10/17/14
to lase...@googlegroups.com
Secondary radiation is a problem regardless. I have not found any description or datasheet of the Misumi material so there are little to go on with that. All I know is that the Lexan 9030 seems to meet the requirement on the CO2 laser wavelength. I do have concerns about secondary radiation, hence my suggestion of sun-film or completly encapsuled with a small Misumi smoke-colored window on top as a solution.
I will not stop my search for information. If anyone has datasheet on Misumis polycarbonate sheets which describes optical properties I would appreciate that so I can compare. However, cost is a concern for such big project and there is no reason to choose a more expensive retailer if there are cheaper equivalent.
I will not stop my search for information. If anyone has datasheet on Misumis polycarbonate sheets which describes optical properties I would appreciate that so I can compare. However, cost is a concern for such big project and there is no reason to choose a more expensive retailer if there are cheaper equivalent.
/Odd
To view this discussion on the web visit https://groups.google.com/d/msgid/lasersaur/a52cf2fd-070e-4918-9ffd-2ca21983ab4e%40googlegroups.com.
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