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Home > Archive > Hardware > September 2003 > Question about acrylic cases.
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Question about acrylic cases.
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| Tennman 2003-09-19, 6:41 pm |
| If anyone on the hardware forum has built a totaly acrylic case and installed all the necessary components to make it a fully functional computer, have you had any problems with EMR?
Second question, how did you ground the computer? | |
| Kasor 2003-09-20, 11:17 pm |
| Why u need to build acrylic case?
U can get the wrist band, boot or mat.. | |
| azimuth40 2003-09-20, 11:33 pm |
| quote:
Originally posted by Kasor
Why u need to build acrylic case?
U can get the wrist band, boot or mat..
Kasor I don't think you understand, he said EMR and you are talking about ESD. Two different things EMR think radio transmitter Electro Magnetic Radiation vs. Electro Static Discharge. Here is a picture of the type of case that he is talking about, it can be made with or without a slight lead impurity to limit EMR to acceptable levels but it is doubtful for the cheap ones. Monitor plastic often has the impuritiy or is simply sprayed on one surface. The computer is grounded by the power supply just like a monitor case, plastic printer, modem, router or any other plastic case product. | |
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| Personally I prefer to hide it in a decent looking case - why have windows & flashing lights etc. - what is it a computer or a damn disco box  | |
| Tennman 2003-09-21, 11:38 am |
| Thanks for the input guys.Yes I am looking into the possibility of building a acrylic case, but I am worried about EMR. As some of you know plastic which is what acrylic is, can act like an capacitor and build up huge charges within the case. I have heard of people touching the cases and getting nasty shocks.This is what I am thinking about doing.
1.> Building the case out of 1/4 inch thick acrylic.
2.> buying and installing standard metal drive cages in which to install the drives.
3.>designing a 1/32 in. alum.mobo. platform on which to mount the mobo using both metal and plastic standoffs.
4.>Soldering a ground wire from the drive cage to the mobo. platform and another wire from the mobo. platform to the power supply houseing. This should help contain stray charge build up in the acrylic case.RussS, lol, i love that answer. Don't get me wrong , I am not laughing at you, but you have a good point.I wont to do research into the EMR problem of acrylic cases. can they be made so as to limit the EMR to at are below U.S. and Worldwide standards ? The purpose of acrylic cases is to allow the componets of the computer to be seen, will complying to EMR standards make this impossible? Let me know what you think. | |
| azimuth40 2003-09-21, 6:04 pm |
| quote:
Originally posted by RussS
Personally I prefer to hide it in a decent looking case - why have windows & flashing lights etc. - what is it a computer or a damn disco box
Well having started in the computer field at a time when most mainframes looked like disco boxes, I don't have a problem with them. I worked and did design on systems where most major flip flops had a led attached, micro-operators (firmware today) had flashing indicator lites. Under the premise that everything old eventually becomes new again (lighted computers), I find it amusing. | |
| azimuth40 2003-09-21, 6:29 pm |
| Well what I think is a lot of this work has been done and you may just be recreating the wheel. I mean isn't this problem solved in every cell phone for example and they come in almost clear models. Short of having a certified EMI test cage, how are you going to test it. You could use a TV and a Radio to get subjective information. However short of a spectrum analyizer I am missing the practical data gathering. You can look into the films used to coat the inside of most plastic based electronics.
Acrylic has more of a problem with outside static generation than surpressing inside EMR. There are metalized plastic shields for the bottom of the motherboard, the main source of radiation. The case that I showed has a metal back for the I/O. For the inside of the case flims exist that are 70 percent plus light transmissive. Lead based and other metalized sprays are problematic without the right safety equipment and robotic arms to monitor thickness. Here is a start that specifically addresses acrylic. Interesting research project, good luck.
http://www.astraproducts.com/i_aremifil.htm | |
| Tennman 2003-09-21, 11:24 pm |
| quote:
Originally posted by azimuth40
Well what I think is a lot of this work has been done and you may just be recreating the wheel. I mean isn't this problem solved in every cell phone for example and they come in almost clear models. Short of having a certified EMI test cage, how are you going to test it. You could use a TV and a Radio to get subjective information. However short of a spectrum analyizer I am missing the practical data gathering. You can look into the films used to coat the inside of most plastic based electronics.
Acrylic has more of a problem with outside static generation than surpressing inside EMR. There are metalized plastic shields for the bottom of the motherboard, the main source of radiation. The case that I showed has a metal back for the I/O. For the inside of the case flims exist that are 70 percent plus light transmissive. Lead based and other metalized sprays are problematic without the right safety equipment and robotic arms to monitor thickness. Here is a start that specifically addresses acrylic. Interesting research project, good luck.
http://www.astraproducts.com/i_aremifil.htm
Thank you azimuth40, I have been researching this subject for days and not found a lot of material on the internet.This info you gave me will help a lot. This problem has been solved in a lot of consumer products as you say. the problem here is that clear acrylic computer cases are so new that very little study has been done specifically about EMR reduction on this type case. Every company that I seen that provides case documentation have a disclaimer on them saying to the effect that this case is to be used for display only, no working computer parts should be installed.
If the EMR shilding reduces the light transmission to 50% or less then there is no point in building transparent computer cases, because you would not really be able to see into them very well,therefore defeating the purpose of the case in the first place.Once again let me think you for your time and help. | |
| azimuth40 2003-09-22, 12:37 am |
| Hey no problem always glad to help. You may be on to something that could make you some bucks as the case mod'ing craze seems to be on a big increase right now. If not maybe there is a project in there for your MSEE quest. | |
| Tennman 2003-09-22, 10:29 am |
| quote:
Originally posted by azimuth40
Hey no problem always glad to help. You may be on to something that could make you some bucks as the case mod'ing craze seems to be on a big increase right now. If not maybe there is a project in there for your MSEE quest.
Hay, I will take either... Right now though I am leaning toward the money LOL |
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