insulating sheet for hard drive PCB

Do you see the insulating material in this parts manual ?

Paul

If it's not included on the drive, you shouldn't need it. If you are paranoid, you could use a simple piece of printer paper trimmed down to size, or use a clear plastic page protector.

It's EMI shielding foil laminated to an electrically insulating layer of polyester (Mylar), vinyl (PVC), kapton, or polysulfone. 3M and Chomerics are 2 makers, and sometimes local distributors will give people small samples. You can probably get by with making your own from aluminum foil and several layers of Mylar,. kapton, or polypropylene tape. Use enough layers to make it thick enough to withstand being pierced by soldered leads (Mylar and kapton resist piercing better than polypropylene does) but not so thick that it fits tightly and blocks air flow. The tape should extend slightly beyond the perimeter of the foil, to prevent shorts against the foil. You may have to cover both sides of the aluminum, in which case at least one spot will have to be left bare to allow direct contact with a ground point (often a metal spring). Actually this homemade lamination may not be completely proper because the insulation isn't anti-static, but in practice it should be safe.

Just re-use the one from your dead HD

A bit more detail might be useful...

What makes you feel your new drive "needs" this added? Is the drive cavity of the notebook irregular and the drive circuit board would be touching metal portions of it? That seems doubtful.

Drives are designed to be used as-is, and notebooks generally to accept "as-is" drives... I tend to suspect that if you needed this plastic sheet it would've been built into the notebook, not on the drive... but then there isn't much info to go on.

If all you want is an insulating plastic sheet for some other use, just grab any random thin sheet of plastic and a suitable adhesive if needed.

Thanks for all your answers.

A bit more detail:

Oddly, the bottom of the HD cavity is in metal, and the drive is mounted on a metal caddy that doesn't prevent contact. That's probably why the laptop manufacturer (Compaq) has glued this insulating sheet on the PCB.

Anyhow, if I don't find a proper insulating sheet I will use a simple sheet of plastic, as suggested. Any comments on which type of plastic might have better anti-static properties, if that matters ? I think the kind of insulating sheet I was looking for also provides some electromagnetic interference shielding. Does this matter for a HD ?

Regards,

alex

Anti-static isn't really an issue, it only needs be thick enough to prevent any edges from wearing through it.

Personally, I wouldn't affix the plastic to the drive at all, I'd put it in the notebook over this problem area. That might also allow the drive to run just a little cooler as more airflow will result across the PCB.

I suspect it was just cosmetic, maybe it was ESD protection during an automated (or manual) assembly process but doing this yourself and being mindful of ESD, once you have the drive installed this should not be a problem. What could be a problem is if you used ESD protective material and allowed the conductive side to touch the PCB which could provide a high resistance electrical path between parts, a path that should not exist. No HDD will need one of these shields in a normal use, hence why they didn't have one installed already.

I don't know about your particular drive, but generally there are not sharp through-hole component leads sticking down below the circuit boards. This plastic sheet may not need have much abrasion resistance beyond a reasonable thickness, anything 12 mils (.012 inch or about 1/3 of a millimeter) thick should be plenty if there aren't any sharp leads resting on it. I'd probably try something like hobby/craft contact cement as an adhesive though you'd want to be sure it didn't get on any outer/visible plastic portions of the notebook.

kony wrote in news:evo6q1lll07qa5j324gefprr2kebosvr0h@

4ax.com:

... snip ...

A simple sheet of plastic will be bad news for ESD, it will charge up to 10,000 volts if you rub it together. This is easily seen with an ESD Static Field Meter. Well, a stupid move, don't do it. Instead of plastic sheet, have you heard of conformal coat spray used in the electronics industry? Well that's a bad idea you'll probably over spray. What about fish paper? As an insulating material, it's safest for anyone who dosen't know a thing about electronics.

The metal of the HD cavity probably proides all the EMI shielding you need, in which case the fish paper mentioned by Newtype is the best solution because it doesn't generate much static and is fairly hard to pierce. Electronics supplies carry it, but you should be able to use thin cardboard gasket material instead. I'm not referring to ordinary cardboard but the thin, dense type that's usually dark gray. The best plastic to use may be mylar.

Rub it together with what, exactly? You're arbitrarily looking for a problem where there isn't one, if you rub "something" against just about any circuit board there is a theoretical potential for ESD, not just some addition of a piece of plastic.

Don't be an idiot. Electrical and electronics Industry uses plastic sheeting for insulation all the time, there's probably even one in your power supply, if not multiple sheets. If you have some irrational fear of what'll happen when you rub two sheets together in an effort to create ES, might I suggest that you not try to create any?

The only stupid thing in this scenario with the drive would be to fasten the conductive side of an ESD material to the drive PCB.

Yep, it is NEVER used for direct mechanical contact between parts that need insulation.

If it weren't for the part about it being entirely unsuited to the task, overspray would not be a problem so long as any possible air intake areas were covered first. Carefully masking around an area is a time-proven way to do this but it's beside the point, this is not a suitable alternative for insulation purposes of the drive.

Paper or cardboard would work, but there isn't much point to either of these unless one simply can't find any plastic, but what 4th world country would one have to live in to not even have access to a discarded product packaging that was plastic?

This need is easily met, you're making a mountain into a molehill.

kony wrote in news:91b7q19cu6bsqun46ekd3sqtg3hp7vk1oa@

4ax.com:

Rub it with itself, what else? Duhh. Oh yeah, you don't about ESD damage. experiment 101, get a ESD Static filed meter. Rub plastic together and bring it 1" from ESD meter, reading will be above 6,000 maybe to 15,000 volts. Simple triboelectric charging experiment. Look up Triboelectric charging.

This arbitrary problem is a present day industry wide problem!

You don't know about triboelectric charging. You take a piece of plastic, your touching it, rubbing it, handling it, charging it up. Do the same with a ESD mylar bag or pink poly bag and you get no charge. which means you don't know how to make a charge or prevent charging up of materials.

Wrong. Electrical uses plastics, electrical not damaged by voltages about 1000 volts. You have to look at ESD ratings. You don't know about ESD. hoo humm,

DOD-STD-1686 ESD/EOS 5.1 VOLTAGE RANGE Equivalent CLASS 1 CLASS 0 0 to to the task, overspray would not be a problem so long as any

Conformal coat spray comes in mainly 3 different ratings, silicone (gc chemicals makes this spray) and gives up to 10,000 volts of barrier protection at 5 to 10 mils. Heavy duty silicone conformal spray, gives bigger voltage barrier. And then the bad cancer causing stuff used for MIL boards, which no can buy anyway.

I doubt that the assembly of a HD in a chassis is going to experience over 10,000 volts or static zap. So Silicone conformal coat spray is a suitable viable option. But if you've never done before this, forget.

Wrong, uhh, Fish paper has a MSDS and you can buy fish paper in different voltage levels, ex. 10,000 volts is common form any electronic surplus store. You can buy fish paper for higher rated voltages. And this higher rated stuff is for 'Electrical' insulation, not electronic. I've seen up to 60,000 volt break down fish paper, so says the mfg MSDS, don't you know?

Paper or cardboard is not a a suitable material because it can not provide any barrier against voltage, it is not an insulator. white paper or cardboard out gasses chlorine causing corrosion but what do you know? so far not much.

Typical tech spew. You have to think about the problem and find the correct solution. Not act, like a typical garage tech junkie. Junk makes junk.

How would you propose to do this? Fold it over, or cut it in half and pretend you're a cricket during mating season? I hardly think that's a realistic scenario unless someone is trying to do it.

So what's the point exactly?

Ok, let's play Devil's advocate- It is a bad idea to take multiple pieces of plastic, rub them together trying to create an ES charge then try to discharge it through the hard drive PCB. With that out of the way, like I already wrote manufacturers use plastic sheeting all the time for insulation and not ESD preventative types, just plain old plastic.

ESD is, yes, but trying hard to create some hypothetical scenario is a pointless exercise, since we can do same with practically any event, even walking across carpeting. Do you propose we float above the floor from now on too?

The answer is simple, the chassis is grounded, installer is discharged and mindful of what's being done... as is always the scenario. If you're really worried about this then I hope you have no plastics in your case else you can never work on a computer again.

Yes, it's possible to create a charge. It's possible to create a charge without any plastic, too, and plastic sheeting IS used for insulation, not ESD rated plastic just plain old untreated sheeting. I don't suppose I need mention that the products using them, work.

You are being ridiculously oversimplistic. Some vague concept about ESD, has to be applied to the actual scenario. Yes, ESD exists, and there has to be a mechanism to cause, and discharge, for there to be a problem. Likewise when working with any computer components.

I do hope you eventually take it OUT of that bag to use it!

... and likewise, the part is removed from the bag to be installed, the bag is not strapped to the part in the system.

I hope you someday see beyond your oversimplified view. This is done so that the parts are protected UNTIL they're readied for use, and similarly so with the hard drive, it should remain in it's ESD bag until installed... at which point it is REMOVED from such bag,

Do go ahead and skip right to the logically fallacy you consider to be your point. Nobody ever claimed ESD doesn't exist. Now fast-forward from protective packaging to actual part usage.

I don't know how to break this to you, but this is not news to me, it's not advancement of your argument but a side-track from the central issue. I encourage you to open your system and count all the semiconductors still wrapped in anti-static baggies.

No, the conformal coating is NOT anti-abrasive, it is a sealing agent only, not a mechanical insulator.. It is not used in place of plastic sheeting. You haven't a clue.

Yes, on standoffs, plastic sheeting, or other methods which isolate the board. The conformal coating is never called upon to take this role.

It's sad when someone like yourself gets so far away from reality that they'll never be able to relearn things correctly. NO, there is no properly engineered card where a conformal coating is called upon to insulate a card from a card guide. The card has the allowance for this contact region, engineered onto it, either an isolated region or a ground. I hope you never actually have to depend on this illusions you've suggested, nor that anyone else ever does.

Sure, it can and does insulate. That doesn't mean it also has the other properties necessary for mechanical fitness like abrasion resistance. I suggest that you stop guessing and take a good hard look at some (any) electronics products, as I"d love to hear of any that are using conformal coating as an insulator against a mechanical contact between conductive metals.

I recommend that anyone reading this, completely ignore you. There is no need to start spraying conformal coating on anything, it'll just make a mess and there is still a more robust insulator needed, IF there are actually any potential points of electrical contact between the laptop bay and the drive PCB.

One would hope that after you're done with all this babbling, you manage to pay attention to what you're doing instead of rubbing sheets of plastic together trying to create ESD, and thus, you won't have 60,000 volts to worry about. Ever heard of "Fire Marshall Bill"?

Actually just about any kind of paper or cardboard suitable thick would work. This is a one-shot installation of a part, and like all the other parts scenarios you foolishly overlook, it does not need continual protection against

60,000 voltage, only to be installed in a ESD safe environment and be an effective insulator against 5V, but as importantly, be mechanically sound from an abrasion and puncture standpoint if the drive is putting pressure on it.

It's somewhat amazing that you take such pains to make even simple things, as difficult as possible. Perhaps you should just focus on same things the entire industry does, that the key is proper handling form the time the part is removed from the bag, until installed in the equipment. Unless you're a tool that's going to be continually shuffling around on your carpeting then trying to discharge your finger on the back of the hard drive circuit board, you do not have a need to continually protect against very high voltage. In other words Fire Marshall Bill, I'm sure if you try hard enough you can manage to damage something- now might I suggest you just blindly follow industry standard procedures which are demonstrated to work, instead?

Then why have you drifted off on a tangent instead?

I look forward to seeing pictures of your entire system dismantled so you can spray conformal coating over everything before placing each piece back in anti-static bags. That's the easy part- I want to see how you'll use the system like that.

There are metal-coated zip lock bags. I know this because several times I've yelled at a certain individual who always rips them open instead of undoing the zip lock seal so the bags could be reused.

Good ESD handling practices greatly reduce mysterious failures.

snipped-for-privacy@whoever.com wrote in news:1134877112.214135.49440 @f14g2000cwb.googlegroups.com:

Your talking about ESD safe anti-static mylar bags with ziploc closure. The zip lock I point out for Kony@NYB ? is a clear zip lock bag for food.