Semi-Standard 19" Front Panels (w/ inserts)

For 19" rack-mount equipment:

We're thinking of modifying our front panels to accommodate inserts instead of having to CNC & silkscreen the whole thing every time a new order comes in. That way, we can "mix and match" a small handful of pre-made inserts to suit the customer's needs.

One of our engineers wants the inserts to fit tightly when installed from t he rear (i.e., back side of the front panel). When viewed from the front, all one would see is a thin line rectangle with rounded corners; no nuts, s crews or other hardware. There would probably be some pemserts (or equiv)t o hold the insert in place, not visible to the user.

So, here's the question: Does anyone have a picture (or a link) to a product that is constructed thi s way? I need it for "Show & Tell".

Thanks !!!

Reply to
mpm
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Some MEs have a fetish for hiding fasteners. They don't want to admit that they use screws. Sometimes I break stuff like that trying to figure how to disassemble it.

I was thinking that it would be cool to n/c mill panels and then ink-jet the graphics directly onto the metal.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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John Larkin

ad of having to CNC & silkscreen the whole thing every time a new order com es in. That way, we can "mix and match" a small handful of pre-made insert s to suit the customer's needs.

the rear (i.e., back side of the front panel). When viewed from the front , all one would see is a thin line rectangle with rounded corners; no nuts, screws or other hardware. There would probably be some pemserts (or equiv )to hold the insert in place, not visible to the user.

his way?

I'm not understanding what you want. Is the insert a whole electronics module or just a smaller front panel?

We do some things with ~19" boxes and modules, but they all go in from the front, (and are expensive.) Schroff is one manufacturer.

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George H.

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George Herold

You can do this with vinyl overlays. Here is the best picture I can find:

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The unit in the top middle is a slide in module. The one pictured is configured for

2 fiber ports. There is a covered slot for a 3rd port version. This one has the DB15 alarm connectors, another version does not so they are DNP and that overlay covers the holes. The overlay is thick so you really cannot tell there are open slots in the common chassis. The overlays have all the printing on them. The common chassis is just black power coated.

There are several led indicators and I was concerned about visibility issues through such a thick laminate but it is not an issue. I dont remember the thickness or where we got them printed. I would guess any local sign shop could do it for you.

--
Chisolm 
Republic of Texas
Reply to
Joe Chisolm

Do adapters that enable you to rack mount standalone products count?

These adapters work with standalone Cisco network appliances. The standalone is secured from the bottom, so you get the thin line rectangle effect:

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And these adapters work with standalone devices such as Mac Minis and Xboxes. A top strap secures some and you sort of get the thin line rectangle effect:

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Thank you, 73,

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Don Kuenz KB7RPU 
There was a young lady named Bright Whose speed was far faster than light; 
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Don Kuenz

Cheaper (and more accurate) to get PCBs made with, say, black silkscreen on white soldermask, or whatever.

Tim

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Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Design 
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Reply to
Tim Williams

The insert would be just a smaller front panel. The closest thing I have found are the inserts on certain model Carver audio amplifiers.

See image at:

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Basically, there's the front panel with a large cutout. Then, an insert panel gets installed from the rear and aligns exactly (leaving only a thin line where they meet), and appears flush when viewed from the front.

The idea is, we could then machine only these inserts, as things change from one model to the next.

Reply to
mpm

tead of having to CNC & silkscreen the whole thing every time a new order c omes in. That way, we can "mix and match" a small handful of pre-made inse rts to suit the customer's needs.

om the rear (i.e., back side of the front panel). When viewed from the fro nt, all one would see is a thin line rectangle with rounded corners; no nut s, screws or other hardware. There would probably be some pemserts (or equ iv)to hold the insert in place, not visible to the user.

this way?

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Thanks Joe. That's close - and what I originally had in mind at the last design meeting . But (most of) the rest of the team wants to look at mounting from the rear, while keeping the front plate flat (i.e., flush mounted from the rear).

Here's a better link for my original thought;

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Reply to
mpm

Is this perhaps a design by committee? Are you inventing a new form factor or rack construction standard?

May I suggest that you reconsider and not use back mounting. Unless you want your module(s) cantilevered off the back of the front panel (probably with visible mounting screws), such a design will only work if the rack plate and the mounting tray are exactly at a 90.00000 degree angle. Any more or less than 90 deg and there will be a gap either at the top or the bottom of the cutout in the panel or between the mounting tray and the module. Also, the very large hole in the rack plate is a huge waste of expensive metal. It's also difficult to remove a module from the back, but quite easy from the front (with proper connectors and extractor). If the module needs a large surface area ground for EMI/RFI, front mounting is somewhat better. For aesthetics, the rounded corners of the typical rack cutout clash with the square corners on everything else.

If you're going to built a modular rack system, may I suggest you look at 1/2 rack, PXI racks, modular relay rack, and various music synthesizer rack systems (i.e. Eurorack): The drilled and tapped square rod is the key component to making it all work. Of course, I can't find a suitable source.

Subtle hints:

  1. Cut a mechanical part in half and you double the cost.
  2. There's no such thing as "semi-standard". It either complies with an established standard or it does not comply. Modifications, such as what you seem to be suggesting are called "proprietary enhancements" which tend to break standards and compatibility with 3rd part products.
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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Jeff Liebermann

Are these custom one-off units or you just want to make the face plate in a way to save on inventory cost?

I think once you put pencil to paper you will find the inserts along with their mounting parts are going to drive your cost way past just having a simple front panel cut and printed. If you decide to go the insert route I would look at using VHB tape instead of screws or PEMS. Just remember with VHB you will have a hell of a time getting the insert out if you want to reconfigure your generic face plate. You could combine the inserts with a thin overlay. That would allow you to relax the tolerances and ease assembly. The thin overlay gives you the print legends and sharp crisp edges (covering any gaps in the inserts).

With a larger cut out you will loose face plate stiffness, even with a insert in place. Depending on the weight and arm, your face plate could start flexing. This may or may not be a factor with your unit, just keep in it mind.

--
Chisolm 
Republic of Texas
Reply to
Joe Chisolm

Thanks, Jeff. I should have clarified: This is the front panel for a rack mount cabinet (4 walls, top & bottom). And yes, unfortunately (or maybe not?), "design by committee". :)

It is hoped by the team that the inserts will make constant design changes (read: whims of the customers) more manageable as we can more easily handle smaller pieces on our CNC, and pre-build some of the assemblies without ha ving someone's head in the box (literally) doing it.

To answer another question: These builds are semi-custom. From a distance, if you don't inspect too closely, they all sort of look th e same. However, it's the differences that are killing production.

Most of the differences relate to how things lay out on the front panel, he nce the team's interest in cutouts / inserts, etc..

Lastly, I think you're right about coming in from the front instead of the rear. I wasn't even going to mention it to the team as I was under the imp ression it was a non-starter with them. That said, we've been passing arou nd several gear photos this past week and they seem to be warming up to the idea.

Reply to
mpm

Thanks Joe, all good comments! The builds really are semi-custom, which by my definition means: just diffe rent enough from one box to the other to drive you crazy! :)

Tape won't do. (These are industrial / military units.) As for the front panel flex, I expected that. We would either switch to st eel, or use a thicker aluminum front panel overall.

Finally: Cost is always a concern, but execution time is much more importa nt to us and our clients. We send out a lot of our front panels now. But the deadlines are so tight, ("Thanks a lot, Sales!), any blip and we're scr ewed. Plus, it usually means a lot of the pre-work assembly can not be sta rted until the panels arrive.

Reply to
mpm

different enough from one box to the other to drive you crazy! :)

I read your other post. You do have a mess on your hands. If you could go with front inserts (rear mount), a flange on the back of the front panel can add strength and allow you to attach the insert from the rear. That is if you can deal with the increased front panel depth. The key we found for visual appearance is getting consistent gaps. Up to a point, the size of the gap between the insert and panel does not matter as long as it is consistent around the insert. This was in a different product than the one I showed in the picture.

VHB is not your normal home depot double sided tape. Your cell phone display probably has VHB as does your monitor and TV. Ambulance side panels, bus bodies, glass curtain walls on high rise buildings are using VHB. I'm doing away with screws and welds where I can. If it does not need to come apart I first look if I can use a VHB tape. 25mil tape to hold enclosures. VHB is good in high vibration environments.

We are also starting to use more structural adhesives. Example would be attaching that flange to the back of the panel. Something like a Dupont betamate or 3m panel bonding adhesive. No screws, no welds, no pems. My latest test is adhesive mounted board standoffs. The current case is steel and thicker than needed to work with the pems. weighs a ton.

to steel, or use a thicker aluminum front panel overall.

important to us and our clients. We send out a lot of our front panels now. But the deadlines are so tight, ("Thanks a lot, Sales!), any blip and we're screwed. Plus, it usually means a lot of the pre-work assembly can not be started until the panels arrive.

Expensive but one with lots of options would be to use a FRP panel of some type. Maybe a 20pcf rigid foam core with carbon fiber or E glass facings. This thing could be made stiff as hell and the insert flange molded in panel. You take your inserts and bond them in place. You might have to add in a EMI screen and hard points for handle screws and such. Expensive but you could selectively place the core material to give you the stiffness you need without much weight.

Ending the night on that crazy idea. Hope you find a solution.

--
Chisolm 
Republic of Texas
Reply to
Joe Chisolm

mpm wrote in news: snipped-for-privacy@googlegroups.com:

This is simple. I have 1U, 2U, 3U and 4U 'ruggedized' designs (read heavy load capacity) Fully compliant rack spec. (as in all weight held by front plate.

Any "cut out" "swap out" panel design ideas you have cannot comprimise the fact that the entire device must be supported by that front plate you are wanting all chopped up.

Best to design a standard, full plate units, and make some custom CAD projects that allow you to compile your 'custom' design and send it out to be machined or do that simple mill work in house.

The reason is that if you make wide and tall cutouts that allow you to add in your custom fill plates to those cut-out positions, the integrity of the rack device itself must be examined carefully.

You can have tabs on the back side of the fill panel that screw cinch into blind PEM locations on the back side of the front panel blank. That will/can also limit that extents of the panel itself. Of course more intricate designs could be done wher you are fixing your custom panels into place with set screws placed on the apron of the cut-out opening.

I simply designed a nice, rigged, heavy handling 4U unit with a bare tray behind it and side edge gussets to brace the tray. That allows a customer to place his instruments/devices on the tray and fashion their own front panel set-up.

Simple plate machining is easy and cheap.

Cheaper than an elabortae 'swap out' 'customization system'. The inventory maintanence alone would make it prohibitive these days.

Reply to
DLUNU

mpm wrote in news: snipped-for-privacy@googlegroups.com:

Another good reason to get a small vertical mill. They are fairly cheap, and you could proof out your design before sending it out, or even do the entire run yourself. The total order count matters there. A few pieces are worth doing in house. Large orders are worth contracting out with first piece or first run promises. That is what you get your sales staff to do. Get the contract machining house to promise a first article or short count first run on a deadline that harms them if not met.

Reply to
DLUNU

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