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How to create a card guide in the sheet metal

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tduong

Mechanical
Dec 17, 2002
7
Please help to show me how to create a card guide in the sheet metal.
Thanks
 
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Could you be more specific ?
Are you looking for general solutions or do you have a design in mind ?
Sheet metal punch manufacturers often give away sample pieces showing their tooling - These are excellent for giving ideas.
Most people do something which pushes up two tabs - Of course it is conductive and has no compliance.
If you want to look at really complicated solutions have a look inside some PC cases !
 
Why would you want to MAKE card guides when there are so many manufacturers who sell them? I don't advocate any particular vendors, but you can try APW Electronic Solutions (formerly Zero Elec Solns/Bircher) for sheet metal (Be-Cu) card guides. If you're going to make your own, the best choice is Be-Cu due to its "springiness" but to get the design right is tricky. Also, due to the environmental sensitivity of working with Beryllium, there aren't many metal fabricators who work with it.

There are so many good manufacturers to choose from. Thomas Register is a good place to browse for sources in the USA.

Bruce
 
One of us is not understanding the question.
Tduong - are you trying to make card guides direct into a sheetmetal enclosure - to avoid extra piece parts, or to make metal card guides to rivet/weld/clip into something ?
I have only ever used plastic guides from Richco and similar.

Steve
 
I am assuming that you want to create support for a PCB directly in a 0.03" - 0.05" sheet metal housing, without separate card guides.
I agree with sjwilson, check tooling catalogs and speak to your fabricator, as they probably have some suitable tooling sets already.
Remember, watch for shorting, plus the board will get scratched so don't run traces under the resist on the slideing areas, etc, etc.
Allow plenty of overlap of the PCB so as not to be tolerance sensitive.
One of the best designs in my opinion shears a pair of slots in the sh. metal side wall.
One above and one below the PCB. But the waste pieces are not sheared thru' - they remain attached at the ends and the 'bridges' that remain are formed inwards like crescents so as to form a groove that the PCB can slide in. Repeat this pattern along the length of the PCB, down both sides. The slot in the side wall might be 0.50" long and 0.08" high, and the crecent at its apex might protrude 0.1" - 0.12" into the box.
It's not too pretty from the outside but it is reliable and tweakable.
 
Tdoung, pick up the Newark Electronics Catalog and look up nylon card guides. Select the guide for your card's thickness and copy the hole pattern for it to your sheet metal so you can snap them in. Be care with the width between slots vs. board width and position. Connectors are usually at the front and rear ends of the card, and these engage fixed connectors in another board or align with a panel.
 
There are numerious styles of card guides; Plastic and metal types that attach to a chassis (sheet metal or machined {typically aerospace/millitary}).

In sheet metal there are two departures. As mentioned above, what's called the "double bridge-lance" style and the formed or wiped up double wall (typically with flared ends). I've used each extensively.

Where EMI/RFI containment within the cage is important, I typcally opt for the double bridge-lance. This is produced in CNC turrets using a "shear-form" tool. In a single stroke of the press, the tooling shears and forms both bridge lances onto the non-burr side of the material. If you want a lead in to make starting the card easier you'll need a custom wide-mouth double-bridge lance produced. While double-bridge lances are not uncommon, they are all bought as custom tools and if your supplier has one that works for you, consider yourself lucky. If you're stamping a double-bridge lance, most toolmakers will recommend or even require a slot on each side of each bridge-lance that is equal to the length and at least 1 material thickness in width (Stainless 1.5 to 2 X mat'l thk).

If smooth riding and ease of starting the card is important, then the flared ended double wall card guide. Whether fabricating or stamping, a slot running the length of each flange is required. Depending upon the tooling, the width of the slot will vary, typically .062 or greater. There will be a minimum allowable spacing between rows and collums of each card guide feature. Check with your supplier. Here again, these tools (for fabrication) are purchased as custom tools. If your supplier has one lying around that will work for your application, you're in luck.

As far as sheet metal card guides goes that's a quick review from a manufacturability standpoint.

Good Luck, Don
 
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