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At this time of year . . .

December 17th, 2013 | Posted by Jacque in Uncategorized - (Comments Off)

. . . we make a lot of lists, drink a lot of eggnog, and remember a lot of things that we’ll “do better next year.”

Here at TGB, Inc., our gift to our extensive list of clients and suppliers is to renew our commitment to provide both the very best service and the greatest possible value in the coming year. We are thankful for each of you and we wish you a peaceful holiday season.

“Somebody just handed me a drawing…”

April 20th, 2012 | Posted by Jacque in Uncategorized - (Comments Off)

Are you a purchasing team member looking for the “right” source for that metal stamped part the engineer just handed to you?  You may have casually asked, “What project is this for?”

“Oh, that’s a metal stamping for the EFG project,” you may have been told.

If you are not experienced with  stampings, you may have taken the drawing back to your desk and puzzled over it.  Let’s start with some basics, and see where we end up, shall we?

There are several different processes used to make metal stamped component parts.  Each process is different in the types of metal used, the equipment utilized, and the volume of parts produced.

Let’s start with a situation where you need a fairly simple part, and you only need five prototypes for the engineering department to work with.  You’ll probably be looking for a fabricated part — formed by using a turret press and a press brake.  Say what?  OK,  the supplier will shear, or cut a piece of metal by using a turret press, and bend it to the form needed, on the press brake.  If he needs a little more precision on the cutting, he can utilize a laser; then he’ll take it over to the press brake for bending.  This prototype process is not as exact as other stamping methods, but it makes up for the difference in accuracy by having far less expensive tooling (or no tooling at all).

The next rung up the ladder is a part that requires stage tooling — tooling that is used for each stage in the process.  There may be one tool for blanking, or shearing a desired shape from a much larger piece of metal; another tool may form, or bend it; and yet another may pierce or notch the metal part.  If it is written in the specification, the finished part may be de-burred, or have the rough edges smoothed.  These custom stage tools may require more substantial tooling costs, but the cost of producing the parts may be lower, and offset that tooling cost. This process is useful for what stampers call “short” or “medium” production runs — low to medium volumes of parts.

The top rung of the ladder is the progressive die process of stamping metal parts. This is the process that has the highest tooling costs — but the piece prices are dramatically lower, so this is typically used for very high volume production.  In this process, the tooling is extremely precise; very close tolerances can be achieved.  Parts are blanked (cut out) and formed (bent) in a long strip — at each step through the die, another step of forming the part is completed. Finally at the end of the die, there is a final operation to remove the finished part from the strip of metal.

Another consideration for a stamped component is the material.  There is a wealth of possible materials: ferrous (containing iron), non-ferrous, even alloys of  exotic metals like titanium and magnesium.  Stampings can be made of carbon steel, stainless steel,  aluminum alloys, copper alloys; and the base metal can be plated with gold, palladium, nickel, and tin, to name a few.

Whew! I think we’ve established one thing — there are a lot of things to consider when metal stamped parts are required.  Choosing the appropriate supplier for your component parts will be just as crucial as selecting the material and the process.

To assure the success of your project, rely on TGB Inc to assist you by matching your project and specifications with just the right manufacturing partner!

 

Many of our readers will find this information “old hat” or say, “that’s a given” but I think it’s time we addressed printed circuit boards in all of their flavors.  Over time, they have been called different things: printed circuit boards (PCBs), printed wiring boards (PWBs), printed circuits, boards and cards.  To add to a new buyer’s confusion, we can provide rigid boards, flexible boards, and rigid-flex.  You can choose your color of solder mask  (default is green), you can specify the number of layers, and you can even have “mouse bites”……huh?!

OK, let’s fall back to what a printed circuit board is, first.  To get really basic, if you have dropped your phone, peered into the dark innards of your old TV, or taken apart your gaming console or PC, you’ve seen a Printed Circuit Board Assembly (PCBA) and what all those components (resistors, capacitors, diodes, etc) are mounted on is the PCB.  Remember seeing those?  Well, that “Bare Board” (see, we’re calling it something different again) is typically made up of multiple plies of epoxy-glass laminate material with copper foil bonded to the outside.  That foil has been plated and etched to form a pattern of conductors (traces or lines, pads, which can be thru-hole or surface mount & plated-thru-holes or PTHs, which can be component or vias).  The laminate acts as a non-conductive insulating base, while the copper pattern acts as a conductive interconnect for the components.

 

traces on printed circuit board

Printed circuit boards can be single sided (1-S), double-sided (2-S), or multi-layer (M/L).  In a four-layer (4-L) board, for example, you have two external circuitry layers and two internal layers all laminated together.  As you might surmise, a M/L is going to be more expensive (the more layers the higher the cost) than a 2-S, which is slightly more than a 1-S.  M/Ls are almost always designed with an even number of layers for purposes of balance or symmetry.

Remember those lines?  Traces, I mean.  Those are made of special copper, selectively covered with soldermask (typically Liquid Photo-Imageable-LPI) with all the component interconnect pads coated with solder (HASL process) to prevent oxidation.  (Unless it’s a lead-free board, but that’s a subject for another day.).  PCB size and thickness are both significant cost drivers.  The tighter those boards are designed or laid out, with high density fine traces and spaces, also drives up the cost.  Even the number of drilled holes, and the sizes of those holes, can make a difference in the cost of the board.

Sometimes a customer will need all of the boards supplied as single pieces (1-up); you pick up one piece and that is one board.  Sometimes they will prefer an “array” of boards; you pick up one piece, there may be two, or five, or twenty or more boards in your hand.  Sometimes the arrays can be V-grooved (scored) & sometimes they are routed with tabs so that they can be snapped apart after assembly.  Remember those “mouse bites” we alluded to?  Those are little chunks of laminate that are removed from the tabs, so that the process of snapping boards apart is made easier.  (No mice are harmed as a result of this procedure.)

Well, hopefully you haven’t crossed your eyes, gone to sleep, or worse, found an error in my explanations.  Maybe this information will help some of our customers who are new to the game. We’ll cover flex boards and lead free process in later posts.

Thanks for coming along on the ride,

Jacque