You will notice flex PCBs within most cellphones or similar miniaturized gadgets. Flex PCBs square measure helpful for creating little cables and intensely light-weight circuits.
However, few outlets however build custom flex PCBs for affordable costs in tiny volumes.
Step 1: Get copper-coated film
Picture of Get copper-coated film
Get some skinny sheets of polyimide that have copper on one or either side. Polyimide may be a yellow chemical compound with a high melting temperature and is typically referred to as Kapton. a standard kind of copper-coated polyimide is DuPont "Pyralux" material.
Pyralux sheets are available in many various forms of polyimide thickness, copper thickness and adhesive thickness (the "adhesive" is between the copper and polyimide holding everything along.) Copper thickness is given in oz per sq ft, whereas adhesive and Kapton thickness is given in mil (1 mil =0.001 inch).
Pyralux LF7062 (pictured) has 1/2 oz copper, one/2 mil adhesive and 1 mil Kapton. This works OK however may be a bit skinny and rippled for the printer to handle.
LF9120 has one oz copper, one mil adhesive and a couple of mil Kapton - appears to figure best within the printer
LF9210 has two oz copper, one mil adhesive and one mil Kapton - stiffer, however works OK
Other choices square measure double sided copper ( a sandwich of Cu/Kapton/Cu command along side adhesive) and a cracked surface, denoted by R at the tip of the half range.
The cracked sheets and double sided sheet work OK. However, Pyralux with two oz or thicker copper will be troublesome to feed to the printer, particularly if there's copper on either side.
See if you'll be able to get a free sample from DuPont. often, Pyralux sheets take place on eBay.
Cut the Pyralux sheets to eight.5x11 or 8.5x14 inches with scissors or a knife. Avoid smudging the copper with fingerprints or oil, which may block the print resolution later. to guard the printer, attempt to keep the perimeters comparatively flat and freed from burrs.
For direct printing on the copper film, find a solid-ink printer. These square measure ordinarily confused with optical device printers, however instead print unfrozen wax. in contrast to most inkjets, the wax makes a decent protecting layer for copper etching, and in contrast to optical device printers, solid ink printers do not think about domestically charging the paper surface, that may be difficult once the paper is replaced by a copper sheet.
Some models square measure Tektronix Phaser 840, 850, 860, and Xerox Phaser 8200, 8400, 8500, 8560, and 8860. you may notice one in AN workplace. Most Phaser models square measure regular optical device printers, thus check below the hood for the solid ink blocks (pictured) if you are not certain.
If you do not have access to a solid ink printer, the "toner transfer" iron on methodology, employing a laser-printed style, might replace this step.
Draw up a style in any graphics program, then use the manual feed receptacle to print it on your Pyralux sheet in black. Cyan, magenta, yellow, inexperienced (50/50 cyan+yellow), red (50/50 yellow+magenta) conjointly appear to figure, simply avoid light-weight shades that square measure composed of small dots on a white background. written areas are protected with wax, and finally end up as copper traces on your layout.
Note additional 3-7-08: Use "high resolution" or "photo" mode once printing. This printer setting is often accessible within the "Print Setup" menu of your graphics program. high-resolution mode prints a lot of slowly and appears to market higher adhesion of wax to copper.
10 mil (250-micron) wide lines and areas were written from a Tektronix Phaser 850, that is AN older model.
In most Phasers the copper facet ought to face down once it goes within the manual feed and comes out the other way up. provides a very little push if the manual feed cog has hassle grabbing onto the sheet (more possible with thicker sheets)
Put the written sheet in ferrous chloride (copper etchant) for a minimum of five minutes. Keep the etchant from more matured your eyes and skin. The print time can rely upon temperature, copper thickness and alternative conditions, taking on to twenty five minutes, thus keep anticipating copper areas to dissolve and therefore the polyimide film to point out up. effervescent with AN vivarium pump, and heating up to 35-40 C can facilitate the print proceed quicker and a lot of equally.
The remaining wax will be clean off with a ScotchBrite pad and heat water, or isopropanol (rubbing alcohol). this will take some effort.
Picture of Populate the board
The flex PCB is currently able to cut apart into tiny circuits (if that is your plan) and to solder. you'll be able to tape it onto a chunk of metal or a daily fibreglass printed circuit to carry it steady whereas acting on it. "Tinnit" nickel plating resolution or similar will be wont to build it easier to solder to, however the freshly incised and cleansed flex PCB is well soldered as is.
Because it's a 1-sided PCB, while not holes, it's most helpful as a small cable or as a board for surface mount elements. Use jumpers if necessary for traces to cross on your layout.
AWM 20624 80C 60V VW-1 Touchpad flexible printed circuit
No comments:
Post a Comment