What Is MicroWipe™ FP Stencil Wiping Paper?

Micro•Wipe™ stencil rolls from MicroCare have been the industry’s leading stencil cleaning roll. Now, the best has gotten better with Micro•Wipe™ FP stencil cleaning fabric.

At a microscopic scale, an SMT stencil looks like thousands of tiny razor blades. Those sharp edges shred old-style stencil wipes, causing defects and rework. Tough, durable MicroWipe FP fabric minimizes this problem.

This  fabric — not paper! — has been engineered from the ground up and optimized for fine-pitch stencils and lead-free solder pastes. This new technology increases through-put while reducing defect rates. Today, more than ever, MicroWipe FP rolls are the smart choice for cleaning stencils. The single most important difference is that this new fabric is so strong and cleans so well the stencil can be wiped dry, without using solvents. This saves money, improves yield, and extends roll life. This is a unique benefit available only from MicroCare.

Not All Papers Are Created Equal

The 'FP' fabric itself is different from traditional stencil roll paper. Let's take a look at the differences:

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Photo, right: Inexpensive stencil rolls normally are made of polyester fibers bonded together with glues. These glues fill the empty space in the paper between the fibers, limiting the amount of solder paste the wipes can scoop up. In addition, the fibers themselves are feeble and prone to shredding. Glue clogs the interior spaces of these cheap stencil roll paper, so the paper can’t pick up as much solder paste as one might hope. 

Cross section of fibers in paper used for stencil cleaning.

Photo, right: More expensive paper, such as the classic Sontara® material, are based on a “sandwich” of hydroentangled mix of cellulose and polyester. The cellulose absorbs the solvent and solder paste while the polyester provides strength, and the two fabrics are bonded together without glues or binders. This is not a bad paper. But the cellulose tends to shred, which decreases throughput and quality.

Cross section of fibers in paper used for stencil cleaning

Photo, right: In contrast, MicroWipe™ FP fabric is a hydroentagled mesh of durable, absorbent, pure, synthetic fiber. The individual fibers are extremely long, hard (uncrushable), clean and lint-free. All of this reduces linting, improves paste pick-up, and enhances absorbency. This improves the results from each cleaning cycle. In effect, each fiber becomes a tiny squeegee, scraping the solder paste off the stencil.  Each fiber is exactly the same as every other, and no glues are used in the paper. These strong fibers pick up solder paste better than any other fiber tested.

Detailed field trials have proven that Micro•Wipe rolls made with MicroWipe™ FP will reduce defect rates and cut production costs while boosting quality. In development for nearly three years, it was subjected to dozens of grueling field trials. Importantly, every customer who conducted a proper test and has tried the Micro•Wipe™ FP fabric agrees the new material cleans better and improves yields.

More Expensive to Buy, But Lots Cheaper to Use

MicroWipe™ FP rolls help produce boards at a lower cost. They reduce the number of time-consuming cleaning cycles, by improving the cleaning during each cycle so companies clean less often. Each cleaning cycle eliminated creates time for approximately five printing cycles (~30 secs. vs. ~150 secs.). If the stencil printer is the bottleneck in your facility, this can produce stunning improvements in throughput. At a major PCB subcontractor using DEK stencil printers, Micro•Wipe™ FP rolls pushed production from 36 to 55 boards per hour – a 60% increase in productivity.

Another improvement results from better, cleaner apertures. A cleaner aperture allows more paste to flow onto the board, resulting in taller solder pads and improved solder joints. In one prolonged test, Micro•Wipe™ FP rolls increased maximum pad height an average of 11%.

Misprints and yield improvements are another area in which Micro•Wipe™ FP technology pays off. One large-scale trial used five SMT lines with DEK printers and Indium 92J solder paste. With Micro•Wipe™ FP rolls, the defect-free through-put jumped to 99.55% from an average of 97.25% — an 83% reduction in defects. All of these improvements makes Micro•Wipe™ FP rolls very cost-effective.

All of the MicroWipe products are available in every popular configuration, with all the different widths, lengths, diameters, cores, and extensions users require. Customized designs are also available, for customers needing large quantities of specialty rolls. For details on the FP rolls or custom roll options, call or email MicroCare tech support. We’ll get you a stencil roll that meets your needs and your budget.