Dry Film Solder Mask Roll - Bungard Solder Mask (0,3m X 1m)

US $120

Ogre, Ogres, Latvia
May 29th

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Bungard Laminat Solder Mask (0,3m x 1m) Laminat Solder Mask is an aqueous processible dry film solder mask with excellent electrical and physical properties, good dimensional stability and chemical resistance. It is applicable on rigid FR4 or polyamide base material, coated with copper, tin, lead, nickel or gold. It comes as a transparent green film, which is supplied in thickness 3 mils (75µm) and 12“ (305mm) width, at roll lengths 1 m. As usual for dry resists, the photo polymer is sandwiched between a thin polyolefine foil and a 25 µm polyester protection foil. Laminat Solder Mask responds to light wavelengths in the near UV, with peaks from 360 to 400 nm. It should be handled in rooms with yellow or gold (UV-safe) light only. Processing: Processing Laminat Solder Mask consists of the steps: cleaning, lamination, exposure, development, and curing. 1.Cleaning The optimum performance of Laminat Solder Mask depends on the condition and cleanliness of the copper surface prior to lamination. The surface must be free of contaminants such as residual water, dust, grease, oxide or other residues. We recommend wet brushing of the boards (with a target roughness of 4 µm), extra fresh water rinse and drying with warm air. It is important to have the board cleaned shortly before lamination. If there was a hold time after cleaning of several hours it is recommended to repeat the cleaning before laminating the board. After cleaning it is recommended to dry the board in an oven at 80 °C for 30 min. Dryness of the board is essential for solder mask adhesion. 2.Lamination Laminat Solder Mask is laminated under heat and pressure. Apply using a hot roll laminator. Recommend temperatures of 110-115 °C and a speed of approx. 0.3 m/min. Lamination of Laminat Solder Mask must be performed in an environment that is free from dust and dirt. Always stack the panels in vertical racks, never in horizontal position. Cut a piece of dry film a little bigger than your board. Solder Mask comes with two transparent protective films one on each side. One side is glossy and the other is dull. You need remove the transparent protective film on the dull side. Easy way is to use two small pieces of scotch tape attached to opposite sites. Adhere the edge of the film to the edge of the board and then run it through the laminator 3 or 4 times. Avoid air bubbles and wrinkles they don't look good. Apply manually. Starting from one corner and ending to the cross corner, use your fingers, rubber roll or palm to remove all air bubble between film and board. Set the iron temperature about 115-125°C. You can play around temperature and laminator sets to get your best results (there is no universal recipe, you will have to find your own). Apply the hot iron down onto the film and PCB, pressing them to make a good flat contact. It’s good idea to have a Teflon or Viton rubber sheet between iron and your PCB. It makes more uniform pressure distribution. After hot lamination please allow PCB to cool down slowly and give some time to settle. 3.Exposure It is recommended to let the panels stabilize to room temperature prior to exposure. Any standard UV exposure unit with light of 360 to 400 nm wavelength will be suitable for exposure. Place your NEGATIVE artwork over the rest protective layer. Use the plane glass to press your artwork to the PCB. It is important to assure an intimate contact between the artwork and the laminate. For very fine line reproduction, a parallel beam exposure unit is recommended. It’s recommended the source of light to be at least 12" away from the artwork. Before actual exposure you need to calibrate your light source in order to find the correct exposure time window which is dependent upon intensity and radiation spectrum as well as photoresist sensitivity. Both underexposure and overexposure have impact upon photoresist resolution. After exposure carefully remove the artwork (DO NOT REMOVE second protective film!) and let the board sit for at least 15 minutes in a cool, UV safe area. 4.Development Between exposure and development a hold time of 5 to 30 minutes should be kept. The max. hold time is 24h. You need NEGATIVE dry film developer (sodium or potassium carbonate (monohydrate) Na2CO3 or K2CO3). Carefully peel off second protective film and develop the board in the developer solution that is mixed by 1g developer powder with 90-100ml of water (~1.1% by weight). It’s recommended to heat up developer solution to 30-40°C in order to speed up development time. Remember that overdevelopment is capable to remove both exposed and unexposed sites, therefore play with developer concentration to reach development time within 2-4min. Take the board out of developer and hold under running water (room temperature) to check the pattern. You can always put it back in the developer if needs more developing time. Carefully rinse the board and dry the remaining photopolymer in the oven at 100°C for 5 minutes. Do not leave the board in the oven too long. 5.Curing Curing Dynamask can be done with UV light and/or heat. Best is a two step procedure. First comes a UV curing for about 30 minutes. Second is a thermal hardening in an oven with fresh air input at 100 °C for 1 h. If the oven does not allow fresh air input the curing must be done only under UV, it should be at least 3-5 time longer than your exposure time. Heating in a closed oven will cause burning effects and vapour condensation on the pads will void solderability. After sufficient curing the solder mask is ready for hot air levelling, wave soldering, IR soldering, and is resistant against most solvents, fluxes and flux cleaners. For orders of two or more rolls I will send one roll the length of the number of rolls combined.