Solder Masking Agents
Red is likely one of the daring and professional trying solder masks colors we provide. A pink solder mask attracts with its sensible hue, and presents great contrast for traces, planes, and empty spaces. The flux residue is able to clean up well when purple solder resists are used.
The panel is exposed to a excessive intensity UV lamp to cure the masks. The gentle passes via a movie that's precisely aligned with the panel. The film is clear in all areas the place masks should cure and cling to the board. In areas the place mask just isn't needed, there are darkened apertures printed on the movie that have been extracted from the masks layers within the customer equipped design files.
This locations the rectangle on the identical location as the pad in the course of the part. Don't fear about whether or not the rectangle is above or beneath the part's heart pad, as a result of a pad always has priority over a rectangle. The pad will minimize through the solder mask and will accept trace connections even when a rectangle is 'on prime' of it. Occasionally, you need the solder mask to cover a portion of a pad, somewhat than exposing the whole pad.
An instance of this is the place there is a pad underneath a chip which is near enough the opposite pins that leaving it completely uncovered may result in accidental solder bridges. You can see the green mask coating everything but the pads.
Notice the textual content, pads, and traces are all made out of the identical materials . Silkscreened onto the PCB sample, epoxy liquid is the lowest price kind of solder mask. Epoxy is a thermosetting polymer that has many applications.
In the photo beneath, see how text and part outlines are actually a special colour than the traces and pads. The ink is non-conductive and may be placed on top of traces without interference. Clean copper solders acceptably, however over time the copper oxides. In that case, you will want to scrub or chemically treat the oxidized copper pads before soldering, or else the solder will not stick reliably. If you etch the board at residence, the elements may have an identical look to the image below.
The dark apertures will block the UV mild from curing the masks underneath. The panel is cleaned to ensure a perfect floor to bond to.
Therefore, lately, I solely order boards with solder mask and silkscreen. As my assortment of boards grew, I recognized this was a false savings. It takes plenty of time to figure out where elements go on boards that lack enough labeling, significantly if the board was designed some time ago. Lack of labels might end in an element being soldered within the mistaken location or forgotten about fully. Select each the half and the rectangle, and choose Align Center and then Align Middle from the Arrange menu.
1This is the board coverage or thickness of the solder mask primarily based on the weight used. However, colour is but one of a number of concerns that influence the kind of solder mask that should, or even can, be used. The main consideration is the kind of system in which the board will be deployed. PCBs destined for utilization in sure industries or for sure purposes must adhere to standards set forth inIPC-SM-840D.
Most solder mask processing is completed in a clean room setting to stop particles from getting on or under the mask. The solder mask is a Liquid UV Photo-imageable Ink which is usually inexperienced in shade. Other colour options like pink, blue, yellow, white, black and purple are also out there. Black is likely one of the most unusual solder masks colors, out there with us.