Laser Cut Tape for PCB Masking Prior to Conformal Coating
Why Custom Masking Tape For Conformal Coating?
Many times the most time-consuming part of the conformal coating process is the tape masking and de-masking process. The time-consuming part of the process is the cutting to size, trimming and then forming of the tape around the area needing to be masked. The other time-consuming part is the de-masking or taking the tape back off of the component. Both of these processes require time. In some cases where there are test points, connectors, shields and other locations which need to be masked off from conformal coating, the preparation of masking the board is the most time-consuming part. With the added pressure of being an “end of the line” process, lead time pressures in the conformal coating of printed circuit boards puts pressure to make the masking and de-masking processes go as quickly as possible.
BEST Inc. has a new way to realize BOTH a reduction in the time it takes to mask as well as insuring a greater quality conformal coating masking process with less rework. Instead of your conformal coating prep technicians having to cut each of the shapes and forming them, BEST will deliver to you custom, laser-cut conformal coating masking shapes on a tape sheet. We call these TapeShapes™. These custom laser cut shapes of tape are then removed from the sheet, saving the cutting time. In most cases we will configure the TapeShapes™ to be one board per sheet or one boards’ worth of conformal coating masks tape shapes in a confined area. This means that when the conformal coating is done the technician can see if all of the shapes have been removed from the backing material meaning that no masking locations have been “missed”.
So instead of spending lots of time cutting out the shapes for masking, let BEST Inc. cut tape sheets will be completed quickly and accurately. The laser cuts will be within a 0.1 mils in precision meaning the keep out areas will be well-defined. This means that consistency in the coating areas will be maintained resulting in pleasing even the most discerning customers.
Files can be delivered to BEST Inc. in one of two ways:
A. You send us the engineering files. We can take the 2D files in many CAD formats (like .dxf and .dwg). We will then layout the shapes either where the SAME SHAPE is repeated as many times as possible on the working surface of the tape sheet –or- ONE OF EACH SHAPE required on the PCB assembly. In this second approach, you can see when all of the shapes have been pulled off the backing to make sure that all areas have been taped off.
B. You send us the dimensions and we take the time to turn them in to engineering drawings which will allow the sheets to be cut.
After we have received your information we will generate a check plot for your approval of dimensions. You will know what you are getting within 24-48 hours.
The shapes will be cut from 3M Type 301 tape. The specifications can be found here. It features a proven, proprietary, solvent-free adhesive formula removes cleanly in one piece with no adhesive residue left on the PCB. It remains in place around corners, over contours and irregular surfaces so that when it is “formed” around the edge of a connector that it can “follow” or “shadow” the shape. It can withstand surface temperatures up to 250 degrees F/ 121 degrees C for up to 30 minutes in conformal coating curing ovens.
The TapeShapes™ program for conformal coating masking in this program includes the following tapes:
- Type 401 Green Mask Tape
- Type 22-SHercon Polyimide Tape
- St-Gobain M797 tape
- Blue Painters Tape
TapeShapes™ trademark of BEST Inc
Type 401 is a 3M product
Order products here.