With a theta mounted on the Z axis, it becomes possible to accurately dispense gaskets along the vertical walls of objects. In this example we have machined sockets which require a seal at the entry point. By itself this is not a difficult concept. The difficulty in doing this kind of thing in production lies with the issue of tip calibration. Using a unique calibration process that definitively locates the dispense tip no matter the tip angle or length of arm from center of rotation, New Precision Technology has simplified this technique, making it a production-friendly process.

In this application we applied a gasket to the inside of the socket as well as to the outside face. The outside face was not necessary, but dispensing the gasket on this face was more observable.

    For short production runs, adjustable fixtures can be quite beneficial. However, to be most effective , they do require that the products to which they are applied are of a type. They are most effective when dealing with various sizes of a similar object. For example rectangular circuit boards, or enclosures of various sizes.

Linear rail adjustable fixtures are excellent choices for short production runs of rectangular circuit boards or other thin, flat, and rectangular products. Usually they are set up to have a fixed bottom left corner, a back adjustable rail, and then stops to constrain left and right motion. Optional steel scales on all four sides makes resetting the fixture back to pre-existing pattern programs a simple task.

Grid fixtures represent the most flexible alternative in the pantheon of fixtures. Our grid fixtures are an array of 8-32 tapped holes on one inch centers. Each grid fixture comes with a kit of standoffs and a set of parallel rails that are slotted for maximum flexibility. The pitfall of this type of fixture is that it is difficult to change the fixture back to a pre-existing configuration once it has been changed. Conversely, the grid fixture is relatively inexpensive because they are made in quantity, all fixtures have machine bushings for mounting, and it now becomes reasonable to have multiples of these to deal with odd components. When an application is known to be at an end, it becomes reasonable to strip the adjustable fixture and put it to use for the next unique application that comes along.

    Form in place shaped gaskets can provide some surprising benefits to traditional circular gaskets. The traditional shape of an FIP gasket is the result of a gasket compound flowing out of a round tube. Rheology aside, the shape is some form of circular arc, however as the tip skims closer to the substrate, the tip starts to carve a shape into the top of the gasket. The result of this action is typically a flattened rectangular shape with rounded vertical walls. This result is due to three factors: the proximity of the tip to the substrate, the flow rate of the compound as it comes out of the dispense tip, and the rate of travel of the tip over the substrate. When the flow rate is high enough, the travel rate is slow enough, or the gap to the substrate is small enough, the substrate in effect becomes the final wall in a pressure vessel.

With this process, it is possible to create shapes in the side of a dispense tip and extrude material out of the side of the needle. And there is no limit to the possibilities. For example, ridges on the top of the gasket will reduce the amount of compressive force required for engagement between surfaces. This can give some of the advantages of foamed gaskets without going to the expense of the foam generating hardware.

    Enter in some information about the type of gasket application along with a few dimensions and this calculator will tell you what size of gasket will be necessary to do the job. It factors in compression set as well, so as long as you know the compression set of the gasket compound, you will get a good starting point for your gasket sizing. All situations are unique and so you may require something other than what is calculated. The classic disclaimer: IT IS LEFT TO THE PART DESIGNER TO DETERMINE SUITABILITY OF PURPOSE. These calculators simply are an attempt to draw attention to gasket design issues.

The tools are ultimately designed to be used in order: Gasket Height/Compression Set, Gasket Material Usage, and finally Pressure Drop/Material Flow.

Update 12/31/08 -
1) Gasket cost calculator fixed.
2) Aspect ratio for 1:2 (half-round gasket profile) is now calculated properly
3) Compression set is now factored in to both Minimum and Maximum range limits.

    Some applications demand high throughput that traditional batch mode machines like NPT's CP systems cannot supply. To address this need, NPT's ICP systems can be married to a rotary indexer so that concurrent operations can be done. Operator load/unload no longer adds to the overall cycle time as parts are loaded/unloaded on a separate "leaf" from the dispensing work area. The rotary indexer can be outfitted with a grid fixture to allow flexible palleting options, and each "leaf" can address a process - UV cure stations, inspection stations, and even other dispensing stations. Modular design allows the user to add leaf operations over time, as the production environment dictates.

More advanced processes can be incorporated as well: automated part load and unload, scanning, and even integration with automated molding machines is possible.