ICP Rabbit Line Configuration|
ICP Rabbit Line Configuraiton 24" x 24" x 3" (600mm x 600mm x 75mm)
This particular configuration was developed a number of years ago, but recent enhancements have made this worth noting again. This design has gone from an 11" x 11" area to a 24" x 24" area. Surprisingly, the reason for this development was an index table application that required the larger dispense area.
An added attribute of the new design is the capacity for much greater head payloads. This design exhibits minimal deflection even with head configurations exceeding 20
Hollow Gasketting Low Viscosity: Tangent Ind.|
Please note: our hollow gasket dispensing technology is patent pending.
We were recently presented with a new (to us) material to test with our hollow gasket process: Tangent Industries 60102 material. This material has some interesting characteristics: low or almost no tack after cure, soft, and relatively low UV exposure energy requirements.
One other characteristic was interesting however: the viscosity relative to silicones (which had occupied the bulk of our previous testing) was much, much lower. The net result of addressing this characteristic has given us process controls far more advanced than our previous attempts and have had follow-on implications for previously tested materials.
Image number one shows the cut-out section of a gasket with approximately a 0.15inch diameter and a hollow that accepts a 0.090 inch pin gauge without deforming (see image two). A 0.107 pin gauge actually still slides easily into the gasket center but it also raises the gasket and so clearly the hollow is larger than the 0.090 height might imply. However, calculating surface areas conservatively, the hollow provides a 34% reduction in material usage.
When designing applications for hollow gaskets, a solid "O" ring interpretation works quite well. Traditional solid FIP gaskets always require an escape zone - somewhere for the gasket to go to when it is under compression. With the hollow gasket, the hollow becomes the escape zone. For a properly designed application where the deformation does not exceed the hollow, no escape zone is necessary.
While extremely crude, images three and four attempt to show the reduction in effective durometer of a gasket due to the hollow. Image three shows the very rough measurement of a solid gasket and image four shows a gasket with the exact same height but with a hollow. This quick visual could do with a more precise technique, but even subjectively the gasket is half to a third the effective durometer. Interesting as well that as the gasket is compressed, a solid, traditional gasket has a somewhat linear increase in resistance. The hollow gaskets have minimal initial resistance and then rapidly increases once the hollow is collapsed.
One concern was whether the gasket could recover once collapsed and as seen in images five and six, the recovery is excellent with this 60102 material.
Images five and six also brought to light the fact that hollow gaskets do not require the same UV intensity of solid gaskets simply because there is less material the UV light needs to penetrate. This enhances the ability of low intensity systems to yield excellent results.
Image seven is simply a fun visual indicator of the difference between solid and hollow gaskets. By using a pin across both a solid and hollow gasket, it is easier to get an appreciation for the difference!
Filled Gasket Dispensing - Insulated Wires|
The same technology that allows for hollow gasket dispensing allows for a simple transition to filling the hollow with something other than air. Currently in our trials we have filled the hollow with black RTV. As the outer "insulator" is transparent, the consistency becomes readily verifiable.
This represents a step forward from our previous work done back in 2006 with dispensing conductive traces on acetate sheet.
While the photos show a single conductor, multiple conductors are possible and our trials have been successful with up to seven conductors.
Please note that electrical connections to these wires present certain challenges! Potential interconnect methods are:
1) Pierced wires (insulation displacement style interconnect)
2) Snap style (YKK Snapet Ligne 14 for example)
3) Z axis conductive adhesives
4) Embedded and encapsulated one-time-use electronics.
As it is also possible to multiple spaced conductors with a hollow center, it becomes possible to implement a clamping ring vis-a-vis the Imperial Eastman pneumatic fitting.
All if these methods however would require further encapsulation to preserve the interconnect.
Hollow Gasket Dispensing - Patent Pending|
Please note: our hollow gasket technology is patent pending.
Our shaped gasket dispensing process, which we developed in 2006, has opened a wealth of new possibilities in manufacturing, allowing us to re-write the book on traditional gasket dispensing. Hollow and filled gaskets offer the following advantages:
1) Hollow gaskets can save 25-75% of material costs
2) Hollow gaskets provide their own compression "zones"
a) No additional provision needs to be made for elastomer squeeze-out
b) Issues with channel wall shear are reduced or eliminated
c) Compressive forces are greatly reduced
d) Compressive forces can be made to toggle the gasket profile
i) The forces can actually diminish with additional compression.
e) Compression set seems to be less pronounced in many cases
3) Materials requiring UV cure are now more efficiently cured
Hollow Horizontal Gasket Dispensing|
Please note: our hollow gasket dispensing technology is patent pending.
Foam in place gasketing is a versatile process, but requires very expensive equipment. Just the foaming equipment is typically $50,000 and when all of the various required components are in place the pumping equipment can spiral to $100,000 pretty easily. While there are PU foam systems that are less expensive, so far we have found them to be maintenance intensive. Ideally, we would like to have the features of foamed gaskets without the upfront, steep hardware costs or maintenance headaches.
Hollow gaskets can fulfill many of the roles assigned to foamed gaskets. These gaskets can be produced using simple materials such as silicones and the pumping equipment is almost an order of magnitude less costly.
Because these are extruded gaskets, many unique profiles can be applied and we are no longer constrained to simple circular sections with the typical height:width ratios of 1:2 or at best 1:1. Instead, we have produced ratios not only of 1:1 but also up to 1.5:1. The profiles can be other than the classical circular section such as triangular, rectangular, "M' shaped, or whatever best serves the sealing need.
These gaskets will have one or more hollow segments and the segments can be filled with air, nitrogen, or even conductive polymers.
These gaskets can even form sealed channels that can transport air or other fluids in a specific pattern, thus forming heat exchangers or allowing seals that can be pressurized AFTER the mating surfaces have been engaged.
Hollow gaskets have several advantages over traditional foamed gaskets:
1) Tall profiles can readily be formed. Current testing has produced 0.5" tall (12.5mm tall) seals.
2) Because of the extrusion process, the height of the gasket can be held to a very high tolerance.
3) Can be easily compressed more than 60% of overall height with light compressive force
4) When compared to the traditional 1:2 (H:W) profile of a foamed seal with 50% foaming, hollow seals use 47.5% less material.
5) When compared to the traditional 1:2 (H:W) profile of a solid material seal, hollow seals can use 74% less material.
In one particular sample case the overall seal height was 0.48" (12.98mm) and the weight of material per inch was 1.56g.
One issue to keep in mind is that these seals are extruded horizontally onto a surface. As a result, ideal applications are not endless! We can only approximate endless by running the start and stop parallel to one another as seen in the 13mm tall sample photo below. On the other hand, this method allows precise gasket extrusion with many possible profiles.