Dimension Bond Technologies

The Challenge that Led to New Technology

In the 1980s, a Gerotor fuel pump manufacturer provided an extremely challenging opportunity to apply a special fuel resistant, low friction polyphenlyenesulfide /polytetrafluoroethylene  (PPS/PTFE) coating to the 25mm inside bore of a powdered metal housing.  Several problems existed because two suppliers provided parts that had bores that were inconsistent in size.  The initial solution was to apply more PPS on the oversize bores of some parts. However, the unique bearing surface – after oven curing the PPS coating – was impossible to change. Once cured, no additional coating could be applied. Therefore, no coating could be added to the undersized parts after oven curing.  Several technical hurdles needed to be solved to provide a usable part. In statistical terms, the CPK of the finished parts of 1.33  was required when incoming lots had CPK values of less than 1.0.

The DIMENSION BOND® Solution

The PPS coating needed to be sprayed into the bores. Conventional spray equipment could not possibly meter, for example, .65 cc to some bores and .66cc to .89cc to selected oversize bores. DimensionBond® staff members embarked on a very arduous task; how to change the amount of material deposited in a bore on each and every part as determined by the dimensional measurement of the part before the spraying process.

Fundamental to the solution was to pre-measure each part and then meter a precise amount of PPS material during the bore coating process to all parts with additional coating material applied to the larger bore parts.  This required research and development of very specialized metering pump technology. Conventional pumps agglomerated the coatings which all contained particles of PTFE.

The metered amount of coating was determined by proprietary  algorithms. The early 386 computers were quickly replaced with more powerful computers as they became available. This allowed the premeasured part dimensions to be determined, a volume of coating calculated and a individual output of coating material apply to each part. The results proved to be very accurate based on multiple Design of Experiments (DOE). The dimensional values were computer acquired to qualify measurements before and after the bore coating process. Each different part was tracked thru the conveyorized system.  The eventual results proved to be able to increase the CPK of an incoming shipment from <1.0 to >1.33.

DIMENSION BOND® New Technology

After two and a half years, DB staff finally had created and manufactured, in house, a pumping/metering system that could meter the liquid PPS material, or any liquid bondable coating, to an accuracy of .01cc per part.  This robust system has been proven over more than 35,000,000 parts with the goal of changing the dimensions of the final coated part so all parts in a lot are within the dimensional requirements, irrespective of the dimensions range of the raw, uncoated parts.

Continuous Process Improvement

Part of this success is due to Moore’s Law of computer processing power. As computer processing power increased in the 1990s DB had the ability to not only measure sizes but also add gravimetric (weight) measuring of the coating on each part. This added another in process verification for the DB process.  Later, temperature correlation of the measured parts and mathematical computational correlations further enhanced the overall accuracy of the DB process. Today, several methods are used to verify the ever improving accuracy of the Dimension Bond process.

US Patents were filed for the DB process in 2000 and in 2004 the first patent, 6,738,680, was granted for the unique and effective DIMENSION BOND® process. This was followed by several more patents between 2002 and 2006 (6,832,577, 6,860,947, 6,997,683, 6,997,992, and 6,998,147) expanding the DB Processing to not only bores but now outer diameters. Laser micrometers played a large part in the dimensional measurement of outer diameters, which were integrated into the DB machine code software and machine controls.

DIMENSION BOND® Uniqueness and Success

All the DB processes use the principles of the in-house developed metering pumps. These liquid/slurry metering devices are unique in that they can meter coating materials containing PTFE and other soft fluoropolymers without agglomeration or coagulation of the coating. The reliability of the metering components has been extended to provide a mean-time-to-failure of more than 2.5 million individually metered part coating applications per maintenance cycle of each and every pump and application devices.

The coating formulations qualified by DB now surpass 100 different types of coatings including those from Whitford, DuPont, Dow Corning, Fuchs, and many more. From the initial automotive fuel pump processed by DB in the 1980s, the range of parts currently processed by DB machinery includes the most complex shapes.  Successes include automotive and industrial rotary, screw type air compressor rotors, bearings for NASCAR® racing engines, Jeep® pistons, Honda/Acura V-Tec® engine shafts, fuel pump parts for Mercedes Benz, TI Automotive, Blackstone, Dana Corp, Airtex and an ever expanding universe of customers who need perfectly and precisely applied bonded bearing surfaces.

Engineering Successes and Disruptive Technology

The bonding of PTFE materials to provide low friction and dry film lubricated surfaces seems to be a relatively straightforward process. These coatings which are thermally bonded to components that are generally hidden from view, once cured, are chemically resistant. That means there’s good news and bad news. The good news is the mechanism fits into another mechanism and is lubricated, generally for the life of the unit. The bad news is that once thermally cured, these PTFE containing materials cannot be added to with extra coating material.

Conventional machinery to apply PTFE coatings is available for frying pans and other noncritical dimensional uses. However, one two parts must fit together, the dimensions of the PTFE coated part can only be generally determined after the parts emerge from a high temperature oven. If incorrectly applied, the coating must be removed and reapplied. This is costly, delays production and is an environmental challenge. Throughput of conventional and even automated PTFE coating systems is never 100%. Dimension Bond changed all that.

The team at Dimension Bond Corporation, starting in the 1980s, continued work on perfecting a pumping system for PTFE liquid coating materials. Conventional pumps did exist. However, the PTFE particles in these coatings agglomerate because of the extreme shear sensitivity or “clumping” of the PTFE particles if they are moved with conventional gear pumps,, and to the automotive paint industry.

Once our process for this disruptive technology was perfected, the team realized that parts that were dimensionally inconsistent could have more or less PTFE driver lubricant coating applied based on the dimensional needs of the individual raw part. This led to the first successes with automotive fuel pumps.

The first commercial success for the Dimension Bond Corporation was a Gerotor fuel pump cam ring. The specific area to be lubricated was the internal bore of a iron sintered iron part. The manufacturer needed a special fuel resistant, low friction polyphenlyenesulfide /polytetrafluoroethylene  (PPS/PTFE) coating precisely applied to the 25mm inside bore of a powdered metal housing.  Several problems existed because two suppliers provided parts that had bores that were inconsistent in size.  The initial solution was to apply more PPS on the oversize bores of some parts. However, the unique bearing surface – after oven curing the PPS coating – was impossible to change. Once cured, no additional coating could be applied. Therefore no coating could be added to the undersized parts after oven curing. Several technical hurdles needed to be solved to provide a usable part. In statistical terms, the CPK of the finished parts of 1.33 was required when incoming lots had CPK values of less than 1.0.

Today, after dozens of patents have been granted by the US Patent and Trademark office, tens-of-thousands of components per day are permanently lubricated by the Dimension Bond process technology. Components that almost fit into another housing or component, from the water conditioning, military, safety systems, aerospace, medical industries, to the global automotive industry, are processed using Dimension Bond technology. Dimension Bond Corporation ships precisely processed, on time and in precise dimensional specification, to multiple points around the world, including Europe, Canada, Australia, Brazil and the United States.