Time filter

Source Type

Morrisville, NC, United States

Hubbard R.L.,Lambda Technologies | Zappella P.,Henkel AG
IEEE Transactions on Components, Packaging and Manufacturing Technology | Year: 2011

Mechanical stress in flip-chip assemblies continues to be a significant problem both for the reliability of the component and for the assembly of a flat component to the next board-level assembly. This paper describes the combination of unique low-temperature multi-step curing profiles with the use of variable frequency microwaves (VFM) to produce lower warpage components both on the die side of the package as well as on the board carrier side. This lower warpage compared to standard convection cure is maintained even after three sequential lead-free solder reflow conditions. Statistical data support this improved co-planarity by Shadow Moiré measurements at various stages of processing from as-received parts through prebake, cure, and three reflow cycles. Typical co-planarity improvement in the 12-65 percent range is observed and verified by confirmation sample sizes used for microwave cured parts and conventional box oven cured parts. Thinned and larger die, and reduced thickness substrate boards showed the most warpage improvement with VFM. Two under-fill chemistries show the same effect despite lower cure temperatures and faster cure cycle times. © 2011 IEEE.

Fox B.R.,University of Oregon | Brinich B.L.,University of Oregon | Male J.L.,Pacific Northwest National Laboratory | Hubbard R.L.,Lambda Technologies | And 3 more authors.
Fuel | Year: 2015

A film-shear reactor was used to significantly enhance the oxidative desulfurization (ODS) of model fuels using hydrogen peroxide as the oxidant. Significant increases in the amount of sulfur removed were seen in comparison to conventionally stirred ODS reactions. For example, up to 50% desulfurization occurred in a single pass of the model fuel through the film-shear reactor at 10°C. The desulfurization reactions were very fast in the reactor, occurring on the time scale of seconds to minutes. Desulfurization was studied under a variety of conditions, and a statistical design of experiment (DOE) showed that the fuel to oxidant ratio was the only statistically significant parameter to impact the extent of desulfurization: a larger amount of oxidant led to higher desulfurization. A variety of benzothiophene contaminants (benzothiophene, 2-methylbenzothiophene, 5-methylbenzothiophene, dibenzothiophene, and 4,6-dimethyldibenzothiophene) were examined, and the film-shear reactor was effective in removing all of these contaminants. The film-shear reactor was effective at both low (0.5-2.0 mL/min) and high (100-300 mL/min) flow rates. Experiments showed that oxygen in air was not an effective oxidant for ODS in the film-shear reactor. Experiments using Mo(CO)6 as a molecular thermometer showed that "hot spots" are not forming in the film-shear reactor, and thus the increase in the ODS rate cannot be attributed to intense thermal activation occurring within the film-shear reactor. It is suggested that superb mixing of the aqueous and fuel phases is responsible for the increased rate of ODS in the reactor. © 2015 Elsevier Ltd. All rights reserved.

Bordelon D.E.,Johns Hopkins University | Goldstein R.C.,AMF Life Systems LLC | Nemkov V.S.,AMF Life Systems LLC | Kumar A.,Lambda Technologies | And 3 more authors.
IEEE Transactions on Magnetics | Year: 2012

In this paper, we describe a modified solenoid coil that efficiently generates high amplitude alternating magnetic fields (AMF) having field uniformity (≤10%) within a 125-cm 3 volume of interest. Two-dimensional finite element analysis (2D-FEA) was used to design a coil generating a targeted peak AMF amplitude along the coil axis of ∼ 100 kA/m (peak-to-peak) at a frequency of 150 kHz while maintaining field uniformity to > 90% of peak for a specified volume. This field uniformity was realized by forming the turns from cylindrical sections of copper plate and by adding flux concentrating rings to both ends of the coil. Following construction, the field profile along the axes of the coil was measured. An axial peak field value of 95.8 ± 0.4 kA/m was measured with 650 V applied to the coil and was consistent with the calculated results. The region of axial field uniformity, defined as the distance over which field ≥ 90% of peak, was also consistent with the simulated results. We describe the utility of such a device for calorimetric measurement of nanoparticle heating for cancer therapy and for magnetic fluid hyperthermia in small animal models of human cancer. © 2006 IEEE.

Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 149.94K | Year: 2005

Although surface treatments like low plasticity burnishing (LPB) and laser shock processing (LSP) impart deep compressive residual stresses that significantly improve damage tolerance, credit for the improved fatigue strength is not generally taken in design. The analytical tools needed to support taking design credit by predicting the fatigue life and optimizing the surface treatment process for the desired fatigue performance do not exist. The development of a suitable design tool is proposed that integrates the Fatigue Design Diagram (FDD) method developed at Lambda Research with FEA and LEFM analysis codes currently used in component design. The FDD is an extension of the Haigh or Goodman diagram in common use by designers, facilitating implementation and ease of use. Phase I will draw upon the extensive surface enhancement database available at Lambda Research for LPB and shot peening to test and demonstrate the feasibility of the FDD approach to predict the fatigue life of components for steels, Ti, Ni, and Al alloys damaged by corrosion, fretting and FOD. In Phase 2, FDD based design software tools will be created that interface with FEA codes currently used by designers. This comprehensive tool will allow the designer to predict fatigue life and distortion of components for a given combined residual and applied stress distribution, and to iteratively optimize residual stress distribution to achieve the desired fatigue life for a given failure mode and component geometry. Commercialization through licensed distribution of the software by FEA code providers will extend the technology to the aerospace, defense, automotive and general industrial markets.

Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase I | Award Amount: 69.99K | Year: 2009

The goal of the proposed SBIR work is to develop Low plasticity burnishing (LPB) as a manufacturing process to increase the high cycle fatigue (HCF) strength of case carburized steels by creating a crack initiation resistant surface structure with superior surface roughness. Bell Helicopter (TPOC: Ryan Ehinger, Project Area Lead for Drive System Research) will be the OEM partner in this proposed program. LPB offers the benefits of controlled depth and magnitude of compression, a smooth often mirror-like surface finish, and very low cold work (hence stable compression). Costs for implementing the LPB process are comparable to conventional shot peening and other peening processes, leading to a highly favorable cost-benefit ratio. The depth of compression can be precisely controlled at every location on the component by initial selection of the tool and closed loop process monitoring and control. LPB tool pressure control provides a process that exceeds six sigma. With a total solution approach, the LPB application and the combined benefits of automated design and analytical tools developed at Lambda will lead to a TRL and MRL of 7 at the end of Phase II of this program.

Discover hidden collaborations