The B. F. Goodrich Company

Dtm Corporation

Pmd Holdings Corp.

3D Systems, Inc.

University of Vermont

Elmer D Dickens, Jr

Eric Martin Weissman

Angelo J Magistro

Glenn A Taylor

William B Spillman, Jr

Biing Lin Lee

Hendra Ng

Paul F Forderhase

Kevin P McAlea

William S Greenlee

Marvin H Lehr

Biing-Lin Lee

Murali Rajagopalan

Frederic W Kunig

Lynn M Soby

Junru Wu

Angelo Joseph Magistro

Glenn Alfred Taylor

Timothy R Hradek

A laser-sinterable powder product has been prepared having unique properties which allow the powder to be sintered in a selective laser sintering machine to form a sintered part which is near-fully dense. For most purposes, the sintered part is indistinguishable from another part having the same dimensions made by isotropically molding the powder. In addition to being freely flowable at a temperature near its softening temperature, a useful powder is disclosed that has a two-tier distribution in which substantially no primary particles have an average diameter greater than 180 &#x3bc;m, provided further that the number average ratio of particles smaller than 53 &#x3bc;m is greater than 80%, the remaining larger particles being in the size range from 53 &#x3bc;m to 180 &#x3bc;m. A powder with slow recrystallization rates, as evidenced by non-overlapping or slightly overlapping endothermic and exothermic peaks in their differential scanning calorimetry characteristics for scan rates of on the order of 10&#xb0; C. to 20&#xb0; C. per minute, will also result in sintered parts that are near-fully dense, with minimal dimensional distortion.

Sinterable semi-crystalline powder and near-fully dense article formed therewith

A system for detecting wear debris particulate from a medical implant within the body of a living animal is provided. The system includes an acoustic transmitter for transmitting acoustic energy from outside the body to a soft tissue region proximate the medical implant containing wear debris particles; an acoustic receiver located outside the body to detect resultant acoustic energy generated by the wear debris particles and produce a received signal indicative thereof; a processor for processing the received signal to evaluate at least one parameter associated with the wear debris particles; and an output for indicating the at least one parameter.

Implant wear debris detection apparatus and method

An implant device which includes a structure implantable within a living animal and a sensor included as part of the structure. The sensor is operatively configured to detect accretion of biological material on the sensor by producing an output which varies as a function of the accretion of biological material on the sensor. A communication element is further included as part of the structure and is operatively coupled to the output of the sensor. The communication element is configured to communicate information based on the output of the sensor wirelessly to a remote element located outside the living animal.

Remotely interrogated implant device with sensor for detecting accretion of biological matter

An analyzer apparatus and method is provided for analyzing restenosis associated with a stent implanted within a living body. The apparatus includes an input for receiving ultrasonic data from an ultrasonic imaging apparatus; digital memory for storing the ultrasonic data at least temporarily; a processor for analyzing the ultrasonic data, the processor being configured to analyze the data in accordance with at least one predefined criteria to diagnose a degree of restenosis experienced by the stent; and an output for outputting information indicative of the diagnosis.

Ultrasonic detection of restenosis in stents

An implant device is provided which is responsive to an external interrogation circuit. The implant device includes a structure implantable within a living animal and operatively configured to carry out or assist in carrying out a function within the living animal. The device further includes an electrically passive sensing circuit integral with the structure for sensing a parameter associated with the function. In particular, the sensing circuit includes an inductive element wherein the sensing circuit has a frequency dependent variable impedance loading effect on the interrogation circuit in response to an interrogation signal provided by the exciter/interrogator element, the impedance loading effect varying in relation to the sensed parameter.

Remotely interrogated diagnostic implant device with electrically passive sensor

A device and system for remotely interrogating a diagnostic implant device utilizes acoustic energy to power and/or interrogate the device. Acoustic energy is utilized to excite the device from outside the body of a patient. By analyzing the response of the device to such excitation, it is possible to ascertain the condition of the device. Additionally, acoustic energy may be used to provide operating power to the device.

Acoustic-based remotely interrogated diagnostic implant device and system

A laser-sinterable powder product has been prepared having unique properties which allow the powder to be sintered in a selective laser sintering machine to form a sintered part which is near-fully dense. For most purposes, the sintered part is indistinguishable from another part having the same dimensions made by isotropically molding the powder. In addition to being freely flowable at a temperature near its softening temperature, a useful powder is disclosed that has a two-tier distribution in which substantially no primary particles have an average diameter greater than 180 .mu.m, provided further that the number average ratio of particles smaller than 53 .mu.m is greater than 80%, the remaining larger particles being in the size range from 53 .mu.m to 180 .mu.m. A powder with slow recrystallization rates, as evidenced by non-overlapping or slightly overlapping endothermic and exothermic peaks in their differential scanning calorimetry characteristics for scan rates of on the order of 10.degree. C. to 20.degree. C. per minute, will also result in sintered parts that are near-fully dense, with minimal dimensional distortion.

Sinterable semi-crystalline powder and near-fully dense article formed

Remotely interrogated implant device with sensor for detecting accretion

A laser-sinterable powder product has been prepared having unique properties which allow the powder to be sintered in a selective laser sintering machine to form a sintered part which is near-fully dense. For most purposes, the sintered part is indistinguishable from another part having the same dimensions made by isotropically molding the powder. In addition to being freely flowable at a temperature near its softening temperature, a useful powder is disclosed that has a two-tier distribution in which substantially no primary particles have an average diameter greater than 180 .mu.m, provided further that the number average ratio of particles smaller than 53 .mu.m is greater than 80%, the remaining larger particles being in the size range from 53 .mu.m to 180 .mu.m. A powder with slow recrystallization rates, as evidenced by non-overlapping endothermic and exothermic peaks in their differential scanning calorimetry characteristics for scan rates of on the order of 10.degree. C. to 20.degree. C. per minute, will also result in sintered parts that are near-fully dense, with minimal dimensional distortion.

Ternary alloys of PVC/CPVC/alloying polymers are disclosed which make use of the unexpected results of interactions between alloying polymers and CPVC and PVC, interactions which result in higher heat distortion temperatures than predictable by linear addition of the properties of the binary blends of PVC/CPVC and PVC/alloying polymer systems. This effect allows replacement of substantial amounts of alloying polymer with a predetermined amount of CPVC without changing substantially HDT or melt viscosity. Such effects allow the use of these ternary alloys in place of binary PVC/alloying polymer systems in injection molding and extrusion applications.

Ternary alloys of poly(vinyl chloride) with high heat distortion

A laser-sinterable powder product has been prepared having unique properties which allow the powder to be sintered in a selective laser sintering (SLS) machine to form a sintered part which is near-fully dense. For most purposes, the sintered part is indistinguishable from another part having the same dimensions made by isotropically molding the powder. In addition to being freely flowable at a temperature near its softening temperature, the powder has a two-tier distribution in which substantially no primary particles has an average diameter greater than 180.mu.m, provided further that the number average ratio of particles smaller than 53.mu.m is greater than 80%, the remaining larger particles being in the size range from 53.mu.m to 180.mu.m. When the powder is a semicrystalline synthetic resin having a number average molecular weight in the range from about 30,000 to 500,000; a molecular weight distribution M.sub.w /M.sub.n in the range from 1 to 5; and, provides a window of sinterability in the temperature range from near the powder's softening temperature T.sub.s to its caking temperature T.sub.c, it is sintered layer-upon layer to form a near-fully dense part of arbitrary shape.

This method teaches how to recover and reuse a powder of a thermally degradable material which is used in a selective laser sintering (SLS) process. To recycle such a laser-sinterable powder successfully in a SLS machine it is protected against degradation by cooling the hot bed while layer-upon-layer (layer-wise) of powder is being sintered, seriatim, to form successive slices fused together to form an article of arbitrary shape (part). The process requires maintaining the powder which has more than 80% of the number of particles &lt;53 .mu.m as a quiescent bed which is nevertheless porous enough to permit flowing a cooling gas downwardly through the bed without disrupting its surface. Since each slice is formed at the surface, and the part, as it is formed, is supported in a well-insulated bed, the powder adjacent the slice is at a much higher temperature than powder in the rest of the bed, which, but for the cooling gas, would get overheated. Overheated powder not only degrades but is fused to the surfaces of the hot part forming a 'growth' which makes the part unusable for its intended purpose. The process allows one to recycle the unused powder from the bed to extinction, economically. If the powder, when hot, is also sensitive to oxygen, an inert gas is used as the cooling gas.

Method of recovering recyclable unsintered powder from the part bed of a

Smoke retardant vinyl chloride and vinylidene chloride polymer compositions are obtained by including cobaltous oxide (CoO) in the composition.

Growing community of inventors

Richfield, OH, United States of America

Elmer D Dickens, Jr