Laser method could machine precision parts Scientists at Battelle Memorial Institute, Columbus, have begun feasibility studies on a precision laser machining technique for prototype plastic parts under a one-year, $115,000 contract from the Department of Defense. Organic chemist Robert E. Schwerzel, who heads the project, says the method would produce locally cross-linked regions within the plastic. Solvent or plasma etching then would remove uncross-linked resin to give the finished part. Two intersecting laser beams, guided by computer, would generate the microscopic cross-linked regions Several seed concepts stem from experiments conducted aboard the space shuttle at intersection points. The plastic what might be done on a manned oxygen. Because of the ways in which resin, on absorbing a photon from one space station, the firm is seeking to these properties affect materials and laser, would reach a singlet first exidentify specific opportunities and processes, products that can be made cited state. Rapid intersystem crossspecific companies, which under on Earth only in test quantities at ing would produce a triplet. Absorpcertain conditions would be willing to extraordinary high cost might become tion of a photon from the second laser make a financial commitment. For viable commercially if produced in an would yield a triplet whose energy lies example, Weinberg, a one-time me- orbiting space factory. above the dissociation energy of the dicinal chemist, expects that pharAmong seed concepts identified by irradiated functional group. Dissomaceutical, chemical, and specialty Booz-Allen are some stemming from ciation of the group would generate metals industries would be particu- experiments already carried out suc- an ion or radical to initiate cross-linklarly interested in conducting so- cessfully on the space shuttle. One is ing. According to Schwerzel, Battelle phisticated materials processing op- the production of unique polymer has come up with three resin candierations in space. He notes that in spheres that would be larger or more dates that might work in this process. carrying out the study, Booz-Allen is uniform than those produced on If successful, the technique would acting as a liaison or buffer between Earth. One specific product might be reduce the time needed to make preindustry and government to protect a commercial standard for various cision parts for testing from months trade secrets. size spheres—for example, for red to a few days, Schwerzel says. ComFor starters, Booz-Allen is provid- blood cells or particles. plex curvatures, internal cavities or ing potential space station users with Another concept proved out on the structures, and threaded screw holes seed concepts. In that way, Weinberg space shuttle is an electrophoresis may be possible. Expected applicaexplains, Booz-Allen can go to a process that uses zero gravity to fa- tions include parts for turbine blades company and state, "You can make cilitate production of biological ma- and engines. this"—not ask "What can you do with terials. A manned space laboratory Initial work that demonstrated the microgravity?" might one day use the technique to potential of the method was done a After determining users' reactions, produce urokinase, a substance ob- few years ago at Formigraphic Engine interest, and willingness to make a tainable from kidney cells that dis- Corp., Oakland, Calif., which will commitment to a space station pro- solves blood clots. Beta cells, which serve as consultant on the present gram, the firm also is identifying are obtained from pancreatic fluids project. The company made doughconditions under which selected po- and are capable of restoring natural nut-shaped objects from commercial tential users would consider making insulin production if injected into a photoresist materials, but these mathe necessary technical and financial patient's liver, also might be amena- terials lacked good physical properinvestments. Such conditions, ble to electrophoretic production in ties needed for prototype parts. Other Weinberg says, might include confi- space. Weinberg says they have work on the optics that will be needed dentiality and patent protection identified a client who's interested in was done at Battelle, in efforts to agreed to by the government to pro- using the unique purification possi- make a three-dimensional display of mote private participation. bilities of space for something that fluorescent spots for air traffic conIt also might include technical could be commercial. trol. considerations. By defining boundary Looking at service concepts, Eventually, Battelle hopes to asconditions for each concept, it can Booz-Allen envisions a space station semble a consortium for continued carry on an iteration between users possibly monitoring hazardous waste funding and development, which may and McDonnell Douglas to determine disposal sites. According to Weinberg, include a laser manufacturer, a prothe architectural options for a space his firm has identified a chemical ducer of computer-guided machine station. company that is interested in such a tools, and a chemical company. In The unique properties of space project. The chemical company has a another phase of the project, Battelle include sterility, "free" vacuum, number of sealed waste sites and ex- may explore photochemical depoly"free" solar energy, zero gravity, pects to have them monitored well merization as a means of sculpting D such parts. D control of magnetism, and absence of into the future. Nov. 8, 1982C&EN
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