Improving Product Development With New Materials

Today's material technologies differ from those of the past in one fundamental way - before, when various urethanes and epoxies were developed, their appearance usually accelerated and transformed the industry. but eventually each was rewarded more for staying the same rather than for radically transforming material technology. Not now. Today, new resins and other materials are immediately put to use developing the next generation of materials.

With companies in every facet of industry looking to reduce time and development costs through new technology introductions, many new materials were introduced recently that offer something for everyone. The gush of products at this year's NPE show was a good example of the growing awareness among companies of the importance of integrating sophisticated materials, components, tooling and other secondary equipment in an overall quest for higher productivity. Following is just a sampling of new materials on the market with much to offer those attempting to improve the product development process.

High-Performance Polyamide

Rather than seeking a one-size-fits-all solution to resin manufacturing, makers are tailoring materials to the exact application with the goal of increasing performance and processing efficiency while lowering costs. DuPont (Wilmington, DE) is introducing a number of new resins to give customers a competitive edge in both existing and new products. Zytel HTN resins have been developed to replace metal structure parts. Zytel HTN is a high-performance polyamide with low moisture absorption, compared with nylon 66 and 6. Moisture and humidity have little effect on properties and dimensions. Zytel HTN also maintains mechanical integrity at significantly higher temperatures than standard nylons.

"With built-in shielding, excellent flow, dimensional stability, toughness and strength, Zytel can deliver significant savings in total system cost and increase design flexibility for housing laptop computers, hard drives, cell phones and other devices," says Ross Peterman, DuPont's product manager for specialty grades of Zytel.

There also is a new application for Zenite LCP, a group of glass and mineral-reinforced liquid crystal polymer resins used for injection molding processing parts. They combine high-temperature performance with excellent dimensional stability, chemical resistance and flame retardant properties without additives. Zenite LCP is used for electrical and electronic components, fiber-optic connectors, and film guides for laser and inkjet printers. Using Zenite LCP, DuPont is now developing lighting components, ignition parts and blow-molded ducting for automotive engines and extruded structures such as fuel tanks.

DuPont also is in the process of introducing new conductive grades of Zytel DMX. They combine built-in shielding with good flow characteristics, dimensional stability, toughness and strength - providing design flexibility for housings of laptops, hard drives, and other electronic devices. Zytel DMX parts reduce molding costs and eliminate painting - when compared with magnesium housings for many cell phones. A number of developmental grades of Zytel DMX offer different combinations of conductivity, attenuation, flame-retardant and mechanical properties. EMI shielding values range from 25 to m75 dB tested at frequencies into the 4-GHz range.

After testing several competitive resins, Tyco Electronics (Trudnov, Czech Republic) chose Zenite for its injection-molded plastics parts. The company specializes in electrical and electronic applications.

"Apart from an ability to withstand high temperatures, we needed something that had high dimensional stability and a low thermal expansion," says Angelo Polese of Tyco Electronic Advanced Group. "Zenite continues to meet all of our requirements, even after 15 million switching cycles."

Polymer Processing System

A system for processing virgin and recycled polymers is offered by Draiswerke, Inc., (Mahwah, NJ). The Gelimat compounder is an ultrahigh-speed thermokinetic mixing, fluxing and compounding system that also can work with highly loaded compounds and masterbatches. An electronic temperature sensor automatically ejects compounded material through a discharge door. The ejected material is then fed into a melt pump, short-barrel extruder, calendar, molding system or other stamping device. Users can change process parameters with a touch of the finger, and the process controls log and geographically display the parameters as they occur. Systems are available from laboratory to large-scale production sizes.

"The DRAIS Gelimat compounder offers super fast processing of compounds to greatly reduce the heat history and processing times of polymers," says Jeff Pawar, marketing executive with Draiswerke. "The Gelimat is not sensitive to moisture as in twin screws, so pre-drying of materials is not required."

Expanded Stereolithography Applications

DSM Somos (New Castle, DE) has a new line of resins that expand stereolithography applications. The Somos 9100 Series is optimized for use with the Argon ion laser on machines such as 3D Systems' SLA-500. Somos 9100 series mimics polypropylenes tensile strength elongation at yield and Young's modulus. It accelerates the design process by creating SLA parts that function comparable to polypropylene parts in hours.

Bill Noack of Morris Technologies (Cincinnati, OH) says that the Somos 9100 resin has allowed him to complete several projects where they were able to directly use the Somos 9100 parts in limited production assemblies. "The material performance was actually superior to what customers were expecting from parts created with the polyurethane casting process," Noack notes.

DSM Somos resins differ from other SLA materials on the market by offering enough durability to allow functional prototyping, but also offering the rigidity and robustness required to survive the room temperature vulcanization (RTV) tooling process.

Polyurethane System

BJB Enterprises (Tustin, CA) has just released its TC-850 polyurethane system. The TC-850 is a 75 shore D material with a five- to six-minute pot life and a one-hour demold time. This system has high tensile and flexural strengths, low viscosity (175 cps) and a higher heat deflection temperature than most hand cast systems. This material also offers a non-mercury based catalyst system. TC-850 has been used in hand casting, vacuum casting and rotational casting quality parts. Also, BJB's F-42 mold exhibits improved tensile strength and substantially higher elongation properties, while still offering sufficient work times and quick demold cycles.

"Customer satisfaction has been very high with the TC-850," says Jill Spilker, marketing assistant at BJB, "The TC-850 offers very low mixed physical properties for finished parts. It also offers low mixed viscosity, quick demold time, non-mercury containing catalyst and excellent heat deflection in comparison to other hand cast thermoset urethane systems."

Thermostat Modeling and Design Compounds

Landec Corp. (Menlo Park, CA) recently received a patent that covers the company's Aeromark line of thermostat modeling and design compounds, which are targeted to prototype and design applications in the automotive and aerospace markets. The company designs and develops, manufactures and sells temperature-activated and other specialty polymers for a variety of food, industrial and medical applications. Landec's temperature activated polymer products can be customized to abruptly change their physical characteristics when heated or culled through a pre-set temperature.

Moldmaking Silicones

Shin-Etsu Chemical Co. (Tokyo, Japan) specializes in two-component addition curing moldmaking silicones. The company currently offers several grades of silicone for the rapid prototyper. The KE1300T is designed as a general-purpose product. The silicone is the most cost-effective choice available without sacrificing quality and consistency. The KE1310ST has good resistance to epoxy resin attack and very good resistance to urethane resin attack, which results in a longer mold life with this product. The KE1310T is designed exclusively for epoxy resins and resists epoxy resin attacks, as well. The KE1311T has release characteristics for urethane resin molding, which results in a very long mold life, in many cases offering double the mold life of KE1300T, say company officials.

"They have all been very well received," says Mark Neuber, national sales and marketing manager for Shin-Etsu. "We believe that among molds, choosing opaque is like choosing to be blind. We don't understand why you would use an opaque when you could use a clear silicone product like the KE1300T. It is cost-effective. Europe and Japan use clear products. We are moving toward clear in this country, but it's slow."

Material Database

The Madison Group's (Madison, WI) Web MCBase material database program lists thousands of resins from more than 50 CAMPUS-participant resin producers. Data in Web MCBase adhere to ISO standards, allowing direct comparisons between material property data, including viscosity curves, stress-strain diagrams and creep modulus curves.

The CD-ROM program can run on any computer with a Web browser and data is centralized on one computer server for internet/intranet applications. The company's website also has a demonstration site of the McBase for those interested in how it works. Among some of the resin suppliers who can be downloaded on the system are GE, Alf Atochem, DuPont, and BASF.

"MCBase is a program that allows the user to view, search and compare all data in one encompassing database," said Paul Gramann, the technical researcher for MCBase. "This database has become the most successful and widely used materials database for plastics, with more than 200,000 copies distributed worldwide."

Injection Moldable Polyimide

Mitsui Chemical America (Purchase, NY) has a new grade injection moldable polyimide, which exhibits the lowest outgassing of any existing advanced engineering resin, according to Mitsui. The grade, Aurum JCR303OF, also provides a low coefficient of friction and has inherent flame-re-tardance, with UL94 V-O rating at 0.5 mm thickness. An end-use arena where the 1.42g/cc material is already shining is latches for sensitive electronics, where demands on parts are strenuous.

A new commercial application for the material is in a precision latch used in a hard disc drive. The polyimide part's role is to restrict the motion of the drive's suspension arm yet maintain mechanicals, low outgassing and resistance to wear. Other market potentials exist in electrical/electronics, semiconductors and other end-users.

The supplier also has introduced a high-purity polyimide designed to withstand the higher reflow temperatures required for lead-free solders. The material possesses an 18 g/10 min melt flow rate, flexural modulus of 569,000 psi and a heat distortion temperature of 455ºF. Tensile strength is 10,950 psi and elongation is out at four percent. Other attributes are excellent resistance to wear and good creep resistance.

Polyethylene Mechanical Properties

DSM Somos (New Castle, DE) has created a prototype part that performs like a polyethylene production part. The DSM 8100 series has many mechanical properties similar to polyethylene. Its elongation at yield is virtually the same as polyethylene. This series of stereolithography (SLA) materials can be used in numerous applications where traditional SLA materials would fail, like applications where snap-fit parts are needed and utilization in high impact applications. The 8100 series, part of their ProtoFunctional materials group, can be used to simulate the performance of actual production parts for both SLA selective laser-sintering (SLS) technologies.

"The DSM Somos 8100 resin series provide the necessary combination of flexibility and rigidity to bring living hinges to life as stereolithography prototypes, because it mimics the mechanical properties of some thermoplastics often used to make living hinges in production parts," says Robert Zubrickie of Tyco Electronics.

Thermoplastic Composite Bonding Adhesive

3M Company (St. Paul, MN) - in its search to find the better adhesive - has come up with Scotch-Weld Structural Plastic Adhesive DP-8005, which has the capabilities to bond with thermoplastic composites. The adhesive is solvent-free and bonds to low surface energy plastics as a well as other plastics, steel, aluminum, concrete, glass and wood. Once fully cured, its bond-line strength is often greater than that of the substrate. In many applications, screws and rivets can be replaced, saving cost, not to mention the time and effort of molding and machining holes. A handheld applicator accurately meters, mixes and dispenses a two-part adhesive from a cartridge. A three minute open time is said to allow easy positioning and repositioning on multiple or large components. Room temperature-curing helps save cost, space and time associated with ovens, UV lamps and heaters. It also resists many chemicals, water, humidity and corrosion.

One company that has benefited from the DP-8005 is Samick Music Corporation, (City of Industry, CA), manufacturer of more than half of the world's guitars and pianos, as well as the patented Sub Teqª 2.6 subwoofer. What brought 3M and Samick together was the music company's need to find an adhesive that would properly adhere to the rubberized end of the cone of the subwoofer's wooden enclosure. Samick had tried several other adhesive brands without much success. After being put through extensive tests, the DP-8005 filled that "missing link" in the music company's production process. The adhesive is directly applied on the production line.

"The DP-8005 has done wonders for our [Sub Teq] production process," says Frank Cates. "It's really been a great fit in our application process. It really solved our problem without having to make extreme engineering changes."

Multi-Purpose and Fast Cure Adhesive

Vantico (Basel, Switzerland), formerly of Ciba's Polymers Division, developed its fast setting and flexible Araldite 2026 multi-purpose and fast cure adhesive suited to both traditional and modern engineering substrates. The company's recent introduction, Araldite 2026, is a resilient, room temperature curing, transparent two-part polyurethane adhesive for transplant substrate bonding. It is water clear, with temperature- and UV-resistant properties, which make it ideal for any application where invisible joints are required or desired. Among the things it can be used on are display cases, roofing, lenses or medical equipment.

Polymer Infiltration Material

DTM (Austin, TX) has available a polymer infiltration material that allows customers to quickly create functional flexible prototypes such as tubing, hoses and gaskets from DSM Desotech's Somos 201 material.

DTM markets the Somos 201 powder, a thermoplastic elastomer, which was developed by the Somos group for use in DTM's sinterstation systems. Somos 201 laser-sintered parts infiltrated with the new polymer material are watertight, exhibit greatly increased burst strength wear resistance, improved tear resistance and enhanced surface finish. The infiltration material available from DTM also allows customers to make parts in any color.

"The ability to rapidly create strong, watertight, flexible prototypes will allow us to address applications where the final part would be made from rubber or a thermoplastic elastomer," says Michelle Wyatt of DSM Somos. "Automotive hoses, gaskets, and door seals are obvious examples."

Powder-Binder Systems

Z Corp. (Burlington, MA) has two powder-binder systems for use with the Z402 3D Printer. Each system provides specific advantages to the customer and can be used interchangeably on the Z402 system. The zp100 powder is a material system based on plaster that quickly delivers high strength and detail. The zp100 is a good fit for customers producing delicate or thin-walled parts or customers that require high strength without any post-infiltration. The powder, for many parts and applications, makes post-infiltration unnecessary.

Company officials say that if additional strength is required, zp100 can be mixed with wax or a range of resins to enhance its strength and physical properties. This, in turn, makes the parts suitable for sanding and painting. Among the materials it can infiltrate are urethane, Sicomet 9000, elastomer and wax.

"The availability of a fast, convenient tool such as the Z402 System has the potential to create an enormous, high-growth market while transforming the design process in much the same way as low-cost desktop printers and fax machines have transformed business communications," says Maria Hatsopoulos, CEO of Z Corp. "Z Corp's technology is the only one capable of addressing the broad market due to its high speed and low cost of materials, as well as full-color capability."

High-Temperature SLA Resins

Rapid Prototyping Chemicals, Inc. (Berne, Switzerland) has several new high temperature SLA resins and other polymer materials. The RPCure 100 ND and RPCure 300 ND are resins for stereolithography equipment with solid state lasers. The RPCure 100 HC is the general-purpose epoxy resin for SLA systems equipped with a solid state laser. The major advantages are high photospeed and dramatically improved humidity resistance.

The RPCure 300 ND has a high build rate with high photosensitivity and good wetting. It also promises no pre-drip or post-drip delays. It has easily removable supports, smooth surfaces, very low water sensitivity that encompasses only small dimensional changes and good solvent resistance.

The RPCure 400 series consists of three epoxy resins for SLA systems equipped with a He/Cd, Ar-UV- or solid-state laser. These resins have an exceptionally high temperature resistance and can be used for functional testing at elevated temperatures. The 400 series resins have the following specific properties: Glass transition temperature at 180º to 185ºC, high modulus and flexural strength, easily removable supports, smooth surfaces, very low water sensitivity, small dimensional changes, good solvent resistance and very little softening at high humidity.

For more information contact Stan Rayford of Dupont Chemicals (Wilmington, DE) at (313) 583-7821; Jeff Pawar of Draiswerke, Inc. (Mahwah, NJ) at (201) 847-0606; Guy Stokes of Landec Corp. (Menlo Park, CA) at (650) 261-3638; Joseph Stroh of 3M Company (Minneapolis/St. Paul, MN) at (800) 362-3550; Antoine Rois, PHD of Madison Group, (Madison, WI) at (608) 231-1907; Karen Kiffney of Z Corp. (Burlington, MA) at (781) 852-501; Michelle Wyatt of DSM Somos (New Castle, DE) at (302) 328-8537; Barbara Tischler of Vantico Co. (Basel Switzerland) at 01442 890000; Jill Spilker of BJB Enterprises (Tustin, CA) at (714) 734-8450; Mitsui Chemical America (Purchase, NY) at www.mitsuichemicals.com; Mark Neuber of Shin-Etsu Chemical Co. (Tokyo, Japan) at (505) 856-0988 and Andy Jacobson of 3M Company (Minniapolis/St.Paul, MN) at (952) 897-9475.