Here’s a great site on how one firm installs a synthetic ice (high density polyethylene) surface
Category Archives: Industrial Plastics
How do you reduce the wear and tear on your dump trucks and trailer, when the only thing between your load and your profit eventually corrodes and wears away?
Simple, use UHMW in high wear applications…
By Ross McShane and Jeff Haarstick
In high wear applications, UHMW-PE, ultra high molecular weight polyethylene, stands alone. UHMW-PE reduces abrasion, increases release, and helps absorb impact all in one. At only a fraction of the weight and cost of steel and aluminum, UHMW-PE can outwear steel two times and aluminum four times. UHMW-PE is commonly produced in sheets by compression molding. Single sheets can be up to 33 feet/10 meters in length; however, average presses are much smaller, typically 4 by 10 feet/1.21 by 3.04 meters. With a butt fusion welder, these sheets can be seamlessly welded together into any length. Additives can also be added to UHMW-PE in premium and specialty grades. Silicone reduces friction, increases slip and lessens noise. Glass spheres increase hardness and abrasion resistance. Ultra violet inhibitors (UVI) can increase the life of UHMW-PE from about a year to five years when continuously exposed to direct sunlight. Other additives include heat stabilization, color, and anti-static. Combining the reduced weight, lower cost, increased wear, and greater flexibility, UHMW-PE becomes the apparent choice when compared to other high wear substitutes.
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For 25 years, Horn Plastics, Inc. has been known in the heavy construction and agricultural industries as an expert group of honest hardworking salespeople who callback in a timely fashion, are knowledgeable of installation advice and dedicated to friendly service. Super-Slide is a non-stick, high wear, premium engineered plastics that can be cut into small wear strips or welded into rolls of any length. For more information on UHMW-PE and Super-Slide products go to www.superslide.com.
Description: “Wet Benches” are stations for wet etching and cleaning of wafers and devices. (“Litho Benches” in contrast, are used for resist processing.) The various wet benches differ in the specific process modules available and the materials allowed at each station. For information about some of the various wet processes available, click <here>. The available Wet Benches are:
Wet Bench Fire Safety: Update
By: Lise Laurin and Marcia Tate
Where there’s smoke there’s fire…but where there’s fire there doesn’t have to be smoke, corrosive fumes, or catastrophic damage, because cooperation between semiconductor and plastics manufacturers, industrial insurance providers, and wet bench manufacturers has resulted in safer, more efficient wet benches.
Today’s wet benches, made from specially engineered plastics, have come a long way from their beginnings in the 1970s, when they were simply modified work benches made of painted steel. By the 1980s, specialized manufacturers were making wet benches from plastics such as polypropylene. In the late 1980s, attempts to produce safer wet benches led to the development of fire retardant polypropylene (FRPP); subsequent research, however, has shown that although the FRPP formula lengthens ignition time, the corrosive smoke from burning FRPP actually causes more damage than was caused by the earlier generations of polypropylene. All plastics burn, but not all burn in the same way.
Readily available, easily fabricated, and able to resist corrosive chemicals without deteriorating or leaching out into the bath, specialized plastics are the material of choice for wet bench construction. Yet in the semiconductor industry, the very nature of the wet bench process—an electronically controlled process usually containing corrosive chemicals and sometimes incorporating electrically heated baths—means there will always be a potential source of ignition nearby. While fire isn’t the only safety issue associated with wet benches, it’s certainly the one that attracts the most attention because of the astronomical amount of damage one fire and its resulting smoke and corrosive fumes can cause.
With loss control as motivation, industrial insurance pro-viders joined plastics manufacturers and wet bench manufacturers to find plastics that don’t propagate fire, release little smoke, and don’t produce corrosive fumes as they burn.
Factory Mutual Research, a division of FM Global, began the move toward safer wet benches by establishing an index against which to measure cleanroom materials: Test Standard FM4910, Cleanroom Materials Flammability Test Protocol (1997). The first and most important feature of the FM4910 test standard is the Fire Propagation Index (FPI), which indicates tendency of a material to propagate fire. The test also indicates the comparative amounts of smoke generated according to the Smoke Development Index (SDI). Initially, the test also measured corrosive fire byproducts (CDI), but that measurement was later dropped.
In order for a material to be considered “fire-safe,” it must have an FPI equal to or less than the established acceptable level of 6. Regular polypropylene, FRPP, and polyvinyl chloride (PVC)—the conventional wet bench materials and the first materials tested—do not meet this minimum requirement.
With this measure as a guide, plastics manufacturers began formulating plastics to meet the specifications and submitting them for testing. Semiconductor manufacturers became concerned that while these new materials might be fire-safe, they might not be compatible with their processes. To address these fears, International SEMATECH, a research consortium of semiconductor manufacturers, established testing procedures to determine the process compatibility of materials destined for use in wet bench construction. The aim was to establish a set of parameters that would allow anyone to test the compatibility of any plastic material.
The Price of Progress
International SEMATECH’s tests of new plastics show that many concerns about the need to compromise purity to gain fire safety are unwarranted. The new standards have not only given plastics manufacturers an incentive to develop new materials, but also provided guidelines as to what criteria the new products must meet. As a result, many of the materials submitted for testing are proving to be superior to conventional wet bench materials.
While most new plastics are more expensive than conventional ones, the materials usually represent only a small percentage of the cost of a wet bench; in most cases the added cost of new materials is less than the cost of the built-in fire suppression system.
Complicating the conversion to new materials, however, is the lack of “off-the-shelf” parts made of fire-safe materials. To maximize safety, wet bench manufacturers must custom-build parts, and this adds to costs. Todd Thomas, president of Amerimade Technology, a wet bench manufacturer, states that at present his company is choosing its new plastics from the poly-propylene family. Since many of the smaller parts, such as fittings and latches, are not yet available in the new materials, keeping materials’ properties as similar as possible allows for easier construction and welding. Although new materials may meet criteria for construction of the wet bench structure, no test results are yet available to qualify these materials for use in process baths. To achieve a totally fire-safe system, the process baths must be upgraded to Teflon or PVDF, materials that are inherently fire-safe.
As more plastics measure up to the FM4910 and SEMA-TECH standards, and as wet bench manufacturers become more comfortable with the characteristics of the new plastics, the costs associated with their use are decreasing. Customers, too, are becoming aware of and educated about the new materials. At first, semiconductor manufacturers showed some reluctance to switch from the materials with which they were familiar; there was uncertainty about whether the change was necessary and concern about potential adverse effects on production. Increased research results, several catastrophic fab fires, and the potential of reduced insurance coverage, however, helped overcome these obstacles. According to Thomas, as recently as one year ago, wet benches constructed of the new fire-safe plastics accounted for only 10-15% of his company’s sales; that figure is now up to 50%. Informed customers are now requesting specific materials.
As plastics manufacturers rushed to submit materials for testing, it became apparent that the limited availability of the Factory Mutual Research test equipment and subsequent high cost and long lead time of the tests were hindering the process. Acceptable alternative materials were not becoming available soon enough to meet demand. Many materials that passed the fire propagation and smoke tests (20% of those submitted for testing) failed the corrosion tests. Specifically, most of the semitransparent plastics suitable for windows in minienvironments were found to produce corrosive fumes as they burned.
Concerned engineers proposed eliminating the corrosion index, allowing the use of materials that do not comply to FM4910 as long as they are not close to an ignition source, and moving to qualify more labs to run the 4910 tests. In response to industry pressure and after a review board concluded that the CDI results were not adequately repeatable, Factory Mutual Research removed the corrosion damage index from the FM4910 test standard. Factory Research Mutual researchers and others involved felt that if a material passes the stringent fire propagation and smoke development tests, it would likely cause minimal corrosion damage.
Still, there was pressure to speed up the qualification process and to make it more economical. HSB Industrial Risk Insurers chartered Underwriters Laboratory (UL) to formulate a less expensive test that could produce results as reliable as those of FM4910. While Factory Mutual Research’s tests require equipment with limited availability, the UL test uses a standard cone calorimeter. No one involved disputed Factory Mutual Research’s contributions, but input from another source was welcome. This “second opinion” validated Factory Mutual Research’s effort and research.
Working with samples donated by plastics distributors, UL and Factory Mutual Research have completed a round-robin of testing to verify the equivalency and repeatability of their tests. Representatives from UL, FM Global, HSB, and several plastics manufacturers met on November 17, 1999, to discuss the results of UL’s test. UL disclosed the results of the tests using the standard cone calorimeter. Valid test results from this less costly, more readily available equipment (installed in more than 100 laboratories worldwide), would enable quicker, less expensive testing and result in more options and lower prices. It would also allow testing in intermediate steps during R&D.
The goal of the round-robin was to formulate a single set of “fire-safety” testing standards to present to the National Fire Protection Association (NFPA) at its annual spring meeting. This would align all parties involved (insurers, materials manufacturers, semiconductor manufacturers, and process equipment manufacturers) striving for the same result, which would ultimately result in better products and safer cleanrooms.
Factory Mutual Research retested eight of the nine plastics used in the UL tests; the results of this round of testing were consistent with Factory Mutual Research’s previous findings but not identical to UL’s findings.
Two types of tests include a “full-scale” test (Photo 1) and a “small-scale” test (Photo 2). Results of the full-scale (“Parallel Panel”) test are obtained by setting up two 2 x 8 ft. panels of the same plastic and starting a fire between the panels. Researchers monitor the panels to discover how quickly they ignite and what happens to them as they burn.
In the small-scale test, small samples of material are burned in a piece of laboratory equipment, where they are monitored to measure the time it takes the material to ignite, how much heat it releases, and the amount of smoke it generates. Since a much smaller sample of plastics is used in the small-scale test, results must be compared to the Parallel Panel test results. UL correlated the cone calorimeter tests (ASTM E1354) to the Parallel Panel tests.
UL and Factory Mutual Research achieved very similar results from the panel tests, but slightly less clear-cut results from the small-scale testing. Factory Mutual Research’s apparatus and the standard cone calorimeter yielded slightly different data. Factory Mutual Research felt that further testing on a wider selection of plastics was advisable; only nine plastics were thoroughly tested using the UL procedure as opposed to the hundreds that have been tested using FM4910. While there was total agreement on the properties of the plastics at the extremes of the test parameters, there were gray areas in the middle ranges.
After reviewing the data, the NFPA committee responsible for presenting recommendations for updating the NFPA 318, the standard of protection of cleanrooms, to the NFPA annual spring meeting discussed adopting FM4910 and UL2360, the new UL subject test standard, as reference standards. A note was included indicating that the subject test standard UL2360 was under development, since UL had not completed its internal standards review process. The recommendation, which will be submitted for final approval at the international annual conference in May 2000, is that in order for a material to be considered fire-safe or noncombustible, it must pass a reference standard test conducted by a recognized testing laboratory and be “listed” by that laboratory. Robert Pearce from HSB stated that both UL and Factory Mutual Research are acceptable testing laboratories.
FM Global and its insureds are already working under a version of the fire-safe standard. Since most wet benches are custom fabricated, Factory Mutual Research must inspect each of its clients’ wet benches, both at the manufacturer’s site and on-site in its final location, to determine whether or not the bench can be considered fire-safe without the addition of a fire suppression system. Once manufacturers have a full complement of fire-safe materials, along with a set of clear-cut standards to follow, this process will flow more smoothly.
Factory Mutual Research has submitted the FM4910 to the NFPA Fire Test Committee, ASTM, and ANSI, which effectively puts it in the public domain. The test would become NFPA Standard 287 upon final review and acceptance in 2000. The test is undergoing final review and comment from ASTM, and adoption is also expected in 2000.
Looking beyond wet benches, other major applications for fire-safe materials in semiconductor applications include wafer carriers, parts cleaners, wall panels, and insulation materials that can represent significant combustible loads. FM Global’s Paul Higgins states that his company is planning to partner with several wafer transport equipment manufacturers to move away from ordinary polypropylene and polycarbonate carriers. New 300 mm wafer carrier storage systems, known as stockers, could present fire protection challenges. Sprinkler systems would not prevent smoke and water damage to their contents, and the larger enclosures required could be very difficult and expensive to protect with fire suppression systems.
So far, the push for fire safety has been a win-win process for all involved. The reduced risk of fire will simplify business for the risk managers and insurers. Semiconductor manufacturers will benefit from more stable insurance coverage—from the knowledge that their facilities and workers are more secure and from knowing that wet benches made from new materials are more process-compatible than their predecessors. Plastics manufacturers have created new markets for superior materials, tailored specifically to their clients’ needs.
From the very beginning of the research to the presentation of the joint findings to the NFPA, there has been a spirit of cooperation among all parties involved. Everyone stands to gain from a clear definition of “fire-safe” and the adoption of standards to ensure uniform requirements throughout the industry.
Thanks to Todd Thomas, Amerimade Technology (Pleasanton, CA); Paul Higgins, FM Global (Johnston, RI): Robert Pearce, HSB Industrial Risk Insurers, (San Francisco, CA).
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Make your own and Save Money!
This pattern is for two Featherboards. You make both at one time. It is easier to rout two than just one. With a longer board than necessary, you use clamps for stops, and to hold your work.
I made mine from 1/2″ HDPE (High Density Polyethylene). You can make them from Hickory, Oak, or Maple.
If you need a good price on HDPE, let me know.
Thermoplastics for aircraft interiors
By Staff | September 2007
GE Plastics (Pittsfield, Mass.) has launched three new resins designed for use in aircraft interiors. Noryl LS6010 is a polyphenylene ether (PPE) that has a specific gravity of 1.1, which is one of the lowest available for thermoplastics used in aerospace. It also features low smoke, good durability and nonhalogenated flame retardance (FR). Applications include rub strips and seat track covers, for which low smoke propagation is mandated. Lexan FST9705 is a polycarbonate (PC) copolymer said to be suitable for personal service units, window reveals and bezels, and offers full flame/smoke/toxicity compliance, including OSU 55/55 heat-release performance. Flame-retardant Ultem 9085 is a polyetherimide (PEI) resin that is said to offer better flow and ductility than GE’s Ultem 9075 resin and can reduce part weight by 5 to 15 percent via thinner walls. The material also provides the highest modulus of any Ultem resin grade. Potential applications include decompression grilles, window reveals and personal service units. 1197
Editor’s Note: I came across kathy Matsushita‘s router jig site and had to share it with everyone in its entirety – please visit her site and look at the tools she’s engineered for herself for making guitars. She’s used UHMW for tracing the router along the edge of a guitar – probably because it has one of the lowest coefficient of friction of any plastic and won’t leave marks.
My Binding Router Jig!!!
Summer 2004 . . . . The credit for this jig goes entirely to Don Williams, who has posted detailed instructions for building and using this jig for routing the binding and purfling ledges of a guitar, using a laminate trimmer. Up to this point, I have been using a Dremel tool with Stew-Mac’s binding attachment to rout all my binding ledges. That worked, but I have always intended to “graduate” to using a more substantial tool for the task. For some reason, I didn’t like the idea of moving the guitar body under the more traditional stationary binding router jig. I felt more comfortable with the idea of moving the router around the body, instead. So, when I saw Don Williams’ version of Harry Fleishman’s original idea (using a pivoting arm and parallelogram — here’s a photo of Harry’s jig as used by a student in Harry’s luthier class), I quickly latched onto it. I built it over several weekends.
The jig uses a 12″ lazy susan underneath the base, 22″ heavy-duty drawer slides, and a parallelogram. This set-up allows you to move the laminate trimmer in virtually any direction and height, always keeping the trimmer perpendicular to the table. You set the guitar body in the cradle, adjusting it so that all sides of the body are perpendicular to the table. The jig’s base is screwed into the workbench.
Here’s the resulting cut, on some scrap plywood I had sitting around. The jig worked very smoothly, and the cuts were nice and clean and consistent!!!
To the left: This is a disc made of UHMW polyethylene. The 3/16″ “donut” ring in the center is what rides on the rim of the guitar body as you rout out the ledges. I will be using the LMI 1″ cutter bit and bearing set with this ji
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Morbo is a biped robot I designed and built to experiment with. It is intended to be a continually developing platform to test various methods of locomotion and processing. Although there are currently several biped kits on the hobby market, I’ve decided to ” roll my own ” so to speak. I love machining and building, and I have a few things I haven’t seen before that I’d like to try.
The above picture shows Morbo in almost the current configuration. Missing in that picture is the wireless link. The current incarnation consists of:
6 Hitec 475HB Servos
PicoPic Serial Servo controller
Sparkfun Electronics Blue SMiRF Bluetooth radio
Custom build aluminum chassis
1500Mah 7.4v LiPo Battery
Medusa Electronics 3.5A BEC
Exerpt (Click On Link For Full Article)
The Multifunctional, Reprogrammable Velcromatic Side Bearings with Magic Slider.
by Jack Brisbin
Printed in Reflections: March, 2004.
While contemplating on building a telescope of my own design, I decided to use existing optics from other telescopes and stuff from the ATM vault of stuff I forgot I had. I wanted to be able to use various finder scopes, eyepieces and secondary mirrors on this particular telescope. This also means you need some type of adjustable (re-programmable) side bearing to compensate for the different changes in weight to balance the telescope and make it more multifunctional.
I have often thought about using Velcro to hold the side bearings (altitude) to the telescope tube and eliminate the cradle and/or sliding weight to balance the tube. By using two strips of Velcro you could reposition the side bearing on the tube and compensate for the weight (balance point) of the telescope. The telescope tube pictured is a square wood tube that is 36’ long and holds an 8” f4.5 mirror.
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How-To: Build your own CNC machine (Part 2)
In today’s How-To, we’re still pimping out our dremel tool with parts from old printers. In Part 1 we got started with the controller and covered all the basics. Today we’ll get into the details and get busy with the power tools. And that, of course, is always the best part.