What are some methods to pick the proper plastic sheet substance? Employ the tools that many professionals use to find the best plastic material for your application.
Where You Should Begin The process of picking the proper plastic material starts with ascertaining the' must have' physical properties required to provide your application. Designing a part with the minimum performance factors in brain will help to eliminate an overly expensive portion. Critical factors to consider are: Temperature requirement (short term and long term) Enviromental or Chemical Needs UV resistance (Will it be in direct sunlight) Color or Transparency Strengths (Impact and Compression) Compliance Issues (Certification for FDA, NSF, Dairy, etc .) Review The Plastic Properties Comparison Chart The first tool suggested is a map produced by the IAPD (International Association of Plastic Distribution - http:// iapd.org /) connected in video below, and are available on this chart are the most common plastic sheet and plastic rod materials that are commonly available. In addition, the chart compares the physical properties of these common plastic materials. Click on painting to access chart. IAPD Plastic Selection Rectangle Chart Included in this chart is a relative cost comparison, which will assist in restriction information materials to proper plastics for a application without over-designing and using an expensive' over kill' material. Some common plastic sheet substances can be very expensive. Materials like PEEK (Polyetheretherketone) can be in the $100 per pound range or more. A Great Place To Start Search With Temperature Resistance After appearing over the IAPD Physical Properties Chart , now it is time to evaluate specifics for your application. The critical factors listed above are ranked by most important to least important. If your portion needs to handle a continuous temperature of 300 degrees F, this is a critical physical property. Picking training materials that softens at 250 degrees is a recipe of natural disasters. Pick training materials that can handle the temperature first. Does Your {Desired End Part|Part| Be Chemical Exposure Next, look at environmental requirements. Proportions exposed to chemicals are important to research. Find the compound make up and the concentration of the compound to insure the material you pick can handle this solution. Many plastics have excellent compound resistance as evidenced by evaluating the container the chemicals are stored in already. A common plastic that is compound resistant is Polypropylene, the same substance used for automotive batteries. While Polypropylene and HDPE sheets are excellent in chemical resist, their temperature range is quite limited. Also, these two plastics can not be readily bonded or glued, and would require heat welding for assembly. Will Your Part Need To Be Protected From The Sun Most plastics do not handle long exposure to direct sunlight without an additional UV additive. The one exception is Acrylic, which is the most UV resistant plastic sheet available. Some plastics manage UV well if they have a carbon black additive, or a extra UV package added at hour of production. How Critical Is The Color The most frequent colours in many plastic sheets are Natural( white to tan) and Black. While other colours are available with a special run, this may require a large minimum ordering. Some plastics, like HDPE are available in many colours and textures for use in marine, playground and food processing applications. In many plastic applications, a machined proportion is being built, and the colour is the least important factor. If it is an internal part of a machine , no one truly cares about the color of the component. Some clients look for materials in a particular coloring to assist' brand' their portions for easy replacement and identification. How Much Stress Will The Part See Strength is a wide range of physical properties embracing many stresses a part may be exposed to. From impact to compressing, expansion to tensile strength, all of these can be critical in designing a plastic part. There are other factors in the' Strength' realm, like Notched Izod and Stress Can Cause Your Plastic Part to Bow, Twist and Crack, water absorption. If your component will be exposed to crushing pressure, pulling apart force-out or impact, these are critical things to consider prior to picking your plastic part. PTFE is a soft and slippery plastic, but will' cold flowing' under high pressure, and High Pressure POM-C Acetal Rod Laminates like G-10 FR 4 sheet can withstand some of the highest pressures. The Notched Izod exams for materials that transgress easily if a scored marking has been attained in the surface. Acrylics break quite easily if scored, but UHMW will not transgress at all under the same test. What Agency Approval May Be Required In many applications a part may require approval or testing to meet a third party certification. One such common application is for materials in food processing applications. Common requests included UL ratings, Fire Ratings, Military specifications and many more. Food contact is a popular request, embracing material that is either FDA( Food and Drug Administration) or NSF( National UL Ratings for Plastic Materials Sanitation Foundation) approved. These bureau insure that substances are rigorously tested and are appropriate their requirements for safety. Some common materials used in food processing that satisfies the FDA certification are Delrin- Acetal, HDPE, UHMW and Nylon, plus many others. Once these steps have been completed, several materials should present themselves as meeting your criteria and physical property requirement. Regrettably there is no one perfect plastic that works in all applications. However, for almost every application, there is a material that will work,
0 Comments
Leave a Reply. |