Use the best available tools to narrow down the best plastic sheet material for your application.
What are the best methods to pick the proper plastic sheet material? Use the tools that the professionals use to find the best plastic material for your application.
Where To Begin
The process of picking the proper plastic material starts with determining the ‘must have’ physical properties needed for your application. Designing a part with the minimum performance factors in mind will help to eliminate an overly expensive part.
Critical factors to consider are:
Temperature requirements (short term and long term)
Chemical or Environmental Requirements
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 Property Comparison Guide
The first tool suggested is a chart produced by the IAPD (International Association of Plastic Distribution – https://iapd.org/) linked in picture below, and listed on this chart are the most common plastic sheet and plastic rod materials that are commonlyavailable. In addition, the chart compares the physical properties of these common plastic materials. Click on picture to access chart. Included in this chart is a relative cost comparison, which will assist in limiting the materials to proper plastics for a application without over-designing and using an expensive ‘over kill’ material. Some common plastic sheet materials can be very expensive. Materials like PEEK (PolyEtherEtherKetone) can be in the $100 per pound range or more.
Start Search With Temperature Resistance
After looking over the IAPD (International Association of Plastic Distribution) Physical Properties Chart above, 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 part needs to handle a continuoustemperature of 300 degrees F, this is a critical physical property. Picking a material that softens at 250 degrees is a recipe for disaster. Pick a material that can handle the temperature first.
Will Part Have Chemical Exposure
Next, look at environmental requirements. Parts exposed to chemicals are important to research. Find the chemical make up and the concentration of the chemical to insure the material you pick can handle this solution. Many plasticshave excellent chemical resistance as evidenced by evaluating the container the chemicals are stored in already. Acommon plastic that is chemical resistant is Polypropylene, the same material used for automotive batteries. While Polypropylene and HDPE sheets are excellent in chemical resistance, their temperature range is quite limited. Also,these two plastics can not be easily bonded or glued, and would require heat welding for assembly.
Does Your Part Live In 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 handle UV well if they have a carbonblack additive, or a extra UV package added at time of production.
How Critical Is The Color
The most common colors in many plastic sheets are Natural (white to tan) and Black. While other colors are available with a special run, this may require a large minimum order. Some plastics, like HDPE are available in many colors andtextures for use in marine, playground and food processing applications. In many plastic applications, a machined partis being made, and the color is the least important factor. If it is an internal part of a machine, no one really cares about the color of the part. Some clients look for materials in a specific color to help ‘brand’ their parts for easy replacementand identification.
Nylon with huge amount of stress, cooled too quickly.
How Much Stress Will The Part See
Strength is a wide range of physical properties covering many stresses a part may be exposed to. From impact to compression, expansion to tensile strength, all of these can be critical in designing a plastic part. There are otherfactors in the ‘Strength’ realm, like Notched Izod and water absorption. If your part will be exposed to crushing pressure, pulling apart force or impact, these are critical things to consider prior to picking your plastic part.
PTFE is asoft and slippery plastic, but will ‘cold flow’ under high pressure, and High Pressure Laminates like G-10 FR 4 sheetcan withstand some of the highest pressures. The Notched Izod tests for materials that break easily if a scored mark has been made in the surface. Acrylics break very easily if scored, but UHMW will not break 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, covering material that is either FDA (Foodand Drug Administration) or NSF (National Sanitation Foundation) approved. These agencies insure that materials are rigorously tested and comply with their requirements for safety. Some common materials used in food processing that meet the FDA certification are Acetal Copolymer – Acetal Homopolymer, HDPE, UHMW and Nylon, plus many others. Once these steps have been completed, several materials should present themselves as meeting your criteria andphysical property requirement. Unfortunately there is no one perfect plastic that works in all applications. However, for almost every application, there is a material that will work, and work better than most other substrates.
If you are still in need of assistance in identifying an appropriate plastic material, contact an experienced Plasticologist at Industrial Plastic Supply, Inc. – call 866-832-9315
Plastics have been around for over a century now, and are used in almost every industry and application. The problem is that society has made the plastics industry the poster child for waste, trash and pollution. This is unfair, and factually incorrect.
Plastic materials are lighter, cost less to produce, use less electrical power to produce, and are safer for use. It is not new phenomenon that a material or product, once used, gets thrown away. This is the normal life cycle of many materials. Some inexpensive plastic materials used in consumer goods are made to throw away once the item has been purchased. Things like the indestructible packing we fight on kids toys, the cheap plastic sporks from restaurants, the prolific plastic water bottles and of course, the plastic grocery bags. All of these materials are 100% recyclable, the hitch is that it requires a little effort to recycle.
Are Plastic Materials The Cause?
On the positive side, the products that plastic currently replaces are much larger, heavier and generally cost more to produce, and use more energy to produce. This means, that the large amount of plastics that are not being properly disposed of, are replacing much larger quantities of materials that would not be recycled. I still remember times when I was a kid, and seeing tin cans in the lakes and rivers when out fishing. People polluting with their trash is not a new thing, now it is just a different group of materials.
Thermoplastic plastic materials are recyclable, and can be used over and over again. Generally, the recycled product would not be for a Food or Medical application. A common use of recycled plastic is with the collected milk jugs and detergent bottles, both HDPE, can be ground and turned into plastic lumber. The plastic lumber can be used to replace standard wood products for decks and outdoor furniture, and it will last for 15 – 20 years with no maintenance or painting. The cost savings and reduced use of natural resources for this one product can be staggering. The color doesn’t fade, it wood won’t split or crack, and it continues to look good for up to two decades.
Our recent article, “Plastic Material Bad Reputation – How did we get here?“, we discuss the factors that have lead to the ‘throw away’ society that we have become. Much of this bad reputation is for products that are designed as one use and then designed to be thrown away. So, if we are to change the bad reputation, companies need to change this design flaw, and start using materials for applications that can be reused easily.
If we can minimize the use of throw away plastics, and recycle the plastic material once we are done with it, we can help to limit plastic in land fills.
The blame for plastic pollution should be placed…on people. The plastic is not the cause of the problem, it is the litter-bug and irresponsible individuals that trash our planet. How do the plastic bottles and grocery bags end up in the ocean. They certainly don’t throw themselves in to the ocean, it is lack of responsibility and negligent behavior.
It really only takes a couple of seconds to throw something into a recycle bin. Even better would be to reuse the plastic bottles or plastic bags. Plastic materials are not the problem, empathetic people are the problem.
You know how bad it is when you get stressed out, with all the day to day challenges and issues? Well, plastics get stressed too.
The process of producing plastics into sheet, rod and tube is a stressful manufacturing process.
Stress free plastic manufacturing
The process to make a plastic sheet, plastic rod or plastic tube requires the plastic resin to be heated to temperatures of 350° – 500º to get the resin to flow through the machines.
The material is then pushed through a die at high pressure.
This heat and pressure cause many stresses to affect the plastic material.
The cooling of the plastic shape is critical
If the plastic cools to quickly, the surface cools and the center is still very hot, this is a major cause of internal stress.
Processed to quickly and voids or cold spots cause poor quality sections.
Processed to slowly and materials burn in the die and visible burn spots appear on the surfaces – bad material
Proper speed provides homogeneous material that has cooled at a uniform rate through the sheet yields a very low stress sheet
The stresses from this production can be very significant and can ruin your parts. One common prevention method is to anneal or stress relieve the raw material prior to machining, and may require stress relieving during machining if large amounts of material are being removed. The stress relieving process is a slow heat and cool process, contact us for details on your material or project.
Here is an example of a highly stressed plastic sheet, it is 1.250″ thick glass filled nylon sheet. The manufacturer sent us this sample to show the ‘quality’ of their material. We attempted to cut off a strip to do some testing, and you can see the results. This material warped so much it stopped our saw! We never did buy anything from this supplier.
Compression Molded Plastic Sheet and Brownies…
Nylon with huge amount of stress, cooled too quickly.
Yes, you read that right, brownies. I still remember the wonderful smell of my Grandma’s house when she was baking her special 2″ thick brownies. The smell was great, but I also remember the critical timing in the oven. She would open the oven and peek in, and close it quickly so as not to let the heat out. Then, when they looked about right she would open the oven and slip a toothpick into the center of the pan and pull it out again slowly. I can remember asking, “Grandma, why do you put in the toothpick into the brownie?”. The answer was, that the outside cooks quicker than the inside, and it takes a while to get the brownies to cook all the way to the center.Then, when they were all cooked, I would have to wait while they cooled. And, sometimes, if I didn’t wait quite long enough, when I would take a bit the center would burn my tongue. Ouch!
The interesting thing is, that plastics are about the same. Most plastics have a very low co-efficient of thermal conductivity (that is sure a mouth-full), which means that heat and cold don’t travel through the plastics well. This means that it takes a while to ‘cook’ the plastic all the way through, and not just the surfaces. And, just like my brownie story, the plastics take a long time to cool. If the outside of the plastic cools much faster than the inside, then large amounts of stress develop.
The process of compression molding of the plastic sheets is ideal for eliminating stress. The sheets cook slowly, so the entire sheet, including the center, is heated to a uniform temperature. The temperature is held at temperature to insure a fully cooked sheet (you can’t use a toothpick here). Then, over several hours, the temperature of the sheet and the entire compression molding press is lowered very s-l-o-w-l-y. This allows the center of the sheet to cool at the same rate as the external surfaces, and this yields a very stress free sheet. The premier manufacturer of this high quality compression molded sheet is Westlake Plastics. We have been a master supplier of the Westlake Plastic materials for over 35 years.
What should you do to eliminate stress?
If you are experiencing problems with your plastic materials, such as twisting, warping, ‘potato chipping’ or any other sign of stress, contact us. It is probably not your fault. There are dozens of manufacturers that produce engineering and mechanical plastic shapes, they are not all the same. During the production of materials, the process should include a secondary annealing step to remove stress from the newly product. By removing all stress from the sheet or rod you are insured of a ‘clean slat’ before you start machining or finishing. We only provide materials from top rated manufacturers, we truly care about the materials you receive from us.
If you have been experiencing problems with the materials you are getting from other suppliers, let us know, we can help eliminate your stress problems. E-mail us or call us at: 866-832-9315
Since 1975 we have provided large diameter plastic rods and thick plastic sheets, plates, slabs and blocks. One of our long time ‘secret’ sources has been Gehr Plastics. Since 1932 the Gehr family has owned and operated the Gehr Plastics company. They are a worldwide leader in semi-finished plastic shapes in thermoplastics, primarily sheet and rod. The headquarters for Gehr Plastics is in Mannheim, in south western Germany. For almost 30 years, Gehr Plastics has had production facilities in the Philadelphia area, providing the USA with the same high quality plastic shapes.When we mention large diameter rod, we mean it! Gehr can produce plastic rod up to almost 20″ diameter in several grades of plastic. They also produce sheet plastics up to 8″ thick, and make the largest materials of most manufacturers of plastic sheets and rods.
At Gehr Plastics, Quality Engineering Plastic Comes First
Our first purchases with Gehr Plastics was in the PVC rod family. Once again, they make huge cross sections in many materials, including the PVC rod. Many manufacturers struggle with large sections of PVC rod because keeping it void free throughout the large diameter is very difficult. Not for Gehr Plastics, they specialize in engineering plastic materials. We have chosen this high quality manufacture for their exceptional product quality. We know the demands of our client base, and only choose the best factories to supply our products. Gehr is definitely one of the premier plastics producers in the world. While the quality of the PVC rod is excellent, the rest of the Gehr Plastics product line is also some of the best plastic semi-finished shapes available in the market place. Here is a list of some of the many materials that Gehr Plastic produces:
14 inch Natural Polypropylene Rod produced by Gehr Plastics, the largest domestic plastic rod currently in production. 12″ diameter UHMW rod from Roechling Plastics, Industrial Plastic Supply is master distributor for both of these manufacturers.
And a new and exciting product – Clear Nylon Rod (Contact us for more information)
Many of the above items are also available in sheets, plates, slabs or blocks.
Gehr Plastics – one of our engineering plastic partners
We have been proud to offer the complete line of plastic rod, sheet, slab, plate and block from Gehr Plastics, and consider them a highly valued partner in supplying these engineering plastic materials to you, our valued client. For more information on the size range, availability and pricing on these and other plastic materials,click hereor call us at 866-832-9315
When we think of plastic, we think of plastic bags you get at the grocery store or maybe your child’s toy that’s made out of cheap throw away material. If you stop and think about it, plastic is everywhere and it’s uses are almost infinite. Take Acetal Copolymer, it is a plastic that replaces metal in numerous applications and is used to make gears, screws and other hard working parts. Consider PTFE for instance which is used to coat your frying pan to make it non-stick, make steam valves and fittings, and chemical resistant parts. Another material is Polycarbonate or Lexan® (a SABIC brand name -formerly G.E. Plastics) which is used to replace glass because it is shatter resistant and is also used for bullet resistant glazing and riot shields. Even the cup of coffee you grab for every morning is made of foamed Styrene – Styrofoam. But plastic has shaped our lives in countless ways, many of them you might not even think of or notice.
Plastics play a big part in the world of medicine. Some other advancements in the area of medicine include assisting people with debilitating injuries and serious afflictions, helping them feel more comfortable and move easier. Prosthetic limbs and joint replacements have come along way since the old days of metal and wood. Since the late 90’s UHMW or (Ultra High Molecular Weight Polyethylene) has become the standard in hip and joint replacements. With plastics like UHMW, which has great wear resistance, excellent strength and very low co-efficient of friction (very slippery), it has made people who need these surgeries have better mobility and better quality of life. These plastics also make prosthetic limbs lighter and stronger for athletes who wish to compete and lead near normal active lifestyles due to the use of plastic polymers (derived from the Greek meaning ‘many parts’) mimicking human flexibility. Prosthetic devices date all the way back to the ancient Egyptians where they used leather and wood for toe and foot replacements. But thanks to today’s technologies and advancements in as plastic, most amputees and athletes can regain their quality of life and enabling them to do what they love.
What has Medical Plastic Done For You Lately?
Another plastic material that has changed the medical field is PEEK (Polyetheretherketone). This material is a newer plastic which has high chemical resistance along with excellent high continuous temperature resistance of up to 480 degrees fahrenheit. PEEK has replaced many metal devices in the medical field, because PEEK is one of the only thermoplastics (plastic which can be bent or shaped) able to withstand high doses of radiation over an extended lifetime. In addition PEEK is used to help many people awaiting kidney transplants because it is used to make a critical component in dialysis machines. These machines need to clean the blood over a period of several hours and because of this, PEEK is the natural solution, as it can be steam cleaned time and time again with little effect on the material. Along with its great chemical, temperature, and fluid handling stability, PEEK is USP Class VI, making it ideal for these types of medical applications. The natural color of PEEK is a beige to tan and is available in sheet and rod. One of the largest manufacturers of PEEK resin is Victrex and their 450G resin.
Plastics In Medicine – Everyday
Plastic materials have become apart of our lives and has changed the way we take care of the sick and injured, how we protect our foods from germs, and prolong the storage of foods. Plastics protect medical instruments and insure they are sterile. It has made people’s lives better in both the short and long term. It has helped reduce pain, gain better movement and has given people their confidence back. The values of plastic can not be understated and in the future, hopefully plastics will save or prolong many more lives through advancements in technology and the limitless possibilities it presents.
For more information on these and other medical grade plastics like: Clear Nylon (look for blog post on this), Ultem, Polysulfone, Radel and more, contact us. E-mail us or call 866-832-9315
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