Behind the Wheel is a blog created by Stellana for the wheel industry. Whether you are new to polyurethane wheels or have been in the business for a long time, this blog is a great tool for polyurethane education, industry safety, company news and updates, and much more.
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Quality | Understanding & Reducing Hysteresis
Understanding and Reducing Failures:
Polyurethane is one of the most versatile materials.1 Physical properties can be adapted to solve challenging problems. Polyurethane
is formed by reacting a polyol (ether-based or ester based) with an isocyanate
(an MDI or TDI). It is then cured at a specific temperature for the optimal
time to reach desired physical properties. Properties are altered based on the
polyol and isocyanate and the application impacts the function. It is critical
to choose the ideal material based on the application and the conditions the
product is expected to withstand.
What is Hysteresis?
Hysteresis is a time-based dependence that relies on present and past inputs. Polyurethane is an excellent insulator and absorbs and stores energy,
which will then be converted to heat. If heat generation is greater than heat dissipation,
the polyurethane will melt internally, resulting in a buildup in pressure as
the material expands. The increase in temperature will change the physical
properties of the material. Evidence of
hysteresis can be indicated with a powder like substance, bumps on the tire, or
visible molten material. The most common causes of hysteresis are overloading
the part or operating at too great a speed.
Contributing factors to heat buildup in tires include: poor
conductivity of polymers, tread thickness, size of tire, speed of rotation,
load on tire, TIR of tire, and length of run. Improper installation- metal hub
rubbing on other metal object causing friction will generate heat.
Metal objects imbedded in the tire promote heat generation.
In the picture, a metal object is imbedded in the tire. The metal will absorb heat and raise the temperature of the wheel. As a result, the material changed physical properties and burned off the adhesive.
Hysteresis is commonly mistaken for bond failure. What is Bond Failure?
Bond failure is a result of improper surface preparation,
contamination, or machine malfunction. A true bond failure will leave adhesive
intact on the metal. The excessive heat generation in the hysteresis process will burn off adhesive on the poly or metals, or both.
Ways to Avoid Hysteresis
You can significantly reduce costs associated with downtime
and extend the life of your product with the proper conditions of the
application. Decrease speed of trucks, load capacity, or length of runs. Experts
will help you choose the correct system based on the application needs. Engineering experts will review
the design of the tire and optimize the cross-sectional thickness, runout, and
By now, we are all aware there is a PPE shortage for many of
the workers who need protective equipment the most. One of the most talked-about
items are masks.
We are also hearing how many companies are experiencing an
extreme decline in business. A local company, PFI Fashions Inc., took what
could be a negative situation and used their open capacity to make a very
positive impact on their local community. Jodie and Billy Joe Todd, owners of PFI, took it upon themselves
to begin manufacturing masks for those in need. Located in Genoa City, WI the full-service company specializes in screen printing, promotional products, and embroidery.
Within the course of a week,
they have completely shifted their production focus to making washable, cotton
face masks. They have been generously donating them to Aurora Hospital, local
EMTs, and the other essential workers who need them the most.
Because of their hard work, we were able to purchase masks
to keep our employees safer at Stellana. We want…
What application comes
to mind when you think of polyurethane wheels and tires? I would bet forklifts
do for many of you. While a countless number of our polyurethane wheels and
tires are used on forklifts, our materials excel within a variety of other applications.
Our engineering expertise and manufacturing experience allow us to produce
high-quality polyurethane for a variety of industries that you may not have
imagined. Stellana is one of the
world’s largest manufacturers of molded polyurethane products. Our engineering
team consists of mechanical and chemical engineers who have a unique
understanding of polymer formation. This department is equipped to tackle
product design, tooling, material selection and carry out a variety of
performance analytics. Whether it is a new design or one in need of
improvement, our engineers find a way to offer the best solution. 7 Surprising
Applications At Stellana, we think of
ourselves as application specialists because of our ability to provide u…
How long will a polyurethane tire last? This is a hard question to answer, and the best answer would be "it depends" because the life is not the same for any two products. Our engineers can calculate estimates for how long they should last, but the material, tire size, load, speed, floor, and environmental conditions all play a factor.
The pictured tire may be an outlier, but its life span is pretty impressive. Bill Rohan, Parts Manager at Trupar America, sent us this photo of a diamond grooved Gmax™ tire that was just shy of turning four years old while on the job. After being placed on the equipment October 15, 2015, this tire just retired July 2, 2019, with total usage of 9190.40 hours.
This tire's life in hours equates to 1 year and 18 days of use, but it was not running continuously. Impressively though, it was working around the clock approximately 47 hours a week over the last 193 weeks. This number, 9190.40, is over double a 4,000.00-hour life – which would be c…