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
At Stellana, we manufacture custom wheels, tires, and profiles from an assortment of different polyurethane bases. Our capabilities allow us to create unique, custom solutions. With the ability to manipulate shape, size, hardness, and cosmetic characteristics we can create most of the structures you can imagine. Despite this, throughout our history, we have established several product lines to excel under many specific warehouse conditions.
Polyurethane Wheels & Tires Forklift wheels and tires are not one size fits all. The three main categories that exist today are polyurethane, pneumatic, and rubber. Polyurethane wheels and tires are one of the primary products manufactured at Stellana. Polyurethane exceeds in indoor use compared to rubber.
Polyurethane is a versatile material that is known for its favorable qualities such as durability, chemical resistance, and overall resilience. Our process allows us to mold and machine polyurethane compounds for nearly every type of service. …
Understanding & Preventing Walk-OffsYour warehouse is in full swing. Forklifts are zipping in and out, moving products. Everything is going to plan, that is until a forklift operator experiences a walk-off. They don’t happen often, but when they do, walk-offs can be a serious safety hazard. You can easily wreck the transmission system if the wheel turns in or drop a load if the forklift comes to an immediate halt. Just think about the situations the operator could be in. Is the operator carrying a heavy load or up in the air on a scissors lift? From the forklift to the operator, to others in the surrounding area, walk-offs affect the entire operation and deserve a further discussion on preventative practices.
How and Why Walk-Offs Happen Walk-offs occur for two main reasons. To understand these two reasons, you need to first understand the basic breakdown of a forklift press-on tire. We’re going to be looking at three main components: the hub, the band, and the urethane. The urethan…
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…