5 Tips in Choosing the Right Caster Wheel for Your Material Handling Application
With all the material handling challenges you face regarding ergonomics, worker safety, noise, productivity, and cost savings, choosing the right heavy-duty industrial wheel for your material handling application can be a big part of the solution.
When choosing a caster, the wheel and the rig are the two parts of the caster you will need to focus on.
For the wheel, determining proper wheel size and wheel material goes a long way in alleviating or preventing problems.
For the rig, performance and longevity depend on three critical design choices: Proper swivel size, a forged vs. stamped section, and the thickness and width of the caster rig.
How to determine wheel size.
When you think size, think load. So first determine the maximum load weight you will be subjecting your dollie, cart or AGV. Let’s say you need casters that can support a maximum weight of 10,000 pounds. If you have casters on all four corners of your cart or rack, you will need casters that are rated to hold at least 3250 pounds. This added capacity is your margin of safety. To compensate for unbalanced or shifting loads, you should shoot for about 30% over your maximum weight. In this example, this would bring the maximum weight to 13,000 pounds, or 3,250 per caster.
This is also where increasing the wheel diameter comes into play. Increasing the wheel diameter means less effort to start rolling and to keep the wheels rolling. While increasing wheel diameter is advantageous, increasing wheel width is not. Wider wheels increase surface pressure, making them more resistant when you are trying to switch directions.
Tread material is another important consideration, and there are a lot of materials to consider. So what’s the best choice: rubber or steel? Wrought iron or polyurethane? They all have trade-offs and knowing the pros and cons of each is critical in determining an acceptable balance between material load capacity and floor protection.
In general, the heavier the desired caster load capacity, the harder the wheel material will be. But harder wheels have a higher potential to damage your floors. Wheels and casters with softer treads are more resilient and offer the most protection to your floors. These types of casters and wheels can also reduce the accumulation of small obstructions like metal shavings, but the tradeoff is that they may be too light-duty for more rugged applications.
For these reasons, polyurethane treads offer one of the best compromises between load capacity and floor protection.
Even better, there’s a wide variety of ways that polyurethane can be engineered to ensure that your casters and wheels are both ergonomic and durable.
The other part of the equation. The caster rig.
A properly manufactured, long-lived industrial caster that requires little upkeep depends mainly upon three key design choices. These are a properly-sized swivel section; hot-forged vs. cold-stamped swivel sections; and leg thickness and width.
The ball bearings between the top plate and the yoke base are arranged in a predetermined radius. The raceway circumference and the ball bearing size determine the carrying capacity of the swivel section.
Balls and raceways on the low end of the industrial caster carrying capacity are generally 0.125 inches and 3 inches in diameter, respectively. For heavy-duty casters, balls and raceways on the higher end range from 0.625 inches, and 6-8 inches in diameter, respectively.
Once you’ve determined the appropriate size of the swivel section, you must consider leg size. The thickness of the leg material and leg width will determine leg size.
The leg impacts the caster application in three significant ways.
1. The thickness and width of the leg supports a static load
2. The leg thickness impacts the amount of side thrust the caster can withstand
3. The leg width impacts the level of force a caster in a trailing position can withstand
Because of these considerations, sizing both leg thickness and width correctly is essential to support loads safely while at rest and while moving.
The third consideration also involves the swivel section. Swivel sections are manufactured by cold-stamping or hot-forging. The cost, quality, and strength of your caster vary widely depending on the method used. Cold-stamping is inexpensive and restricted by the thickness of the metal. For industrial casters, cold-stamping is generally limited to 0.25-inch steel plates. The more expensive hot-forging uses much thicker plates, in the range of 0.875 inches. Hot-forged steel produces the highest quality and strongest material for manufacturing heavy-duty industrial casters.
Our expert engineers at Caster Concepts are adept in designing the appropriate caster for your needs. If you’re struggling with these design choices, and want to ensure you’re making the best decisions, please don’t hesitate to call our highly experienced engineering team at Caster Concepts.