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How to Improve the Life Expectancy of Your Gas Springs, Pt. II

In the first part of this extended article, we talked about how to extend the life expectancy of your gas springs — and here, we continue that conversation. Let’s get right back into it.

Things to Avoid
To keep your gas springs working better, longer, never use the bottom of the spring as the strike surface — the top of the piston rod is the correct option. Rather than using improper or inadequate guidance, which can lead to side loading due to axial misalignment, us guide retainer sets, roller bearings, wear plates, and a hardened strike surface. That will extend spring life as well. Anything more than a single degree of side load on the piston rod is asking for a gas spring that fails years earlier than it could.

Along that same vein, avoid contaminants. Even minor contamination within a die can cause premature failure. Die designers ought to specify drainage holes in the spring pockets so that fluid doesn’t pool around the springs. Gas springs shouldn’t be exposed to caustic draw-die compounds or other contaminants; if your production line makes this a necessity, contact the gas spring’s manufacturer to talk about what protective measures you can take.

Preventative Maintenance
Of course, any discussion of extending the functional lifespan of any piece of equipment, from gas springs to pneumatic cylinders, needs to touch on the cornerstone of equipment care: preventative maintenance. Sound preventative maintenance procedures require users to check the pressure, temperature, and physical condition of the springs for signs of wear.

If a random sample of springs in a die exhibit signs of being overworked, overpressured, or overheated, every other spring should be examined as well. A significant variation in spring pressure or condition could indicate a flaw in the die’s design, build, or operation. If a specific spring’s pressure is low, check for leaks, then recharge and check for leaks again.

The physical condition of a spring should be determined with a visual examination; there should be no need to dismantle the spring. Worn springs that are still viable should be rebuilt. If the rod is damaged, it obviously will need to be replaced as well.

Following these four major areas of care should help any project keep its gas springs lasting as long as their construction allows — good luck!

How to Improve the Life Expectancy of Your Gas Springs, Pt. I

The number one determinant of the life expectancy of a gas spring is, perhaps without much surprise, the manufacturer. Choosing a manufacturer whose representatives will offer you assistance choosing the best design for your job — and then actually listening to the reps — is a great step toward a long-lasting gas spring. Also, talking to your supplier about performance guidelines — specifically, operating temperature, speed, and charging pressure — can help you understand how to stay within a spring’s operating parameters, which will help it last.

The decision of which gas spring to use should be based on several criteria. The spring must match the task it’s intended for, it’s location in the die, and the mounting method most appropriate for the task.

Tool Build and Die Design
Die design is one of the most important parts of optimizing gas spring life. Such springs have standard operating specifications — for example, a spring may be charged to a maximum pressure of 150 bar (2175 psi), and reach a maximum operating temperature of 160 degrees Fahrenheit. Exceeding either of those guidelines will rapidly slash the life expectancy of that spring.

Futhermore, unless there is no other option, you should never use more than 90% of the stroke of a gas spring — and a rod travel of 75% to 80% is even better, as it reduced both in-cylinder pressure rise and the amount of heat produced per stroke. Further, aiming to distribute loads evenly between springs so that no one spring outworks the others and none are approaching full capacity goes a long way toward keeping a spring functioning in the long term.

Accessorizing for Lifespan
Gas spring accessories like nitrogen-gas surge tanks added to a piped system will add volume so as to maintain a lower pressure rise. Piping gas springs together with pneumatic fittings can give you the ability to monitor and control force from outside the die, giving you the ability to manually modify a spring’s operations based on external conditions like load, which further enhances the lifespan.

This is still only scratching the surface — come back next week for part II of our guide to maximize gas spring lifespan.