In this video, W.C. Branham’s Chad Randleman demonstrates how to adjust the internal cushion screws on your pneumatic rodless air cylinder. Most cylinders come standard with adjustable internal pneumatic cushions. Cushions can be found at either end of the cylinder and are provided to decelerate the load at end of the stroke and provide a dampening effect.
Locating the cushion screws
Commonly on cylinders, like on pneumatic cable cylinders, the cushion screws can be found on each head with a hex head cap screw. On our MAGTEC® magnetically coupled line of cylinders, the cushion screws can be located as a brass slotted screw on each head. On our DURATRK™ cylinders the cushion screws are located inside the cover strip retainer block.
Making the adjustments
Most cushion screws are simply adjustable with a standard slotted wrench. It’s important when adjusting the cushion screws to make sure that the cylinders attached to the load represent the actual load and velocity that will be occurring to see if the cushioning effect is adequate. Once that’s done and you can cycle your cylinder back and forth with the load attached, simply adjust your screws by first closing it completely, turning it clockwise until it stops. (Tip: It’s suggested to back it off a quarter turn as a starting point.) From there, you can cycle it back and forth and see what the cushioning effect is, and only make minor adjustments by slightly turning clockwise or counter clockwise to increase or decrease the effect until you get them set to where you are satisfied.
After making the adjustments, W.C. Branham recommends observing the cylinder and even timing it as necessary to see if your cushioning effect is approximately a two-thousand second count. Once you do that, your load will be able to safely decelerate at the end of stroke on each end.
It’s important to refer to the manufacturer's catalog information to see that your load versus velocity falls within the acceptable limits of their internal cushions. If not, external cushioning devises may be required.