o-ring width
o-ring width
(OP)
Hi,
I used the Parker o-ring handbook for most of my o-ring groove design. I just have one question regarding different o-ring width.
What is the advantage of using a smaller or bigger o-ring? Imagine if the ID of the o-ring groove is 1 inches, is there a different if I use a 1/16, 1/8, 3/32, or 3/16 width o-ring?
All feedback are greatly appreciated.
I used the Parker o-ring handbook for most of my o-ring groove design. I just have one question regarding different o-ring width.
What is the advantage of using a smaller or bigger o-ring? Imagine if the ID of the o-ring groove is 1 inches, is there a different if I use a 1/16, 1/8, 3/32, or 3/16 width o-ring?
All feedback are greatly appreciated.





RE: o-ring width
RE: o-ring width
There can be secondary factors like available space, strength of o-ring if it needs to be stretched during installation...
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: o-ring width
Since you brought up compression ratio, I assume it is the same as Squeeze percentage on Parker handbook. In term of stretching the o-ring during installation, is there any guideline on how much should the o-ring be stretched to achieve certain compression ratio? I am having trouble find this info.
What I usually do is use the nominal ID of the o-ring as my ID for the groove, and get the groove width and depth based on Parker handbooks. I noticed that the o-ring only stretches very little. I haven't run into any problem by doing so, but I want to make sure that I am doing it right, not by dumb luck.
Example: take O-ring # 131 as example, it has an actual ID of 1.674, so I make the ID of my groove to be 1-11/16 = 1.688, slightly bigger than the ID of the o-ring. Would this provide enough stretch for the o-ring?
RE: o-ring width
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: o-ring width
RE: o-ring width
RE: o-ring width
However, I can't find mean I.D of o-ring from table 4-1 at all.
Can you give me some guidance on this?
RE: o-ring width
RE: o-ring width
RE: o-ring width
Oring squeeze is always a percentage of the x-section, therefore the bigger the x-section, the larger the actual squeeze. The larger the squeeze the more forgiving the seal is to flatness variations in the sealing face, and to scratches somewhat, due to the wider contact width. Another consideration is bigger orings are simply easier to handle, the groove is easier to wipe clean and things like that.
Timelord
RE: o-ring width
One project I worked with used a rectangular groove (face shape) for a box. I put in a large groove for a large section o-ring but this was changed by later workers to a very small groove**. Pretty much ever single gasket got pinched or cut because, as the lid was closed, the difference between almost closed and closed-enough to trap the gasket in the groove was tiny. For those not cut on install, whenever the lid came off, continued curing of the gasket would bond it a little to the lid and box. Being little it always broke. Not only was it uncertain that the seal actually sealed, it was so often cut on install that the production and spares items went into the prototypes.
A thicker gasket has n^2 times area for strength and n times area for sticking, so it is n times less likely to break and it's a lot easier to guide it into the groove in the first place. My gasket was 3/16; the substitute was 1/16th. They kept the flange the same size; just made the groove smaller, so no savings on size.
**Why, you ask? Because it was the same groove size used on a small connector and -that- worked, so why change the size when the groove length is maybe 30 times longer?
RE: o-ring width
RE: o-ring width
Maybe someone that uses it more often can point you to it.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: o-ring width
Note that while it is always a very good idea to use standard sizes when possible, every o-ring manufacture makes hundreds of additional sizes and if you are using large quantities will want you to pay for your own tooling which makes if easy to justify any size your heart desires. Every o-ring we buy comes off tooling we purchased. O-ring tooling is cheap and quickly made compared to injection molding or stamping tooling.
I never use the design guide tables because I made a spread sheet that calculates the stretch and corrected squeeze for the full range of component tolerances over the full range of operating temperature.
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