Ceetak discusses: Standard vs. custom seal design

What’s the best option for you?

The benefits of designing a valve, or actuator application around a standard seal size are generally well known. The expectation of standard seals is they are massed produced to similar quality levels, and readily available and stocked by a multitude of global suppliers. 

With this thinking, designing hardware around a standard seal size should probably result in the lowest overall cost of the assembly, and allow rapid production with no concerns on product quality. However, before you reach for the standard sizing list, we explore the considerations of standard vs. custom when designing your application seals.  

The wonderful world of standard seals

Where do you start when specifying your seal? An O-ring perhaps; defined by only two dimensions it should be the simplest seal solution. Easy to standardise? Yes, but then we look at sizing; with British Standard ISO 3601 (349 different sizes alone), British Metric, Swedish, Japanese, French and German ranges, this amounts to over 3,000 size combinations. Then consider elastomer options; different hardness’s, colours, and institute approvals such as NORSOK M-710 for example, the range expands to over 27,000 part numbers! 

Given the shelf-life of elastomers, the cost of holding stock and warehousing a vast range of often slow-moving part numbers, it’s often not a viable economic option for manufacturers. 

Why would custom seal design work for you?

If you have a standard seal that works well for your application, you might think there’s no real reason to replace it! But with potential restrictions and availability of stock, it may be worth seriously considering a custom seal design, especially for a new valve application. 

Advances in seal manufacturing including CNC lathes and milling machines mean production of bespoke mould tools are much faster and more accurate than older NC machines. Single cavity compression moulds can be produced in a few hours, and even complex multicavity injection mould tools can be produced rapidly with the use of common bolsters requiring only specific inserts to be produced for a custom size. 

Single minute exchange of dies (SMED) coupled with faster curing elastomers and lean manufacturing techniques applied to the production process can also reduce lead times for bespoke rubber parts to just a handful of weeks or less. 

It is worth considering that designing around a standard seal may compromise the design of the valve, pump, actuator, or regulator. By designing a custom seal, you can optimise the performance of the final assembly, minimise the space envelope and allow integration of multiple seals into a single gasket; also reducing part count and assembly times. 

With the added reassurance of an inherently tighter control on material specification and source of supply, utilizing a custom size or design of seal can give timescales and costs that equal, or are superior to what’s achievable when using a standard catalogue item. 

How Ceetak can help you select the right solution

We understand the challenges, technical demands and the need for long service life and minimal maintenance needed for valve application sealing.  Our extensive expertise means we consult with you about standard vs. custom solutions ensuring optimal performance both on seal design and material. 

Your application is unique and so is our service!

For more information about how Ceetak’s products and services can benefit your organisation, visit www.ceetak.com or to speak to one of our expert team, phone +44 (0)1234 832200. 

Tel:         +44 (0)1234 832200

Email:      enquiries@ceetak.com 

Website:  www.ceetak.com

Published: 9th August 2023