JÄGER Busi­ness Blog

Seal­ing tech­nol­o­gy: Sev­en tips for
ana­lyz­ing the frame­work conditions

03.11.2021   |   Bas­t­ian Wondratschek 


Secure the Start of Production 

Find out which fac­tors influ­ence your SOP!

Seals are often con­sid­ered a means to an end in design. Yet the design and selec­tion of rub­ber or plas­tic seals can be high­ly com­plex. There are a lot of fac­tors that affect the per­for­mance and life of a seal, and if it is designed incor­rect­ly, it will fail soon­er or lat­er. Under cer­tain cir­cum­stances, this can dam­age the machine or sys­tem in which the seal is installed.

To pre­vent this, it makes sense to take a detailed look at the gen­er­al con­di­tions before select­ing or devel­op­ing a seal. The fol­low­ing sev­en ques­tions will help you with this analysis:

1. What are the pre­vail­ing oper­at­ing temperatures?

The oper­at­ing tem­per­a­ture is one of the most impor­tant gen­er­al con­di­tions in seal­ing tech­nol­o­gy. If a com­po­nent is oper­at­ed out­side its opti­mum tem­per­a­ture range, its phys­i­cal prop­er­ties may change. This applies to both down­ward and upward deviations.

The tem­per­a­tures to which a seal is exposed depend on sev­er­al fac­tors, e. g. the ambi­ent tem­per­a­ture. Here, the room or out­side tem­per­a­ture plays a role, but also the con­di­tions inside a machine or sys­tem. For exam­ple, the tem­per­a­tures inside an engine are dif­fer­ent from those out­side the vehi­cle. The tem­per­a­tures of the media with which the seal comes into con­tact should also be tak­en into account. For exam­ple, a pipe that trans­ports water vapor can become very hot, regard­less of its location.

There is also the ques­tion of tem­per­a­ture fluc­tu­a­tions. Is the tem­per­a­ture con­stant or do peaks occur? Espe­cial­ly fre­quent changes between hot and cold can dam­age a seal in the long run.

2. Which sub­stances does the seal come into con­tact with?

The chem­i­cal resis­tance of a seal depends on the mate­ri­als with which it comes into con­tact. On the one hand, the sub­stances that have a per­ma­nent effect on the seal must be tak­en into account (as a rule, these are also the sub­stances against which the seal is to be sealed), for exam­ple acids, bases, gaso­line or sol­vents. On the oth­er hand, design­ers should also con­sid­er sub­stances with which the seal only comes into con­tact tem­porar­i­ly, such as clean­ing agents or disinfectants.

It is also impor­tant to note that the con­tact media can influ­ence the tem­per­a­tures to which the seal is exposed. For exam­ple, if a machine is reg­u­lar­ly cleaned with hot steam, all its com­po­nents must be resis­tant to heat and steam, even if this is not rel­e­vant throughout.

3. What kind of mechan­i­cal stress­es act on the seal?

With regard to the mechan­i­cal prop­er­ties of a seal, it is impor­tant whether it is sub­ject­ed to sta­t­ic or dynam­ic stress­es. For exam­ple, a flat seal at rest must meet dif­fer­ent cri­te­ria than a bel­lows seal that is con­stant­ly in motion. The inten­si­ty of the stress should also be tak­en into account in the design con­sid­er­a­tions. For exam­ple, does the seal have to with­stand slight move­ments or is it exposed to strong vibra­tions? This will affect the seal mate­r­i­al, as well as the opti­mum shape of the component.

4. Is the seal intend­ed for out­door use?

Machines that are oper­at­ed out­doors are exposed to UV radi­a­tion dur­ing the day and often to ozone pol­lu­tion in the sum­mer months. Both of these fac­tors neg­a­tive­ly impact the life of many rub­ber and plas­tic com­pounds. There­fore, if the seal is intend­ed for out­door use, care should be tak­en when select­ing the mate­r­i­al to ensure that it is resis­tant to UV light and ozone.

5. Is it a vis­i­ble part?

If a seal is locat­ed inside a machine or sys­tem, its appear­ance is usu­al­ly sec­ondary. How­ev­er, if it is a vis­i­ble part, aes­thet­ic fac­tors may become rel­e­vant depend­ing on the appli­ca­tion. This includes, but is not lim­it­ed to, gap dimen­sions, dis­col­oration, and visu­al effects result­ing from the man­u­fac­tur­ing method. Here are some exam­ples of unsight­ly features:

All these are pure­ly opti­cal fac­tors that have no prac­ti­cal effect on the func­tion of the seal. Nev­er­the­less, they should be tak­en into account in the design, because the aes­thet­ics of a machine or sys­tem can be quite rel­e­vant. This applies in par­tic­u­lar to objects that are seen by customers. 

Water­jet cutting

6. Are cer­tain cer­ti­fi­ca­tions or approvals relevant?

Seals used in the med­ical and food indus­tries in par­tic­u­lar must meet strict require­ments, cer­ti­fi­ca­tions and qual­i­ty stan­dards. This pri­mar­i­ly affects the choice of mate­ri­als. Under no cir­cum­stances may a seal release harm­ful sub­stances to food or med­i­cines, regard­less of the envi­ron­men­tal fac­tors. In some sce­nar­ios, it makes sense to man­u­fac­ture seals from detectable mate­ri­als so that detached par­ti­cles can be iden­ti­fied and removed more eas­i­ly if necessary.

7. What quan­ti­ties are needed?

The planned quan­ti­ties of a seal are pri­mar­i­ly rel­e­vant to the type of pro­duc­tion. In the case of small pro­duc­tion quan­ti­ties, it makes sense to cut the mold­ed parts by plot­ter or water­jet. If the quan­ti­ties increase, on the oth­er hand, tool-based process­es (e.g. punch­ing) make more sense. The break-even point depends on geom­e­try and mate­r­i­al and must be deter­mined indi­vid­u­al­ly. How­ev­er, the envis­aged quan­ti­ties should be tak­en into account ear­ly on in the prod­uct devel­op­ment process so that the seal can be designed to meet pro­duc­tion requirements.


The devel­op­ment and selec­tion of a seal is much more com­plex than it appears. Many fac­tors play a role, from the ambi­ent tem­per­a­ture to mechan­i­cal stress­es and pre­scribed cer­ti­fi­ca­tions to the appear­ance of the com­po­nent. All these aspects must be tak­en into account when select­ing or devel­op­ing a seal. It is there­fore impor­tant to car­ry out a detailed analy­sis of the frame­work con­di­tions at the beginning.

Secure the Start of Production 

Learn which fac­tors influ­ence your SOP! 

Author: Bas­t­ian Wondratschek

Bas­t­ian Won­dratschek has been part of Jäger’s sales team since 2019. The trained whole­sale and for­eign trade mer­chant orig­i­nal­ly comes from the steel indus­try. As a sales rep­re­sen­ta­tive he is respon­si­ble for cus­tomer ser­vice at our Stuttgart location. 

Share this post!

Share on facebook
Share on linkedin
Share on telegram
Share on whatsapp
Share on xing
Share on email
Share on facebook
Share on linkedin
Share on xing
Share on email

Covid-19 Contents