No particular process is implied, or forbidden.

Plates could be made by photoetching or laser cutting or plasma cutting or shearing or punching or ...

Mike Halloran
Pembroke Pines, FL, USA

For certain applications there might be some restrictions on processes used to manufacture the heat exchanger components. For example, plate/fin type construction is often preferred over tube/fin for aircraft applications because plate/fin is typically stronger and more durable. Aircraft applications usually have strict controls over every process used in the manufacture of something like a heat exchanger core. This would include the process used to cut and form the plates. A mechanical process like shearing or stamping might be acceptable, while a thermal process like laser, plasma or EDM might not, due to the effect a thermal process would have on the material properties.

@Mike Halloran

The problem with sheet metal pressing is that they use a special white fluid so that the metal sheet may not burst open when pressed in a die to create different patterns on the heat exchanger plate. I am not sure that the fluid is hygenic or not, because the heat exchanger is to be used in a dairy industry. Thanks for your help anyway :)

@tbuelna the heat exchanger has to be used for dairy industry i.e. for the treatment of milk i just want to know the conventional Plate heat exchanger manufacturing techniques like shearing and stamping enough and are hygenic or not. Thanks for your help anyway :)

@both of you can i get the name of some book regarding heat exchanger manufacturing????

OF COURSE a metal fabricator will feel free to use a die lubricant of his choice, UNLESS YOU TELL THEM about your application. Since you failed to reveal the extent and nature of your problem here, you got answers that were not directly helpful to you.

Use of any of several key words would have changed the answer you got.
SANITARY gets you something that arrives clean and is easy to clean.
DAIRY gets you something specifically adapted to the milk industry.

A search on sanitary heat exchangers should be productive.
A search on dairy heat exchangers will get you the exact products you seek to design.

The SME Die Design Handbook covers a lot of topics related to hx manufacture, but is not solely about heat exchangers.

Mike Halloran
Pembroke Pines, FL, USA

Naumanmasoodkhan-

If the heat exchanger core is constructed using a process like furnace brazing, then the stamped plates would need to be thoroughly cleaned of any surface contaminants prior to brazing. So there should not be any trace of lubricants used to shear/form the plates after brazing.

Regarding your specific question in the last post about whether the typical processes used to shear/form sheet metal are "hygienic or not", the answer is definitely no. The raw sheet metal is not delivered or maintained under hygienic conditions. The machinery and tooling used to shear/form the sheet metal is not operated under hygienic conditions. And the shearing/forming process involves non-hygienic materials coming into contact with the sheet metal.

The materials used in the fabrication process of the plates is irrelevant to whether or not the finished plate exchanger is hygienic! There will obviously be a lot of cleaning, and likely also a lot of polishing, before those plates are ready for use in a hygienic application. Whatever is used during the drawing/stamping process will be long gone by that point!

I'd look particularly at the gasketing if you're worried about hygiene, because if they are designed wrong there is no doubt there will be plenty of places where material could hang up and resist being removed by cleaning. You don't want to have to disassemble the entire exchanger for cleaning after every use!

The cleanliness of the equipment used to fabricate these sheet metal components is not totally irrelevant in regards to use with processing a food product. For example, if the stamping/shearing equipment was previously used with a material containing a toxic metal like lead, beryllium, cadmium, etc. how would you ensure that all traces of these contaminants were removed from the sheet metal parts?

A good analogy is how recent regulation changes have required elimination of even trace amounts of beryllium from most aluminum castings. To comply with this requirement, aluminum foundries must use equipment that has never previously been used to process any aluminum containing beryllium. They must have documentation to prove this if they deliver castings for certain applications, like products being exported to the EU.

How something is made and cleaned is only a small part of hygienic service.
The real question should can this heat exchanger be cleaned and kept hygienic.
The plate and frame heat exchangers used for this service are a special design so that they can be cleaned daily, and not trap traces of contamination.
You need to find a unit that meets A3 or EHEDG standards.

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Plymouth Tube

Obviously, one would design the heat exchanger so that it can be cleaned in service, and also specify cleaning the components at each step in the manufacturing process that the application requires. But the OP specifically asked about whether the materials and processes typically used to manufacture sheet metal components of a heat exchanger are "hygienic".

Then you go back to the applicable spec and make sure that you use materials that are considered acceptable.
Elastomers and gaskets are a real source of pain in this service.

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Plymouth Tube