Handle stainless steel products correctly to avoid problems

New evolutions in mechanical engineering

Electro-polishing, micro-undulation, amorphization, desulphurization, micro-deburring, blasting, grinding and polishing, pickling and passivation...: a selection of Packo Surface Treatment's wide range of finishes. Thanks to these surface treatments problems with stainless steel can be avoided. At the specialist from Diksmuide, business unit of Packo Inox, one notices remarkable evolutions in the stainless steel machine construction, such as the switch from anti-adhesive coatings to anti-adhesive electrochemical surface transformations, and the step to overhaul and upgrade of existing systems.

The activities of Packo Inox, part of the Verder Group, are divided into three business units. For example, Packo pumps has now supplied more than 350,000 stainless steel pumps to companies in the food, pharmaceutical and general industries around the world. Packo Hygienic Components produces stainless steel products of hygienic design: milk pumps, collection and buffer vessels, filters, manifolds, installation systems, tube heat exchangers, mixers... Finally, Packo Surface Treatment has been a leading player in the field of surface treatment for more than four decades. 

"This department started in 1974 with the electropolishing of stainless steel parts for milking machines. After all, ammonia and chlorine were causing corrosion of the stainless steel in the milking parlors after only a few weeks. Electrochemical polishing suddenly solved the problem of corrosion and that of cleanability," says manager Marc Quaghebeur. "In the meantime, we are active in the most diverse sectors and the possible surface treatments have also expanded considerably, including de-rouging, refurbishment, de-blurring, micro-undulation, non-fingerprint finishing, E-polidur hardening, pickling, blasting, coating... If a customer has a problem, in many cases we already have a solution for it at Packo. In recent years, however, we have seen some remarkable evolutions in stainless steel machining."

To anti-adhesive electrochemical surface treatments

Thus, in the food industry, anti-stick coatings (Teflon type, nano, and others) are giving way to anti-stick electrochemical surface treatments, such as micro-ondulation, amorphizing, and electropolishing. In each of these cases, the surface remains the stainless steel itself, so no coatings, which by definition dissolve from the stainless steel anyway and end up in the food. Whether or not coatings are harmful to people's health has been an issue for some time and is also attracting increasing attention from food inspectors. The PFOS scandal may be no stranger to this. Many end users and machine builders therefore want to avoid damage claims and opt for anti-adhesive solutions that will never flake off.

"At Packo, we have developed suitable solutions for a wide variety of applications. For example, for the bakery sector we have perfected a micro-undulation procedure, which offers excellent non-stick properties in dough applications. Today we are also looking at replacing coatings in baking trays with a metal-like finish. Furthermore, electropolishing and amorphizing have long prevented clogging in applications involving flour, flour and other powders," Quaghebeur explains. "For installations in meat processing plants, electropolishing is also increasingly being chosen. This avoids sticking, guarantees easy cleaning and prevents biofilm and fouling, contamination and bacterial growth. In applications involving starch, for example in potatoes, mashed potatoes and cereals, we work with amorphizing because of its anti-stick properties, and in filling installations for drinking water, amorphizing to prevent limescale is a must. Finally, in rubber and latex applications, micro-ondulation is just about the only anti-adhesive treatment to date that offers adequate results."   

Reconditioning and upgrading of existing stainless steel equipment

A second remarkable trend is due to the reduced supply of spare parts and finished products. As a result, in the pharmaceutical and food industries, more and more used and second-hand equipment is being used, which means that the overhaul and upgrading of stainless steel equipment has become very important. 

"At Packo Surface Treatment, we have the knowledge and technologies to repair damage and wear on products. Every day we receive vessels, reactors, mixers, filters, pumps and dosing sluices. We replace couplings, grind and weld up scratches, repair wear and corrosion, passivate or electropolish. So the customer gets a part in a very short time and at a limited cost that is sometimes better in the end than a new product," Marc Quaghebeur explains. "In their first life, many of the devices used did not have a high-quality finish, but when they are overhauled, treatments such as electropolishing, amorphizing or micro-ondulation are almost always provided. The almost improbable advantages of these finishes in terms of cleanability, anti-adhesion, bacteria resistance and corrosion protection are now so well known that they have become self-evident in many applications. We also refinish street and garden furniture and cladding in stainless steel, and it costs customers a lot less than they would pay for a total replacement."