Magnetic Shields Ltd - Kent, UK

Vertical Tabs

Company: 
Magnetic Shields Ltd
Website: 
www.magneticshields.co.uk
Location: 
Kent, UK
Product: 
Custom Built Dual Aquablast Unit
Case study overview
What The Customer Says: 

“We are able to put a course media in one side of the machine, to remove marks and ridges, and a finer abrasive on the opposite side to allow for a cosmetic finish The guillotine door separates the two wash chambers, so we can use both of them at the same time. We are also able to open up the door to create one large wash chamber for bigger components. The machine really is ideal for our needs.”

Established over 55 years ago, Magnetic Shields Ltd specialises in manufacturing magnetic shields for companies and organisations worldwide.

Components that require shielding are those that are sensitive to magnetic and electrical fields, such as transformers, motors and magnets. These, and other components, are found in a variety of different industries such as aerospace, military and electronics. These types of components require low frequency magnetic shielding in order to prevent them becoming faulty and defective.

Magnetic Shields' customers include a number of Formula 1 teams, CERN, the particle physics laboratory in Geneva, as well as customers who use the products for space applications.

The shields are usually made from Mu-Metal®, which is a very high permeability alloy containing Nickel, Molybdenum and Iron which is extremely effective at screening low frequency magnetic fields. The magnetic shields can vary in size, with some of the smallest pieces of equipment being just 1.5cm³, and the largest being rooms or chambers which can be several metres in width and length.

Magnetic Shields' customers are constantly seeking higher levels of surface finish for their products, and therefore decided that it required a new method of finishing some of the shields before they were given a final heat treatment in the manufacturing process. Magnetic Shields reviewed a range of options for surface finish and decided the best option was a custom built Aquablast machine from Vixen Surface Treatments.

Peter Harden, production director at Magnetic Shields, said: “We required an effective machine that could remove small surface marks and weld discolouration from the shields.

“We had initially tried sandblasting the parts, but found that it was too harsh on the shields, and the finish was far too coarse - this ultimately resulted in damage. After research into wetblasting, we realised that this was a far better option and contacted Vixen to help us with our application.”

Vixen worked closely with Peter and the team at Magnetic Shields, and came up with the idea of designing and building a custom built Aquablast machine specifically for their application.

The custom machine consisted of two Aquablast 1215 machines joined together with a pneumatic guillotine door between them. The machine also has a 700mm turntable complete with a track, to allow a pass-through facility from one side of the machine to the other. This design enables the team at Magnetic Shields to use two types of media in either side of the machine.

(Above: shields before and after Aquablasting)

Peter added: “We are able to put a course media in one side of the machine, to remove marks and ridges, and a finer abrasive on the opposite side to allow for a cosmetic finish.

“The guillotine door separates the two wash chambers, so we can use both of them at the same time. We are also able to open up the door to create one large wash chamber for bigger components. The machine really is ideal for our needs.”

Magnetic Shields is currently in the process of trialling various different types of abrasives in the Aquablast unit, in order to ascertain different levels of finish that can be achieved on the shields.

In the prepping chamber of the machine, where ridges and weld marks are removed from the shields, the operator can use an 80/90 grade Aluminium Oxide abrasive which is ideal for the removal of stubborn marks and ridges. The media is mixed with the water and blasted onto the part, where the water’s cushioning effect ensures no media is impregnated onto the shields.

In the opposite chamber, a finishing media is used. This is usually a 50/80 grade glass bead media and is particularly effective at providing a professional sheen finish for the end result. This grade of media can be changed to add different effects onto the parts.

Peter said: “By using different types of media in our Vixen machine, we now have the ability to offer our customers different types of finishes for their shields, which we were unable to do with sandblasting units. This will ultimately enable us to expand our business further and attract new customers.”

Overall, Magnetic Shields is very pleased with its custom-built Aquablast machine, and the team were very happy with the service provided by Vixen’s sales and aftersales departments. They are considering buying more machines from Vixen in the future, with the possibility of an automated option.

® Mumetal is a registered trademark of the Carpenter Technology Corporation

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