Vol. 4
July Issue
Year 2003


in Vol. 4 - July Issue - Year 2003
Blast Machine for Medical Prosthesis

 In the Spotlight

USF Matrasur is a well-known French specialist in Air blasting industry, belonging to the global USF Surface Preparation Group. Located in the south of Paris, they are a preferred partner and supplier to Automotive and Aeronautic Industries, but also to small and medium-size companies, through their standard hand blasting cabinet range.

USF Surface Preparation Group is well known on the surface preparation market as a major manufacturer and supplier for Air and Shot Blasting, Mass Finishing or Shot-Peening.

The company DEPUY, who belongs to the JOHNSON & JOHNSON Group, is one of the world leaders in the medical prosthesis market. Due to a quality concern, company DEPUY – located in Chaumont / France – wanted to blast their prosthesis. They therefore needed a reliable and performing machine conforming to the very high quality expectations of their business sector. By the end of 2002, rigorous assessment of a number of blasting machines led to the selection of a MATRASUR automatic air blast machine from USF Traitement de Surface, French branch of USF SPG.
The machine utilises a 4-position precision indexing turntable, equipped with 8 integral satellites into which the parts are located and can blast 2 parts at a time. The turntable operates on a "revolving door" basis, which enables 2 new parts to be loaded and 2 processed ones to be unloaded from a single work  station, whilst other parts are being processed in the machine’s blast enclosure.
Efficient sealing of the satellites as the turntable indexes ensures both noise and dust protection between the blasting and the loading sections of the machine. An automatic air-washing system is also incorporated between the blasting and unloading stages to remove any residual dust from the parts.
DEPUY’s machine was especially designed to work with aluminium oxide. This solution was unanimously chosen by both DEPUY and USF because of their specific application and the expected results.

Working Principle

The Machine is equipped with an array of 6 pressure- fed blast nozzles. The nozzles can move vertically for full height treatment of parts up to 500mm, and also move laterally to adapt to part diameters up to 250mm, therefore its name: PS250/500. A PLC governs part rotation speed, transfer speed, vertical stroke and horizontal positioning of the nozzles, as well as cycle time.
After blasting, a high performance recovery and dust collection system transfers used aluminium oxide from the machine and passes it through an adjustable high volume cyclone, which removes contaminants and dust. The media then travels through a vibrating sieve to remove any remaining particles and is transferred to a storage hopper for recycling to the blast nozzles. A special rotating mechanism insulates the storage hopper from the screen and cyclone, and ensures a smooth regular media flow. Dust and debris are directed to a high efficiency dust collector, designed for easy removal and disposal. The high volume of air created by the dust collector is used to maintain the dust collector cabinet in overpressure, which avoids the risk of dust leakage.
USF Surface Preparation Group offers a very wide range of standard automatic machines, to respond to any of your needs: traversing, carousel, multi-axles or barrel type machines. Trials at test centres will help to define the best parameters for a specific application.

For Information:
USF Traitement de Surface
28-30, Rue de Tournenfils - BP 19
91541 MENNECY Cedex - France
Tel. +, Fax +33.1.64 570559
E-mail: USF-info@usftds.com