Metal Finishing Guide Book


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5. FIND A WAY Everyone has their own idea of what blasting is. There is suction, direct-pressure, wheel and wet slurry. Manual cabinets, suit-up/walk-in blast rooms, and automation of every description. And more. Bicarb blasting, dry ice blasting, vacuum blasting, laser coating removal all have their place. Keep in mind that no tool does it all, and some are much better at a particular process than another. Today there are more choices than ever, and it will pay to work with your local supplier to make sure you have the advantages of modern techniques. Ask for a test to prove the process before making a commitment. Investigate the properties of different blast media, such as: • • • • Figure 5. A "Pencil Blast" nozzle with its tank and foot treadle. Micro-blasters make for easy access of detail areas on parts large and small. They are often used for such work as deburring aerospace parts and select coating removal14. Particle shape Hardness & density Grit size Durability You may find, with testing, that you can strip paint off of glass without etching, eliminate masking, use less topcoat, etc. A good supplier can help you determine the best choice. Accessing hard-to-reach recessed areas on the workpiece can make blasting frustrating or impossible. Direct-pressure systems are especially useful for blasting inside tubes and odd shapes; specialized nozzles make this possible. And direct-pressure is effective at some distance, so you can effectively blast an area far from the nozzle. Using a cabinet that is too small will restrict you from moving the end of a part in front of the operator. Custom features can be built into professional-grade blast cabinets to fit the machine to the part or process, as mentioned earlier. 6. SEND YOUR BLAST MACHINE TO REFORM SCHOOL Blasting with abrasives can be tough on the equipment, but that does not mean consumables and maintenance will be an ongoing problem. The solution is to equip your machinery with appropriate wear protection from the start. That includes heavy-duty hoses, protective linings, rubber curtains, and long-life nozzles. Invest in these and your costs will decrease. YouÕll spend more time producing and less time fixing. Larger blast cabinets last longer, too, because the abrasive is not going in ÒhotÓ on the cabinet wall, having had time to dissipate its energy. Automated systems often have a run-time meter to keep track of actual blasting hours. Utilize it to keep a log and anticipate Ð not react to Ð your maintenance needs. Preventive maintenance beats fixing. Set up a schedule. Refer to manufacturerÕs manuals, and consider farming out PM to experts on a regular, scheduled basis, perhaps spring and fall. 16

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