Vol. 7
September Issue
Year 2006

MFN Trainer Column

in Vol. 7 - September Issue - Year 2006
"I did not know that..."

MFN Trainer Rick Symanski

This column is a regular feature and is written by one of our MFN trainers or the Editorial Office. Readers are invited to send comments or questions to info@mfn.li. For more information about the trainers, see our website www.mfn.li/workshops.

For the majority of people who use glass beads in their cabinets, they know there are more usages than just removing rust from parts or refinishing a surface. It never fails to amaze me the number of people who say, “I didn’t know that”, when you tell them about the many functions that glass beads can perform other than those noted above.

Blasting can be done on scales ranging from benchtop cabinets where the operator works through gloves outside the cabinet to where the operator is suitably clothed and protected working inside the blastroom.

The subject of shot peening is probably the most misunderstood topic of all. Shot peening has broad applications in the fabrication of metal products for improving their performance, such as, leveling out the compressive stress layer and even eliminating microscopic surface defects. It continually offers manufacturers a system to produce high quality products in a cost efficient and reliable repeatable way!

“How does it do that?” Without getting into the actual working technicalities of the process, the simplified answer is the automated process which controls the many variables affecting the desired results.

The benefits of shot peening are many. To name a few of the benefits, they include increasing fatigue life of the part, reducing stress cracking, straightening out parts deformed during the manufacturing process, the process is economical as the media can easily be recycled. And it reduces labor costs as it produces more efficient parts with less down time!

So, to cut a long story short, consider shot peening of your parts; you won’t be unhappy with the results.

Let's talk about abrasives in general for a moment. Basically, the air compressor propels the abrasive, the blast machine stores it and dispenses it, the blast hose transports it and the nozzle accelerates it. While all steps are important, it is the abrasive that does the physical work.

There are three sources for abrasives. These are natural, manufactured and by-products. Natural abrasives are minerals such as sand, garnet, walnut shells, etc. Manufactured abrasives are steel shot, steel grit, plastic, glass, wheat starch, aluminum oxide and others.
By-products include leftover slag from either a smelting operation or a power generating station, etc.

Recyclable materials tend to be lower in free silica and produce less dust overall.

Be sure to choose a durable, recyclable media which will reduce the overall media cost. Today's vacuum recovery systems with containment capability allow for more efficient recycling.

One of the more common abrasives used today is sand. While it is dangerous to use due to the silica dust, it remains the lowest cost abrasive. After just one cycle the sand used turns to dust. Using sand produces a fine crystal like, silica dust which remains airborne for long periods of time, and the greatest consequence is the serious health hazard it produces when inhaled.

I will leave you with one thought: No dust is safe to breath, even when the blast abrasive is nontoxic. Please exercise extreme care.

Best Regards

Rick Symanski

Author: Rick Symanski