E-Archive

Articles

in Vol. 14 - January Issue - Year 2013
Cleans Delicate Metals without Damaging or Texturizing; Works in Wheel Blast and Pressure Air Blast Machines
Hand tools, before and after blasting to remove heat treatment scale without damage to the engraving on the work pieces

Hand tools, before and after blasting to remove heat treatment scale without damage to the engraving on the work pieces

Aluminum turbocharger housing, before & after blasting during the remanufacturing process; note no damage to identifying marks

Aluminum turbocharger housing, before & after blasting during the remanufacturing process; note no damage to identifying marks

Aluminum die castings, before and after blasting to deflash without damage to the cast-in part numbers and information

Aluminum die castings, before and after blasting to deflash without damage to the cast-in part numbers and information

In the Spotlight

GMA Industries is a leading supplier of virgin and recycled abrasive media for blasting operations and finishing applications. Located in Romulus, Michigan, it celebrated its 30th anniversary in 2012. Ervin Industries, headquartered in Ann Arbor, Michigan, has been serving the metalworking industry for 90 years with abrasive applications, materials, and new technologies. It is the world leader in the blast cleaning and shot peening industries.

NU•SOFT, a new metallurgically enhanced cast steel shot, has been developed in the United States to blast clean soft or delicate metal parts without damaging or texturizing the surface, destroying intricate detail or markings, or changing critical dimensions. This is good news for all manufacturers of parts that are too delicate for more aggressive cleaning methods and are produced in such large quantities that manual cleaning with glass beads or other non-abrasive cleaners isn’t a practical option.
"We long recognized the need for an abrasive medium that was strong enough to remove heat treatment scale, de-flash aluminum die castings and de-burr stampings and fabrications in high volume production, but gentle enough not to damage more delicate parts," said Dennis Denyer, Sales Manager, GMA Industries, Romulus, Michigan. "So we teamed up with Ervin Industries in nearby Ann Arbor, to develop ultra-low-carbon NU•SOFT cast steel shot with a hardness of 12 to 15 HRC, or <200 HV."
Because it has the same density as standard cast steel shot, it works in both traditional centrifugal wheel-type blast machines and pressure-type air cabinets with no drop in amps and does not require any special modifications to the blast equipment or separators.
NU•SOFT is made from virgin, premium, cast steel shot. It is manufactured in an ISO-certified facility (also in Michigan) and formed into fully round shot particles.
The new media doesn’t work-harden in use, so its performance is consistent throughout its life cycle. It also has proven to be extremely easy on the blast machines themselves, greatly extending the life of the wear parts. NU•SOFT has as much as a one-third longer life than standard SAE grade steel shot, based upon tests performed in an Ervin Shot Tester, the standard in abrasive life testing. And experience has shown that it is often possible to substitute larger NU•SOFT Steel Shot sizes for finer SAE shot, thus further extending the life of the shot within the blast machine before being drawn out by the separator. And because the product is non-hazardous in and of itself, the fine dust that is generated by the cleaning process can be disposed of in the same way as standard steel shot or grit fines.
Currently, the product is available in five sizes ranging from NS-70 to NS-330. There is a size ideally suited for most delicate blast cleaning applications and additional sizes may be made available depending on the need. The media is packaged in 50-pound pails, 500-and 750-pound kegs, and 2,000-pound drums. 
Originally developed for cleaning molds in the glass and rubber industries, NU•SOFT Steel Shot is now used in many other applications, which include:
Mold Cleaning - Cleans molds in the glass- and rubber-making industries, as well as permanent molds used in some aluminum foundries.
Extrusion Dies - Cleans dies in the aluminum extrusion industry. Dies can be blast cleaned with this media without the fear of changing critical dimensions.
Automobile Parts Remanufacturing - There are a number of applications related to auto parts remanufacturing for NU•SOFT, including blast cleaning machined surfaces without texturing the surfaces or damage to threads or tapped holes. Components in A/C compressors and alternators can be blasted without damage. Carbon build-up on exhaust valves also can be removed without stretching or bending valve stems.
Investment Casting - Removes shell from delicate investment castings without resorting to soaking in a caustic solution. Because the new media, in most cases, is softer than the castings themselves, it is possible to extend blast cycles to remove more shell, all without damage to the castings.
Aluminum Die Casting - De-flashes die castings and applies a uniform matte finish without damaging cast-in logos, part numbers or other critical information.
Fastener Manufacturing - Removes plating or e-coating from fasteners without damaging the threads.
Production Painting - Removes paint build-up from small fixtures prior to their re-use, without damage to the fixtures.
Bearing Manufacturing - De-burrs bearing cages without distortion or lodging of vibratory media.

How does NU•SOFT Steel Shot compare with other abrasives?

PRODUCT

HARDNESS

DURABILITY

DENSITY

EQUIPMENT REQ.

Glass Beads

50-60 Rc (5-7 Mohs)

5-8 cycles

2.6 g/cc

air blast

SAE Steel Shot

42–65 Rc (6-8 Mohs)

2500-3500 cycles

7.4 g/cc

air or cent. wheel

Stainless Shot

20 Rc ( Work-hardens to 60 Rc)

3500-4500 cycles

7.0 g/cc

air or cent. wheel

Plastic Media

3-4 Mohs

4-6 cycles

1.5 g/cc

air blast

Ceramic Beads

60-65 Rc (5-7 Mohs)

300-500 cycles

3.7 g/cc

air or cent. wheel

NU•SOFT

<20 Rc (3-3.5 Mohs)

6000-7000 cycles

7.4 g/cc

air or cent. wheel

For Information:
GMA Industries, Inc.
38127 Ecorse Road
Romulus, MI 48174-0037, USA
Tel. +1.734.595 7300
Fax +1.734.595 1310
E-mail: sales@gmaind.com
www.gmaind.com