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EXCERPTS
FROM NORTH AMERICAN DIE CASTING ASSOCIATION (NADCA) - DIE COATINGS AND
SURFACE TREATMENT TASK GROUP RESEARCH RESULTS
Long range objectives of research:
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10 to 20 times |
- Reduce surface lubrication
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30 to 50% |
- Reduce casting ejection
distortions
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50% |
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50% |
- Improve net shape capability
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20 to 30% |
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25 to 50% |
- Reduce die repair (erosion,
galling) expenses
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50 to 85% |
Selected research results:
- 'At one of the participating die casting
companies, prior to the use of the coating, the cores were pulled out
every 4 hr for cleaning of the soldered material. This took on an
average of 30 min, i.e. 1 hr per 8-hr shift. The life of the uncoated
core pin was about 15,000 shots, after which the dies were
disassembled and the cores replaced. The use of coated core pins
completely eliminated the need for periodic cleaning of the cores and
most of them lead to an increase in die life by more than 10x (127,500
shots) with significant savings in terms of machine downtime and labor
of the order of $25,000 for one die.' - from NADCA Journal Jan/Feb
1997/41 ('Die Coatings/Surface Treatment Task Group Guides
R&D')
- 'Of the various PVD nitride coatings and
surface treatments tried, CrN has shown the best promise (low
temperature application, low chemical solubility). Processes like
chemical vapor deposition (CVD), plasma assisted chemical vapor
deposition (PACVD) and thermoreactive deposition (TD) deposit coatings
with uniform properties and very good adhesion to the surface. These
processes are carried out at higher temperatures when compared to the
PVD process and this limits their use since they might affect the
properties of the die steel' - from International Die Casting Congress
and Exposition, Cleveland, OH, 1999 (T99-111 'Coatings and Surface
Treatments for Die Casting Dies: Composition, Coating Techniques and
Causes for Failure')
Task Group members:
Doehler-Jarvis Technologies - DCD
Technologies - Eastern Alloys - Patterson Mold - Advanced Heat Treat -
Balzers Tool Co. - General Die Casters - Ganton Technologies - GM
Powertrain - Saint Clair Die Casting - Anderson Die Casting - Arvin TD -
Multi-Arc Co. - Tool Products - Contech-Ahresty - Alcoa - R.B.Alexander&Assoc.
- Sun Steel Treating - Diltech/Dynacast - Maytag - DuPage Die Casting -
Oak Ridge National Laboratory - CMI Tech Center - CMI Precision Mold -
Briggs&Straton - Muskegon Castings - Chem Tren - Perf.Engineering
Coatings - Sputtek Inc. - Badger Metal.
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