 
|
Die Coatings/Surface
Treatment
Task Group Guides R & D Peter P Ried, Jr., Director Advanced
Engineering
Doehler-Jarvis Technologies, Toledo, Ohio
Dr. Rajiv Shivpuri, Professor, Dept. of
Industrial and Systems Engineering
The Ohio State University, Columbus, Ohio
The Die Coatings and Surface Treatment Task Group is
chaired by Peter. P. Ried, Jr., Director, Advance Engineering, Doehler-Jarvis
Technologies. This Task Group reports as a subcommittee to the NADCA Die Materials
Committee. The mission of the task group is comprehensive:
- To act as the coordinating entity and as the customer for
research in die coatings and surface treatments for die casting applications
- To monitor and guide contemporary research activity in this
areas, to test and analyze the effectiveness of die coatings and surface treatments in the
laboratory and on actual dies
- To classify, model, and study coating and surface treatment
types, coating/substrate system, and surface physical chemistry.
- To evaluate prior research and develop a database on the
coating application techniques, and use in die casting industry.
- To disseminate qualitative and quantitative knowledge-based
data on die coating and surface treatments and substrates.
- To recommend specific die coating and/or surface treatment
and substrate systems with appropriate die casting die manufacturing, care and usage
guidelines to achieve the optimum combination of long life with low operating costs.
With these objectives in mind the task group is monitoring
a DOE/NADCA sponsored project "Evaluation of Chromium Carbide and other PVD Coating
to Improve the Wear Resistance of Aluminum Die Casting Dies." This project is being
conducted at The Ohio State University with Dr. Rajiv Shivpuri, Prot~ssor, Department of
Industrial and Systems Engineering, as the Principal Investigator. In the phase-I of the
project (1995-96), the primary goal is to evaluate selected commercially available
coatings, which have shown potential for wear resistance, in production scale tests and
hence generate production scale data on the long term use (>100,000 shots) of coatings
for the benefit of the die casting industry.
The industnal participation was in terms of providing beta
test sites, sample coatings, heat treatment services, and steel test specimens. The
phase-I project team consisted of die casting companies (Pace Industries, Inc.,
Doehler-Janis Pottstown), coating companies (Multi-Arc, Inc., Balzers Tool Coating, Arvin
TD, Advance Heat Treat), heat treaters (FPM Heat Treatment) and steel suppliers Latrobe
Steel).
Die selection was based on the following criteria, as
defined by the industrial monitoring team:
- Die should have multiple cavities
- Die must have symmetry
- Die must be well known by the die easter and the process
well established
- Local die process conditions known and documented near test
feature
- Set-up frequency should be known
- Downtime causes must be documented in rank order of
frequency
- Test core pin or insert geometry are well known
The tests were conducted on the basis of a randomized
design. The objective of this design was to generate robust data (by blocking the
influence of local variabilities such as difference in core pin attributes and flow
conditions) which will permit it to be extended and applied to other dies. Candidate
coatings were applied using Physical Vapour Deposition (PVD) and Therm-Reactive Deposition
and Diffusion (TRD & D) method as described in Table 1.
Coatings were applied to core pins by participating coating
companies according to their coating process specifications. The coated core pins were the
put into production as per the experimental design. Periodic in-situ observation was
carried out to monitor the coating performance.
For example, 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 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 1Ox (127,500 shots) with significant saving in terms of machine downtime and
labour of the order of $25,000 for one die. The fact that the cost of the coating was less
than 10% of the savings made by the die caster, makes coating an economically viable
solution to die wear problems.
The team also did substantial work on generation of fatigue
data of coating/substrate combinations, conducted an extensive literature search on die
coatings and an industrial survey on the use of die coatings. The literature search
primarily focused on the coatings that are used in the die casting industry, the coating
application technology and results obtained by laboratory and/or production tests. This
document will be included as a part of the final report for the project report (due April
1997) which will form the basis for the database being built by the subcommittee.
The proposed phase-II (1997-99) of the project will focus
on extending the current production scale evaluation to die inserts and die cavities of
both multi-cavity and large single cavity dies. It will also address practical issues like
repairability of dies, part ejection, effect of alloy composition and die heat treatment.
One of the deliverables of the project will be to develop a comprehensive Design
Methodology for the selection and use of coatings for extended die life.
The key benefits of participation in the proposed program
will be:
- Extended die life by the use of wear resistant coatings
- Reduced die maintenance
- Reduced machine downtime
- Reduced labor costs
- Access to generated knowledge-based information
The task group solicits participation from die casters,
coating suppliers, heat treater, and steel suppliers in the proposed phase-II program.
Involvement in and contributions to the Die Coatings and Surface Treatment Task Group may
take one or more of several forms. These include:
- funding research directly,
- providing technical direction and oversight through the Task
Group, and
- executing a systematic testing program and tracking plan,
providing failed pins along with relevant background data in cooperation with the
Principal Investigator.
If your company is interested in participating, please
contact:
Mr. Peter Ried, Chair, Die Coating and Surface Treatment Task Group
T: 419.470.8170
F: 419.470.8185
or Dr. Rajiv Shivpuri
T: 614.292.7874
F: 614.292.7852
Table 1: Coating materials and processes
Published
in January/February 1997/41 issue of
North American Die Casting Association Joumal.
NOTES ON THE
MEETING OF NADCA DIE COATINGS AND SURFACE TREATMENT TASK GROUP
October 3, 1997 - Ohio State University, Columbus, OH
Long Range objectives of
research:
| reduce soldering |
10 to 20 times |
| reduce surface lubrication |
30 to 50% |
| reduce casting ejection distortions |
50% |
| reduce ejection forces |
50% |
| improve net shape capability |
20 to 30% |
| reduce scrap |
25 to 50% |
| reduce die repair expenses |
50 to 85% |
Participants:
- 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
- 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
|
|
