Massachusetts has tough pollution regulations. Ask any finishing
company in the state. Delta Electronics, (Beverly, MA) is aware of
this, yet it continues to use cyanide-plating baths, as it has since
1981. Why? "We haven't found anything that works better on our product," stated
Rick Allard.
Delta Manufacturing produces hundreds of different connectors for
the communications, military and other industries. The company is
vertically integrated. The connectors are made from raw bar stock
and are manufactured through to finishing at Delta. If the company
doesn't have a connector to fit your need, it will work with you
to design a connector that suits your application. Not only does
Delta work with customers to develop the right connector, it also
knows the right finish for the part.
"When my father, Nick Nikitas, founded Delta in 1955, he envisioned
the company not only as an outlet for his creative and inventive
energy, but also as an organization that would reflect his own work
ethic and dedication," stated Diane Delaney, president. "We have
worked hard to continue this commitment to on-time delivery, high
quality and new product development. All of the elements that combine
to produce total customer satisfaction."
Customer satisfaction is why Delta has stayed with cyanide plating
baths. "We have tried non-cyanide plating baths, but we can't get
the appearance that our customers demand. Even plating to mil-spec,
which all of our plating is, the non-cyanide baths just didn't give
us what we wanted for our customers," stated Mr. Allard. "Waste treatment
really isn't a problem. We do cyanide destruct and drop the metals
out and neutralize them. We meet the effluent limits without a problem."
Delta uses Technic's
Orosene 999, a bright, cobalt-hardened 24-caret acid gold process
in its rack and barrel plating operations. The process provides the
connectors with a low-stress deposit and a hardness range of 130-200
Knoop. Using this bath, Delta is able to meet the specifications
of MIL-G-45204C, Type and II, Grade C.
Gold is replenished by adding 1 Troy ounce of gold salts every 14
amp/hr. The brightener is added at a rate of 20 milliliters per ounce
of gold added. pH rises slowly during operation, and the platers
at Delta monitor it regularly. Operating parameters are outlined
in Table 1.
The silver process, also from Technic, produces extremely bright,
ductile silver deposits on the connectors. The finish has excellent
wear resistance, which is important to Delta's quality control. Delta
platers produce finishes meeting Federal Specifications QQ-S-365B,
Type III. In the bath, silver metal is replenished by the corrosion
of the silver anode; however, the bath is analyzed to ensure that
the concentration is correct.
The bath also uses potassium cyanide and potassium carbonate. Potassium
cyanide is monitored using a Hull cell. The potassium carbonate level
rises as the bath is electrolyzed. When the concentration is greater
than 8 ounces per gallon, Delta removes the carbonates and reconstitutes
the bath. A Hull cell is also used to monitor the brightener level.
Brightener is added (200 milliliters) after every 100 amp/hr of plating.
See Table 2.
Tarniban 51 is used as an anti-tarnish agent on the silver-plated
parts at Delta. Parts are immersed in the solution for 1-2 min at
80-120F. This is followed by a cold water rinse, hot water rinse
(below 150F) and drying with warm air.
These precious metals are what make the connectors work. Nickel
is plated first onto stainless steel parts prior to gold plating.
Beryllium copper and brass parts receive a copper strike to promote
adhesion. Beryllium copper substrates all go through heat-treating
and a bright acid dip prior to any plating. The bright acid dip removes
the deposits left by the heat-treating process. Mr. Allard estimates
that 80% of the plating done at Delta is gold. All contacts plated
at Delta are gold. Teflon is used as the standard insulation on all
connectors.
| TABLE
1: Gold Bath Operating Parameters |
| |
Range |
Optimum |
| Gold Metal |
0.75-1.5
Troy oz |
1.0 Troy
oz/gal |
| Specific
Gravity |
1.09-1.15
(12-10 deg Be; ) |
12 deg
Be; minimum |
| Brightener |
200-400
ml/gal |
300 ml/gal |
| pH |
4.0-4.5 |
4.2 |
| Temperature |
80-100F |
90F |
| Current
Density |
1-10 asf |
3 asf
barrel/10 asf rack |
| Deposition
rate |
0.0001
inch in 26 min |
| Filtration |
Continuous |
| Agitation |
Filter
pump, sparger, cathode rod |
| Anode:
Cathode ratio |
1:1
to 1:3 |
|
| TABLE
2: Silver Bath Plating Parameters |
| |
Range |
Optimum |
| Silver
Metal |
3.5-5.0
Troy oz/gal |
4.5 Troy
oz/gal |
| Free Potassium
CN |
16.0-18.0
oz/gal |
14.5 oz/gal |
| Potassium
Carbonate |
2.0
oz/gal |
| Specific
Gravity |
12.5 deg
Be; minimum |
| Temperature |
ambient |
< 80F |
| Anodes |
Silver
99.99% pure |
| Anode:
Cathode ratio |
1:1
or greater |
| Current
Density |
3-20 asf |
10 asf |
| Deposition
Rate |
2.5
microns in 3-7 min |
| Agitation |
Cathode
rod |
|
Parts manufactured and plated at Delta range from delicate parts
that are 50 thousandth of an inch in diameter with holes and slots
that require complete coverage, to one-inch-sq flanges and larger
that also require full coverage. Everything is manufactured from
brass or stainless steel bar stock, often using equipment designed
and modified by Mr. Nikitas. Apparently, Mr. Nikitas was well known
for tinkering with and improving the machinery in his shop. "He would
get an idea about a machine and work on it all weekend," noted Mr.
Allard. "The machinist would come in on Monday, and there would be
a sign on the machine saying 'Do Not Touch.'"
Mr. Nikitas' daughter, Diane Delaney, has continued with her father's
commitment to machine enhancements by adding several million dollars
of new CNC equipment.
Mr. Allard commented, "At Delta Electronics, we know that in order
to best serve our customers coaxial connector needs, we have to keep
up with the latest in equipment and processes. All of our operating
systems are designed to enable us to provide the high quality, on-time
delivery and connectors with electrical and mechanical performance
that will help guarantee your product's success."
Ms. Delaney added, "But machines and systems only work as well as
the people who control them. At Delta we have not forgotten the traditions
of family ownership and New England craftsmanship that have formed
the basis of our business philosophy since 1955. Every Delta employee
uses these values to further our focus on providing the best in connector
value."