Crimping

The following are a series of procedures that APP suggests for maintaining and extending the performance life of connectors.  Following them can result in lower connector operating costs as well as greater efficiency and productivity.

The following information is presented in two sections:

1. The first section describes the correct methods for crimping and soldering connectors.
2. The second section describes preventive maintenance checks and corrective procedures that extend connector performance life.

Connector Installation Tips

The following guidelines are recommended for optimizing the assembly of Anderson connectors.

1. Reference the assembly instructions specific to the connector.  Assembly instructions for a connector can be obtained from APP or an authorized representative. 
2. Contact APP or an authorized representative to obtain the proper assembly tools.
3. Reference all applicable electrical standards requirements such as NEC, UL, CSA, etc.
4. Perform a sample assembly of a few pieces for assembly verification testing.  Test these samples for proper crimp dimensions, crimp tightness, crimp resistance and operating temperature.  Contact the APP Application Engineering Department for the recommended specifications for these parameters.
5. Perform periodic assembly verification testing to assure assembly process and tooling are performing correctly.  Typically, crimp dimensions are checked at short intervals and crimp resistance and secureness are checked at longer intervals.  The changes in the wire gage, wire stranding, wire coatings, contact crimp tools, crimp dies and crimp dimensions will affect the quality characteristics of the crimp.  Verification testing should be performed when any of these change.

Important Assembly Notes:

Proper crimping and cleaning of the wire is essential for optimizing connector service.  A proper crimp that is performed on oxidized wire may have high resistance and could result in excess heat.  Cutting back cable to a non-oxidized area and / or cleaning the wire with a wire brush or 3M Scotch Bright ™ is recommended.

Please note: tin plated wire resists surface contamination caused by oxidation.

Connector Crimping and Soldering

1. Stripping Cable Insulation

Problems with cable harness and connector systems often begin with improper or accidental cutting of wire strands while stripping cable insulation.  Each strand is important, and all of them must be included in the contact barrel to avoid unnecessary hot spots during operation.  When removing insulation, position a sharp blade at  a right angle and apply steady, controlled pressure, cutting only the cable insulation, not the copper wire.  Strip cable to the proper length for the contact being crimped.  Proper lengths are listed in the instruction sheet with each APP connector.

2. Cleaning Copper Wire

Aged and badly tarnished copper should be thoroughly scraped with a stiff wire brush that
penetrates the entire bundle cleaning every strand.  The wires will then be ready for insertion into the contact barrel when they are brushed to their original bright copper finish.  Contact barrels are lined with silver or tin plating to assure consistent conductivity, which will be reduced if the barrel is crimped around aged or tarnished wire.

3. Crimping

The best preparation will be defeated if inadequate tools or improper crimping procedures are performed.  Never use a hammer and chisel or the "squeeze-in-a-vise" method.  They won't do the job and will result in substantial reduction in connector life.

Use a crimp tool.  Make sure the stripped cable is inserted all the way into the barrel of the contact and that the contact point is centered in the crimp tool.  A crimp tool will effectively compress the contact barrel tightly around the cable strands, allowing them to be pressed tightly against each other and against the inside wall of the contact barrel.

When the crimp has been completed, check the appearance of the contact.  A properly crimped contact barrel is compacted tightly with the outer strands.  The outer strands on an improperly crimped barrel will be loose and will not have adequate clamping force.  Test for low pull-out force.  If the cable can be loosened, recrimp until it is tight.

4. Soldering

The alternative to crimping is to solder all cable strands within the contact barrel.   When using an open flame, make sure that you are not in an area where explosive gasses are present.  The right proportion of solder is essential if this procedure is employed.   Use a quality 60/40 solder (60 percent tin, 40 percent lead) in wire form with a rosin flux core.  Cable strands should be separately fluxed with rosin paste, and the contact should be held in a vise with the barrel end facing up.  Apply heat to the outside of the barrel while the solder flows in beside the wire strands.

Here are some things to avoid when soldering:

A.  Don't use too much solder, to the point that it flows out of the contact barrel.

B.  Don't allow flux or solder on the outside of the contact.  This will interfere with contact mounting within the installation or with the contact connection to a mating connector.

C.  Don't overheat and cause excessive solder to "wick" up into the cable and stiffen it.  This could interfere with contact flexibility when connectors are mated.

D.  Don't solder when contact is in the connector housing.  Solder away from the housing and then insert the contact into the housing.

NOTE: Underwriters Laboratories (UL) requires the use of a cable clamp for soldered connections to unsupported leads.

5.  Inserting Contact into Housing

Contacts should never be forced into housing.  If the contact does not fit easily, check the contact barrel for distortion.  Replace the barrel if it is distorted or shows signs of wear or damage.