8/12/2019 Crimp Philosophy
1/26
1
Global Crimp TechnologyPrepared By John Yurtin
Revised and Updated 2-3-05
CTIS # 29957
Connection Systems Training
8/12/2019 Crimp Philosophy
2/26
2
Having a good technical understanding of crimping can help
you properly apply terminals within the vehicle. Crimps areessential to the performance of the wiring system and are
often overlooked in troubleshooting electrical problems.
This training help you understand the importance of thecrimps and the performance requirements so you can better
support customers.
Excellence
Performance Goal: Do itright the first time everytimeMethod: Innovation andcontinuous improvement
8/12/2019 Crimp Philosophy
3/26
3
Crimp Validation
The purpose of crimp validation is to assure thecrimp attachment of a terminal to a wire willfunction properly in the vehicle application.
Electrical capability is the most important function. The terminal, at its root, is an electrical component.
Its functionality must be described in terms of electricalperformance.
Mechanical capability is also an important function.
The terminal crimp must be able to withstand a certainamount of handling and vehicle stress.
8/12/2019 Crimp Philosophy
4/26
4
The quality of a crimp connection is based on many criteria:
good electrical properties Low and stable electrical resistance
resistant to the growth of insulating films
good mechanical properties high pull off forces
good physical attributes good compaction
good bell mouth (flare)
minimal burrs
good CCW/CCH ratio
Crimp Performance
8/12/2019 Crimp Philosophy
5/26
5
TerminalsMaterial, Plating, Features, Design
Cable
Material, Plating, Gauge size, Stranding
Crimp Tooling
Geometry, Size, Thickness
Determination of Crimp Configuration
The best possible crimp configuration is analytically,physically and optically determined.
Crimp Components and Crimp Design
8/12/2019 Crimp Philosophy
6/26
6
The Optimum Compaction LevelDetermined through the combination of terminal, cable(s), core
crimp tooling and core crimp dimensions.
Crimp performance is verified through testing.
Core Crimp Dimensions ensuretheQuality Factor
The crimp validation process will determine the core crimp
height and width.
crimpheight
Crimp Performance
8/12/2019 Crimp Philosophy
7/267
1.0 mm 1.1 mm 1.2 mm 1.3 mm
Excessive compaction Ideal compaction Insufficient compaction Insufficient compaction
- no voids - no voids - includes small voids - includes many voids
- good electrical
properties
- good electrical
properties
- poor electrical properties - poor electrical
properties
- poor mechanicalproperties
- good mechanicalproperties
-superior mechanicalproperties
-poor mechanicalproperties
The optimum compaction level will be determinedby the crimp height and tooling
Crimp Micrographs & Crimp Performance
8/12/2019 Crimp Philosophy
8/268
1000.60.81.01.21.4
150
0.4
0
0.0
1.00 1.05 1.10 1.15 1.20 1.25
200 1.6
500.2
Power
Core Crimp Height
Pull
80 (Min)Environmental
ValidatedCrimp Height
Crimp Performance Curve
8/12/2019 Crimp Philosophy
9/269
Cross Sections not ideal
Conductor crimp attributes considered undesirable
Extreme ram-horning
Overlapping wings
Conductor crimp attributes considered unacceptable
One or both wings (grips) penetrate (crash) to theterminal floor or wall
Open wings with conductor exposed or folded down intocore but not touching (not locked)
One or both wing (grip) details do not capture strands
No strand compaction
One or both wings folded back
Terminal stock cracked / broken
Note: With OEM customer approval, the above attributes listed as unacceptable may be considered acceptable if it can be
shown that all other requirements of this specification are met and past production experience has shown them to be
functional in the intended application.
8/12/2019 Crimp Philosophy
10/2610
Ideal Cross Section
8/12/2019 Crimp Philosophy
11/26
11
Example of a Really Bad Cross Section
8/12/2019 Crimp Philosophy
12/26
12
Crimp Validation Testing - Summary
Determination of Crimp ConfigurationThe best possible crimp configuration (terminal design, cable, crimptooling crimp height and crimp width) is analytically, physically andoptically determined.
Cross Section ReductionThe reduction of the cross section of the copper (compaction) is estimatedusing a computer program, then verified using actual cross sections.
Determination of the Mechanical Characteristics of the
Crimp ConnectionThe mechanical capability of a Crimp Connection (cable/crimp/terminaltransition metal) is determined by means of the pull force of the crimp
connection. The Average-3 sigma pull force must meet the SpecificationStandards ( min. pull force) across a 3 CCH tolerance range.
8/12/2019 Crimp Philosophy
13/26
13
Crimp Validation Testing - Summary Pull Test: EST460
20 samples (prep 23) X-3 to limits: (Newtons) .22:40, .35:60(annealed); .35:70(hard drawn); .5:80; .8:90; 1.0:120; 2.0:200; 3.0:250; 5.0:300; 8.0:350N
Current Cycle Test: EST913
8.3 days (200 hours + resistance measurement time)
10 samples (prep 12-one end, or 7-both ends)
45 minutes on, 15 minutes off for 200 hours:
.35:10; .5:14; .8:18; 1.0:22; 2.0:30; 3.0:40; 5.0:65; 8.0:100 Amps
Accelerated Environmental Test: EST931
7 days (168 hours + resistance measurement time)
10 samples (prep 12)
Dry Circuit Resistance test with 4 wire milliOhm meter
Maximum resistance change must be less than 0.3m or 9Rc Resistance
Thermal Shock 72 hours:(30 min at -40C, 30 min at +125C) Resistance
Temp/Humidity 4 Cycles (16 hours at 95-98% R.H., 65C, 2 hours at -40C, 2 hours at +85C, 4 hours at +25C) Resistance
8/12/2019 Crimp Philosophy
14/26
14
Component and Systems EvaluationLaboratories
Component & Systems Validation Lab
8/12/2019 Crimp Philosophy
15/26
15
Sample Preparation area at the Engineering Service Center. All of the
samples used for validation testing are built by trained technicians.
Component & Systems Validation Lab
8/12/2019 Crimp Philosophy
16/26
16
Cross sectioning equipment at the Component and Systems Evaluation
Laboratories. There is also a metallurgical lab on site that can be usedif the terminal must be potted prior to sectioning.
Component & Systems Validation Lab
8/12/2019 Crimp Philosophy
17/26
17
USCAR-21 Crimp Specification
8/12/2019 Crimp Philosophy
18/26
18
Why a Standard USCAR Crimp Specification?
OEMs and Terminal Manufactures were specifying Different CrimpPerformance Tests prior to 2002.
There was a need for common testing to reduce costs and improve Vehicle Life Electricalperformance.
OEMs are more and more going to Common Component and Wiring
Assembly Suppliers. Need for Standardization.
Increased need to address the needs of Wiring Harness Suppliers
USCAR-21 Compliments the existing Electrical Performance Specificationsnow offered by USCAR , which had not previously addressed specificCrimp Technology needs.
8/12/2019 Crimp Philosophy
19/26
19
Paragraph 1.2
Crimp applications validated to this specification supercede any crimp
information on Ford, GM, or DaimlerChrysler component prints. It is preferred
that the terminal supplier do testing and selection of crimp tooling and supply
detailed crimp information or make crimp tooling available to the wiring assembly
supplier actually doing the production crimping. If the wiring supplier deviates
from this information or it is not available, then the responsibility for testing to thisspecification or getting approval from the customer with appropriate test data
showing that the crimp will function in its intended circuit lies with the wiring
harness supplier.Paragraph 1.8
Crimp validation testing and design is primarily the responsibility of the terminalsupplier. Tooling and/or design for the crimp shall be made available to the full
service wiring supplier. Should the wiring supplier choose to deviate in any way
from the established and validated design, then the wiring supplier shall be
responsible for completing this test procedure using the alternative crimp
design.
USCAR-21 Requirements
8/12/2019 Crimp Philosophy
20/26
20
Crimp Resistance vs. Time on a TypicalUnstable Crimp
8/12/2019 Crimp Philosophy
21/26
21
Strand Movement due to Loose Crimp(Low Energy Circuit Intermittency)
8/12/2019 Crimp Philosophy
22/26
22
USCAR-21 Ideal Cross Section
Symmetric
Compaction of all strands
Ends of wings touch only conductor
Terminal stock free of cracks / breaks
Core wings "Locked" (No Gap) at top of crimp
8/12/2019 Crimp Philosophy
23/26
23
Spring-back
Shapes areimportant forthe stabilityof the crimp.
8/12/2019 Crimp Philosophy
24/26
24
USCAR-21 Conductor Crimp Burrs
A major cause of seal failure
An indicator of improper setup or worn tools
Can lead to cracks in the terminal material Can be dangerous
0.1 mm max.
8/12/2019 Crimp Philosophy
25/26
25
USCAR-21 Insulation Crimp CrossSections
Symmetric crimp
No insulation penetrationWings (grips) embrace insulation to provide strain relief
Insulation Crimp cross sections considered ideal
B
Shape Overlap Round Bypass
8/12/2019 Crimp Philosophy
26/26
26
USCAR-21 Insulation Crimp CrossSections
Insulation crimp attributes considered undesirable
Insulation wings contact conductor (no damage toconductor)
Insulation extruded outward between open insulationwings
Insulation crimp attributes considered unacceptable
One or both wings (grips) penetrate (crash) to theterminal floor or wall
One or both wings (grips) penetrate and damage theconductor
Insulation split behind crimp (away from terminal)
Less than 3-point contact
No contact
Top Related