Crimp Philosophy

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


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


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.


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


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


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


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


8/268

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


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.


10/2610

Ideal Cross Section


11/26

11

Example of a Really Bad Cross Section


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.


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


14/26

14

Component and Systems EvaluationLaboratories

Component & Systems Validation Lab


15/26

15

Sample Preparation area at the Engineering Service Center. All of the

samples used for validation testing are built by trained technicians.



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.



17/26

17

USCAR-21 Crimp Specification


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.


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


20/26

20

Crimp Resistance vs. Time on a TypicalUnstable Crimp


21/26

21

Strand Movement due to Loose Crimp(Low Energy Circuit Intermittency)


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


23/26

23

Spring-back

Shapes areimportant forthe stabilityof the crimp.


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.


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


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

Crimp Philosophy

Documents

Transcript of Crimp Philosophy