| Abstract | Moderna automobilska industrija značajno doprinosi globalnom zagađenju okoliša i ima velike utjecaje na promjenu klime. Potrošnja goriva snažno je pod utjecajem mase automobila. Postavljaju se sve veći zahtjevi na unaprjeđenje svih sustava motornih vozila, pa tako i na električne komponente.
Spajanje terminala metodom steznog spajanja (svakodnevni izraz je „krimpanje“, prema engl. crimp) s vodičem (žicom) čine stezni spoj koji ima niži električni otpor i manju mogućnost korozije u odnosu na lemljeni spoj.
U radu je isplanirano ispitivanje za tri različite debljine električnog vodiča (žice), tri različite prevlake (kositar, srebro, zlato) na terminalima i tri različite visine steznog spajanja terminala i žice. Provedena ispitivanja mogu se podijeliti na dva dijela.
Prvi dio ispitivanja utvrdio je utjecaj nezavisnih varijabli na zavisne varijable metodom odzivne površine. Nezavisne varijable su tri različite debljine žice (0,5 mm², 0,75 mm² i 1 mm²), tri visine stezno spojenog vodiča (1,35 mm, 1,39 mm i 1,43 mm) i tri različite cijene za tri različita terminala (0,2 USD za terminal s kositrenom prevlakom, 0,4 USD za terminal s prevlakom srebra i 0,6 USD za terminal s prevlakom zlata), dakle ukupno 27 kombinacija za plan pokusa. Zavisne varijable su električni otpor i vlačna čvrstoća spoja. Optimiranjem je dobiveno predviđanje koji bi materijal prevlake, debljina žice i visina steznog spajanja vodiča bila najpovoljnija za postizanje što manjih vrijednosti otpora i što većih vrijednosti vlačne čvrstoće.
Drugi dio ispitivanja uključuje izradu ukupno 270 uzoraka (za 27 kombinacija) na kojima je provedena vizualna kontrola, analiza spoja svjetlosnim mikroskopom, mjerenje električnog otpora prije i poslije normiranim postupkom unesenog toplinskog umora materijala te određivanje vlačne čvrstoće spoja na univerzalnoj kidalici.
Utvrđeno je da terminal s prevlakom kositra, na debljini žice 0,75 mm² i visini steznog spajanja vodiča na visinu 1,43 mm daje najbolja mehanička, električna i eksploatacijska svojstva, uz što manje troškove. |
| Abstract (english) | The modern automotive industry contributes significantly to global environmental pollution and has a major impact on the climate change. Fuel consumption is strongly influenced by the weight of the car. There are increasing demands for the improvement of all motor vehicle systems, including electrical components.
The connection of the terminal by the method of plastic connection (crimping) with a conductor (wire) makes a connection that has a lower electrical resistance and is more corrosion resistant compared to soldering.
In this thesis, an experiment was designed for three different thicknesses of electrical conductor, three different coatings (tin, silver, gold) at the terminals and three different heights of crimp connection of the terminal and wire. The study can be divided into two parts.
The first part of the study determined the influence of independent variables on the dependent variables using the Response Surface Method. The independent variables were three different wire thicknesses (0.5 mm², 0.75 mm² and 1 mm²), three crimp heights (1.35 mm, 1.39 mm, 1.43 mm) and three different prices for three different terminals (0.2 US$ for the tin-coated terminal, 0.4 US$ for the silver-coated terminal, 0.6 US$ for the gold-coated terminal), i.e. a total of 27 experiments. The dependent variables were electrical resistance and tensile strength of the crimp.
By optimizing, a prediction model was achieved to determine which coating material, wire thickness and crimping height would be the most favorable for achieving the lowest possible resistance values and the highest possible tensile strength values.
In the second part of the test, 270 samples (27 combinations) were made, on which visual control is performed, analysis of the connection with a light microscope, measurement of electrical resistance before and after thermal fatigue by standardized procedures and determination of tensile strength on the universal testing machine.
The tin-coated terminal, with a wire thickness of 0.75 mm and a crimping height of 1.43 mm, provides the best mechanical, electrical and operational properties, at the lowest available cost. |
