Procjena sposobnosti procesa izrade hidrauličkih cilindara

master's thesis

• Title (english): Capability estimation of hydraulic cylinders manufacturing process
• Author: Ante Topić
• Mentor: Biserka Runje (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2015-12-03, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; General Mechanical Engineering (Construction)

Abstract

U radu je opisan i razrađen postupak procjene sposobnosti procesa, te su definirani uvjeti koje je potrebno zadovoljiti prije postupka procjene. Sposobnost procesa se procjenjuje računanjem indeksa sposobnosti procesa. Kako bi mogli procjenjivati sposobnost procesa raspodjela podataka mora se aproksimirati normalnom raspodjelom, te proces mora biti stabilan i bez značajnih uzroka varijacija. Pouzdana procjena sposobnosti procesa može se donijeti samo temeljem praćenja procesa primjenom odgovarajuće kontrolne karte i nakon dovođenja procesa u stanje statističke kontrole. U radu su također opisane najčešće korištene kontrolne karte kao i sam odabir odgovarajuće kontrolne karte i njihova analiza.

Sposobnost procesa daje odnos postavljenih specifikacija i tolerancija, određenih zahtjevima kupaca i ponašanja, odnosno rasipanja procesa.

Tolerancije predstavljaju dopušteno odstupanje od određenih vrijednosti ili standarda i imaju različita značenja u različitim stadijima procesa. Analiza tolerancija postala je sve važnija i važnija, a značajnu pažnju dobila je proizvodnoj industriji. Konačni cilj analize tolerancija je ne samo poboljšavanje proizvoda nego i smanjenje cijene proizvoda. Da bi se u današnje vrijeme proizveo six sigma proizvod bez mijenjanja specifikacija moraju se smanjiti varijacije proizvoda. Statističko određivanje tolerancija je viša razina određivanja tolerancija pri kojoj se određuju statističke karakteristike varijable A koje su određene varijacijom varijable B. Većina inženjera primjenjuje neki od načina određivanja tolerancija dok su najčešće metode obrađene u radu, Metoda najgorih slučajeva (Worst Case Analysis - WCA), suma kvadrata korijena (Sum of Squares - RSS) te metoda Monte Carlo (MCA) poznata još kao Six Sigma analiza tolerancija.

Na kraju rada nalaze se mjerenja i rezultati ocjena sposobnosti procesa izrade hidrauličkog cilindra tvrtke Hidropneumatika.

Abstract (english)

This study shows principle of process capability estimation and defines all conditions needed before estimation can be successful engaged. To be able to estimate capability of process, data management has to be approximated evenly and entire process has to be stable without noticeable anomalies. Reliable estimation of process capability can only be initiated with proper process monitoring using appropriate control card and after process itself is in statically controlled environment. Study also shows most used control cards and their analysis.

Process ability is defined by user specification, and tolerance which are defined by consumers, also known as process scattering. Tolerance itself defines maximum deviation from standard or user defined values. They also have different meanings depending on process stage. Tolerance analysis became very important, with most use in industry of manufacturing. Its final goal is not only improvement of final product, but also reduction of its cost. To be able to manufacture six sigma product without changing specifications, we have to reduce deviation of product itself. Static tolerance determination is superior tolerance determination which defines characteristics of variable A which is defined by deviation of variable B. Most engenders use method of tolerance estimation, the most common methods that are explained in this study are The Worst Case Analysis - WCA, Sum of Squares - RSS and Monte Carlo also known as Six Sigma analysis.

And at the end, there is detailed measurement and results of hydraulic cylinder process capability estimation made in company Hidropneumatika.

• Keywords: kontrolne karte; sposobnost procesa; statističke tolerancije
• Keywords (english): process capability; control charts; statistical tolerance
• Language: croatian
• URN:NBN: urn:nbn:hr:235:726513
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-05-22 14:56:59