An approach to the capability analysis of a multi-spindle machining centre

In many industries, there is a growing need to produce products with strict tolerances of individual product characteristics. Increasing productivity and profitability are also sought, demanding the production of more products per unit time, and at a lower cost with the available production equipment and with minimal investment. A Strong competition creates the need to improve production efficiency. One way of addressing the challenge of precise parts manufacturing is by analysing the capabilities of the production equipment. Assessing process capability using statistical modelling plays a key role in the business decision-making process in quality management. This paper presents a statistically based approach to capability analysis of a multi-spindle machining centre

Influence of the Process Input Parameters on the Cross-Wire Weld Breaking Force

Cross-wire welding is a type of electric resistance welding called projection welding that is used in the production of a variety of products. This paper deals with the case where steel wires of equal radii are joined together to form a reinforced steel mesh. The objective of the study is to determine the correlation between the welding parameters and the breaking force of the weld. Each weld is cut out from the given wire mesh and tested separately by destructive testing on the universal testing machine. A modular testing fixture was constructed for the tests. Although the tests are still in the initial stage, the results already give a good insight into the influence of the process input parameters on the breaking strength of the weld

Design for Six Sigma Digital Model for Manufacturing Process Design

The transition to digital manufacturing has become more important as the quantity and quality of the use of computer systems in manufacturing companies has increased. It has become necessary to model, simulate and analyse all machines, tools, and raw materials to optimise the manufacturing process. It is even better to determine the best possible solution at the stage of defining the manufacturing process by using technologies that analyse data from simulations to calculate an optimal design before it is even built. In this paper, Design for Six Sigma (DFSS) principles are applied to analyse different scenarios using digital twin models for simulation to determine the best configuration for the manufacturing system. The simulation results were combined with multi-criteria decision-making (MCDM) methods to define a model with the best possible overall equipment effectiveness (OEE). The OEE parameter reliability was identified as the most influential factor in the final determination of the most effective and economical manufacturing process configuration

Logical procedure for determing the appropriate method of calculating the process capability

Različite vrste utjecaja koji djeluju unutar relativno jednostavnih proizvodnih procesa dovode do toga da u tim procesima vlada složeni sustav djelovanja na izlazne parametre procesa. Predviđanje izlaznih parametara u budućnosti predstavlja izazov i zahtijeva upotrebu niza statističkih alata kao važnih dijelova sustava osiguranja kvalitete unutar proizvodnih sustava. Različite matematičke distribucije vjerojatnosti kojima se mogu opisati izlazni parametri vrlo često otežavaju procjenu sposobnosti procesa. Odabir načina izračuna sposobnosti procesa zahtijeva pred-procesiranje podataka s kojima je moguće doći do konciznog i preciznog zaključka o stanju procesa. U ovom je radu predložen postupak pred-procesiranja podataka temeljem kojeg je moguće odabrati prikladnu formulu za izračun sposobnosti procesa. Prikazane su matematičke metode koje su sastavni dio postupka, kao i njihova primjena na primjeru iz automobilske industrije.Various types of influences that operate within a relatively simple production systems lead to the fact that, in these processes, a complex system of governing actions on the output parameters exists. Predicting output parameters in the future is a challenge and requires the use of many statistical tools as an important part of quality assurance in production systems. Various mathematical probability distributions that can describe the output parameters often make it difficult to assess process capability. Selection of process capability calculating formula requires data pre-processing with which it is possible to reach concise and accurate conclusions about the state of the process. This paper proposes the procedure for data pre-processing based on which it is possible to choose the appropriate formula for the calculation of process capability. Mathematical methods that are an integral part of the process are presented as well as their application in the example from the automotive industry

Formation of Built-Up Layer on the Tool in Turning Operation of Magnesium Alloys

The present work highlights some factors which affect formation of a protective built-up layer (BUL) on the rake face of the cutting tool when cutting magnesium alloys. This work suggests that BUL can positively affect tool life, surface roughness, cutting speed and tool forces. The BUL is formed in cutting magnesium alloys with the PCD tool inserts at cutting speed range from 500 to 2500 m/min and at the carbide tool inserts at lower cutting speed range around 550 m/min. It has been found that deposit layers primarily have similar chemical composition as MnAl inclusions which are incorporated in the structure of the examined AZ91 magnesium alloys

Optimizing the conceptual model of the control subsystem in the manufacturing system design : doctoral thesis

Rekonfigurabilni proizvodni sustavi pružaju proizvodnim organizacijama mogućnost odgovora na promjenjive zahtjeve tržišta, koji se iskazuju u vidu sve kraćih životnih ciklusa proizvoda i sve naglašenije personalizacije proizvoda, da promjenom konfiguracije proizvodnog sustava na brz i troškovno učinkovit način postignu potrebne promjene značajki proizvodnosti i promjenjivosti sustava. Tradicionalnim pristupom projektiranja proizvodnog sustava, postizanje odgovarajućih vrijednosti proizvodnosti i promjenjivosti primarni su ciljevi rane faze projektiranja dok se kvaliteta proizvoda kao treći, prvim dvjema ciljevima konkurirajući cilj projektiranja zanemaruje. Projektiranje kontrolnog podsustava i određivanje potrebnih napora za kontrolom kvalitete proizvoda takvim se tradicionalnim pristupom vrše tek u kasnim fazama projektiranja proizvodnog sustava ili čak i kasnije, što može dovesti do uvijek nepovoljnih, naknadnih povećanja potrebnih investicijskih ulaganja i troškova proizvodnje. Doktorski rad je posvećen ranom karakteriziranju napora pri izvođenju statističke kontrole procesa, potrebnih za postizanje indeksa sposobnosti konfiguracije proizvodnog sustava zadanog projektnim zadatkom. Rano karakteriziranje takvih napora podrazumijeva njihovo prepoznavanje već u ranoj fazi projektiranja proizvodnih sustava, prije definiranja konačnog koncepta proizvodnog sustava, detaljiziranja pojedinih operacija i izrade plana realizacije proizvodnje. U radu je predložena metoda simultanog projektiranja konceptualnih modela proizvodnog sustava i pripadajućeg optimalnog kontrolnog podsustava kojom se u ranoj fazi projektiranja omogućuje određivanje dodatnih značajki pojedinih koncepata proizvodnih sustava. Pri procjeni opterećenosti kontrolnog podsustava koriste se modeli neizrazite logike koji su za tu potrebu prilagođeni posebnostima statističke kontrole procesa, kako bi se u ranoj fazi projektiranja odredili redovi veličina parametara planova kontrole, a time i potrebni napori za održavanjem povoljne razine kvalitete proizvoda. Metoda pretpostavlja postojanje baze podataka iskustvenih saznanja o procesima, koje proizvodne organizacije održavaju i koriste u svrhu boljeg predviđanja pogrešaka i njihovih posljedica.Reconfigurable manufacturing systems are manufacturing systems designed to be able for rapid change in its structure, as well as its hardware and software components, in order to quickly adjust its production capacity and functionality within a certain part family in response to sudden market changes or intrinsic system change. Such abilities of manufacturing systems are achieved in their design processes. Traditional objectives in manufacturing system design are productivity and flexibility but in the early stage of design process quality is usually neglected. Control subsystem design and determination of efforts necessary for product quality control are usually done at later stages of manufacturing system design, which can lead to unfavourable increase in the value of the expected investments and production costs. Since system's configuration does affect product quality significantly, necessary efforts for quality control becomes more important for frequently changed system reconfigurations. This thesis focuses on a quality as a third objective of early manufacturing system design process, considering sometimes complex variability distributions within manufacturing process. Therefore, method for early determination of statistical process control efforts required to maintain a favourable configuration capability index are proposed. Fuzzy logic model for predicting expected configuration capability index are available in literature, although it is tailored for systems with 100% in process control. Fuzzy variables in this paper are redesigned to fit inspection errors of statistical process control, in order to allow system designer to define required statistical process control efforts for each system configuration and make better choices in the early stages of manufacturing system design. This method assumes the existence of a database of empirical knowledge about the processes that manufacturing companies maintain in order to better predict process capabilities, errors and their effects

Optimizing the conceptual model of the control subsystem in the manufacturing system design : doctoral thesis

Rekonfigurabilni proizvodni sustavi pružaju proizvodnim organizacijama mogućnost odgovora na promjenjive zahtjeve tržišta, koji se iskazuju u vidu sve kraćih životnih ciklusa proizvoda i sve naglašenije personalizacije proizvoda, da promjenom konfiguracije proizvodnog sustava na brz i troškovno učinkovit način postignu potrebne promjene značajki proizvodnosti i promjenjivosti sustava. Tradicionalnim pristupom projektiranja proizvodnog sustava, postizanje odgovarajućih vrijednosti proizvodnosti i promjenjivosti primarni su ciljevi rane faze projektiranja dok se kvaliteta proizvoda kao treći, prvim dvjema ciljevima konkurirajući cilj projektiranja zanemaruje. Projektiranje kontrolnog podsustava i određivanje potrebnih napora za kontrolom kvalitete proizvoda takvim se tradicionalnim pristupom vrše tek u kasnim fazama projektiranja proizvodnog sustava ili čak i kasnije, što može dovesti do uvijek nepovoljnih, naknadnih povećanja potrebnih investicijskih ulaganja i troškova proizvodnje. Doktorski rad je posvećen ranom karakteriziranju napora pri izvođenju statističke kontrole procesa, potrebnih za postizanje indeksa sposobnosti konfiguracije proizvodnog sustava zadanog projektnim zadatkom. Rano karakteriziranje takvih napora podrazumijeva njihovo prepoznavanje već u ranoj fazi projektiranja proizvodnih sustava, prije definiranja konačnog koncepta proizvodnog sustava, detaljiziranja pojedinih operacija i izrade plana realizacije proizvodnje. U radu je predložena metoda simultanog projektiranja konceptualnih modela proizvodnog sustava i pripadajućeg optimalnog kontrolnog podsustava kojom se u ranoj fazi projektiranja omogućuje određivanje dodatnih značajki pojedinih koncepata proizvodnih sustava. Pri procjeni opterećenosti kontrolnog podsustava koriste se modeli neizrazite logike koji su za tu potrebu prilagođeni posebnostima statističke kontrole procesa, kako bi se u ranoj fazi projektiranja odredili redovi veličina parametara planova kontrole, a time i potrebni napori za održavanjem povoljne razine kvalitete proizvoda. Metoda pretpostavlja postojanje baze podataka iskustvenih saznanja o procesima, koje proizvodne organizacije održavaju i koriste u svrhu boljeg predviđanja pogrešaka i njihovih posljedica.Reconfigurable manufacturing systems are manufacturing systems designed to be able for rapid change in its structure, as well as its hardware and software components, in order to quickly adjust its production capacity and functionality within a certain part family in response to sudden market changes or intrinsic system change. Such abilities of manufacturing systems are achieved in their design processes. Traditional objectives in manufacturing system design are productivity and flexibility but in the early stage of design process quality is usually neglected. Control subsystem design and determination of efforts necessary for product quality control are usually done at later stages of manufacturing system design, which can lead to unfavourable increase in the value of the expected investments and production costs. Since system's configuration does affect product quality significantly, necessary efforts for quality control becomes more important for frequently changed system reconfigurations. This thesis focuses on a quality as a third objective of early manufacturing system design process, considering sometimes complex variability distributions within manufacturing process. Therefore, method for early determination of statistical process control efforts required to maintain a favourable configuration capability index are proposed. Fuzzy logic model for predicting expected configuration capability index are available in literature, although it is tailored for systems with 100% in process control. Fuzzy variables in this paper are redesigned to fit inspection errors of statistical process control, in order to allow system designer to define required statistical process control efforts for each system configuration and make better choices in the early stages of manufacturing system design. This method assumes the existence of a database of empirical knowledge about the processes that manufacturing companies maintain in order to better predict process capabilities, errors and their effects

Formation of Built-Up Layer on the Tool in Turning Operation of Magnesium Alloys

The present work highlights some factors which affect formation of a protective built-up layer (BUL) on the rake face of the cutting tool when cutting magnesium alloys. This work suggests that BUL can positively affect tool life, surface roughness, cutting speed and tool forces. The BUL is formed in cutting magnesium alloys with the PCD tool inserts at cutting speed range from 500 to 2500 m/min and at the carbide tool inserts at lower cutting speed range around 550 m/min. It has been found that deposit layers primarily have similar chemical composition as MnAl inclusions which are incorporated in the structure of the examined AZ91 magnesium alloys

Reconfigurable manufacturing system and the need for new Taylorism

Pojam proizvodnja danas je mnogo širi nego što je to bio prije 10 godina. Industrijski poslovni sustavi svoju konkurentnost temelje na kreativnosti i inovacijama kao i na agilnosti svojih proizvodnih kapaciteta. Industrijski poslovni sustavi istodobno (simultano) planiraju, stvaraju, inoviraju i upravljaju životnim ciklusom proizvoda, dobavnim lancima, proizvodnim procesima i ostalim aspektima poslovanja. Životni ciklus proizvoda i dalje se skraćuje dok se raznolikost palete proizvoda povećava time dajući novu dimenziju pojmu masovna prilagodba proizvoda. Proizvodni sustavi uvode nova tehnološka rješenja kako bi odgovorili na iznenadne promjene u okruženju često ne vodeći računa o socio-tehničkom aspektu njihovog uvođenja. Efikasnost proizvodnog sustava ovisi o efikasnosti socio-tehničkog sustava. U ovom radu predstavljen je pristup upravljanju i organizaciji socio-tehničkih sustava unutar rekonfigurabilnih proizvodnih sustava, koji predstavljaju ključnu tehnologiju budućeg razvoja proizvodnje, a utemeljen je na Tejlorovim principima menadžmenta.The concept of manufacturing is much broader today than it was 10 years ago. Industrial enterprises base their competitiveness on creativity and innovation as well as agility of manufacturing capacity. Industrial enterprises plan, create, innovate and manage the product lifecycle, supply chain, manufacturing processes and other aspects of business concurrently (simultaneously). Shortening of the product life cycle is continuing while the diversity of product range is increasing, thereby giving a new dimension to the concept of product mass customization. Manufacturing systems introduce new technological solutions in response to sudden changes in the environment and they often do not take into account the socio-technical aspect of their introduction. The effectiveness of the production system depends on the effectiveness of socio-technical system. In this paper, the approach for management and organization of socio-technical systems within reconfigurable manufacturing systems, which represents a key technology for future development of manufacturing, is presented and is based on the Taylor’s principles of management