Exploratory case studies to improve efficiencies through lean techniques in continuous processes in two South African companies

Abstract

Lean manufacturing principles have various tools and techniques that have been commonly used in discrete manufacturing processes. The literature on the use of lean techniques in continuous processes is scant, particularly from a South African perspective. Therefore, it is not clear whether manufacturers using continuous processes use lean techniques in their automated processes. This study aimed to explore lean techniques that can improve efficiencies in continuous processes in two South African case studies by identifying the various forms of waste that exist within their continuous process manufacturing environments, determining the lean techniques that are used in the two continuous process environments, and identifying how efficiencies can be improved within the two continuous process manufacturing environments. The interpretative paradigm was chosen, and an exploratory study was conducted that followed a qualitative research methodology. The data were collected through a desktop literature review, workplace observations of two case study environments that use continuous processes, and twenty-four semistructured face-to-face interviews. These interviews were analysed using content analysis, and workplace observations and a literature review were used to triangulate the data collected. The findings of the study revealed: recycling of waste can also be viewed as a form of waste due to the additional employment of resources in the form of staff, energy, time, effort and money; workers need to be involved in the decision-making capability of the production facility by sharing information, deciding how work is performed and suggesting continuous improvement and enhancement of production efficiency; management has put standard operating procedures in place for workers, but workers do not follow those standard operating procedures; there are various continuous improvement methods (Six Sigma DMAIC, Fishbone, 5 Whys and root cause analysis) used in continuous processes to solve production problems; maintenance staff prioritise maintenance to machines that prevent the complete stoppage of the production process in continuous process facilities; maintenance staff mostly conduct reactive maintenance to avoid lengthy production downtime; the lean manufacturing techniques that are applied in continuous processes are TPM (preventative and corrective maintenance), continuous improvement (Six Sigma DMAIC, 5 Whys, root cause analysis and fishbone analysis), 5S, recycling and TQM. The following recommendations were made: managers must monitor the adherence to standard operating procedures; a monthly forum should be established where workers can be taught and informed of the impact of the statistical data and number of defects and allowed to provide input into how process efficiencies can be improved; management must facilitate proper maintenance execution through effective monitoring and control strategies; and lean manufacturing should be adopted as a philosophy within the case study examples. This study is of value to all organisations that use the continuous process. Recommendations for future studies are as follows: the sample can be enlarged to generalise the findings, and other countries may be considered

Dintlhatheo tsa tlhagiso e e fokotsang tshenyo mme e oketsa tlhagiso di na le didiriswa le dithekeniki tse di farologaneng tse di ntseng di dirisiwa ka tlwaelo mo tlhagisong ya ditlhagiswa tse di bonalang. Dikwalo tse di ka ga tiriso ya dithekeniki tse difokotsang tshenyo mme di oketsa tlhagiso ga di kalo, bogolo segolo mo ntlheng ya Aforikaborwa. Ka jalo, ga go bonale sentle gore a batlhagisi ba ba dirisang ditirego tse di tswelelang pele ba dirisa dithekeniki tse di fokotsang tshenyo mme di oketsa tlhagiso mo ditiregong tsa bona tsa itiriso. Thutopatlisiso eno e ne e ikaeletse go tlhotlhomisa dithekeniki tse di fokotsang tshenyo mme di oketsa tlhagiso tse di ka tokafatsang nonofo ya ditirego tse di tswelelang pele mo dithutopatlisisong tsa tobiso di le pedi tsa Aforikaborwa, ka go supa mefuta e e farologaneng ya tshenyo e e gona mo tikologong ya tsona ya tlhagiso ya tirego e e tswelelang pele, le go supa ka moo nonofo e ka tokafadiwang ka gona mo ditikologong tse pedi tsa tlhagiso ya tirego e e tswelelang pele. Go tlhophilwe sekao sa thanolo, mme go dirisitswe thutopatlisiso e e tlhotlhomisang e latela mokgwa wa patlisiso o o lebelelang mabaka. Go kokoantswe data ka tshekatsheko ya dikwalo mo khomphiuteng, kelotlhoko ya kwa mafelotirong ya ditikologo tse pedi tsa thutopatlisiso ya tobiso tse di dirisang ditirego tse di tswelelang pele, le dikopanopotsolotso tsa namana tse di batlileng di rulagane di le 24. Dikopanopotsolotso di lokolotswe go dirisiwa tokololo ya diteng, mme data e e kokoantsweng ka kelotlhoko ya kwa mafelotirong le tshekatsheko ya dikwalo e dirisitswe ka mekgwa e e farologaneng. Diphitlhelelo tsa thutopatlisiso di senotse gore: go dirisiwa gape ga leswe go ka tsewa e le mokgwa wa tshenyo ka ntlha ya tiriso ya ditlamelo tsa tlaleletso di tshwana le badiri, motlakase, nako, matsapa le tšhelete; badiri ba tshwanetse go nna le seabe mo bokgoning jwa tseoditshwetso jwa setheo ka go abelana tshedimosetso, go swetsa gore tiro e dirwa jang le go tshitshinya tokafatso e e tswelelang pele le tokafatso ya nonofo ya tlhagiso; botsamaisi bo beetse badiri dithulaganyo tse di rileng tsa go dira, fela badiri ga ba latele dithulaganyo tseo tse di beilweng; go na le mekgwa e e farologaneng ya tokafatso e e tswelelang pele (Six Sigma DMAIC, Lerapo la tlhapi (Fishbone), Goreng ba ba 5 (5 Whys) le tokololo ya sebako sa motheo) e e dirisiwang mo ditiregong tse di tswelelang pele go rarabolola mathata a tlhagiso; badiri ba tlhokomelo/paakanyo ba baya paakanyo ya metšhini e e thibelang go emisiwa gotlhelele ga tlhagiso jaaka setlapele mo ditlamelong tsa tirego e e tswelelang pele; badiri ba tlhokomelo/paakanyo gantsi ba dira paakanyo go tsiboga e le go tila gore go nne le nako e telele e go se nang tlhagiso mo go yona; dithekeniki tsa tlhagiso tse di fokotsang tshenyo mme di oketsa tlhagiso tse di dirisiwang mo ditiregong tse di tswelelang pele ke TPM (paakanyo ya thibelo le paakanyo), tokafatso e e tswelelang pele (Six Sigma DMAIC, Goreng ba ba 5 (5 Whys), tokololo ya sebako sa motheo le tokololo ya lerapo la tlhapi), 5S, tiriso gape le TQM. Go dirilwe dikatlenegiso tse di latelang: batsamaisi ba tshwanetse go baya leitlho kobamelo ya dithulaganyo tse di beilweng tsa tiro; go tshwanetse ga simololwa foramo ya kgwedi le kgwedi moo badiri ba ka rutwang le go sedimosediwa ka ditlamorago tsa data ya dipalopalo le palo ya diphoso mme ba letlelelwe go dira dikakgelo malebana le gore nonofo ya ditirego e ka tokafadiwa jang; botsamaisi bo tshwanetse go bebofatsa tiragatso e e siameng ya paakanyo ka ditogamaano tsa peoleitlho e e bokgoni le taolo; mme tlhagiso e e fokotsang tshenyo mme e oketsa tlhagiso e tshwanetse go amogelwa jaaka mogopolo mo dikaing tsa thutopatlisiso ya tobiso. Thutopatlisiso eno e mosola mo ditheong tse di dirisang tirego e e tswelelang pele. Dikatlenegiso tsa dithutopatlisiso tsa mo isagong di a latela: go ka okediwa sampole gore diphitlhelelo di kgone go akaretsa, mme go ka akanngwa ka dinaga tse dingwe.

Izimiso zokukhiqiza ukuqedwa kanzima kwemfucuza zinamathuluzi namasu ahlukahlukene asetshenziswe ngokuvamile ezinqubeni zokukhiqiza ezihlukene. Imibhalo ephathelene nokusetshenziswa kwezindlela zokuqedwa kanzima kwemfucuza ezinqubeni eziqhubekayo mincane, ikakhulukazi ngokombono waseNingizimu Afrika. Ngakho-ke, akucaci ukuthi abakhiqizi abasebenzisa izinqubo eziqhubekayo basebenzisa amasu okuqedwa kanzima kwemfucuza ezinqubeni zabo ezizenzakalelayo. Lolu cwaningo luhlose ukuhlola amasu okuqedwa kanzima kwemfucuza angathuthukisa ukusebenza kahle ezinqubeni eziqhubekayo ezicwaningweni ezimbili zaseNingizimu Afrika ngokuhlonza izinhlobo ezahlukene zemfucuza ezikhona ngaphakathi kwenqubo yazo eqhubekayo yokukhiqiza izindawo, kunqunywa amasu okuqedwa kanzima kwemfucuza asetshenziswa ezindaweni ezimbili eziqhubekayo zenqubo, kanye nokuhlonza ukuthi ukusebenza ngempumelelo kungathuthukiswa kanjani phakathi kwezinqubo ezimbili eziqhubekayo zokukhiqiza izindawo. Kwakhethwa indlela ebandakanya abacwaningi ukuze bahumushe izingxenye zocwaningo, kwase kwenziwa ucwaningo lokuhlola olulandela indlela yocwaningo egxile ekutholeni imininingwane ngokusebenzisa ukuxhumana okuvulekile nokuxoxa. Imininingwane yaqoqwa ngokubuyekezwa kwemibhalo ekuqoqeni imininingwane ezinsizeni ezikhona, ukubhekwa kwendawo yokusebenza kwezindawo ezimbili zezifundo ezisebenzisa izinqubo eziqhubekayo, kanye nezingxoxo ezingamashumi amabili nane zobuso nobuso ezingahlelekile. Lezi zingxoxo zahlaziywa kusetshenziswa ukuhlaziya okuqukethwe, futhi ukubhekwa kwendawo yokusebenza nokubuyekezwa kwemibhalo kwasetshenziswa ukuhlukanisa indawo ibe ngonxantathu ukuze kulawe imininingwane eqoqiwe. Okutholwe ocwaningweni kwembule: ukugaywa kabusha kwemfucuza kungabuye kubhekwe njengohlobo lokumosha ngenxa yokuqashwa okwengeziwe kwezinsiza ezifana nabasebenzi, amandla, isikhathi, umzamo kanye nemali; abasebenzi kudingeka babambe iqhaza ekuthatheni izinqumo kwesikhungo sokukhiqiza ngokwabelana ngolwazi, banqume ukuthi umsebenzi wenziwa kanjani futhi baphakamise ukuthuthukiswa okuqhubekayo kanye nokuthuthukiswa kokusebenza kahle kokukhiqiza; abaphathi babeke izinqubo ezijwayelekile zokusebenza kubasebenzi, kodwa abasebenzi abazilandeli lezo zinqubo ezijwayelekile zokusebenza; kunezindlela ezihlukahlukene eziqhubekayo zokuthuthukisa (Isu lekhwalithi eliqhutshwa yimininingwane elisetshenziselwa ukuthuthukisa izinqubo, indlela ebonakalayo yokubheka imbangela nomphumela, indlela yokubuza futhi ephendula umbuzo othi "Kungani?" kanye nenqubo yokuthola umnyombo wezinkinga ukuze kutholakale izixazululo ezifanele) ezisetshenziselwa izinqubo eziqhubekayo zokuxazulula izinkinga zokukhiqiza; abasebenzi bezokulungisa babeka phambili ukugcinwa kwemishini evimbela ukumiswa okuphelele kwenqubo yokukhiqiza ezikhungweni zenqubo eqhubekayo, abasebenzi bezokulungisa bavame ukwenza umsebenzi wokulungisa ukugwema isikhathi eside sokukhiqiza; amasu okukhiqiza kokuqedwa kanzima kwemfucuza asetshenziswa ezinqubeni eziqhubekayo yi-TPM (ukugcinwa kokuvimbela nokulungiswa), ukuthuthukiswa okuqhubekayo (Isu lekhwalithi eliqhutshwa yimininingwane elisetshenziselwa ukuthuthukisa izinqubo, indlela yokubuza futhi ephendula umbuzo othi "Kungani?", ukuhlaziya kokuthola umnyombo wezinkinga ukuze kutholakale izixazululo ezifanele kanye nokuhlaziya okubonakalayo kokubheka imbangela nomphumela), uhlelo lokuhlela izindawo ukuze umsebenzi wenziwe ngempumelelo nangokuphepha (5S), ukugaywa kabusha kanye nokuphathwa kwekhwalithi okuphelele (TQM). Kwenziwa iziphakamiso ezilandelayo: abaphathi kumele baqaphe ukulandelwa kwezinqubo ezijwayelekile zokusebenza; kufanele kusungulwe isithangami sanyanga zonke lapho abasebenzi bengafundiswa khona futhi baziswe ngomthelela wemininingwane yezibalo kanye nenani lamaphutha futhi bavunyelwe ukunikeza umbono wokuthi ukuphumelela kwezinqubo kungathuthukiswa kanjani; abaphathi kumele benze lula ukugcinwa kokulungiswa ngendlela efanele ngamasu okuqapha nokulawula ngempumelelo; futhi ukukhiqizwa kokuqedwa kanzima kwemfucuza kufanele kwamukelwe njengesimo sokuziphatha ngaphakathi kwezibonelo zesifundo socwaningo. Lolu cwaningo lubalulekile kuzo zonke izinhlangano ezisebenzisa inqubo eqhubekayo. Iziphakamiso zezifundo zesikhathi esizayo zimi kanje: isampuli ingakhuliswa ukuze kuhlanganiswe okutholakele, futhi amanye amazwe angacatshangelwa.