Puidu hööveldamise efektiivsuse tõstmine ettevõtte X näitel

Lõputöö oli ajendatud vajadusest uurida ja lahendada planeerimata seisakute põhjused puidu hööveldamise protsessis, et tõsta seeläbi höövelduspingi OEE taset. Autor kogus andmeid, analüüsis protsesside kitsaskohti ja töötas välja parandusmeetmed, et tõsta protsessi efektiivsust ja vähendada raiskamist, tuginedes Lean‒filosoofia põhimõtetele.

Kvantitatiivne analüüs, mis viidi läbi ettevõtte X höövelduspinkide puhul, tuvastas perioodiliselt madalad seadme kasutamise efektiivsuse näitajad ja pikad seisakute ajad. Lisaks tuvastati Global Reader programmis seisakute dokumenteerimata jätmine. Vaatluste ja analüüsi käigus identifitseeriti peamised takistused efektiivsuses, milleks olid raiskamised logistikale ning uue seadme õppimisele kuluv aeg. Autori poolt rakendatud parandusmeetmete hulka kuulusid Global Reader programmi andmete täiendamine, seadistuskaartide kasutuselevõtt ja lõikuripeade märgistamine.

Kontrollfaasis rakendati logistika efektiivsuse tõstmiseks Lean‒tootmise põhimõtteid, kus hööveldamisega samal ajal transporditi töötlemisse minev materjal puhvertsooni. Tulemuseks oli, et kontrollfaasi vaatluste järgselt suudeti saavutada 13% parem töötulemus võrreldes eelnevaga, näidates seeläbi höövli töömahtude suurenemist.

Kokkuvõttes tõestas autor, et süsteemsete parandusmeetmete ja Lean‒tootmise põhimõtete rakendamine on suurendanud OEE tulemust märkimisväärselt 25%, vähendades samas seisakute arvu 3%. OEE näitaja tõus 39%-lt 64%-le on märgatav paranemine. Kuid Lean‒filosoofia järgi on pidev areng oluline. Seetõttu tegi autor ettepanekuid protsessi edasiseks parendamiseks. Eesmärk on saavutada ja ületada 70% stabiilne OEE tase: • Global Reader programmi täiendamine Operaatori vaatega, mis tagab tööprotsesside täpsema jälgimise ja katkestuste analüüsi. • Rakendada 5S meetodit, alustades höövelduspingi ümbrusest ja teraruumist, aidates luua paremini organiseeritud töökeskkonda, mis tõstab nii tootmise kvaliteeti kui ka töötajate rahulolu. • Tõhustatud masinate efektiivse hooldussüsteemi (TPM) ja kindlaksmääratud hooldusgraafiku väljatöötamine, mis ennetab seisakuid ja pikendab seadmete tööiga. • Siselogistiku ametikoha loomine, et hallata ja optimeerida materjalivoo protsesse, mis tagavad vajalike materjalide kiire ja õigeaegse kättesaadavuse kõigil tööpinkidel. See roll keskendub materjalide sujuvale ja tõhusale liikumisele läbi tootmisüksuste. Lisaks vähendab ooteaegu ning suurendab sellega tootmisüksuste jõudlust ja tulemuslikkust. • Pöörata tähelepanu hööveldusseadme seadistamise täiustamisele, mis kujutab endast loogilist, ent töömahukat jätku käesolevale lõputööle. Töö käigus tehtud parenduste alusel on võimalik edasi liikuda seadistusaegade optimeerimisele, protseduure standardiseerides ja lihtsustades läbi SMED‒metoodika.

Toetudes Six Sigma DMAIC‒mudelile viis autor läbi eduka protsessiparenduse, kinnitades mudeli efektiivsust praktilises rakenduses, mis on tõestatud mudeli tõhustust ka varasemates akadeemilistes uurimustöödes. Antud lähenemisviis võimaldas süstemaatiliselt tuvastada ja kõrvaldada tootmise ebatõhususe põhjused, tõstes seeläbi protsessi üldist toimivust.

Autori arvates on Six Sigma DMAIC-mudeli kasutamine tootmisprotsesside parandamisel äärmiselt oluline ja rakendatav, sest see pakub tööstussektori spetsialistidele, kes soovivad protsesside efektiivsust tõsta, väärtuslikke teadmisi ja praktilisi lahendusi. Mudeli rakendamine võimaldab mitte ainult ebatõhususe põhjuste süsteemset tuvastamist ja kõrvaldamist, vaid ka protsesside jõudluse märkimisväärset tõhustamist. Autor tõstab siiski esile, et mudeli tõhusus ei sõltu üksnes sellest endast. Mudeli edu määravad organisatsiooniline kultuur ja töötajate pühendumus. Pidevad parendustegevused on mudeli edukaks rakendamiseks kriitilised.

The author chose the Bachelor thesis topic Improving the Efficiency of Wood Planing: A Case Study of Company X.

Today’s wood industry faces several challenges that require improving efficiency and reducing environmental impact. One critical aspect that directly affects resource use and productivity is the efficiency of wood planing.

The choice of the thesis topic was driven by company X’s need to enhance their planer machine's overall equipment effectiveness (OEE) to a consistent 70%. This need arises from the company’s expanding product portfolio, which necessitates frequent resetting and adjustment for various products. The company’s general manager has set the OEE value at 70%, as this value will support the pursuit of flexibility and efficiency in production while accounting for the complexity and diversity of the processes. The remaining 30% of each workday will be reserved for other stages of the wood planing process, which are critical for the smoothness of the production.

The author has focused on two research questions: • What are the main reasons for unplanned production stops, and how have these affected the low OEE in the wood planing process? • Which incisive remedies are available for the planer machine’s planer to improve its setup and effectiveness?

The data analysis conducted by the author has shown: • The low value of OEE and the reasons for unplanned production stops are unclear. The identification of the stops is complicated, as the data from the program Global Reader is inconsistent; thus, the exact reasons for the stops remain unknown. • The OEE values from November and December in 2023 fall between 32–39%. It should be noted that the low values in 2023 reflect the beginning of the utilisation of the new machine – the observed lowered values indicate the difficulties of adjusting and technical challenges. The previous planer machine was characterised by its complexity and the time needed for adjustments. As a development strategy, the company purchased a new modern planer machine that is easier to learn, takes less time to reset and adjust, and assures a more precise processing.

The author created an Ishikawa (a cause and effect) diagram, and its analysis resulted in focusing on two main problems:

1. The in-depth analysis of the production stops on the Weinig P400 planer machine.
2. Improvement of the program Global Reader to ensure a higher accuracy and reliability of the data.

The author conducted on-site observations on three different days, gathering arithmetic values, which enabled categorising the distribution of the machine’s worktime and production stops into four distinct categories: wood planing 71%, setup 8%, logistics 16%, break-downs 5%.

The primary activity of the wood planing process is the planing itself, accounting for 71% of the activities. The supporting activities constitute 24%, and emergency activities make up the remaining 5%. While recapping the analysis, the main incentives for Lean‒production were optimising logistical processes, standardising the setup and adjustment, and increasing efficiency.

One remedy the author used was supplementing the data in Global Reader. Using the data collected during one day of on-site observations, the author added entries to the program to present the scope of the collected data and the program's potential. These entries also gave answers as visual representations of the questions from the data analysis regarding the reasons for production stops and which information needs to be provided by the machine’s operator in the program’s field.

The author also introduced setting cards, which include essential data for the optimal setup of the planer machine, including the names of the profile and figure, feed rate, and the unique codes of the cutter head spindles. The spindle codes and concurring cutter head values are also visible on the cutter heads. The spindle codes are guidelines for installing the cutter head on the concurring spindles of the planer machine. The values equal the parameters of the cutter head in the planer machine's program, providing the basis for processing the sample piece.

Analysis of the new data from March gave the OEE value of 64%, an upward trend of improvements compared to the previous 32-39%.

Then, the author conducted the last on-site observation, during which 84% of the time was spent on wood planing, 8% on setup, and 8% on logistics. Thus, the primary activity of the wood planing process is the planing itself, accounting for 84% of the activities. The supporting activities make up the remaining 16%. The previous results were wood planing 71% and the remaining 29%.

Although the obtained rise of OEE from 39% to 64% indicates an improving trend, the Lean-philosophy emphasises the need for continued development. Thus, the author gave additional suggestions for pursuing further development to achieve and exceed the stabile 70% value of OEE: • The program Global Reader requires complementing with the Operator view, enabling a better overview of the processes and analysis of production stops. • Implementation of the 5S method, starting from the surroundings of the planer machine and the cutter head room, thus ensuring a well-organised work environment that will enhance production quality and employee satisfaction. • Develop total productive maintenance (TPM) and a fixed maintenance schedule, as this will help prevent production stops and increase the lifetime of the machines. • Creation of a logistics specialist position to manage and optimize material flow processes, ensuring quick and timely availability of necessary materials at all workstations. This role focuses on smooth and efficient movement of materials through production units, reducing waiting times, and thereby enhancing the performance and productivity of the production units. • Turn more attention to improving the setup of the planer machine. This would be a logical yet labour-intensive continuation of this thesis. The improvements from the thesis would enable moving forward to optimising setup time by standardising the processes and simplifying using the SMED method (Single Minute Exchange of Die).

The author has successfully enhanced the process based on the Six Sigma DMAIC‒model, confirming the model’s efficiency in a practical application, as previous academic research has proven. This approach enabled the systematic identification and elimination of the reasons for inefficient production, thus increasing the efficiency of the whole process. The thesis supports the importance of the Six Sigma DMAIC‒model and its applicability during the improvement of production processes, offering valuable knowledge and practical solutions for industry specialists who aim to increase the efficiency of the processes.