TAKT Production System for Assembly (including material supply) of Crushing Equipment at Sandvik

Abstract

Title: TAKT Production System for Assembly (including material supply) of Crushing Equipment at Sandvik

Problem formulation: A major part of Sandvik’s production system is driven by forecasting. While this method provides a structured approach for anticipating future demand, it introduces several operational challenges that disrupt the capacity of the equipment assembly line and flexibility. These challenges could also have a direct impact on profitability, including:
1. Unstable workflows: Fluctuations in forecast accuracy often led to irregularities in production planning. These discrepancies can cause unstable resource utilization, resulting in periods of both underutilization and overutilization of labour and machinery.
2. Excess inventory: Inaccurate demand forecasting frequently results in overproduction, leading to excessive inventory levels. This issue can increase the operational costs associated with storage and inventory management.

Purpose: Lean manufacturing principles focus on simplifying processes and aligning production closely with customer demand. However, in a heavy manufacturing environment like Sandvik's, transitioning to a takt-based production system is difficult. The challenges include managing a diverse product mix, exploring long production cycles and dealing with complex processes. To achieve this, the following objectives will guide the research:
1. Evaluate the feasibility and impact of takt production for equipment assembly in Sandvik Rock Processing: If existing processes are already streamlined, shifting to takt flow would be less disruptive.
2. Identify potential benefits and challenges associated with adopting a takt-based system: Validate concepts such as efficient use of resources, agile workflow, and complex assembly.

Research questions: Based on the objectives discussed in the previous section, the following research questions will guide the study:
RQ1: How can a takt-time-based production system be implemented in Sandvik Rock Processing’s equipment production unit to stabilize production processes and align output with demand?
RQ2: What are the key advantages and potential challenges of adopting a takt-based production setup for equipment assembly in the context of mining and construction solutions?
RQ3: What effects do shifting to a takt-based production system have on lead times, inventory levels, and working capital efficiency in HVLV assembly?

Method: The methodology selected in the thesis follows a Design Science Research Approach, combining qualitative, and quantitative techniques to evaluate the feasibility of a takt-based production system at Sandvik. It begins with a literature review to explore existing research on takt production, lean manufacturing, and demand-driven production in high-variety, low-volume settings. This is followed by data collection, and current situation analysis, involving field observations, interviews, and historical data analysis to identify inefficiencies in the system.

Conclusion: A takt-time-based production has been developed and subsequently compared with the existing production system. Some of the results are that based on the simulation, it can potentially reduce the lead time between 63%-75% for crushers’ models and have a significant impact on the inventory reducing the costs. CONWIP and Kanban systems are adopted for crusher assembly and module production to stabilise the crusher assembly and ensure the smooth flow of modules to crusher assembly, respectively.

Popular Abstract

TAKT Production System for Assembly (including material supply) of Crushing Equipment at Sandvik

In manufacturing industries, producing heavy equipment and heavy machinery for the mining and construction sector is often a complex and slow process. Unlike the repetitive manufacturing environment of mass-production automotive factories, companies like Sandvik build highly customized products in small quantities. This high-variety, low-volume (HVLV) setting brings challenges: unpredictable demand, unstable production workflows, long production lead times, and high inventories. The thesis conducted at Sandvik Rock Processing Business Unit explores how these challenges can be tackled by employing takt-time — a lean manufacturing concept that synchronizes production pace with customer demand.
Takt-time is commonly employed in mass production, where processes are repetitive and standardised. But can it work in a setting of unpredictable, low demand and high variety of Sandvik’s crusher assembly? This is the key question of our research.
The study focused on Sandvik’s small crusher assembly line, which manufactures small crushers. This area was chosen because it has relatively structured processes and higher production volumes compared to the larger crusher assembly line. The research was conducted in collaboration with Sandvik and follows the Design Science Research Methodology, combining theory and practice through interviews, observations and simulations.
In the first step, Sandvik’s current production model was analysed. The current production planning relied heavily on forecasts. This approach leads to unstable production workflows and excessive inventory, tying up valuable resources. Shop floor visits, interviews with employees and system records helped in understanding the current production system, order management and information flow across various IT systems. The current production system consists of high variability in processing times, demand and material flow.
Precedence table and activity-on-arc diagram were employed to redesign the current sequence of operations in the small crusher assembly. Simulation modelling aided in assessing the feasibility and capacity of the proposed production system. Further, the proposed production system was supported by two lean tools: CONWIP (Constant Work-In-Process) for crusher assembly and the Kanban system for module assembly. These lean tools help in stabilising the production workflows by controlling the flow of material, limiting the amount of WIP (Work-In-Process) and ensuring a smooth supply of modules.
The results were promising. Depending on the variant of the crushers, the assembly lead times could be reduced by up to 70%. To buffer variability in the production system, the following buffers are employed: 1. Time buffer 2. Inventory buffer 3. Capacity buffer. The inventory buffer is employed for high-demand variants of crushers; the time buffer is employed for low-demand variants of crushers and the capacity buffer is employed for urgent or unexpected demand. Finally, the authors made three proposals. Depending on the proposal, the inventory can be reduced or increased slightly.
An implementation plan was developed to ensure a smooth transition. A risk assessment was done to identify potential disruptions, along with suggesting mitigation strategies.
The research addresses the challenges, limitations and benefits of applying takt-time in HVLV production environments. It provides insights for other companies in the heavy equipment sector that struggle with similar production issues. The research demonstrates that in spite of various challenges, with the right approach, lean thinking can benefit the HVLV production environment of heavy equipment industries.

Published January 2025 by Piyush Kumar and Yanely Ticona
Division of Engineering Logistics at The Faculty of Engineering – LTH, Lund University

• author: Kumar, Piyush and Ticona Fretel, Yanely Amalia
• supervisor: Sandeep Jagtap
• organization: Production Management; Engineering Logistics
• course: MTTM02 20251
• year: 2025
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Takt-time implementation, high variety-low volume, unstable workflows, excess inventory, CONWIP, Kanban
• other publication id: 6036
• language: English
• id: 9192991
• date added to LUP: 2025-06-17 17:06:33
• date last changed: 2025-06-17 17:06:33