Types of maintenance Breakdown, Spares Planning and control11th April 2021
Planned maintenance means that the organization is prepared for a breakdown and even expects it to happen. The equipment runs until it breaks, which initiates a run to failure (RTF) trigger. While RTF triggers can be unplanned, breakdown-maintenance plans use RTF as a way of lowering the cost of maintenance.
This kind of plan needs to be rigorously documented and controlled. Employees should be clear on exactly which parts will break down and which parts will be maintained normally via preventive maintenance. Without these checks, a breakdown maintenance plan can be exploited or run awry.
Unplanned breakdown maintenance
Unplanned breakdown maintenance, on the other hand, occurs when a piece of equipment fails or breaks unexpectedly also called an unplanned downtime event. While some facilities may not utilize a planned maintenance plan, nearly every facility needs resources in place for unplanned maintenance. After all, every piece of equipment will break or fault at some point in its life.
Condition-based maintenance is sometimes considered to be a more advanced alternative to preventive maintenance. Rather than being inspected according to a schedule, machines and systems are carefully observed for changes that could indicate upcoming failure.
With condition-based maintenance, technicians observe the system running and identify variables that could affect functioning, like temperature, vibration speed, power, the presence or absence of moisture, and more.
Corrective maintenance is initiated when a problem is discovered while working on another work order. With corrective maintenance issues are caught ‘just in time’.
For example, during a scheduled maintenance check or while fixing another issue, a maintenance technician notices that a pipe in a HVAC system is not working as it should. Corrective maintenance is then scheduled for a future date where the problem is repaired or replaced.
Failed equipment can lead to disastrous consequences, but a clearly-documented maintenance plan can actually have a few significant benefits for an organization.
- Minimizes maintenance cost by cutting out unnecessary preventive maintenance
- Lowers cost of replacing disposable items frequently (light bulbs, tools, fuses)
- Downtime for repairs is consolidated
- Low staffing needs
- Simple and easy to understand when maintenance is required
The downsides of breakdown-maintenance are especially important to weigh given the nature of the maintenance plan. For example, breakdown-maintenance should never be used with safety equipment because a single lapse can cost one or multiple employees their health or their lives.
- Form of waste in a manufacturing environment
- Safety issues can occur with unplanned failures
- Can be costly depending on parts that fail
- Requires careful planning and execution
- Can be difficult to pinpoint source of issues
Spares Planning and control
Spare Parts Management purpose is to provide “the right parts, in the right quantity, to the right place, at the right time, with the right level of quality, and at the least total cost to the organization”.
Effective management of maintenance spare parts is a critical contributor to equipment operating performance and to the cost of the maintenance investment.
The scope of Spare Parts Management therefore includes all functions from the supplier through to the point of use. identification and coding, criticality classification, procurement, quality inspection, stocking policies, links to work planning (kitting, staging), supplier management and internal performance.
For managing parts inventory more effectively:
Identify all spare parts: Make sure that all parts required for maintaining the asset are properly identified. If, for example, a part is required for a major overhaul, there may be several items that are purchased for a one-time use. Once the machinery overhaul is completed, there may be unused parts which have future use and should be inventoried. Other equipment in the plant may be able to use the same parts. So, rather than maintenance storing these parts without any correlation with the asset, the items should be added to the inventory control system and placed into parts inventory on the EAMS/CMMS.
Classify all spare parts: Classify the spare parts as per criticality. This classification will support the process to define an effective safety stock:have the right parts, at the right time, with the lowest possible cost at the minimum inventory value.
Utilize and Manage the Bill of Materials (BOM): Having accurate BOMs will support the scheduled preventive maintenance (PM) that is needed on a given piece of equipment. This process will allow the generation of a work order with the scheduled date of the PM.
BOMs will make ordering parts and placing work orders simpler. Additionally, make sure that your BOMs are kept up to date, considering the asset status and modifications.
Use the work order: All spare parts that have been used have to be linked to a work order. For PM, work orders requested in advance can be pulled and staged for pickup or delivered to the requesting department. This will reduce the maintenance department’s wait time at the parts warehouse for their work order to be fulfilled. Work orders need to be created for all parts issuance so that inventory remains accurate.
In case of emergency, it would be possible to understand the historical information related to breakdowns to improve the parts in stock, when this is reasonable.
Limited access to the parts warehouse inventory: Limiting access to the parts warehouse inventory is mandatory to maintain inventory accuracy. Adopt a policy that parts inventories are “off limits” and only parts department employees have access, utilizing badge access to entry and exit points. Allowing everyone to have access can quickly make parts inventories inaccurate.
Optimize the warehouse: Centralize and consolidate parts – Having all your parts centralized (in one or satellite warehouses) and consolidated can make security easier but also makes this potentially large asset easier to control and maintain inventory accuracy.
Use an Inventory control system: By utilizing your ERP’s warehouse functionality or a warehouse management system (WMS) to manage your parts inventory will ensure accuracy and ease of managing your parts warehouse. This should be linked to the EAMS/CMMS.
Using barcodes and scanning functionality in conjunction with the system will improve the efficiency of the management processes in the parts warehouse and inventory accuracy.
Define a stock location for every part: Ensure that stock locations are created at the lowest detail, typically a bin and slot location for each SKU, allowed by your systems.
Implement cycle counting for inventory control: Cycle Counting is a Periodic inventory system audit-practice in which different portions of an inventory are counted or physically checked on a continuous schedule, related with inventory ABC classification. The usual class breakpoints applied are:
A = 10% of line items, gives 65% of turnover
B = 20% of line items, gives 25% of turnover
C = 70% of line items, gives 10% of turnover
Each portion is counted at a definite, preset frequency to ensure counting of each item at least once in an accounting period.
Some variation about these figures is usual, but significant differences can indicate problems with stock holding policy.
Standardize Spare Parts: Standardizing for spare parts management, usually means agreeing that a certain type/model of equipment will be used and with that the spare parts required for each installation will be the same. This is different to industry-wide standardization. This can contribute to improve the MTTR, the negotiations with the Spare Parts Suppliers and the stocks.
Develop Spare Parts Management Processes: Make sure that your Spare Parts Management Processes are developed as per best practices to ensure sustainability and a base for training.
Decide based on accurate data: Use quality data for decision making: develop your reports and KPI´s considering the Spare Parts Management Processes, to support the improvement and base for Spare parts maintenance budget.
Benefits of spare parts management:
- Allows you to keep spare inventory levels low, reducing carrying and storage costs but providing access to spare parts when needed.
- Better service to your customers. The longer your operations are up and running, the better you’re able to deliver the services and support your customers demand.
- Enhanced part visibility so your supply chain can show where the need is and where the parts are headed.
- Improved equipment uptime as you limit how long equipment is down and don’t have to wait to generate revenue or find a funding source to repair a part when it breaks.
- Quicker repairs and replacements for defective parts, plus assistance with larger failures.
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