Spare Parts Inventory Control

Spare parts of equipment/machine for manufacturing plant is so significant that we have to control with an appropriate manner.

Once a machine is stopped we have to define the cause of the stoppage. If we have found out the necessity of replacement of the spare parts, we have to ask the store personnel for the availability of the parts replacement.

What if the spare parts are no available at the storage? It results in the production line is stopped as well as the machine is temporarily suspended to operate and no production output until the time of the succeeding of the replacement of the spare parts. It would be a big opportunity loss for the company. In order to control the spare parts, here are some basic tips.

1. Set up Centralized Spare Parts Warehouse (: CSPW). The warehouse should control only good spare parts. What are the good spare parts? The good spare parts are brand new parts with no quality defects at all. If some maintenance personnel withdraws a parts from defective machine/equipment because he thought it’d be useable for future projects, such parts should be stored at Maintenance storage, which would be no inventory values for the company.
2. In the CSPW, all the rack have location numbers to easily identify the location of the parts so that all the spare parts have a location number.
3. Each shelf has a Kanban card, describing location number, name of the supplier of the parts, part number, part name, item description/specification, unit of measurement, re-order point, and lead-times.
4. Spare parts master list for the above no. 3 needs to be prepared by an Excel spreadsheet as the Kanban database.
5. The Kanban is removed upon on or under the reordering point (: ROP) by a storekeeper in CSPW to place an order through the Procurement.
6. After succeeding in the order placement by the procurement, the said Kanban is posted in designated number in Delivery Control Board (: DVCB) by the storekeeper for monitoring the date of delivery. So the storekeeper has to move the Kanban card one day earlier number along with the date by manually. For instance, if the Kanban card is located in no. 2 of DVCB, it means that the delivery should be the day after tomorrow to easily follow up to the supplier.
7. When the spare parts are arrived and verified by the storekeeper, then the spare parts are stored to the designated shelf and the said Kanban card has to be placed into the shelf.

The above is a general flow of the Kanban card in CSPW.

And, of course, this activity relates to Preventive Maintenace. The storekeeper must be aware of their preventive maintenance schedule for an entire year to arrange such spare parts that they will surely replace from the current parts of an equipment.

Also, the volume or quantity of the inventory for spare parts is in conjunction with MTBF (: Mean Time Between Failure). Based on the data, the maintenance personnel must notice the tendency of the stoppage then inform the storekeeper personnel of the required quantity of the parts in stock if the stoppage and/or the preventive maintenance is relating with the spare parts.

Trade-off

It is so important to control the spare parts with no stock out in CSPW. But the big inventory of the parts makes the company critical in cash flow. What is the trade-off? The facility maintenance personnel should define the critical spare parts through the parts list per machine. And they have to inform the storekeeper personnel of the initial required quantity for every spare part. Then the said quantity will have to be changed based on the MTBF.

Conclusion

Spare parts inventory control is under the activity of Continuous Improvement or KAIZEN. Based on exploring the Preventive Maintenance and Down Maintenance, what we need to do is to fine-tune the quantity or volume of ROP for the spare parts all the time so that both Kanban card and the Kanban database will be updated. The Kanban system is an inexpensive way but it is so powerful tool to rationalize the inventory by visual monitoring.