Indirect material procurement: the consumables that keep a line running

Why a spend with no bill of materials still behaves like production material

Consumption is real and roughly proportional to output, but no system calculates it. Abrasive use rises with the weld metres laid down; insert consumption tracks the machining hours and the material being cut; glove and wipe usage follows headcount and shift pattern. Because these links are never modelled, the plant discovers them empirically after a shortage. A workable middle ground is to identify the handful of consumables whose absence stops a specific process, tie their reorder trigger to a production measure rather than a calendar review, and leave the long tail on simple bin replenishment.

The long tail is a transaction problem before it is a price problem

Most plants find that a large share of purchase transactions and a small share of purchase value sit in this category. The money is lost in raising, approving, receiving and paying for hundreds of small orders, not in the unit prices. Consolidating to fewer distributors, moving to catalogues with pre-agreed pricing, and giving stores authority to replenish within a set list removes the administration without removing the control. The mistake is to chase unit-price savings line by line across the tail while the transaction cost of doing so exceeds whatever is recovered.

Consumables that quietly change what the product is

Some indirect items touch the product even though they do not become it. Cutting fluid, release agents, cleaning solvents, masking materials, adhesives used in fixturing, and surface protection films can all leave residue, affect subsequent coating adhesion, or introduce a substance a customer has restricted. Swapping to a cheaper equivalent is not a purchasing decision alone in those cases; it needs process engineering and, where a restricted substance declaration exists, chemical compliance review. Maintain a short list of consumables that are specification-controlled and flag them so no substitution happens quietly at the counter.

Standardising what the shop floor is allowed to ask for

Variety in this category grows from below. Each supervisor has a preferred brand of abrasive, each cell a different glove, each department its own tape. Rationalising to an agreed range cuts stockholding, improves the price you can negotiate and makes substitution safer. It also generates resistance, because operators experience the change directly. Pilot the alternative in one cell with the people who use it, measure consumption rather than opinion, and roll forward from that evidence. Imposing a new range from the purchasing office without that step reliably produces a hidden cupboard of the old product.

Where the responsibility for consumables should sit

Two failure modes recur. In the first, purchasing owns everything and the buyer becomes a clerk processing bin-refill requests with no time for the spend that matters. In the second, production buys freely and the plant accumulates duplicate items, uncontrolled suppliers and no visibility of what it consumes. The functional split gives purchasing the supplier agreements, the catalogue and the substitution rules, and gives stores or the production area the day-to-day pull inside those boundaries. Review the category as a whole periodically rather than transaction by transaction. Publish the split as a written rule, because ambiguity in this category is resolved by whoever is most inconvenienced at the time.

Frequently asked questions

Where is the boundary between indirect material and MRO supply?

Indirect material is consumed by producing: abrasives, fluids, packaging, protective equipment, shop supplies. Maintenance, repair and operations supply keeps equipment working: bearings, seals, drive belts, sensors, filters, lubricants, machine spares. The two overlap at items like filters and lubricants, which some plants treat as consumables and others as maintenance stock. What matters is that each item has one owner and one replenishment rule, not which label the plant chooses for it.

Is it worth putting consumables on a supplier-managed replenishment arrangement?

Frequently yes, because the value at stake is administrative rather than commercial. Handing bin management, counting and refilling to a distributor removes transactions and stockouts at the same time. The conditions are that the range is standardised first, the pricing is fixed for a defined period so the arrangement cannot drift upward unnoticed, and consumption data comes back to you in a usable form. Without that data you lose sight of what the plant actually uses.

How do you stop consumable spend creeping upward year on year?

Track consumption per unit of output rather than total spend, because total spend rises legitimately with production volume and tells you nothing. Rising usage per output unit points at a process problem more often than a purchasing one: a blunt tooling policy, a machine running out of tolerance, wasteful dispensing, or poor stores control. Investigate the process before renegotiating the price, since the price rarely explains the drift and the process usually does.