Inventory Management for Aluminum Fabrication: A Complete Guide

Ask a fabrication owner how much aluminum is on the racks and you usually get a shrug. Ask what that metal is worth, how much of it will never become a window, or how many days of production it covers, and the shrug turns into a guess. Aluminum is the largest line item on the balance sheet of almost every fenestration shop, and it is the one the business watches least closely.

This guide is built around the seven numbers that make a stock room visible: turnover, scrap rate, offcut recovery, stockout frequency, days of stock, WIP ageing, and material cost per order. Each one has a target, a cost when it drifts, and a way to track it in WindowCraft Pro.

The Seven Numbers Worth Watching

None of these is hard to calculate. The obstacle is that manual measurement is stale by the time it reaches a decision, so the shop runs on memory instead of arithmetic.

• Inventory turnover: how many times a year your stock converts into delivered orders.
• Scrap rate: the share of purchased aluminum that ends in the bin, not in a frame.
• Offcut recovery: the percentage of usable cut pieces reused on a later order.
• Stockout frequency: how often a required profile is missing when the saw needs it.
• Days of stock: how many days of current consumption sit on the racks today.
• WIP ageing: how long a half-finished order waits between cutting and assembly.
• Material cost per order: the true aluminum cost of the average job you ship.

1. Inventory Turnover: How Fast Metal Becomes Money

A shop that keeps six months of every profile 'just in case' is financing a warehouse, not a workshop. Four to six turns a year is healthy for a fabrication business. Two turns means a large share of working capital is parked in metal that will not move this quarter, quietly earning nothing.

Manual methods rarely see turnover because purchase records and consumption records live in different places, months apart. WindowCraft Pro derives it from live stock and real consumption, so the figure moves as orders are cut. That turns a vague “we have plenty” into a specific “we hold 220 days of this profile and should stop buying it until March.”

2. Scrap and Offcut Recovery: The Two Rates That Define Margin

A typical aluminum shop loses eight to twelve percent of purchased metal to saw waste, drops, and mistakes. A shop that records and reuses its offcuts runs at five to six percent. On SAR 300,000 of annual aluminum, that difference is roughly SAR 12,000 to 18,000 recovered every year from a change in habit rather than a change in suppliers.

The recovery rate is the number most shops cannot state. A 60cm offcut of a standard profile is worth real money, but only if the estimator knows it exists before quoting. When the saw cuts in WindowCraft Pro, the offcut is logged with profile, length, and finish, so it is searchable stock instead of a pile near the saw.

3. Stockouts and Days of Stock: The Cost of Both Extremes

A stockout is never just a missing profile. The line stops, the order slips, and the replacement usually arrives on a rush order that costs a premium. Ten stockout events a year, each with a few hours of idle labour and one expedited delivery, adds up to more than the metal that would have prevented every one of them.

The opposite failure is quieter. Carrying ninety days of every fast-mover feels safe until you price the shelf space, the insurance, and the cash it locks up. The healthy band for fabrication is 30 to 45 days across the profile families you cut weekly. WindowCraft Pro flags the reorder point per profile and suggests a quantity from recent consumption, so the buyer works from a number instead of a feeling.

4. WIP Ageing and Material Cost per Order

Work-in-progress is inventory too, and it is the most expensive kind because it already carries labour. An order that sits between cutting and assembly for three weeks is holding a bay, blocking a schedule slot, and delaying the invoice. Tracking WIP ageing turns “the shop feels full” into “eleven orders are over ten days old.”

Material cost per order is the number the owner actually wants, and the one manual systems are worst at producing. Purchase totals are easy; consumption is not. Under the manual method, stock records say what was bought, not what each job used — and the gap between the two is where over-ordering and waste hide. Per-order allocation from the cutting list closes that gap.

Benchmarking Your Stock Room: Manual vs Measured

Here is the same operation scored two ways. The middle column is what manual tracking typically delivers; the right column is the target a measured operation can hold.

Building the Measurement Habit: A 90-Day Rollout

• Days 1–30: load the profile catalog and opening stock counts, then let the system calculate turnover and days of stock from real orders.
• Days 31–60: record offcuts at the saw and start allocating consumption from the cutting list, so scrap and recovery rates become facts.
• Days 61–90: set reorder points for the profiles you cut weekly, and review the WIP ageing list in the Monday production meeting.
• After 90 days: compare the seven numbers against the benchmarks above and decide where to push next.

Key Takeaways