A full order book is supposed to be good news. For a defense manufacturer, it can be the thing that quietly drains the bank account. Revenue climbs on every monthly statement while the cash to make payroll gets harder to find, because the backlog is converting into work-in-process and long-lead inventory faster than it converts into deposits and collected invoices.

This is a working-capital problem wearing a growth-story costume. The order book is not the asset the founder thinks it is until it becomes cash, and the days between the order and the deposit are where the business lives or runs out of room. Those days are operational, not financial, which means they are recoverable.

Why a growing backlog can starve the business

A growing backlog starves cash when the cash conversion cycle, the time from paying for materials and labor to collecting from the customer, stretches faster than orders close. Every new order pulls cash out of the bank for materials, machine time, and labor long before it puts cash back in.

The trend is not subtle. AlixPartners found the aerospace and defense cash conversion cycle lengthened from 138 to 159 days between 2018 and 2022, a 21-day increase, driven largely by inventory accumulation as supply chains lengthened. For a manufacturer at SMB scale, 21 extra days of working capital tied up across a growing backlog is the difference between funding the next contract from operations and funding it from a line of credit.

The cash conversion cycle has three levers:

  • Days inventory outstanding (DIO): how long material sits as raw stock and work-in-process before it ships.
  • Days sales outstanding (DSO): how long an invoice sits before the customer pays.
  • Days payable outstanding (DPO): how long you hold your own payables before paying suppliers.

Your order book is not cash. It is a promise to spend cash now and collect later. The job is shortening the later.

For most defense shops, the cycle balloons on the DIO side, because that is where the work physically sits.

Where the cash actually gets trapped

The cash is trapped in three places, and an ERP report rarely shows all three clearly.

Long-lead inventory

Defense work runs on long-lead components: castings, forgings, specialized electronics, materials with allocation queues measured in months. To protect schedule, shops buy early and buy deep, and that inventory sits on the floor as cash that cannot be used for anything else. J.P. Morgan's 2026 analysis of defense supply chains points to rising working-capital intensity across the value chain as long-lead inventory accumulates, and finds the balance-sheet pressure concentrated upstream, on exactly the Tier 1 and Tier 2 suppliers who build inventory and expand capacity ahead of funding.

The trap is that buying early feels like good operations. It protects delivery. It also converts cash into shelf stock for months, and when it is done across a growing backlog, the cash drain compounds order by order.

Work-in-process that does not move

The second trap is WIP that stalls between operations. A part waiting for the next machine, an inspection queue, a job paused for a missing component. Every parked job is cash standing still. The longer the routing, the more cash is frozen mid-process, and the backlog hides it because the order looks healthy on paper while the part sits.

Undocumented rework, the Hidden Factory

The third trap is the most expensive and the least visible. The Hidden Factory is the undocumented rework, tribal knowledge, and off-the-books problem solving that consumes capacity without ever appearing in the ERP. Quality pioneer Armand Feigenbaum estimated this loss could reach 40 percent of total capacity. Every reworked part is material and labor spent twice, with the second spend invisible to the system, which means cash leaves the building with no record of where it went.

Rework lengthens DIO directly. A part that should ship in 12 days ships in 20 because it went around twice, and those 8 extra days are working capital with nothing to show for it.

The operational levers that release the cash

Recovering cash conversion days is an operations job, not a finance job. You do not negotiate the cash back. You remove the constraints holding it in place.

  • Map the value stream to find the parked WIP. A current-state value stream map shows where parts wait and for how long. The wait time between operations is non-value-added time, and it is also frozen cash. Cutting it shortens DIO and releases WIP into shipments.
  • Find and close the Hidden Factory. A 30-day diagnostic of value stream mapping, Gemba walks where you watch the work actually happen, and targeted Kaizen events surfaces the undocumented rework. Closing the rework loop recovers capacity and shortens DIO at the same time, because parts stop going around twice.
  • Right-size long-lead inventory to demand, not to fear. Buying long-lead components against a disciplined demand signal rather than a worst-case buffer keeps schedule protected while freeing the cash that over-buffering locks up. The goal is the minimum inventory that protects delivery, not the maximum that feels safe.
  • Shorten DSO with milestone and progress billing. Long-cycle defense work supports progress payments and milestone invoicing. Billing at defined milestones rather than at final delivery pulls cash forward and shrinks the gap between spending and collecting. On qualifying DoD contracts, progress payments are a contractual mechanism, not a favor to ask for.
  • Use DPO deliberately. Aligning supplier payment terms with the cash cycle, without breaking supplier relationships, holds cash in the business a few days longer on the payable side to offset the days locked up in inventory.

Each lever moves one component of the cash conversion cycle. Together, on a shop carrying a heavy backlog, they recover the kind of double-digit day count AlixPartners measured the industry losing.

What recovering cash conversion days does to the business

Days are the right unit because days translate directly to cash and to capacity. Cutting the cycle from 159 days back toward 138 is roughly three weeks of working capital returned to the business per turn of the cycle. That is capital the founder can use to fund the next contract from operations instead of from the line of credit, which lowers borrowing cost and removes the cash ceiling on growth.

The capacity recovered from closing the Hidden Factory is the second dividend. Capacity that was being consumed by rework becomes capacity to ship the backlog faster, which shortens the cycle again. The levers compound: faster flow releases cash, released cash funds throughput, throughput burns down the backlog that was trapping the cash.

The bottom line

A growing backlog kills working capital when long-lead inventory, stalled work-in-process, and undocumented rework trap cash between the order and the deposit, so revenue rises while the bank balance does not. AlixPartners measured the aerospace and defense cash conversion cycle lengthen from 138 to 159 days, and the recovery is operational: map the value stream, close the Hidden Factory, right-size inventory to real demand, and pull billing forward with milestones. Recovering cash conversion days turns the order book from a cash drain back into the asset it was supposed to be. Start by measuring the cycle and finding where the days are hiding.

Sources

  • Navigating the Skies of Working Capital: Call for Action in the Aerospace and Defense Industry, AlixPartners, June 2, 2023. The cash conversion cycle expanding by 21 days, from 138 days in 2018 to 159 days in 2022, with elevated inventory named as the central driver. The study covers 98 publicly listed aerospace and defense companies globally, so it measures an industry trend, not an SMB benchmark. Worth noting for a shop at this scale: the report puts the increase at 31 days for Tier 2-3 suppliers specifically, against 21 days for the industry overall. Retrieved July 16, 2026.
  • Working Capital Solutions for Defense Sector Supply Chains, J.P. Morgan, 2026. Rising working-capital intensity across the defense value chain as long-lead inventory accumulates, and the finding that balance-sheet pressure is concentrated upstream on Tier 1 and Tier 2 suppliers who build inventory and expand capacity ahead of funding. Retrieved July 16, 2026.
  • Dr. Armand Feigenbaum on the Cost of Quality and the Hidden Factory, IndustryWeek, July 4, 1994. Feigenbaum in his own words, putting the hidden factory at "anywhere from about 20% to 40% of total capacity of many American companies."
  • FAR Subpart 32.5, Progress Payments Based on Costs. The regulation that makes progress payments a contract financing mechanism rather than a favor. Note the customary rate is 80 percent of costs, and 85 percent for contracts with small business concerns. Retrieved July 16, 2026.
  • FAR Subpart 32.10, Performance-Based Payments. The milestone mechanism: payments triggered by "specifically described events (e.g., milestones)" or measurable performance criteria. The FAR calls performance-based payments "the preferred Government financing method" where practical. Retrieved July 16, 2026.
  • Value Stream Mapping, Lean Enterprise Institute. The current-state map, and the wait time between operations as non-value-added time.

Related case study

The backlog-to-cash sequence in this article is running live at a defense shop. Case Study: Standard Work 2.0™ at a Defense ATE Contract Manufacturer follows a greater-Boston ATE contract manufacturer converting a multi-million-dollar backlog into shipped product, with $130K in software cost avoidance identified along the way.